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Sample records for geothermal system california

  1. Geothermal systems of the Mono Basin-Long Valley region, eastern California and western Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Higgins, C.T.; Flynn, T.; Chapman, R.H.; Trexler, D.T.; Chase, G.R.; Bacon, C.F.; Ghusn, G. Jr.

    1985-01-01

    The region that includes Mono Basin, Long Valley, the Bridgeport-Bodie Hills area, and Aurora, in eastern California and western Nevada was studied to determine the possible causes and interactions of the geothermal anomalies in the Mono Basin-Long Valley region as a whole. A special goal of the study was to locate possible shallow bodies of magma and to determine their influence on the hydrothermal systems in the region. (ACR)

  2. Thermal modeling of the Clear Lake magmatic system, California: Implications for conventional and hot dry rock geothermal development

    Energy Technology Data Exchange (ETDEWEB)

    Stimac, J.; Goff, F.; Wohletz, K.

    1997-06-01

    The combination of recent volcanism, high heat flow ({ge} HFU or 167 mW/m{sup 2}), and high conductive geothermal gradient (up to 120{degree} C/km) makes the Clear Lake region of northern California one of the best prospects for hot dry rock (HDR) geothermal development in the US. The lack of permeability in exploration wells and lack of evidence for widespread geothermal reservoirs north of the Collayomi fault zone are not reassuring indications for conventional geothermal development. This report summarizes results of thermal modeling of the Clear Lake magmatic system, and discusses implications for HDR site selection in the region. The thermal models incorporate a wide range of constraints including the distribution and nature of volcanism in time and space, water and gas geochemistry, well data, and geophysical surveys. The nature of upper crustal magma bodies at Clear Lake is inferred from studying sequences of related silicic lavas, which tell a story of multistage mixing of silicic and mafic magma in clusters of small upper crustal chambers. Thermobarometry on metamorphic xenoliths yield temperature and pressure estimates of {approximately}780--900 C and 4--6 kb respectively, indicating that at least a portion of the deep magma system resided at depths from 14 to 21 km (9 to 12 mi). The results of thermal modeling support previous assessments of the high HDR potential of the area, and suggest the possibility that granitic bodies similar to The Geysers felsite may underlie much of the Clear Lake region at depths as little as 3--6 km. This is significant because future HDR reservoirs could potentially be sited in relatively shallow granitoid plutons rather than in structurally complex Franciscan basement rocks.

  3. California Geothermal Forum: A Path to Increasing Geothermal Development in California

    Energy Technology Data Exchange (ETDEWEB)

    Young, Katherine R. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2017-01-01

    The genesis of this report was a 2016 forum in Sacramento, California, titled 'California Geothermal Forum: A Path to Increasing Geothermal Development in California.' The forum was held at the California Energy Commission's (CEC) headquarters in Sacramento, California with the primary goal being to advance the dialogues for the U.S. Department of Energy's Geothermal Technologies Office (GTO) and CEC technical research and development (R&D) focuses for future consideration. The forum convened a diverse group of stakeholders from government, industry, and research to lay out pathways for new geothermal development in California while remaining consistent with critical Federal and State conservation planning efforts, particularly at the Salton Sea.

  4. Geothermal energy in California: Status report

    Energy Technology Data Exchange (ETDEWEB)

    Citron, O.; Davis, C.; Fredrickson, C.; Granit, R.; Kerrisk, D.; Leibowitz, L.; Schulkin, B.; Wornack, J.

    1976-06-30

    The potential for electric energy from geothermal resources in California is currently estimated to be equivalent to the output from 14 to 21 large (1000 MW) central station power plants. In addition, since over 30 California cities are located near potential geothermal resources, the non-electric applications of geothermal heat (industrial, agriculture, space heating, etc.) could be enormous. Therefore, the full-scale utilization of geothermal resources would have a major impact upon the energy picture of the state. This report presents a summary of the existing status of geothermal energy development in the state of California as of the early part of 1976. The report provides data on the extent of the resource base of the state and the present outlook for its utilization. It identifies the existing local, state, and federal laws, rules and regulations governing geothermal energy development and the responsibilities of each of the regulatory agencies involved. It also presents the differences in the development requirements among several counties and between California and its neighboring states. Finally, it describes on-going and planned activities in resource assessment and exploration, utilization, and research and development. Separate abstracts are prepared for ERDA Energy Research Abstracts (ERA) for Sections II--VI and the three Appendixes.

  5. Engineered Geothermal System Demonstration Project

    Energy Technology Data Exchange (ETDEWEB)

    Petty, Susan

    2014-06-19

    In June 2009, AltaRock Energy began field work on a project supported by the U.S. Department of Energy entitled “Use of Multiple Stimulations to Improve Economics of Engineered Geothermal Systems in Shallow High Temperature Intrusives.” The goal of the project was to develop an Engineered Geothermal System (EGS) in the portion of The Geysers geothermal field operated by the Northern California Power Agency (NCPA). The project encountered several problems while deepening Well E-7 which culminated in the suspension of field activities in September 2009. Some of the problems encountered are particular to The Geysers area, while others might be encountered in any geothermal field, and they might be avoided in future operations.

  6. Regional Systems Development for Geothermal Energy Resources Pacific Region (California and Hawaii). Task 3: water resources evaluation. Topical report

    Energy Technology Data Exchange (ETDEWEB)

    Sakaguchi, J.L.

    1979-03-19

    The fundamental objective of the water resources analysis was to assess the availability of surface and ground water for potential use as power plant make-up water in the major geothermal areas of California. The analysis was concentrated on identifying the major sources of surface and ground water, potential limitations on the usage of this water, and the resulting constraints on potentially developable electrical power in each geothermal resource area. Analyses were completed for 11 major geothermal areas in California: four in the Imperial Valley, Coso, Mono-Long Valley, Geysers-Calistoga, Surprise Valley, Glass Mountain, Wendel Amedee, and Lassen. One area in Hawaii, the Puna district, was also included in the analysis. The water requirements for representative types of energy conversion processes were developed using a case study approach. Cooling water requirements for each type of energy conversion process were estimated based upon a specific existing or proposed type of geothermal power plant. The make-up water requirements for each type of conversion process at each resource location were then estimated as a basis for analyzing any constraints on the megawatts which potentially could be developed.

  7. Market Analysis of Geothermal Energy for California and Hawaii

    Energy Technology Data Exchange (ETDEWEB)

    None

    1978-10-01

    This is one of the earlier market analyses for geothermal electric power and direct heat. The market for geothermal power was found to be large enough to absorb anticipated developments in California. For direct use, geothermal resources and urban markets in CA and HI are not well collocated.

  8. Geothermal System Extensions

    Energy Technology Data Exchange (ETDEWEB)

    Gunnerson, Jon [Boise City Corporation, ID (United States); Pardy, James J. [Boise City Corporation, ID (United States)

    2017-09-30

    This material is based upon work supported by the Department of Energy under Award Number DE-EE0000318. The City of Boise operates and maintains the nation’s largest geothermal heating district. Today, 91 buildings are connected, providing space heating to over 5.5 million square feet, domestic water heating, laundry and pool heating, sidewalk snowmelt and other related uses. Approximately 300 million gallons of 177°F geothermal water is pumped annually to buildings and institutions located in downtown Boise. The closed loop system returns all used geothermal water back into the aquifer after heat has been removed via an Injection Well. Water injected back into the aquifer has an average temperature of 115°F. This project expanded the Boise Geothermal Heating District (Geothermal System) to bring geothermal energy to the campus of Boise State University and to the Central Addition Eco-District. In addition, this project also improved the overall system’s reliability and increased the hydraulic capacity.

  9. Geothermal regimes of the Clearlake region, northern California

    Energy Technology Data Exchange (ETDEWEB)

    Amador, M. [ed.; Burns, K.L.; Potter, R.M.

    1998-06-01

    The first commercial production of power from geothermal energy, at The Geysers steamfield in northern California in June 1960, was a triumph for the geothermal exploration industry. Before and since, there has been a search for further sources of commercial geothermal power in The Geysers--Clear Lake geothermal area surrounding The Geysers. As with all exploration programs, these were driven by models. The models in this case were of geothermal regimes, that is, the geometric distribution of temperature and permeability at depth, and estimates of the physical conditions in subsurface fluids. Studies in microseismicity and heat flow, did yield geophysical information relevant to active geothermal systems. Studies in stable-element geochemistry found hiatuses or divides at the Stoney Creek Fault and at the Collayomi Fault. In the region between the two faults, early speculation as to the presence of steamfields was disproved from the geochemical data, and the potential existence of hot-water systems was predicted. Studies in isotope geochemistry found the region was characterized by an isotope mixing trend. The combined geochemical data have negative implications for the existence of extensive hydrothermal systems and imply that fluids of deep origin are confined to small, localized systems adjacent to faults that act as conduits. There are also shallow hot-water aquifers. Outside fault-localized systems and hot-water aquifers, the area is an expanse of impermeable rock. The extraction of energy from the impermeable rock will require the development and application of new methods of reservoir creation and heat extraction such as hot dry rock technology.

  10. Monitoring the hydrologic system for potential effects of geothermal and ground-water development in the Long Valley Caldera, Mono County, California, USA

    International Nuclear Information System (INIS)

    Farrar, C.D.; Lyster, D.L.

    1990-01-01

    In the early 1980's, renewed interest in the geothermal potential of the Long valley caldera, California, highlighted the need to balance the benefits of energy development with the established recreational activities of the area. The Long Valley Hydrologic Advisory Committee, formed in 1987, instituted a monitoring program to collect data during the early stages of resource utilization to evaluate potential effects on the hydrologic system. This paper reports that early data show declines in streamflow, spring flow, and ground-water levels caused by 6 years of below-average precipitation. Springs in the Hot Creek State Fish Hatchery area discharge water that is a mixture of nonthermal and hydrothermal components. Possible sources of nonthermal water have been identified by comparing deuterium concentrations in streams and springs. The equivalent amount of undiluted thermal water discharged from the springs was calculated on the basis of boron and chloride concentrations. Quantifying the thermal and nonthermal fractions of the total flow may allow researchers to assess changes in flow volume or temperature of the springs caused by ground-water or geothermal development

  11. Population analysis relative to geothermal energy development, Imperial County, California

    Energy Technology Data Exchange (ETDEWEB)

    Pick, J.B.; Jung, T.H.; Butler, E.

    1977-01-01

    The historical and current population characteristics of Imperial County, California, are examined. These include vital rates, urbanization, town sizes, labor force composition, income, utility usage, and ethnic composition. Inferences are drawn on some of the important social and economic processes. Multivariate statistical analysis is used to study present relationships between variables. Population projections for the County were performed under historical, standard, and geothermal projection assumptions. The transferability of methods and results to other geothermal regions anticipating energy development is shown. (MHR)

  12. Evaluation of the Geothermal Public Power Utility Workshops in California

    Energy Technology Data Exchange (ETDEWEB)

    Farhar, B. C.

    2004-10-01

    The federal government devotes significant resources to educating consumers and businesses about geothermal energy. Yet little evidence exists for defining the kinds of information needed by the various audiences with specialized needs. This paper presents the results of an evaluation of the Geothermal Municipal Utility Workshops that presented information on geothermal energy to utility resource planners at customer-owned utilities in California. The workshops were sponsored by the Western Area Power Administration and the U.S. Department of Energy's GeoPowering the West Program and were intended to qualitatively assess the information needs of municipal utilities relative to geothermal energy and get feedback for future workshops. The utility workshop participants found the geothermal workshops to be useful and effective for their purposes. An important insight from the workshops is that utilities need considerable lead-time to plan a geothermal project. They need to know whether it is better to own a project or to purchase geothermal electricity from another nonutility owner. California customer-owned utilities say they do not need to generate more electricity to meet demand, but they do need to provide more electricity from renewable resources to meet the requirements of the state's Renewable Portfolio Standard.

  13. Refining Southern California Geotherms Using Seismologic, Geologic, and Petrologic Constraints

    Science.gov (United States)

    Thatcher, W. R.; Chapman, D. S.; Allam, A. A.; Williams, C. F.

    2017-12-01

    Lithospheric deformation in tectonically active regions depends on the 3D distribution of rheology, which is in turn critically controlled by temperature. Under the auspices of the Southern California Earthquake Center (SCEC) we are developing a 3D Community Thermal Model (CTM) to constrain rheology and so better understand deformation processes within this complex but densely monitored and relatively well-understood region. The San Andreas transform system has sliced southern California into distinct blocks, each with characteristic lithologies, seismic velocities and thermal structures. Guided by the geometry of these blocks we use more than 250 surface heat-flow measurements to define 13 geographically distinct heat flow regions (HFRs). Model geotherms within each HFR are constrained by averages and variances of surface heat flow q0 and the 1D depth distribution of thermal conductivity (k) and radiogenic heat production (A), which are strongly dependent on rock type. Crustal lithologies are not always well known and we turn to seismic imaging for help. We interrogate the SCEC Community Velocity Model (CVM) to determine averages and variances of Vp, Vs and Vp/Vs versus depth within each HFR. We bound (A, k) versus depth by relying on empirical relations between seismic wave speed and rock type and laboratory and modeling methods relating (A, k) to rock type. Many 1D conductive geotherms for each HFR are allowed by the variances in surface heat flow and subsurface (A, k). An additional constraint on the lithosphere temperature field is provided by comparing lithosphere-asthenosphere boundary (LAB) depths identified seismologically with those defined thermally as the depth of onset of partial melting. Receiver function studies in Southern California indicate LAB depths that range from 40 km to 90 km. Shallow LAB depths are correlated with high surface heat flow and deep LAB with low heat flow. The much-restricted families of geotherms that intersect peridotite

  14. Environmental assessmental, geothermal energy, Heber geothermal binary-cycle demonstration project: Imperial County, California

    Energy Technology Data Exchange (ETDEWEB)

    1980-10-01

    The proposed design, construction, and operation of a commercial-scale (45 MWe net) binary-cycle geothermal demonstration power plant are described using the liquid-dominated geothermal resource at Heber, Imperial County, California. The following are included in the environmental assessment: a description of the affected environment, potential environmental consequences of the proposed action, mitigation measures and monitoring plans, possible future developmental activities at the Heber anomaly, and regulations and permit requirements. (MHR)

  15. Honey Lake Geothermal Project, Lassen County, California

    Science.gov (United States)

    1984-11-01

    The drilling, completion, and testing of deep well WEN-2 for a hybrid electric power project which will use the area's moderate temperature geothermal fluids and locally procured wood fuel is reported. The project is located within the Wendel-Amedee Known Geothermal Resource Area.

  16. Boron isotopes in geothermal systems

    International Nuclear Information System (INIS)

    Aggarwal, J.

    1997-01-01

    Boron is a highly mobile element and during water-rock reactions, boron is leached out of rocks with no apparent fractionation. In geothermal systems where the water recharging the systems are meteoric in origin, the B isotope ratio of the geothermal fluid reflects the B isotope ratio of the rocks. Seawater has a distinctive B isotope ratio and where seawater recharges the geothermal system, the B isotope ratio of the geothermal system reflects the mixing of rock derived B and seawater derived B. Any deviations of the actual B isotope ratio of a mixture reflects subtle differences in the water-rock ratios in the cold downwelling limb of the hydrothermal system. This paper will present data from a variety of different geothermal systems, including New Zealand; Iceland; Yellowston, USA; Ibusuki, Japan to show the range in B isotope ratios in active geothermal systems. Some of these systems show well defined mixing trends between seawater and the host rocks, whilst others show the boron isotope ratios of the host rock only. In geothermal systems containing high amounts of CO 2 boron isotope ratios from a volatile B source can also be inferred. (auth)

  17. Geothermal energy: opportunities for California commerce. Phase I report

    Energy Technology Data Exchange (ETDEWEB)

    1982-01-01

    California's geographic and end-use markets which could directly use low and moderate temperature geothermal resources are ranked and described, as well as those which have the highest potential for near-term commercial development of these resources. Building on previous market surveys, the assessment determined that out of 38 geothermal resource areas with characteristics for direct use development, five areas have no perceived impediments to near-term development: Susanville, Litchfield, Ontario Hot Springs, Lake Elsinore, and the Salton Sea Geothermal Field. Twenty-nine applications were compared with previously selected criteria to determine their near-term potential for direct use of geothermal fluids. Seven categories were found to have the least impediments to development; agriculture and district heating applications are considered the highest. Ten-year projections were conducted for fossil fuel displacement from the higher rated applications. It is concluded that greenhouses have the greatest displacement of 18 x 10/sup 6/ therms per year.

  18. California low-temperature geothermal resources update: 1993

    Energy Technology Data Exchange (ETDEWEB)

    Youngs, L.G.

    1994-12-31

    The US Department of Energy -- Geothermal Division (DOE/GD) recently sponsored the Low-Temperature Geothermal Resources and Technology Transfer Program to bring the inventory of the nation`s low- and moderate-temperature geothermal resources up to date and to encourage development of the resources. The Oregon Institute of Technology, Geo-Heat Center (OIT/GHC) and the University of Utah Research Institute (UURI) established subcontracts and coordinated the project with the state resource teams from the western states that participated in the program. The California Department of Conservation, Division of Mines and Geology (DMG) entered into contract numbered 1092--023(R) with the OIT/GHC to provide the California data for the program. This report is submitted in fulfillment of that contract.

  19. Project Title: Geothermal Play Fairway Analysis of Potential Geothermal Resources in NE California, NW Nevada, and Southern Oregon: A Transition between Extension$-$Hosted and Volcanically$-$Hosted Geothermal Fields

    Energy Technology Data Exchange (ETDEWEB)

    McClain, James S. [Univ. of California, Davis, CA (United States). Dept. of; Dobson, Patrick [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Glassley, William [Univ. of California, Davis, CA (United States). Dept. of Earth and Planetary Sciences; Schiffman, Peter [Univ. of California, Davis, CA (United States). Dept. of Earth and Planetary Sciences; Zierenberg, Robert [Univ. of California, Davis, CA (United States). Dept. of Earth and Planetary Sciences; Zhang, Yingqi [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Conrad, Mark [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Siler, Drew [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Gasperikova, Erika [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Spycher, Nicolas F. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2016-09-30

    Final report for the UCD-LBNL effort to apply Geothermal Play Fairway Analysis to a transition zone between a volcanically-hosted and extensionally-hosted geothermal. The project focusses on the geothermal resources in northeastern California.

  20. Potential of geothermal systems in Picardy

    OpenAIRE

    Dourlat, Estelle

    2017-01-01

    Geothermal systems are not only about electrical plants or urban heating networks, but also concerned with geothermal energy assisted with a heat pump. In the former region of Picardy (North of France), 97% of the territory is suitable for very low temperature geothermal power. The French Agency for the Environment and Energy Management and the Picardy Region decided in 2016 to finance a facilitator to encourage geothermal use. To carry out this aim, it is important to consider the geothermal...

  1. Geotherm: the U.S. geological survey geothermal information system

    Science.gov (United States)

    Bliss, J.D.; Rapport, A.

    1983-01-01

    GEOTHERM is a comprehensive system of public databases and software used to store, locate, and evaluate information on the geology, geochemistry, and hydrology of geothermal systems. Three main databases address the general characteristics of geothermal wells and fields, and the chemical properties of geothermal fluids; the last database is currently the most active. System tasks are divided into four areas: (1) data acquisition and entry, involving data entry via word processors and magnetic tape; (2) quality assurance, including the criteria and standards handbook and front-end data-screening programs; (3) operation, involving database backups and information extraction; and (4) user assistance, preparation of such items as application programs, and a quarterly newsletter. The principal task of GEOTHERM is to provide information and research support for the conduct of national geothermal-resource assessments. The principal users of GEOTHERM are those involved with the Geothermal Research Program of the U.S. Geological Survey. Information in the system is available to the public on request. ?? 1983.

  2. Geothermal Heat Flow in the Gulfs of California and Aden.

    Science.gov (United States)

    Von Herzen, R P

    1963-06-14

    Eighteen measurements in and near the gulfs of California and Aden indicate the geothermal flux is several times the world-wide mean of 1.2 x 10(-6) cal/cm(2) sec in both regions. Both gulfs closely coincide with the intersection of oceanic rises with continents and have likely been formed under tensional forces, which suggests an association with mantle convection currents.

  3. Geothermal systems: Principles and case histories

    Science.gov (United States)

    Rybach, L.; Muffler, L. J. P.

    The classification of geothermal systems is considered along with the geophysical and geochemical signatures of geothermal systems, aspects of conductive heat transfer and regional heat flow, and geothermal anomalies and their plate tectonic framework. An investigation of convective heat and mass transfer in hydrothermal systems is conducted, taking into account the mathematical modelling of hydrothermal systems, aspects of idealized convective heat and mass transport, plausible models of geothermal reservoirs, and preproduction models of hydrothermal systems. Attention is given to the prospecting for geothermal resources, the application of water geochemistry to geothermal exploration and reservoir engineering, heat extraction from geothermal reservoirs, questions of geothermal resource assessment, and environmental aspects of geothermal energy development. A description is presented of a number of case histories, taking into account the low enthalpy geothermal resource of the Pannonian Basin in Hungary, the Krafla geothermal field in Northeast Iceland, the geothermal system of the Jemez Mountains in New Mexico, and extraction-reinjection at the Ahuachapan geothermal field in El Salvador.

  4. California: basic data for thermal springs and wells as recorded in GEOTHERM. Part A

    Energy Technology Data Exchange (ETDEWEB)

    Bliss, J.D.

    1983-07-01

    This GEOTHERM sample file contains 1535 records for California. Three computer-generated indexes give one line summaries of each GEOTHERM record. Each index is sorted by different variables to assist in locating geothermal records describing specific sites. 7 refs. (ACR)

  5. Geothermal energy: opportunities for California commerce. Phase I report

    Energy Technology Data Exchange (ETDEWEB)

    Longyear, A.B. (ed.)

    1981-12-01

    The potential geothermal direct-use energy market and its application to projects in California are assessed. Project identification effort is to be focused on those that have the highest probability for near-term successful commercial operations. Near-term herein means 2 to 5 years for project implementation. Phase I has been focused on defining and assessing: (1) the geothermal direct-use resources that are suitable for near-term utilization; and (2) the generic applications (municipal heating districts, horticultural greenhouse firms, laundries, etc.) that are suitable for near-term projects. Five economic development regions in the state, containing recognized geothermal direct-use resources, have been defined. Thirty-eight direct use resources have been evaluated in these regions. After assessment against pre-selected criteria, twenty-seven have been rated with a priority of I, II or III, thereby qualifying them for further marketing effort. The five areas with a priority of I are summarized. These areas have no perceived impediments to near-term development. Twenty-nine generic categories of applications were assessed against previously selected criteria to determine their near term potential for direct use of geothermal fluids. Some twenty industry, commercial and institutional application categories were rated with a priority of I, II or III and warrant further marketing efforts. The seven categories with a priority of I are listed. These categories were found to have the least impediments to near-term application projects.

  6. Boise geothermal district heating system

    Energy Technology Data Exchange (ETDEWEB)

    Hanson, P.J.

    1985-10-01

    This document describes the Boise geothermal district heating project from preliminary feasibility studies completed in 1979 to a fully operational system by 1983. The report includes information about the two local governments that participated in the project - the City of Boise, Idaho and the Boise Warm Springs Water District. It also discusses the federal funding sources; the financial studies; the feasibility studies conducted; the general system planning and design; design of detailed system components; the legal issues involved in production; geological analysis of the resource area; distribution and disposal; the program to market system services; and the methods of retrofitting buildings to use geothermal hot water for space heating. Technically this report describes the Boise City district heating system based on 170/sup 0/F water, a 4000 gpm production system, a 41,000 foot pipeline system, and system economies. Comparable data are also provided for the Boise Warm Springs Water District. 62 figs., 31 tabs.

  7. NATIONAL GEOTHERMAL DATA SYSTEM (NGDS) GEOTHERMAL DATA DOMAIN: ASSESSMENT OF GEOTHERMAL COMMUNITY DATA NEEDS

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Arlene [United States Department of Energy; Blackwell, David [Southern Methodist University; Chickering, Cathy [Southern Methodist University; Boyd, Toni [Oregon Institute of Technology; Horne, Roland [Stanford University; MacKenzie, Matthew [Uberity Technology Corporation; Moore, Joseph [University of Utah; Nickull, Duane [Uberity Technology Corporation; Richard, Stephen [Arizona Geological survey; Shevenell, Lisa A. [University of Nevada, Reno

    2013-01-01

    To satisfy the critical need for geothermal data to ad- vance geothermal energy as a viable renewable ener- gy contender, the U.S. Department of Energy is in- vesting in the development of the National Geother- mal Data System (NGDS). This paper outlines efforts among geothermal data providers nationwide to sup- ply cutting edge geo-informatics. NGDS geothermal data acquisition, delivery, and methodology are dis- cussed. In particular, this paper addresses the various types of data required to effectively assess geother- mal energy potential and why simple links to existing data are insufficient. To create a platform for ready access by all geothermal stakeholders, the NGDS in- cludes a work plan that addresses data assets and re- sources of interest to users, a survey of data provid- ers, data content models, and how data will be ex- changed and promoted, as well as lessons learned within the geothermal community.

  8. The Geothermal Probabilistic Cost Model with an Application to a Geothermal Reservoir at Heber, California

    Science.gov (United States)

    Orren, L. H.; Ziman, G. M.; Jones, S. C.

    1981-01-01

    A financial accounting model that incorporates physical and institutional uncertainties was developed for geothermal projects. Among the uncertainties it can handle are well depth, flow rate, fluid temperature, and permit and construction times. The outputs of the model are cumulative probability distributions of financial measures such as capital cost, levelized cost, and profit. These outputs are well suited for use in an investment decision incorporating risk. The model has the powerful feature that conditional probability distribution can be used to account for correlations among any of the input variables. The model has been applied to a geothermal reservoir at Heber, California, for a 45-MW binary electric plant. Under the assumptions made, the reservoir appears to be economically viable.

  9. Enhanced Geothermal Systems

    Energy Technology Data Exchange (ETDEWEB)

    Jeanloz, R. [The MITRE Corporation, McLean, VA (United States); Stone, H. [The MITRE Corporation, McLean, VA (United States); et al.

    2013-12-31

    DOE, through the Geothermal Technologies Office (GTO) within the Office of Energy Efficiency and Renewable Energy, requested this study, identifying a focus on: i) assessment of technologies and approaches for subsurface imaging and characterization so as to be able to validate EGS opportunities, and ii) assessment of approaches toward creating sites for EGS, including science and engineering to enhance permeability and increase the recovery factor. Two days of briefings provided in-depth discussion of a wide range of themes and challenges in EGS, and represented perspectives from industry, government laboratories and university researchers. JASON also contacted colleagues from universities, government labs and industry in further conversations to learn the state of the field and potential technologies relevant to EGS.

  10. Analysis of induced seismicity at The Geysers geothermal field, California

    Science.gov (United States)

    Emolo, A.; Maercklin, N.; Matrullo, E.; Orefice, A.; Amoroso, O.; Convertito, V.; Sharma, N.; Zollo, A.

    2012-12-01

    Fluid injection, steam extraction, and reservoir stimulation in geothermal systems lead to induced seismicity. While in rare cases induced events may be large enough to pose a hazard, on the other hand the microseismicity provides information on the extent and the space-time varying properties of the reservoir. Therefore, microseismic monitoring is important, both for mitigation of unwanted effects of industrial operations and for continuous assessment of reservoir conditions. Here we analyze induced seismicity at The Geysers geothermal field in California, a vapor-dominated field with the top of the main steam reservoir some 1-3 km below the surface. Commercial exploitation began in the 1960s, and the seismicity increased with increasing field development. We focus our analyses on induced seismicity recorded between August 2007 and October 2011. Our calibrated waveform database contains some 15000 events with magnitudes between 1.0 and 4.5 and recorded by the LBNL Geysers/Calpine surface seismic network. We associated all data with events from the NCEDC earthquake catalog and re-picked first arrival times. Using selected events with at least 20 high-quality P-wave picks, we determined a minimum 1-D velocity model using VELEST. A well-constrained P-velocity model shows a sharp velocity increase at 1-2 km depth (from 3 to 5 km/s) and then a gradient-like trend down to about 5 km depth, where velocities reach values of 6-7 km/s. The station corrections show coherent, relatively high, positive travel time delays in the NW zone, thus indicating a strong lateral variation of the P-wave velocities. We determined an average Vp-to-Vs ratio of 1.67, which is consistent with estimates from other authors for the same time period. The events have been relocated in the new model using a non-linear probabilistic methods. The seismicity appears spatially diffused in a 15x10 km2 area elongated in NW-SE direction, and earthquake depths range between 0 and 6 km. As in previous

  11. Significant Problems in Geothermal Development in California, Final Report on Four Workshops, December 1978 - March 1979

    Energy Technology Data Exchange (ETDEWEB)

    None

    1979-07-15

    From November 1978 through March 1979 the California Geothermal Resources Board held four workshops on the following aspects of geothermal development in California: County Planning for Geothermal Development; Federal Leasing and Environmental Review Procedures; Transmission Corridor Planning; and Direct Heat Utilization. One of the objectives of the workshops was to increase the number of people aware of geothermal resources and their uses. This report is divided into two parts. Part 1 provides summaries of all the key information discussed in the workshops. For those people who were not able to attend, this part of the report provides you with a capsule version of the workshop sessions. Part 2 focuses on the key issues raised at the workshops which need to be acted upon to expedite geothermal resource development that is acceptable to local government and environmentally prudent. For the purpose of continuity, similar Geothermal Resources Task Force recommendations are identified.

  12. Program planner's guide to geothermal development in California

    Energy Technology Data Exchange (ETDEWEB)

    Yen, W.W.S.; Chambers, D.M.; Elliott, J.F.; Whittier, J.P.; Schnoor, J.J.; Blachman, S.

    1980-09-30

    The resource base, status of geothermal development activities, and the state's energy flow are summarized. The present and projected geothermal share of the energy market is discussed. The public and private sector initiatives supporting geothermal development in California are described. These include legislation to provide economic incentives, streamline regulation, and provide planning assistance to local communities. Private sector investment, research, and development activities are also described. The appendices provide a ready reference of financial incentives. (MHR)

  13. National Geothermal Data System: Transforming the Discovery, Access, and Analytics of Data for Geothermal Exploration

    Energy Technology Data Exchange (ETDEWEB)

    Patten, Kim [Arizona Geological Survey

    2013-05-01

    Compendium of Papers from the 38th Workshop on Geothermal Reservoir Engineering Stanford University, Stanford, California February 11-13, 2013 The National Geothermal Data System (NGDS) is a distributed, interoperable network of data collected from state geological surveys across all fifty states and the nation’s leading academic geothermal centers. The system serves as a platform for sharing consistent, reliable, geothermal-relevant technical data with users of all types, while supplying tools relevant for their work. As aggregated data supports new scientific findings, this content-rich linked data ultimately broadens the pool of knowledge available to promote discovery and development of commercial-scale geothermal energy production. Most of the up-front risks associated with geothermal development stem from exploration and characterization of subsurface resources. Wider access to distributed data will, therefore, result in lower costs for geothermal development. NGDS is on track to become fully operational by 2014 and will provide a platform for custom applications for accessing geothermal relevant data in the U.S. and abroad. It is being built on the U.S. Geoscience Information Network (USGIN) data integration framework to promote interoperability across the Earth sciences community. The basic structure of the NGDS employs state-of-the art informatics to advance geothermal knowledge. The following four papers comprising this Open-File Report are a compendium of presentations, from the 38th Annual Workshop on Geothermal Reservoir Engineering, taking place February 11-13, 2013 at Stanford University, Stanford, California. “NGDS Geothermal Data Domain: Assessment of Geothermal Community Data Needs,” outlines the efforts of a set of nationwide data providers to supply data for the NGDS. In particular, data acquisition, delivery, and methodology are discussed. The paper addresses the various types of data and metadata required and why simple links to existing

  14. Analysis of requirements for accelerating the development of geothermal energy resources in California

    Science.gov (United States)

    Fredrickson, C. D.

    1978-01-01

    Various resource data are presented showing that geothermal energy has the potential of satisfying a singificant part of California's increasing energy needs. General factors slowing the development of geothermal energy in California are discussed and required actions to accelerate its progress are presented. Finally, scenarios for developing the most promising prospects in the state directed at timely on-line power are given. Specific actions required to realize each of these individual scenarios are identified.

  15. Distribution of high-temperature (>150 °C) geothermal resources in California

    Science.gov (United States)

    Sass, John H.; Priest, Susan S.

    2002-01-01

    California contains, by far, the greatest geothermal generating capacity in the United States, and with the possible exception of Alaska, the greatest potential for the development of additional resources. California has nearly 2/3 of the US geothermal electrical installed capacity of over 3,000 MW. Depending on assumptions regarding reservoir characteristics and future market conditions, additional resources of between 2,000 and 10,000 MWe might be developed (see e.g., Muffler, 1979).

  16. Health effects and related standards for fossil-fuel and geothermal power plants. Volume 6 of health and safety impacts of nuclear, geothermal, and fossil-fuel electric generation in California. [In California

    Energy Technology Data Exchange (ETDEWEB)

    Case, G.D.; Bertolli, T.A.; Bodington, J.C.; Choy, T.A.; Nero, A.V.

    1977-01-01

    This report reviews health effects and related standards for fossil-fuel and geothermal power plants, emphasizing impacts which may occur through emissions into the atmosphere, and treating other impacts briefly. Federal regulations as well as California state and local regulations are reviewed. Emissions are characterized by power plant type, including: coal-fired, oil-fired, gas-fired, combined cycle and advanced fossil-fuel plants; and liquid and vapor geothermal systems. Dispersion and transformation of emissions are treated. The state of knowledge of health effects, based on epidemiological, physiological, and biomedical studies, is reviewed.

  17. Computational modeling of shallow geothermal systems

    CERN Document Server

    Al-Khoury, Rafid

    2011-01-01

    A Step-by-step Guide to Developing Innovative Computational Tools for Shallow Geothermal Systems Geothermal heat is a viable source of energy and its environmental impact in terms of CO2 emissions is significantly lower than conventional fossil fuels. Shallow geothermal systems are increasingly utilized for heating and cooling of buildings and greenhouses. However, their utilization is inconsistent with the enormous amount of energy available underneath the surface of the earth. Projects of this nature are not getting the public support they deserve because of the uncertainties associated with

  18. Towards the Understanding of Induced Seismicity in Enhanced Geothermal Systems

    Energy Technology Data Exchange (ETDEWEB)

    Gritto, Roland [Array Information Technology, Greenbelt, MD (United States); Dreger, Douglas [Univ. of California, Berkeley, CA (United States); Heidbach, Oliver [Helmholtz Centre Potsdam (Germany, German Research Center for Geosciences; Hutchings, Lawrence [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2014-08-29

    This DOE funded project was a collaborative effort between Array Information Technology (AIT), the University of California at Berkeley (UCB), the Helmholtz Centre Potsdam - German Research Center for Geosciences (GFZ) and the Lawrence Berkeley National Laboratory (LBNL). It was also part of the European research project “GEISER”, an international collaboration with 11 European partners from six countries including universities, research centers and industry, with the goal to address and mitigate the problems associated with induced seismicity in Enhanced Geothermal Systems (EGS). The goal of the current project was to develop a combination of techniques, which evaluate the relationship between enhanced geothermal operations and the induced stress changes and associated earthquakes throughout the reservoir and the surrounding country rock. The project addressed the following questions: how enhanced geothermal activity changes the local and regional stress field; whether these activities can induce medium sized seismicity M > 3; (if so) how these events are correlated to geothermal activity in space and time; what is the largest possible event and strongest ground motion, and hence the potential hazard associated with these activities. The development of appropriate technology to thoroughly investigate and address these questions required a number of datasets to provide the different physical measurements distributed in space and time. Because such a dataset did not yet exist for an EGS system in the United State, we used current and past data from The Geysers geothermal field in northern California, which has been in operation since the 1960s. The research addressed the need to understand the causal mechanisms of induced seismicity, and demonstrated the advantage of imaging the physical properties and temporal changes of the reservoir. The work helped to model the relationship between injection and production and medium sized magnitude events that have

  19. Geotechnical environmental aspects of geothermal power generation at Herber, Imperial Valley, California

    Energy Technology Data Exchange (ETDEWEB)

    1976-10-01

    The feasibility of constructing a 25-50 MWe geothermal power plant using low salinity hydrothermal fluid as the energy source was assessed. Here, the geotechnical aspects of geothermal power generation and their relationship to environmental impacts in the Imperial Valley of California were investigated. Geology, geophysics, hydrogeology, seismicity and subsidence are discussed in terms of the availability of data, state-of-the-art analytical techniques, historical and technical background and interpretation of current data. Estimates of the impact of these geotechnical factors on the environment in the Imperial Valley, if geothermal development proceeds, are discussed.

  20. Hybrid Solar-Geothermal Energy Absorption Air-Conditioning System Operating with NaOH-H2O—Las Tres Vírgenes (Baja California Sur), “La Reforma” Case

    OpenAIRE

    Yuridiana Rocio Galindo-Luna; Efraín Gómez-Arias; Rosenberg J. Romero; Eduardo Venegas-Reyes; Moisés Montiel-González; Helene Emmi Karin Unland-Weiss; Pedro Pacheco-Hernández; Antonio González-Fernández; Jorge Díaz-Salgado

    2018-01-01

    Solar and geothermal energies are considered cleaner and more useful energy sources that can be used to avoid the negative environmental impacts caused by burning fossil fuels. Several works have reported air-conditioning systems that use solar energy coupled to geothermal renewable energy as a thermal source. In this study, an Absorption Air-Conditioning System (AACS) used sodium hydroxide-water (NaOH-H2O) instead of lithium bromide-water to reduce the cost. Low enthalpy geothermal heat was ...

  1. Energy efficiency comparison between geothermal power systems

    Directory of Open Access Journals (Sweden)

    Luo Chao

    2017-01-01

    Full Text Available The geothermal water which can be considered for generating electricity with the temperature ranging from 80℃ to 150℃ in China because of shortage of electricity and fossil energy. There are four basic types of geothermal power systems: single flash, double flash, binary cycle, and flash-binary system, which can be adapted to geothermal energy utilization in China. The paper discussed the performance indices and applicable conditions of different power system. Based on physical and mathematical models, simulation result shows that, when geofluid temperature ranges from 100℃ to 130℃, the net power output of double flash power is bigger than flash-binary system. When the geothermal resource temperature is between 130℃ and 150℃, the net power output of flash-binary geothermal power system is higher than double flash system by the maximum value 5.5%. However, the sum water steam amount of double flash power system is 2 to 3 times larger than flash-binary power system, which will cause the bigger volume of equipment of power system. Based on the economy and power capacity, it is better to use flash-binary power system when the geofluid temperature is between 100℃ and 150℃.

  2. National Geothermal Data System (NGDS) Geothermal Data: Community Requirements and Information Engineering

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Arlene [United States Department of Energy; Blackwell, David [Southern Methodist University; Chickering, Cathy [Southern Methodist University; Boyd, Toni [Oregon Institute of Technology; Horne, Roland [Stanford University; MacKenzie, Matthew [Uberity Technology Corporation; Moore, Joseph [University of Utah; Nickull, Duane [Uberity Technology Corporation; Richard, Stephen [Arizona Geological survey; Shevenell, Lisa A. [University of Nevada, Reno

    2013-10-01

    To satisfy the critical need for geothermal data to advance geothermal energy as a viable renewable energy contender, the U.S. Department of Energy is investing in the development of the National Geothermal Data System (NGDS). This paper outlines efforts among geothermal data providers nationwide to supply cutting edge geo-informatics. NGDS geothermal data acquisition, delivery, and methodology are discussed. In particular, this paper addresses the various types of data required to effectively assess geothermal energy potential and why simple links to existing data are insufficient. To create a platform for ready access by all geothermal stakeholders, the NGDS includes a work plan that addresses data assets and resources of interest to users, a survey of data providers, data content models, and how data will be exchanged and promoted, as well as lessons learned within the geothermal community.

  3. Statistical study of seismicity associated with geothermal reservoirs in California

    Energy Technology Data Exchange (ETDEWEB)

    Hadley, D.M.; Cavit, D.S.

    1982-01-01

    Statistical methods are outlined to separate spatially, temporally, and magnitude-dependent portions of both the random and non-random components of the seismicity. The methodology employed compares the seismicity distributions with a generalized Poisson distribution. Temporally related events are identified by the distribution of the interoccurrence times. The regions studied to date include the Imperial Valley, Coso, The Geysers, Lassen, and the San Jacinto fault. The spatial characteristics of the random and clustered components of the seismicity are diffuse and appear unsuitable for defining the areal extent of the reservoir. However, from the temporal characteristics of the seismicity associated with these regions a general discriminant was constructed that combines several physical parameters for identifying the presence of a geothermal system.

  4. Geothermal development of the Salton Trough, California and Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, T.D.; Howard, J.H.; Lande, D.P. (eds.)

    1975-04-01

    A geological description is given of the Salton Trought followed by a chronological history of attempts to exploit the area's geothermal resources. In addition, detailed descriptions are given of all ongoing geothermal projects in the area and the organizations conducting them.

  5. Development of geothermal-well-completion systems. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, E.B.

    1979-01-01

    Results of a three year study concerning the completion of geothermal wells, specifically cementing, are reported. The research involved some specific tasks: (1) determination of properties an adequate geothermal well cement must possess; (2) thorough evaluation of current high temperature oilwell cementing technology in a geothermal context; (3) basic research concerning the chemical and physical behavior of cements in a geothermal environment; (4) recommendation of specific cement systems suitable for use in a geothermal well.

  6. Geothermal GW cogeneration system GEOCOGEN

    Energy Technology Data Exchange (ETDEWEB)

    Grob, Gustav R

    2010-09-15

    GEOCOGEN is the GW zero pollution, no risk solution to replace nuclear and fossil fuelled power plants. It can be built near the energy consumption centers, is invisible and produces electricity and heat at a fraction of the cost of any other the energy mix options. It is a break through deep well geothermal energy technology lasting forever driving also millions of electric vehicles.

  7. Performance of deep geothermal energy systems

    Science.gov (United States)

    Manikonda, Nikhil

    Geothermal energy is an important source of clean and renewable energy. This project deals with the study of deep geothermal power plants for the generation of electricity. The design involves the extraction of heat from the Earth and its conversion into electricity. This is performed by allowing fluid deep into the Earth where it gets heated due to the surrounding rock. The fluid gets vaporized and returns to the surface in a heat pipe. Finally, the energy of the fluid is converted into electricity using turbine or organic rankine cycle (ORC). The main feature of the system is the employment of side channels to increase the amount of thermal energy extracted. A finite difference computer model is developed to solve the heat transport equation. The numerical model was employed to evaluate the performance of the design. The major goal was to optimize the output power as a function of parameters such as thermal diffusivity of the rock, depth of the main well, number and length of lateral channels. The sustainable lifetime of the system for a target output power of 2 MW has been calculated for deep geothermal systems with drilling depths of 8000 and 10000 meters, and a financial analysis has been performed to evaluate the economic feasibility of the system for a practical range of geothermal parameters. Results show promising an outlook for deep geothermal systems for practical applications.

  8. Geothermal development and land use/energy planning by the State of California and its political subdivisions

    Energy Technology Data Exchange (ETDEWEB)

    1978-07-30

    California law contains several vehicles for the implementation of geothermal planning. These mechanisms and their impact are examined. First, at the State level upon the California Energy Commission and the Division of Oil and Gas in the Department of Conservation. After some background on county planning in California, the unique situation in the counties of greatest geothermal potential is presented: Imperial County and the four Geysers counties as well as their joint powers agency. Conclusions and recommendations are included. (MHR)

  9. Feasibility of geothermal space/water heating for Mammoth Lakes Village, California. Final report, September 1976--September 1977

    Energy Technology Data Exchange (ETDEWEB)

    Sims, A.V.; Racine, W.C.

    1977-12-01

    Results of a study to determine the technical, economic, and environmental feasibility of geothermal district heating for Mammoth Lakes Village, California are reported. The geothermal district heating system selected is technically feasible and will use existing technology in its design and operation. District heating can provide space and water heating energy for typical customers at lower cost than alternative sources of energy. If the district heating system is investor owned, lower costs are realized after five to six years of operation, and if owned by a nonprofit organization, after zero to three years. District heating offers lower costs than alternatives much sooner in time if co-generation and/or DOE participation in system construction are included in the analysis. During a preliminary environmental assessment, no potential adverse environmental impacts could be identified of sufficient consequence to preclude the construction and operation of the proposed district heating system. A follow-on program aimed at implementing district heating in Mammoth is outlined.

  10. Aqueous systems and geothermal energy

    International Nuclear Information System (INIS)

    Anon.

    1977-01-01

    Significant unpublished results reported include: osmotic coefficients of KCl solutions vs. molality at 109 to 201 0 C; cadmium ion diffusivities in CaCl 2 hydrous melts; a x-ray diffraction study of the uranyl complex in water; solubility of amorphous silica in aqueous NaNO 3 solutions at 100 to 300 0 C; and corrosion of carbon steel by geothermal brine

  11. Igneous-related geothermal systems

    Energy Technology Data Exchange (ETDEWEB)

    Smith, R L; Shaw, H R

    1976-01-01

    A preliminary survey of the geothermal resource base associated with igneous-derived thermal anomalies in the upper 10 km of the crust is presented. The approach to numerical estimates of igneous-related heat contents rests on estimates of the probable volumes of high-level magma chambers and determinations of the radiometric ages of the youngest volcanism from those chambers combined with simple thermal calculations based on these values. (MHR)

  12. The impact of injection on seismicity at The Geysers, California Geothermal Field

    OpenAIRE

    Majer, Ernest L.; Peterson, John E.

    2007-01-01

    Water injection into geothermal systems has often become a required strategy to extend and sustain production of geothermal resources. To reduce a trend of declining pressures and increasing non-condensable gas concentrations in steam produced from The Geysers, operators have been injecting steam condensate, local rain and stream waters, and most recently treated wastewater piped to the field from neighboring communities. If geothermal energy is to provide a significant increase in energy in ...

  13. The Impact of Injection on Seismicity at The Geyses, California Geothermal Field

    OpenAIRE

    Majer, Ernest L.; Peterson, John E.

    2008-01-01

    Water injection into geothermal systems has often become a required strategy to extended and sustain production of geothermal resources. To reduce a trend of declining pressures and increasing non-condensable gas concentrations in steam produced from The Geysers, operators have been injecting steam condensate, local rain and stream waters, and most recently treated wastewater piped to the field from neighboring communities. If geothermal energy is to provide a significant increase in ene...

  14. ERDA test facilities, East Mesa Test Site. Geothermal resource investigations, Imperial Valley, California

    Energy Technology Data Exchange (ETDEWEB)

    1976-01-01

    Detailed specifications which must be complied with in the construction of the ERDA Test Facilities at the East Mesa Site for geothermal resource investigations in Imperial Valley, California are presented for use by prospective bidders for the construction contract. The principle construction work includes a 700 gpm cooling tower with its associated supports and equipment, pipelines from wells, electrical equipment, and all earthwork. (LCL)

  15. Induced seismicity associated with enhanced geothermal system

    Energy Technology Data Exchange (ETDEWEB)

    Majer, Ernest; Majer, Ernest L.; Baria, Roy; Stark, Mitch; Oates, Stephen; Bommer, Julian; Smith, Bill; Asanuma, Hiroshi

    2006-09-26

    Enhanced Geothermal Systems (EGS) offer the potential to significantly add to the world energy inventory. As with any development of new technology, some aspects of the technology has been accepted by the general public, but some have not yet been accepted and await further clarification before such acceptance is possible. One of the issues associated with EGS is the role of microseismicity during the creation of the underground reservoir and the subsequent extraction of the energy. The primary objectives of this white paper are to present an up-to-date review of the state of knowledge about induced seismicity during the creation and operation of enhanced geothermal systems, and to point out the gaps in knowledge that if addressed will allow an improved understanding of the mechanisms generating the events as well as serve as a basis to develop successful protocols for monitoring and addressing community issues associated with such induced seismicity. The information was collected though literature searches as well as convening three workshops to gather information from a wide audience. Although microseismicity has been associated with the development of production and injection operations in a variety of geothermal regions, there have been no or few adverse physical effects on the operations or on surrounding communities. Still, there is public concern over the possible amount and magnitude of the seismicity associated with current and future EGS operations. It is pointed out that microseismicity has been successfully dealt with in a variety of non-geothermal as well as geothermal environments. Several case histories are also presented to illustrate a variety of technical and public acceptance issues. It is concluded that EGS Induced seismicity need not pose any threat to the development of geothermal resources if community issues are properly handled. In fact, induced seismicity provides benefits because it can be used as a monitoring tool to understand the

  16. Materials selection guidelines for geothermal energy utilization systems

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, P.F. II; Conover, M.F.

    1981-01-01

    This manual includes geothermal fluid chemistry, corrosion test data, and materials operating experience. Systems using geothermal energy in El Salvador, Iceland, Italy, Japan, Mexico, New Zealand, and the United States are described. The manual provides materials selection guidelines for surface equipment of future geothermal energy systems. The key chemical species that are significant in determining corrosiveness of geothermal fluids are identified. The utilization modes of geothermal energy are defined as well as the various physical fluid parameters that affect corrosiveness. Both detailed and summarized results of materials performance tests and applicable operating experiences from forty sites throughout the world are presented. The application of various non-metal materials in geothermal environments are discussed. Included in appendices are: corrosion behavior of specific alloy classes in geothermal fluids, corrosion in seawater desalination plants, worldwide geothermal power production, DOE-sponsored utilization projects, plant availability, relative costs of alloys, and composition of alloys. (MHR)

  17. A case study of radial jetting technology for enhancing geothermal energy systems at Klaipeda geothermal demonstration plant

    NARCIS (Netherlands)

    Nair, R.; Peters, E.; Sliaupa, S.; Valickas, R.; Petrauskas, S.

    2017-01-01

    In 1996 a geothermal energy project was initiated at Klaipėda, Lithuania, to demonstrate the feasibility of using low enthalpy geothermal water as a renewable energy resource in district heating systems. The Klaipėda geothermal plant is situated within the West Lithuanian geothermal anomaly with a

  18. Niland development project geothermal loan guaranty: 49-MW (net) power plant and geothermal well field development, Imperial County, California: Environmental assessment

    Energy Technology Data Exchange (ETDEWEB)

    1984-10-01

    The proposed federal action addressed by this environmental assessment is the authorization of disbursements under a loan guaranteed by the US Department of Energy for the Niland Geothermal Energy Program. The disbursements will partially finance the development of a geothermal well field in the Imperial Valley of California to supply a 25-MW(e) (net) power plant. Phase I of the project is the production of 25 MW(e) (net) of power; the full rate of 49 MW (net) would be achieved during Phase II. The project is located on approximately 1600 acres (648 ha) near the city of Niland in Imperial County, California. Well field development includes the initial drilling of 8 production wells for Phase I, 8 production wells for Phase II, and the possible need for as many as 16 replacement wells over the anticipated 30-year life of the facility. Activities associated with the power plant in addition to operation are excavation and construction of the facility and associated systems (such as cooling towers). Significant environmental impacts, as defined in Council on Environmental Quality regulation 40 CFR Part 1508.27, are not expected to occur as a result of this project. Minor impacts could include the following: local degradation of ambient air quality due to particulate and/or hydrogen sulfide emissions, temporarily increased ambient noise levels due to drilling and construction activities, and increased traffic. Impacts could be significant in the event of a major spill of geothermal fluid, which could contaminate groundwater and surface waters and alter or eliminate nearby habitat. Careful land use planning and engineering design, implementation of mitigation measures for pollution control, and design and implementation of an environmental monitoring program that can provide an early indication of potential problems should ensure that impacts, except for certain accidents, will be minimized.

  19. Energy source completion for geothermal district heating systems

    International Nuclear Information System (INIS)

    Popovski, Kiril

    2000-01-01

    Geothermal district heating systems differs from the others mainly in the part of energy source completion and its connection to the heat distribution systems rather known problem. Even rather known problematic in the countries where geothermal energy is in wide application, new appearances of mistakes are always present due to the fact that necessary literature is difficult to be found. Essentials of the geothermal well completion and connection of geothermal source to the district heating distribution system are summarized in the paper and several examples of geothermal projects in flow are presented. (Author)

  20. Draft environmental impact report. California Department of Water Resources, Bottle Rock geothermal power plant, Lake County, CA

    Energy Technology Data Exchange (ETDEWEB)

    1979-12-01

    The California Department of Water Resources (DWR) proposes to construct the Bottle Rock power plant, a 55 MW geothermal power plant, at The Geysers Known Geothermal Resource Area (KGRA). The plant is projected to begin operation in April of 1983, and will be located in Lake County near the Sonoma County line on approximately 7.2 acres of the Francisco leasehold. The steam to operate the power plant, approximately 1,000,000 pounds/h, will be provided by McCulloch Geothermal Corporation. The power plant's appearance and operation will be basically the same as the units in operation or under construction in the KGRA. The power plant and related facilities will consist of a 55 MW turbine generator, a 1.1 mile (1.81 km) long transmission line, a condensing system, cooling tower, electrical switchyard, gas storage facility, cistern, and an atmospheric emission control system. DWR plans to abate hydrogen sulfide (H/sub 2/S) emissions through the use of the Stretford Process which scrubs the H/sub 2/S from the condenser vent gas stream and catalytically oxides the gas to elemental sulfur. If the Stretford Process does not meet emission limitations, a secondary H/sub 2/S abatement system using hydrogen peroxide/iron catalyst is proposed. The Bottle Rock project and other existing and future geothermal projects in the KGRA may result in cumulative impacts to soils, biological resources, water quality, geothermal steam resources, air quality, public health, land use, recreation, cultural resources, and aesthetics.

  1. Geothermal energy systems plan for Boise City

    Energy Technology Data Exchange (ETDEWEB)

    1979-01-01

    This is a plan for development of a downtown Boise geothermal district space heating system incorporating legal, engineering, organizational, geological, and economic requirements. Topics covered include: resource characteristics, system design and feasibility, economic feasibility, legal overview, organizational alternatives, and conservation. Included in appendices are: property ownership patterns on the Boise Front, existing hot well data, legal briefs, environmental data, decision point communications, typical building heating system retrofit schematics, and background assumptions and data for cost summary. (MHR)

  2. Geothermal direct-heat study: Imperial County, California

    Energy Technology Data Exchange (ETDEWEB)

    1983-05-01

    Potential applications of geothermal energy which would be compatible with the agricultural activities in the county were identified and a plan to attract potential users to the area was developed. The intent of the first effort was to identify general classifications of industries which could utilize geothermal heat in production processes. Two levels of analyses were utilized for this effort. Initially, activities relying on previously developed engineering and industrial concepts were investigated to determine capital costs, employment, and potential energy savings. Second, innovative concepts not yet fully developed were investigated to determine their potential applicability to the agricultural base of the county. These investigations indicated that the major potential applications of geothermal heat would involve industries related to food processing or other direct agriculture-related uses of raw materials produced or imported to the county. An implementation plan which can be utilized by the county to market direct heat applications was developed. A socioeconomics analysis examined the potential effects on the county from development of direct heat projects. The county's planning and permitting requirements for dirct heat projects were also examined.

  3. Geothermal ORC Systems Using Large Screw Expanders

    OpenAIRE

    Biederman, Tim R.; Brasz, Joost J.

    2014-01-01

    Geothermal ORC Systems using Large Screw Expanders Tim Biederman Cyrq Energy Abstract This paper describes a low-temperature Organic Rankine Cycle Power Recovery system with a screw expander a derivative of developed of Kaishan's line of screw compressors, as its power unit. The screw expander design is a modified version of its existing refrigeration compressor used on water-cooled chillers. Starting the ORC development program with existing refrigeration screw compre...

  4. Operation strategy analysis of a geothermal step utilization heating system

    International Nuclear Information System (INIS)

    Zheng, Guozhong; Li, Feng; Tian, Zhe; Zhu, Neng; Li, Qianru; Zhu, Han

    2012-01-01

    Geothermal energy has been successfully applied in many district heating systems. In order to promote better use of geothermal energy, it is important to analyze the operation strategy of geothermal heating system. This study proposes a comprehensive and systematic operation strategy for a geothermal step utilization heating system (GSUHS). Calculation models of radiator heating system (RHS), radiant floor heating system (RFHS), heat pump (HP), gas boiler (GB), plate heat exchanger (PHE) and pump are first established. Then the operation strategy of the GSUHS is analyzed with the aim to substantially reduce the conventional energy consumption of the whole system. Finally, the energy efficiency and geothermal tail water temperature are analyzed. With the operation strategy in this study, the geothermal energy provides the main heating amount for the system. The heating seasonal performance factor is 15.93. Compared with coal-fired heating, 75.1% of the standard coal equivalent can be saved. The results provide scientific guidance for the application of an operation strategy for a geothermal step utilization heating system. -- Highlights: ► We establish calculation models for the geothermal step utilization heating system. ► We adopt minimal conventional energy consumption to determine the operation strategy. ► The geothermal energy dominates the heating quantity of the whole system. ► The utilization efficiency of the geothermal energy is high. ► The results provide guidance to conduct operation strategy for scientific operation.

  5. High Temperature Perforating System for Geothermal Applications

    Energy Technology Data Exchange (ETDEWEB)

    Smart, Moises E. [Schlumberger Technology Corporation, Sugar Land, TX (United States)

    2017-02-28

    The objective of this project is to develop a perforating system consisting of all the explosive components and hardware, capable of reliable performance in high temperatures geothermal wells (>200 ºC). In this light we will focused on engineering development of these components, characterization of the explosive raw powder and developing the internal infrastructure to increase the production of the explosive from laboratory scale to industrial scale.

  6. Advanced Horizontal Well Recirculation Systems for Geothermal Energy Recovery in Sedimentary and Crystalline Formations

    Energy Technology Data Exchange (ETDEWEB)

    Bruno, Mike S. [Terralog Technologies USA, Inc., Calgary (Canada); Detwiler, Russell L. [Terralog Technologies USA, Inc., Calgary (Canada); Lao, Kang [Terralog Technologies USA, Inc., Calgary (Canada); Serajian, Vahid [Terralog Technologies USA, Inc., Calgary (Canada); Elkhoury, Jean [Terralog Technologies USA, Inc., Calgary (Canada); Diessl, Julia [Terralog Technologies USA, Inc., Calgary (Canada); White, Nicky [Terralog Technologies USA, Inc., Calgary (Canada)

    2012-12-13

    There is increased recognition that geothermal energy resources are more widespread than previously thought, with potential for providing a significant amount of sustainable clean energy worldwide. Recent advances in drilling, completion, and production technology from the oil and gas industry can now be applied to unlock vast new geothermal resources, with some estimates for potential electricity generation from geothermal energy now on the order of 2 million megawatts. The primary objectives of this DOE research effort are to develop and document optimum design configurations and operating practices to produce geothermal power from hot permeable sedimentary and crystalline formations using advanced horizontal well recirculation systems. During Phase I of this research project Terralog Technologies USA and The University of California, Irvine (UCI), have completed preliminary investigations and documentation of advanced design concepts for paired horizontal well recirculation systems, optimally configured for geothermal energy recovery in permeable sedimentary and crystalline formations of varying structure and material properties. We have also identified significant geologic resources appropriate for application of such technology. The main challenge for such recirculation systems is to optimize both the design configuration and the operating practices for cost-effective geothermal energy recovery. These will be strongly influenced by sedimentary formation properties, including thickness and dip, temperature, thermal conductivity, heat capacity, permeability, and porosity; and by working fluid properties.

  7. Enthalpy restoration in geothermal energy processing system

    Science.gov (United States)

    Matthews, Hugh B.

    1983-01-01

    A geothermal deep well energy extraction system is provided of the general type in which solute-bearing hot water is pumped to the earth's surface from a relatively low temperature geothermal source by transferring thermal energy from the hot water to a working fluid for driving a primary turbine-motor and a primary electrical generator at the earth's surface. The superheated expanded exhaust from the primary turbine motor is conducted to a bubble tank where it bubbles through a layer of sub-cooled working fluid that has been condensed. The superheat and latent heat from the expanded exhaust of the turbine transfers thermal energy to the sub-cooled condensate. The desuperheated exhaust is then conducted to the condenser where it is condensed and sub-cooled, whereupon it is conducted back to the bubble tank via a barometric storage tank. The novel condensing process of this invention makes it possible to exploit geothermal sources which might otherwise be non-exploitable.

  8. Hybrid Solar-Geothermal Energy Absorption Air-Conditioning System Operating with NaOH-H2O—Las Tres Vírgenes (Baja California Sur, “La Reforma” Case

    Directory of Open Access Journals (Sweden)

    Yuridiana Rocio Galindo-Luna

    2018-05-01

    Full Text Available Solar and geothermal energies are considered cleaner and more useful energy sources that can be used to avoid the negative environmental impacts caused by burning fossil fuels. Several works have reported air-conditioning systems that use solar energy coupled to geothermal renewable energy as a thermal source. In this study, an Absorption Air-Conditioning System (AACS used sodium hydroxide-water (NaOH-H2O instead of lithium bromide-water to reduce the cost. Low enthalpy geothermal heat was derived from two shallow wells, 50 and 55 m deep. These wells are of interest due to the thermal recovery (temperature vs. time of 56.2 °C that was possible at the maximum depth, which can be used for the first stage of the process. These wells were coupled with solar energy as a geothermal energy application for direct uses such as air-conditioning systems. We studied the performance of an absorption cooling system operating with a NaOH-H2O mixture and using a parabolic trough plant coupled with a low enthalpy geothermal heat system as a hybrid heat source, as an alternative process that can help reduce operating costs and carbon dioxide emissions. The numerical heat transfer results showed the maximum convective heat transfer coefficient, as function of fluid velocity, and maximum temperature for a depth higher than 40 m. The results showed that the highest temperatures occur at low fluid velocities of less than or equal to 5.0 m/s. Under these conditions, reaching temperatures between 51.0 and 56.2 °C in the well was possible, which is required of the geothermal energy for the solar energy process. A water stream was used as the working fluid in the parabolic trough collector field. During the evaluation stage, the average experimental storage tank temperature achieved by the parabolic trough plant was 93.8 °C on October 23 and 92.9 °C on October 25, 2017. The numerical simulation used to evaluate the performance of the absorption cycle used a generator

  9. Fluids in volcanic and geothermal systems

    Science.gov (United States)

    Sigvaldason, Gudmundur E.

    -rift volcanism is accordingly not fed directly by mantle derived liquids. The model predicts that all volcanic fluids, with the exception of those which are associated with the most primitive olivine tholeiites, are partly or wholly recycled through all stages of hydrothermal and metamorphic reactions. In that sense associated volcanic and geothermal systems are a part of the same chemical fractionation column. It is concluded that the chemistry of fluids in volcanic and geothermal systems can be viewed in the perspective of predictable crustal fractionation processes before any conclusion need be drawn concerning more deep seated causes for chemical anomalies.

  10. Geothermal space/water heating for Mammoth Lakes Village, California. Quarterly technical progress report, 13 December 1976-12 March 1977

    Energy Technology Data Exchange (ETDEWEB)

    Sims, A.V.; Racine, W.C.

    1977-01-01

    During the second three months of this feasibility study to determine the technical, economic and environmental feasibility of heating Mammoth Lakes Village, California using geothermal energy, the following work was accomplished. A saturation survey of the number and types of space and water heaters currently in use in the Village was completed. Electric energy and ambient temperature metering equipment was installed. Peak heating demand for Mammoth Lakes was estimated for the years 1985, 1990 and 2000. Buildings were selected which are considered typical of Mammoth Lakes in terms of their heating systems to be used in estimating the cost of installing hydronic heating systems in Mammoth. Block diagrams and an order of magnitude cost comparison were prepared for high-temperature and low-temperature geothermal district heating systems. Models depicting a geothermal district heating system and a geothermal-electric power plant were designed, built and delivered to ERDA in Washington. Local input to the feasibility study was obtained from representatives of the State of California Departments of Transportation and Fish and Game, US Forest Service, and Mono County Planning Department.

  11. Choosing a Geothermal as an HVAC System.

    Science.gov (United States)

    Lensenbigler, John D.

    2002-01-01

    Describes the process of selecting and installing geothermal water source heat pumps for new residence halls at Johnson Bible College in Knoxville, Tennessee, including choosing the type of geothermal design, contractors, and interior equipment, and cost and payback. (EV)

  12. Geothermal energy control system and method

    Science.gov (United States)

    Matthews, Hugh B.

    1977-01-01

    A geothermal energy transfer and utilization system makes use of thermal energy stored in hot solute-bearing well water to generate super-heated steam from an injected flow of clean water; the super-heated steam is then used for operating a turbine-driven pump at the well bottom for pumping the hot solute-bearing water at high pressure and in liquid state to the earth's surface, where it is used by transfer of its heat to a closed-loop boiler-turbine-alternator combination for the generation of electrical or other power. Residual concentrated solute-bearing water is pumped back into the earth. The clean cooled water is regenerated at the surface-located system and is returned to the deep well pumping system also for lubrication of a novel bearing arrangement supporting the turbine-driven pump system. The bearing system employs liquid lubricated thrust and radial bearings with all bearing surfaces bathed in clean water serving as a lubricant and maintained under pressure to prevent entry into the bearings of contaminated geothermal fluid, an auxiliary thrust ball bearing arrangement comes into operation when starting or stopping the pumping system.

  13. Reinjection of geothermal water-imperative of geothermal system Geoterma - Kochani

    International Nuclear Information System (INIS)

    Naunov, Jordan

    2007-01-01

    Geothermal locality 'Podlog-Banja' - Kochani, Republic of Macedonia, represent one of the more significant aquifers of geothermal water, not only in local frames but also in world scale, especially if we have in mind the possible capacity of exploitation of 300 l, with average temperature of 75° C. Many years of exploitation was escorted with constant irreversible drop down of piezo metric level of underground waters and because of this reason, there was a necessary of installation of reinjection system of used geothermal water, especially for two factors: Keeping of balance conditions in the underground from one side and reduction of thermal pollution to the environment especially from energetic and ecological aspect. In this written effort beside the basic information for geothermal system 'Geoterma' will be present all significant phases and elements of the system for reinjection, it's exploration, implementation, construction and of course the effects from the same one. (Author)

  14. Selected geothermal resources data: hydrothermal convection systems in the states of Alaska, Arizona, California, Colorado, Hawaii, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, Washington, and Wyoming

    Energy Technology Data Exchange (ETDEWEB)

    Renner, J.L.

    1976-02-01

    Data collected as part of the U.S. Geological Survey's research and land classification programs, from professional publications, and industry sources has been compiled in computer format. Location, surface manifestations, chemistry, physical properties, exploratory and development work, and references pertinent to 290 hydrothermal convection systems comprise the data base.

  15. Geological model of supercritical geothermal reservoir related to subduction system

    Science.gov (United States)

    Tsuchiya, Noriyoshi

    2017-04-01

    Following the Great East Japan Earthquake and the accident at the Fukushima Daiichi Nuclear power station on 3.11 (11th March) 2011, geothermal energy came to be considered one of the most promising sources of renewable energy for the future in Japan. The temperatures of geothermal fields operating in Japan range from 200 to 300 °C (average 250 °C), and the depths range from 1000 to 2000 m (average 1500 m). In conventional geothermal reservoirs, the mechanical behavior of the rocks is presumed to be brittle, and convection of the hydrothermal fluid through existing network is the main method of circulation in the reservoir. In order to minimize induced seismicity, a rock mass that is "beyond brittle" is one possible candidate, because the rock mechanics of "beyond brittle" material is one of plastic deformation rather than brittle failure. Supercritical geothermal resources could be evaluated in terms of present volcanic activities, thermal structure, dimension of hydrothermal circulation, properties of fracture system, depth of heat source, depth of brittle factures zone, dimension of geothermal reservoir. On the basis of the GIS, potential of supercritical geothermal resources could be characterized into the following four categories. 1. Promising: surface manifestation d shallow high temperature, 2 Probability: high geothermal gradient, 3 Possibility: Aseismic zone which indicates an existence of melt, 4 Potential : low velocity zone which indicates magma input. Base on geophysical data for geothermal reservoirs, we have propose adequate tectonic model of development of the supercritical geothermal reservoirs. To understand the geological model of a supercritical geothermal reservoir, granite-porphyry system, which had been formed in subduction zone, was investigated as a natural analog of the supercritical geothermal energy system. Quartz veins, hydrothermal breccia veins, and glassy veins are observed in a granitic body. The glassy veins formed at 500-550

  16. IKEA Geothermal System Could Inform Others | News | NREL

    Science.gov (United States)

    0 » IKEA Geothermal System Could Inform Others IKEA Geothermal System Could Inform Others August 500 feet under the IKEA store construction site in Centennial, Colo. Credit: Pat Corkery It will take less energy and money to make the IKEA store opening next year in suburban Denver feel pleasant when

  17. Geological, Geophysical, And Thermal Characteristics Of The Salton Sea Geothermal Field, California

    Energy Technology Data Exchange (ETDEWEB)

    Younker, L.W.; Kasameyer, P. W.; Tewhey, J. D.

    1981-01-01

    The Salton Sea Geothermal Field is the largest water-dominated geothermal field in the Salton Trough in Southern California. Within the trough, local zones of extension among active right-stepping right-lateral strike-slip faults allow mantle-derived magmas to intrude the sedimentary sequence. The intrusions serves as heat sources to drive hydrothermal systems. We can characterize the field in detail because we have an extensive geological and geophysical data base. The sediments are relatively undeformed and can be divided into three categories as a function of depth: (1) low-permeability cap rock, (2) upper reservoir rocks consisting of sandstones, siltstones, and shales that were subject to minor alterations, and (3) lower reservoir rocks that were extensively altered. Because of the alteration, intergranular porosity and permeability are reduced with depth. permeability is enhanced by renewable fractures, i.e., fractures that can be reactivated by faulting or natural hydraulic fracturing subsequent to being sealed by mineral deposition. In the central portion of the field, temperature gradients are high near the surface and lower below 700 m. Surface gradients in this elliptically shaped region are fairly constant and define a thermal cap, which does not necessarily correspond to the lithologic cap. At the margin of the field, a narrow transition region, with a low near-surface gradient and an increasing gradient at greater depths, separates the high temperature resource from areas of normal regional gradient. Geophysical and geochemical evidence suggest that vertical convective motion in the reservoir beneath the thermal cap is confined to small units, and small-scale convection is superimposed on large-scale lateral flow of pore fluid. Interpretation of magnetic, resistivity, and gravity anomalies help to establish the relationship between the inferred heat source, the hydrothermal system, and the observed alteration patterns. A simple hydrothermal model is

  18. National Geothermal Data System: A Geothermal Data System for Exploration and Development

    Energy Technology Data Exchange (ETDEWEB)

    Allison, Lee [Executive Office of the State of Arizona (Arizona Geological Survey); Richard, Stephen [Executive Office of the State of Arizona (Arizona Geological Survey); Patten, Kim [Executive Office of the State of Arizona (Arizona Geological Survey); Love, Diane [Executive Office of the State of Arizona (Arizona Geological Survey); Coleman, Celia [Executive Office of the State of Arizona (Arizona Geological Survey); Chen, Genhan [Executive Office of the State of Arizona (Arizona Geological Survey)

    2012-09-30

    Geothermal-relevant geosciences data from all 50 states (www.stategeothermaldata.org), federal agencies, national labs, and academic centers are being digitized and linked in a distributed online network funded by the U.S. Department of Energy Geothermal Data System (GDS) to foster geothermal energy exploration and development through use of interactive online ‘mashups,’data integration, and applications. Emphasis is first to make as much information as possible accessible online, with a long range goal to make data interoperable through standardized services and interchange formats. A growing set of more than thirty geoscience data content models is in use or under development to define standardized interchange formats for: aqueous chemistry, borehole temperature data, direct use feature, drill stem test, seismic event hypocenter, fault feature, geologic contact feature, geologic unit feature, thermal/hot spring description, metadata, quaternary fault, volcanic vent description, well header feature, borehole lithology log, crustal stress, gravity, heat flow/temperature gradient, permeability, and feature description data like developed geothermal systems, geologic unit geothermal characterization, permeability, production data, rock alteration description, rock chemistry, and thermal conductivity. Map services are also being developed for isopach maps, aquifer temperature maps, and several states are working on geothermal resource overview maps. Content models are developed based on existing community datasets to encourage widespread adoption and promulgate content quality standards. Geoscience data and maps from other GDS participating institutions, or “nodes” (e.g., U.S. Geological Survey, Southern Methodist University, Oregon Institute of Technology, Stanford University, the University of Utah) are being supplemented with extensive land management and land use resources from the Western Regional Partnership (15 federal agencies and 5 Western states) to

  19. Hydrogeology of the Krafla geothermal system, northeast Iceland

    DEFF Research Database (Denmark)

    Pope, Emily Catherine; Bird, D. K.; Arnórsson, S.

    2016-01-01

    The Krafla geothermal system is located in Iceland's northeastern neovolcanic zone, within the Krafla central volcanic complex. Geothermal fluids are superheated steam closest to the magma heat source, two-phase at higher depths, and sub-boiling at the shallowest depths. Hydrogen isotope ratios...... of geothermal fluids range from -87‰, equivalent to local meteoric water, to -94‰. These fluids are enriched in 18O relative to the global meteoric line by +0.5-3.2‰. Calculated vapor fractions of the fluids are 0.0-0.5 wt% (~0-16% by volume) in the northwestern portion of the geothermal system and increase...... the benefits of combining phase segregation effects in two-phase systems during analysis of wellhead fluid data with stable isotope values of hydrous alteration minerals when evaluating the complex hydrogeology of volcano-hosted geothermal systems....

  20. On-line corrosion monitoring in geothermal district heating systems

    DEFF Research Database (Denmark)

    Richter, S.; Hilbert, Lisbeth Rischel; Thorarinsdottir, R.I.

    2006-01-01

    General corrosion rates in the geothermal district heating systems in Iceland are generally low, of the magnitude 1 lm/y. The reason is high pH (9.5), low-conductivity (200 lm/y) and negligible dissolved oxygen. The geothermal hot water is either used directly from source or to heat up cold ground...

  1. The significance of "geothermal microzonation" for the correct planning of low-grade source geothermal systems

    Science.gov (United States)

    Viccaro, Marco; Pezzino, Antonino; Belfiore, Giuseppe Maria; Campisano, Carlo

    2016-04-01

    Despite the environmental-friendly energy systems are solar thermal technologies, photovoltaic and wind power, other advantageous technologies exist, although they have not found wide development in countries such as Italy. Given the almost absent environmental impact and the rather favorable cost/benefit ratio, low-enthalpy geothermal systems are, however, likely to be of strategic importance also in Italy during the next years. The importance of geology for a sustainable exploitation of the ground through geothermal systems from low-grade sources is becoming paramount. Specifically, understanding of the lithological characteristics of the subsurface along with structures and textures of rocks is essential for a correct planning of the probe/geo-exchanger field and their associated ground source heat pumps. The complex geology of Eastern Sicily (Southern Italy), which includes volcanic, sedimentary and metamorphic units over limited extension, poses the question of how thermal conductivity of rocks is variable at the scale of restricted areas (even within the same municipality). This is the innovative concept of geothermal microzonation, i.e., how variable is the geothermal potential as a function of geology at the microscale. Some pilot areas have been therefore chosen to test how the geological features of the subsurface can influence the low-enthalpy geothermal potential of an area. Our geologically based evaluation and micro-zonation of the low-grade source geothermal potential of the selected areas have been verified to be fundamental for optimization of all the main components of a low-enthalpy geothermal system. Saving realization costs and limiting the energy consumption through correct sizing of the system are main ambitions to have sustainable development of this technology with intensive utilization of the subsurface. The variegated territory of countries such as Italy implies that these goals can be only reached if, primarily, the geological features

  2. RiverHeath: Neighborhood Loop Geothermal Exchange System

    Energy Technology Data Exchange (ETDEWEB)

    Geall, Mark [RiverHeath LLC, Appleton, WI (United States)

    2016-07-11

    The goal of the RiverHeath project is to develop a geothermal exchange system at lower capital infrastructure cost than current geothermal exchange systems. The RiverHeath system features an innovative design that incorporates use of the adjacent river through river-based heat exchange plates. The flowing water provides a tremendous amount of heat transfer. As a result, the installation cost of this geothermal exchange system is lower than more traditional vertical bore systems. Many urban areas are located along rivers and other waterways. RiverHeath will serve as a template for other projects adjacent to the water.

  3. Radon and temperature as tracer of geothermal flow system: application to Arxan geothermal system, Northeastern China

    Science.gov (United States)

    Gu, X.; Shao, J.; Cui, Y.

    2017-12-01

    In this work, hydrogeological and hydrochemical investigations were applied to explain geothermal system factors controlling groundwater mineralization in Arxan geothermal system, Northeastern China. Geothermal water samples were collected from different locations (thermal baths and wells). Radon concentrations of water samples representing different water types and depths were controlled using RAD7. In addition to radon concentration, physical parameters such as temperature (T), pH, electrical conductivity (EC) and TDS were measured in situ, while major ions were analyzed in laboratory. Temperature spatial variability in the study area was described using kriging interpolation method. Hydrochemical analysis and thermal parameters suggest two distinct hydrogeological systems. The first type was dominated by a moderate temperature (25 41°C) with a chemical facies Na-HCO3, which characterizes Jurassic deep water. The second water type was characterized by Ca.Na-HCO3 type with a temperature <25 °C and represents the shallow aquifer. Superficial aquifer displays higher radon concentration (37 to 130 Bq/L), while deep groundwater from Jurassic aquifer shows relatively a low radon concentration (6 to 57.4 Bq/L). Seasonal and geographical variations of radon give insight into the processes controlling radon activities in the Arxan groundwater. Radon concentrations along with spatial distribution of water temperature reveal the existence of vertical communication between shallow aquifer and deep Jurassic aquifer through vertical faults and fractures system, the emanation of radon from thermal water and groundwater is controlled by the geological structure of the area. Furthermore, the knowledge and conclusion demonstrates that combined use of radon and temperature as tracers can give insight into the characteristics of geological structure and geothermal flow system.

  4. A Technology Roadmap for Strategic Development of Enhanced Geothermal Systems

    Energy Technology Data Exchange (ETDEWEB)

    Ziagos, John [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Phillips, Benjamin R. [SRA International, Inc. and Geothermal Technologies Office, Washington, DC (United States); Boyd, Lauren [Geothermal Technologies Office, Washington, DC (United States); Jelacic, Allan [SRA International, Inc., Washington, DC (United States); Stillman, Greg [Geothermal Technologies Office, Washington, DC (United States); Hass, Eric [U.S. DOE, Golden, CO (United States)

    2013-02-13

    Realization of EGS development would make geothermal a significant contender in the renewable energy portfolio, on the order of 100+ GWe in the United States alone. While up to 90% of the geothermal power resource in the United States is thought to reside in Enhanced Geothermal Systems (EGS), hurdles to commercial development still remain. The Geothermal Technologies Office, U.S. Department of Energy (DOE), began in 2011 to outline opportunities for advancing EGS technologies on five- to 20-year timescales, with community input on the underlying technology needs that will guide research and ultimately determine commercial success for EGS. This report traces DOE's research investments, past and present, and ties them to these technology needs, forming the basis for an EGS Technology Roadmap to help guide future DOE research. This roadmap is currently open for public comment. Send your comments to geothermal@ee.doe.gov.

  5. Identification of environmental issues: Hybrid wood-geothermal power plant, Wendel-Amedee KGRA, Lassen County, California: First phase report

    Energy Technology Data Exchange (ETDEWEB)

    1981-08-14

    The development of a 55 MWe power plant in Lassen County, California, has been proposed. The proposed power plant is unique in that it will utilize goethermal heat and wood fuel to generate electrical power. This report identifies environmental issues and constraints which may impact the proposed hybrid wood-geothermal power plant. (ACR)

  6. Geothermal heat-pump systems of heat supply

    International Nuclear Information System (INIS)

    Vasil'ev, G.P.

    2004-01-01

    The data on the multilayer operation of the objects, located in the climatic conditions of the central area of Russia and equipped with the geothermal heat-pumping systems of the heat supply are presented. The results of the analytical studies on evaluating the geothermal heat-pumping systems of the heat supply integration efficiency into the structure of the energy supply system, prevailing in the country, are presented [ru

  7. 36Cl/Cl ratios in geothermal systems: preliminary measurements from the Coso Field

    International Nuclear Information System (INIS)

    Nimz, G.J.; Moore, J.N.; Kasameyer, P.W.

    1997-01-01

    The 36 Cl/Cl isotopic composition of chlorine in geothermal systems can be a useful diagnostic tool in characterizing hydrologic structure, in determining the origins and age of waters within the systems, and in differentiating the sources of chlorine (and other solutes) in the thermal waters. The 36 Cl/Cl values for several geothermal water samples and reservoir host rock samples from the Coso, California geothermal field have been measured for these purposes. The results indicate that most of the chlorine is not derived from the dominant granitoid that host the geothermal system. If the chlorine was originally input into the Coso subsurface through meteoric recharge, that input occurred at least 1-1.25 million years ago. The results suggest that the thermal waters could be connate waters derived from sedimentary formations, presumably underlying and adjacent top the granitic rocks, which have recently migrated into the host rocks. Alternatively, most of the chlorine but not the water, may have recently input into the system from magmatic sources. In either case, the results indicate that most of the chlorine in the thermal waters has existed within the granitoid host rocks for no more than about 100,00-200,00 years. this residence time for the chlorine is similar to residence times suggested by other researchers for chlorine in deep groundwaters of the Mono Basin north of the Coso field

  8. 36Cl/Cl ratios in geothermal systems: preliminary measurements from the Coso Field

    Energy Technology Data Exchange (ETDEWEB)

    Nimz, G.J.; Moore, J.N.; Kasameyer, P.W.

    1997-07-01

    The {sub 36}Cl/Cl isotopic composition of chlorine in geothermal systems can be a useful diagnostic tool in characterizing hydrologic structure, in determining the origins and age of waters within the systems, and in differentiating the sources of chlorine (and other solutes) in the thermal waters. The {sub 36}Cl/Cl values for several geothermal water samples and reservoir host rock samples from the Coso, California geothermal field have been measured for these purposes. The results indicate that most of the chlorine is not derived from the dominant granitoid that host the geothermal system. If the chlorine was originally input into the Coso subsurface through meteoric recharge, that input occurred at least 1-1.25 million years ago. The results suggest that the thermal waters could be connate waters derived from sedimentary formations, presumably underlying and adjacent top the granitic rocks, which have recently migrated into the host rocks. Alternatively, most of the chlorine but not the water, may have recently input into the system from magmatic sources. In either case, the results indicate that most of the chlorine in the thermal waters has existed within the granitoid host rocks for no more than about 100,00-200,00 years. this residence time for the chlorine is similar to residence times suggested by other researchers for chlorine in deep groundwaters of the Mono Basin north of the Coso field.

  9. Potential for enhanced geothermal systems in Alberta, Canada

    International Nuclear Information System (INIS)

    Hofmann, Hannes; Weides, Simon; Babadagli, Tayfun; Zimmermann, Günter; Moeck, Inga; Majorowicz, Jacek; Unsworth, Martyn

    2014-01-01

    The province of Alberta has a high demand of thermal energy for both industrial and residential applications. Currently, the vast majority of the heat used in these applications is obtained by burning natural gas. Geothermal energy production from deep aquifer systems in the sedimentary basin could provide an alternative sustainable source of heat that would significantly reduce greenhouse gas emissions. To date there has been no geothermal field development in Alberta because the average geothermal gradient was considered to be too low for economic geothermal energy generation. However, with new technologies for Enhanced Geothermal Systems (EGS), it may be possible to develop geothermal resources from the sedimentary rocks in the Western Canadian Sedimentary Basin (WCSB). A numerical feasibility study based on a regional geological model and existing and newly gained data was conducted to identify scenarios for geothermal energy production in the region. In central Alberta, three Devonian carbonate formations (Cooking Lake, Nisku, Wabamun) and the Cambrian Basal Sandstone Unit were identified as the highest geothermal potential zones. Thermal-hydraulic reservoir simulations for a 5 km × 5 km site in the city of Edmonton were performed to evaluate reservoir development concepts for these four potential target formations; therefore, hydraulic fracturing treatments were also simulated. Different utilization concepts are presented for possible applications of geothermal energy generation in residential, industrial and agricultural areas. The Cooking Lake formation and the Basal Sandstone Unit are potentially the most promising reservoirs because the most heat can be extracted and the applications for the heat are widespread although the costs are higher than utilizing the shallower formations. Reservoir stimulation considerably improves the economics in all formations

  10. National Geothermal Data System: Interactive Assessment of Geothermal Energy Potential in the U.S.

    Energy Technology Data Exchange (ETDEWEB)

    Allison, Lee [Executive Office of the State of Arizona (Arizona Geological Survey); Richard, Stephen [Executive Office of the State of Arizona (Arizona Geological Survey); Clark, Ryan; Patten, Kim; Love, Diane; Coleman, Celia; Chen, Genhan; Matti, Jordan; Pape, Estelle; Musil, Leah

    2012-01-30

    Geothermal-relevant geosciences data from all 50 states (www.stategeothermaldata.org), federal agencies, national labs, and academic centers are being digitized and linked in a distributed online network via the U.S. Department of Energy-funded National Geothermal Data System (NGDS) to foster geothermal energy exploration and development through use of interactive online ‘mashups,’data integration, and applications. Emphasis is first to make as much information as possible accessible online, with a long range goal to make data interoperable through standardized services and interchange formats. An initial set of thirty geoscience data content models is in use or under development to define a standardized interchange format: aqueous chemistry, borehole temperature data, direct use feature, drill stem test, earthquake hypocenter, fault feature, geologic contact feature, geologic unit feature, thermal/hot spring description, metadata, quaternary fault, volcanic vent description, well header feature, borehole lithology log, crustal stress, gravity, heat flow/temperature gradient, permeability, and feature descriptions data like developed geothermal systems, geologic unit geothermal properties, permeability, production data, rock alteration description, rock chemistry, and thermal conductivity. Map services are also being developed for isopach maps, aquifer temperature maps, and several states are working on geothermal resource overview maps. Content models are developed preferentially from existing community use in order to encourage widespread adoption and promulgate minimum metadata quality standards. Geoscience data and maps from other NGDS participating institutions, or “nodes” (USGS, Southern Methodist University, Boise State University Geothermal Data Coalition) are being supplemented with extensive land management and land use resources from the Western Regional Partnership (15 federal agencies and 5 Western states) to provide access to a comprehensive

  11. Direct use applications of geothermal resources at Desert Hot Springs, California. Final report, May 23, 1977--July 31, 1978. Volume II: appendixes

    Energy Technology Data Exchange (ETDEWEB)

    Christiansen, C.C.

    1978-07-01

    The following appendixes are included: Desert Hot Springs (DHS) Geothermal Project Advisory Board, Geothermal Citizens Advisory Committee, community needs assessment, geothermal resource characterization, a detailed discussion of the geothermal applications considered for DHS, space/water heating, agricultural operations, detailed analysis of a geothermal aquaculture facility, detailed discussion of proposed energy cascading systems for DHS, regulatory requirements, environmental impact assessment, resource management plan, and geothermal resources property rights and powers of cities to regulate indigenous geothermal resources and to finance construction of facilities for utilization of such resources. (MHR)

  12. Monitoring reservoir response to earthquakes and fluid extraction, Salton Sea geothermal field, California

    Science.gov (United States)

    Taira, Taka’aki; Nayak, Avinash; Brenguier, Florent; Manga, Michael

    2018-01-01

    Continuous monitoring of in situ reservoir responses to stress transients provides insights into the evolution of geothermal reservoirs. By exploiting the stress dependence of seismic velocity changes, we investigate the temporal evolution of the reservoir stress state of the Salton Sea geothermal field (SSGF), California. We find that the SSGF experienced a number of sudden velocity reductions (~0.035 to 0.25%) that are most likely caused by openings of fractures due to dynamic stress transients (as small as 0.08 MPa and up to 0.45 MPa) from local and regional earthquakes. Depths of velocity changes are estimated to be about 0.5 to 1.5 km, similar to the depths of the injection and production wells. We derive an empirical in situ stress sensitivity of seismic velocity changes by relating velocity changes to dynamic stresses. We also observe systematic velocity reductions (0.04 to 0.05%) during earthquake swarms in mid-November 2009 and late-December 2010. On the basis of volumetric static and dynamic stress changes, the expected velocity reductions from the largest earthquakes with magnitude ranging from 3 to 4 in these swarms are less than 0.02%, which suggests that these earthquakes are likely not responsible for the velocity changes observed during the swarms. Instead, we argue that velocity reductions may have been induced by poroelastic opening of fractures due to aseismic deformation. We also observe a long-term velocity increase (~0.04%/year) that is most likely due to poroelastic contraction caused by the geothermal production. Our observations demonstrate that seismic interferometry provides insights into in situ reservoir response to stress changes. PMID:29326977

  13. Monitoring reservoir response to earthquakes and fluid extraction, Salton Sea geothermal field, California.

    Science.gov (United States)

    Taira, Taka'aki; Nayak, Avinash; Brenguier, Florent; Manga, Michael

    2018-01-01

    Continuous monitoring of in situ reservoir responses to stress transients provides insights into the evolution of geothermal reservoirs. By exploiting the stress dependence of seismic velocity changes, we investigate the temporal evolution of the reservoir stress state of the Salton Sea geothermal field (SSGF), California. We find that the SSGF experienced a number of sudden velocity reductions (~0.035 to 0.25%) that are most likely caused by openings of fractures due to dynamic stress transients (as small as 0.08 MPa and up to 0.45 MPa) from local and regional earthquakes. Depths of velocity changes are estimated to be about 0.5 to 1.5 km, similar to the depths of the injection and production wells. We derive an empirical in situ stress sensitivity of seismic velocity changes by relating velocity changes to dynamic stresses. We also observe systematic velocity reductions (0.04 to 0.05%) during earthquake swarms in mid-November 2009 and late-December 2010. On the basis of volumetric static and dynamic stress changes, the expected velocity reductions from the largest earthquakes with magnitude ranging from 3 to 4 in these swarms are less than 0.02%, which suggests that these earthquakes are likely not responsible for the velocity changes observed during the swarms. Instead, we argue that velocity reductions may have been induced by poroelastic opening of fractures due to aseismic deformation. We also observe a long-term velocity increase (~0.04%/year) that is most likely due to poroelastic contraction caused by the geothermal production. Our observations demonstrate that seismic interferometry provides insights into in situ reservoir response to stress changes.

  14. Ground Source Geothermal District Heating and Cooling System

    Energy Technology Data Exchange (ETDEWEB)

    Lowe, James William [Ball State Univ., Muncie, IN (United States)

    2016-10-21

    Ball State University converted its campus from a coal-fired steam boiler district heating system to a ground source heat pump geothermal district system that produces simultaneously hot water for heating and chilled water for cooling. This system will include the installation of 3,600 four hundred feet deep vertical closed loop boreholes making it the largest ground source geothermal district system in the country. The boreholes will act as heat exchangers and transfer heat by virtue of the earth’s ability to maintain an average temperature of 55 degree Fahrenheit. With growing international concern for global warming and the need to reduce worldwide carbon dioxide loading of the atmosphere geothermal is poised to provide the means to help reduce carbon dioxide emissions. The shift from burning coal to utilizing ground source geothermal will increase electrical consumption but an overall decrease in energy use and reduction in carbon dioxide output will be achieved. This achievement is a result of coupling the ground source geothermal boreholes with large heat pump chiller technology. The system provides the thermodynamic means to move large amounts of energy with limited energy input. Ball State University: http://cms.bsu.edu/About/Geothermal.aspx

  15. Radiator Enhanced Geothermal System - A Revolutionary Method for Extracting Geothermal Energy

    Science.gov (United States)

    Karimi, S.; Marsh, B. D.; Hilpert, M.

    2017-12-01

    A new method of extracting geothermal energy, the Radiator Enhanced Geothermal System (RAD-EGS) has been developed. RAD-EGS attempts to mimic natural hydrothermal systems by 1) generating a vertical vane of artificially produced high porosity/permeability material deep in a hot sedimentary aquifer, 2) injecting water at surface temperatures to the bottom of the vane, where the rock is the hottest, 3) extracting super-heated water at the top of the vane. The novel RAD-EGS differs greatly from the currently available Enhanced Geothermal Systems in vane orientation, determined in the governing local crustal stress field by Shmax and Sl (meaning it is vertical), and in the vane location in a hot sedimentary aquifer, which naturally increases the longevity of the system. In this study, we explore several parameters regimes affecting the water temperature in the extraction well, keeping in mind that the minimum temperature of the extracted water has to be 150 °C in order for a geothermal system to be commercially viable. We used the COMSOL finite element package to simulate coupled heat and fluid transfer within the RAD-EGS model. The following geologic layers from top to bottom are accounted for in the model: i) confining upper layer, ii) hot sedimentary aquifer, and iii) underlying basement rock. The vane is placed vertically within the sedimentary aquifer. An injection well and an extraction well are also included in the simulation. We tested the model for a wide range of various parameters including background heat flux, thickness of geologic layers, geometric properties of the vane, diameter and location of the wells, fluid flow within the wells, regional hydraulic gradient, and permeability and porosity of the layers. The results show that among the aforementioned parameters, background heat flux and the depth of vane emplacement are highly significant in determining the level of commercial viability of the geothermal system. These results indicate that for the

  16. Implementing Geothermal Plants in the Copenhagen District Heating System

    DEFF Research Database (Denmark)

    Jensen, Louise Overvad; Hallgreen, Christine Erikstrup; Larsen, Esben

    2003-01-01

    of geothermal energy in Denmark as well as the Danish potential, which, in former investigations, has been found to be around 100.000 PJ annually, and the economical potential is less, about 15 PJ/year. Since a considerable amount of the Danish power supply is tied to weather and the demand for heating......The possibility of implementing geothermal heating in the Copenhagen district-heating system is assessed. This is done by building up general knowledge on the geological factors that influence the development of useable geothermal resources, factors concerning the exploration and utilization......, an increasing demand for flexibility has been raised. Implementing geothermal heating would improve the flexibility in the Eastern Danish power system. Based on this information, as well as, on the hourly values of the expected production and consumption in 2010 and 2020, a model of the Copenhagen power...

  17. Land subsidence caused by the East Mesa geothermal field, California, observed using SAR interferometry

    Science.gov (United States)

    Massonnet, D.; Holzer, T.; Vadon, H.

    1997-01-01

    Interferometric combination of pairs of synthetic aperture radar (SAR) images acquired by the ERS-1 satellite maps the deformation field associated with the activity of the East Mesa geothermal plant, located in southern California. SAR interferometry is applied to this flat area without the need of a digital terrain model. Several combinations are used to ascertain the nature of the phenomenon. Short term interferograms reveal surface phase changes on agricultural fields similar to what had been observed previously with SEASAT radar data. Long term (2 years) interferograms allow the study of land subsidence and improve prior knowledge of the displacement field, and agree with existing, sparse levelling data. This example illustrates the power of the interferometric technique for deriving accurate industrial intelligence as well as its potential for legal action, in cases involving environmental damages. Copyright 1997 by the American Geophysical Union.

  18. Investigating ultra high-enthalpy geothermal systems: a collaborative initiative to promote scientific opportunities

    Science.gov (United States)

    Elders, W. A.; Nielson, D.; Schiffman, P.; Schriener, A., Jr.

    2014-12-01

    Scientists, engineers, and policy makers gathered at a workshop in the San Bernardino Mountains of southern California in October 2013 to discuss the science and technology involved in developing high-enthalpy geothermal fields. A typical high-enthalpy geothermal well between 2000 and 3000 m deep produces a mixture of hot water and steam at 200-300 °C that can be used to generate about 5-10 MWe of electric power. The theme of the workshop was to explore the feasibility and economic potential of increasing the power output of geothermal wells by an order of magnitude by drilling deeper to reach much higher pressures and temperatures. Development of higher enthalpy geothermal systems for power production has obvious advantages; specifically higher temperatures yield higher power outputs per well so that fewer wells are needed, leading to smaller environmental footprints for a given size of power plant. Plans for resource assessment and drilling in such higher enthalpy areas are already underway in Iceland, New Zealand, and Japan. There is considerable potential for similar developments in other countries that already have a large production of electricity from geothermal steam, such as Mexico, the Philippines, Indonesia, Italy, and the USA. However drilling deeper involves technical and economic challenges. One approach to mitigating the cost issue is to form a consortium of industry, government and academia to share the costs and broaden the scope of investigation. An excellent example of such collaboration is the Iceland Deep Drilling Project (IDDP), which is investigating the economic feasibility of producing electricity from supercritical geothermal reservoirs, and this approach could serve as model for future developments elsewhere. A planning committee was formed to explore creating a similar initiative in the USA.

  19. Geothermal probabilistic cost study

    Energy Technology Data Exchange (ETDEWEB)

    Orren, L.H.; Ziman, G.M.; Jones, S.C.; Lee, T.K.; Noll, R.; Wilde, L.; Sadanand, V.

    1981-08-01

    A tool is presented to quantify the risks of geothermal projects, the Geothermal Probabilistic Cost Model (GPCM). The GPCM model is used to evaluate a geothermal reservoir for a binary-cycle electric plant at Heber, California. Three institutional aspects of the geothermal risk which can shift the risk among different agents are analyzed. The leasing of geothermal land, contracting between the producer and the user of the geothermal heat, and insurance against faulty performance are examined. (MHR)

  20. Isotope and hydrogeochemical studies of southern Jiangxi geothermal systems, China

    International Nuclear Information System (INIS)

    Zhou Wenbin; Li Xueli; Shi Weijun; Sun Zhanxue

    1999-01-01

    Southern Jiangxi is a geothermally active region, especially in Hengjing area. According to the work plan of IAEA Regional Collaboration in the Development of Geothermal Energy Resources and Environment Management through Isotope Techniques in East Asia and the Pacific (RAS-8-075), field investigation was carried out in Hengjing, southern Jiangxi Province, to demonstrate the use of isotope and geochemical techniques in low to medium temperature geothermal system. During the field investigation, 19 samples were taken from cold springs, hot springs and surface water in the area to determine their hydrochemical and gas compositions, hydrogen, oxygen, carbon and helium isotopes. The results of the study have shown that the geothermal waters in the studying region are of the same characteristics with the local meteoric water in oxygen and hydrogen isotope composition, indicating the geothermal waters are mainly derived from the local precipitation, while the gas composition and carbon and helium isotopes reveal that some gases in the geothermal waters have mantle origin. (author)

  1. The Newcastle geothermal system, Iron County, Utah

    Energy Technology Data Exchange (ETDEWEB)

    Blackett, R.E.; Shubat, M.A.; Bishop, C.E. (Utah Geological and Mineral Survey, Salt Lake City, UT (USA)); Chapman, D.S.; Forster, C.B.; Schlinger, C.M. (Utah Univ., Salt Lake City, UT (USA). Dept. of Geology and Geophysics)

    1990-03-01

    Geological, geophysical and geochemical studies contributed to conceptual hydrologic model of the blind'' (no surface expression), moderate-temperature (greater than 130{degree}C) Newcastle geothermal system, located in the Basin and Range-Colorado Plateau transition zone of southwestern Utah. Temperature gradient measurements define a thermal anomaly centered near the surface trace of the range-bounding Antelope Range fault with and elongate dissipative plume extending north into the adjacent Escalante Valley. Spontaneous potential and resistivity surveys sharply define the geometry of the dominant upflow zone (not yet explored), indicating that most of the thermal fluid issues form a short segment along the Antelope Range fault and discharges into a gently-dipping aquifer. Production wells show that this aquifer lies at a depth between 85 and 95 meter. Electrical surveys also show that some leakage of thermal fluid occurs over a 1.5 km (minimum) interval along the trace of the Antelope Range fault. Major element, oxygen and hydrogen isotopic analyses of water samples indicate that the thermal fluid is a mixture of meteoric water derived from recharge areas in the Pine Valley Mountains and cold, shallow groundwater. A northwest-southeast trending system of faults, encompassing a zone of increased fracture permeability, collects meteoric water from the recharge area, allows circulation to a depth of 3 to 5 kilometers, and intersects the northeast-striking Antelope Range fault. We postulate that mineral precipitates form a seal along the Antelope Range fault, preventing the discharge of thermal fluids into basin-fill sediments at depth, and allowing heated fluid to approach the surface. Eventually, continued mineral deposition could result in the development of hot springs at the ground surface.

  2. Temporary Cementitious Sealers in Enhanced Geothermal Systems

    Energy Technology Data Exchange (ETDEWEB)

    Sugama T.; Pyatina, T.; Butcher, T.; Brothers, L.; Bour, D.

    2011-12-31

    Unlike conventional hydrothennal geothermal technology that utilizes hot water as the energy conversion resources tapped from natural hydrothermal reservoir located at {approx}10 km below the ground surface, Enhanced Geothermal System (EGS) must create a hydrothermal reservoir in a hot rock stratum at temperatures {ge}200 C, present in {approx}5 km deep underground by employing hydraulic fracturing. This is the process of initiating and propagating a fracture as well as opening pre-existing fractures in a rock layer. In this operation, a considerable attention is paid to the pre-existing fractures and pressure-generated ones made in the underground foundation during drilling and logging. These fractures in terms of lost circulation zones often cause the wastage of a substantial amount of the circulated water-based drilling fluid or mud. Thus, such lost circulation zones must be plugged by sealing materials, so that the drilling operation can resume and continue. Next, one important consideration is the fact that the sealers must be disintegrated by highly pressured water to reopen the plugged fractures and to promote the propagation of reopened fractures. In response to this need, the objective of this phase I project in FYs 2009-2011 was to develop temporary cementitious fracture sealing materials possessing self-degradable properties generating when {ge} 200 C-heated scalers came in contact with water. At BNL, we formulated two types of non-Portland cementitious systems using inexpensive industrial by-products with pozzolanic properties, such as granulated blast-furnace slag from the steel industries, and fly ashes from coal-combustion power plants. These byproducts were activated by sodium silicate to initiate their pozzolanic reactions, and to create a cemetitious structure. One developed system was sodium silicate alkali-activated slag/Class C fly ash (AASC); the other was sodium silicate alkali-activated slag/Class F fly ash (AASF) as the binder of temper

  3. Calc-silicate mineralization in active geothermal systems

    Energy Technology Data Exchange (ETDEWEB)

    Bird, D.K.; Schiffman, P.; Elders, W.A.; Williams, A.E.; McDowell, S.D.

    1983-01-01

    The detailed study of calc-silicate mineral zones and coexisting phase relations in the Cerro Prieto geothermal system were used as examples for thermodynamic evaluation of phase relations among minerals of variable composition and to calculate the chemical characteristics of hydrothermal solutions compatible with the observed calc-silicate assemblages. In general there is a close correlation between calculated and observed fluid compositions. Calculated fugacities of O{sub 2} at about 320{degrees}C in the Cerro Prieto geothermal system are about five orders of magnitude less than that at the nearby Salton Sea geothermal system. This observation is consistent with the occurrence of Fe{sup 3+} rich epidotes in the latter system and the presence of prehnite at Cerro Prieto.

  4. Environmental impact directory system: preliminary implementation for geothermal energy

    Energy Technology Data Exchange (ETDEWEB)

    Hess, F.D.; Hall, R.T.; Fullenwider, E.D.

    1976-07-01

    An Environmental Impact Directory System (EIDS) was proposed as a method for a computerized search of the widely distributed data files and models pertaining to energy-related environmental effects. To define the scope and content of the system, an example was prepared for the case of geothermal energy. The resulting sub-directory is known as GEIDs (Geothermal Environmental Impact Directory System). In preparing or reviewing an Environmental Impact Statement (EIS), the user may employ GEIDS as an extensive checklist to make sure he has taken into account all predictable impacts at any level of severity.

  5. Geothermal in transition

    International Nuclear Information System (INIS)

    Anderson, J.L.

    1991-01-01

    This article examines the current market for geothermal projects in the US and overseas. The topics of the article include future capacity needs, upgrading the Coso Geothermal project, the productivity of the Geysers area of Northern California, the future of geothermal, and new projects at Soda Lake, Carson Basin, Unalaska Island, and the Puna Geothermal Venture in Hilo, Hawaii

  6. California community water systems inventory dataset, 2010

    Data.gov (United States)

    California Environmental Health Tracking Program — This data set contains information about all Community Water Systems in California. Data are derived from California Office of Drinking Water (ODW) Water Quality...

  7. Companion Study Guide to Short Course on Geothermal Corrosion and Mitigation in Low Temperature Geothermal Heating Systems

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, II, P F

    1985-04-24

    The economic utilization of geothermal resources with temperatures less than 220 degrees Fahrenheit for purposes other than electric power generation (direct utilization) requires creation of systems with long plant life and minimum operation and maintenance costs. Development of such systems requires careful corrosion engineering if the most cost effective material selections and design choices are to be made. This study guide presents guidelines for materials selection for low-temperature geothermal systems (120 - 200 degrees Fahrenheit), as well as guidance in materials design of heat pump systems for very-lowtemperature geothermal resources (less than 120 degrees Fahrenheit). This guideline is divided into five sections and an Appendix.

  8. Standard Guide for Specifying Thermal Performance of Geothermal Power Systems

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2000-01-01

    1.1 This guide covers power plant performance terms and criteria for use in evaluation and comparison of geothermal energy conversion and power generation systems. The special nature of these geothermal systems makes performance criteria commonly used to evaluate conventional fossil fuel-fired systems of limited value. This guide identifies the limitations of the less useful criteria and defines an equitable basis for measuring the quality of differing thermal cycles and plant equipment for geothermal resources. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  9. Groundwater Monitoring and Engineered Geothermal Systems: The Newberry EGS Demonstration

    Science.gov (United States)

    Grasso, K.; Cladouhos, T. T.; Garrison, G.

    2013-12-01

    Engineered Geothermal Systems (EGS) represent the next generation of geothermal energy development. Stimulation of multiple zones within a single geothermal reservoir could significantly reduce the cost of geothermal energy production. Newberry Volcano in central Oregon represents an ideal location for EGS research and development. As such, the goals of the Newberry EGS Demonstration, operated by AltaRock Energy, Inc., include stimulation of a multiple-zone EGS reservoir, testing of single-well tracers and a demonstration of EGS reservoir viability through flow-back and circulation tests. A shallow, local aquifer supplied the approximately 41,630 m3 (11 million gals) of water used during stimulation of NWG 55-29, a deep geothermal well on the western flank of Newberry Volcano. Protection of the local aquifer is of primary importance to both the Newberry EGS Demonstration and the public. As part of the Demonstration, AltaRock Energy, Inc. has developed and implemented a groundwater monitoring plan to characterize the geochemistry of the local aquifer before, during and after stimulation. Background geochemical conditions were established prior to stimulation of NWG 55-29, which was completed in 2012. Nine sites were chosen for groundwater monitoring. These include the water supply well used during stimulation of NWG 55-29, three monitoring wells, three domestic water wells and two hot seeps located in the Newberry Caldera. Together, these nine monitoring sites represent up-, down- and cross-gradient locations. Groundwater samples are analyzed for 25 chemical constituents, stable isotopes, and geothermal tracers used during stimulation. In addition, water level data is collected at three monitoring sites in order to better characterize the effects of stimulation on the shallow aquifer. To date, no significant geochemical changes and no geothermal tracers have been detected in groundwater samples from these monitoring sites. The Newberry EGS Demonstration groundwater

  10. Recommendations of the workshop on advanced geothermal drilling systems

    Energy Technology Data Exchange (ETDEWEB)

    Glowka, D.A.

    1997-12-01

    At the request of the U.S. Department of Energy, Office of Geothermal Technologies, Sandia National Laboratories convened a group of drilling experts in Berkeley, CA, on April 15-16, 1997, to discuss advanced geothermal drilling systems. The objective of the workshop was to develop one or more conceptual designs for an advanced geothermal drilling system that meets all of the criteria necessary to drill a model geothermal well. The drilling process was divided into ten essential functions. Each function was examined, and discussions were held on the conventional methods used to accomplish each function and the problems commonly encountered. Alternative methods of performing each function were then listed and evaluated by the group. Alternative methods considered feasible or at least worth further investigation were identified, while methods considered impractical or not potentially cost-saving were eliminated from further discussion. This report summarizes the recommendations of the workshop participants. For each of the ten functions, the conventional methods, common problems, and recommended alternative technologies and methods are listed. Each recommended alternative is discussed, and a description is given of the process by which this information will be used by the U.S. DOE to develop an advanced geothermal drilling research program.

  11. Active geothermal systems as natural analogs of HLW repositories

    International Nuclear Information System (INIS)

    Elders, W.A.; Williams, A.E.; Cohen, L.H.

    1988-01-01

    Geologic analogs of long-lived processes in high-level waste (HLW) repositories have been much studied in recent years. However, most of these occurrences either involve natural processes going on today at 25 degree C, or, if they are concerned with behavior at temperatures similar to the peak temperatures anticipated near HLW canisters, have long since ended. This paper points out the usefulness of studying modern geothermal systems as natural analogs, and to illustrate the concept with a dramatic example, the Salton Sea geothermal system (SSGS)

  12. Hydrochemical Characteristics and Evolution of Geothermal Fluids in the Chabu High-Temperature Geothermal System, Southern Tibet

    Directory of Open Access Journals (Sweden)

    X. Wang

    2018-01-01

    Full Text Available This study defines reasonable reservoir temperatures and cooling processes of subsurface geothermal fluids in the Chabu high-temperature geothermal system. This system lies in the south-central part of the Shenzha-Xietongmen hydrothermal active belt and develops an extensive sinter platform with various and intense hydrothermal manifestations. All the geothermal spring samples collected systematically from the sinter platform are divided into three groups by cluster analysis of major elements. Samples of group 1 and group 3 are distributed in the central part and northern periphery of the sinter platform, respectively, while samples of group 2 are scattered in the transitional zone between groups 1 and 3. The hydrochemical characteristics show that the geothermal waters of the research area have generally mixed with shallow cooler waters in reservoirs. The reasonable reservoir temperatures and the mixing processes of the subsurface geothermal fluids could be speculated by combining the hydrochemical characteristics of geothermal springs, calculated results of the chemical geothermometers, and silica-enthalpy mixing models. Contour maps are applied to measured emerging temperatures, mass flow rates, total dissolved solids of spring samples, and reasonable subsurface temperatures. They indicate that the major cooling processes of the subsurface geothermal fluids gradually transform from adiabatic boiling to conduction from the central part to the peripheral belt. The geothermal reservoir temperatures also show an increasing trend. The point with the highest reservoir temperature (256°C appears in the east-central part of the research area, which might be the main up-flow zone. The cooling processes of the subsurface geothermal fluids in the research area can be shown on an enthalpy-chloride plot. The deep parent fluid for the Chabu geothermal field has a Cl− concentration of 290 mg/L and an enthalpy of 1550 J/g (with a water temperature of

  13. Control methodologies based on geothermal recirculating aquaculture system

    International Nuclear Information System (INIS)

    Farghally, Hanaa M.; Atia, Doaa M.; El-madany, Hanaa T.; Fahmy, Faten H.

    2014-01-01

    One of the most common uses of geothermal heat is in RAS (recirculation aquaculture systems) where the water temperature is accurately controlled for optimum growing conditions for sustainable and intensive rearing of marine and freshwater fish. This paper presents a design for RAS rearing tank and plate type heat exchanger to be used with geothermal energy as a source of heating water. A well at Umm Huweitat on the Red Sea is used as a source of geothermal energy. The heat losses from the RAS tank are calculated using Geo Heat Center Software. Then a plate type heat exchanger is designed using the epsilon–NTU (number of transfer units) analysis method. For optimal growth and abundance of production, a different techniques of control system are applied to control the water temperature. The total system is built in MATLAB/SIMULINK to study the overall performance of control unit. Finally, a comparison between PI, Fuzzy-PID, and Fuzzy Logic Control has been done. - Highlights: • Design recirculating aquaculture system using geothermal energy. • Design a PI controller for water temperature control. • Design a Fuzzy logic controller for water temperature control. • Design a Fuzzy-PID controller for water temperature control. • Comparison between different control systems

  14. Phase 1 Feasibility Study, Canby Cascaded Geothermal Project, April 2, 2013

    Energy Technology Data Exchange (ETDEWEB)

    Merrick, Dale E [CanbyGeo, LLC

    2013-04-02

    A small community in Northern California is attempting to use a local geothermal resource to generate electrical power and cascade residual energy to an existing geothermal district heating system, greenhouse, and future fish farm and subsequent reinjection into the geothermal aquifer, creating a net-zero energy community, not including transportation.

  15. COTHERM: Geophysical Modeling of High Enthalpy Geothermal Systems

    Science.gov (United States)

    Grab, Melchior; Maurer, Hansruedi; Greenhalgh, Stewart

    2014-05-01

    In recent years geothermal heating and electricity generation have become an attractive alternative energy resource, especially natural high enthalpy geothermal systems such as in Iceland. However, the financial risk of installing and operating geothermal power plants is still high and more needs to be known about the geothermal processes and state of the reservoir in the subsurface. A powerful tool for probing the underground system structure is provided by geophysical techniques, which are able to detect flow paths and fracture systems without drilling. It has been amply demonstrated that small-scale features can be well imaged at shallow depths, but only gross structures can be delineated for depths of several kilometers, where most high enthalpy systems are located. Therefore a major goal of our study is to improve geophysical mapping strategies by multi-method geophysical simulations and synthetic data inversions, to better resolve structures at greater depth, characterize the reservoir and monitor any changes within it. The investigation forms part of project COTHERM - COmbined hydrological, geochemical and geophysical modeling of geoTHERMal systems - in which a holistic and synergistic approach is being adopted to achieve multidisciplinary cooperation and mutual benefit. The geophysical simulations are being performed in combination with hydrothermal fluid flow modeling and chemical fluid rock interaction modeling, to provide realistic constraints on lithology, pressure, temperature and fluid conditions of the subsurface. Two sites in Iceland have been selected for the study, Krafla and Reykjanes. As a starting point for the geophysical modeling, we seek to establish petrophysical relations, connecting rock properties and reservoir conditions with geophysical parameters such as seismic wave speed, attenuation, electrical conductivity and magnetic susceptibility with a main focus on seismic properties. Therefore, we follow a comprehensive approach involving

  16. The Geysers-Clear Lake geothermal area, California - an updated geophysical perspective of heat sources

    Science.gov (United States)

    Stanley, W.D.; Blakely, R.J.

    1995-01-01

    The Geysers-Clear Lake geothermal area encompasses a large dry-steam production area in The Geysers field and a documented high-temperature, high-pressure, water-dominated system in the area largely south of Clear Lake, which has not been developed. An updated view is presented of the geological/geophysical complexities of the crust in this region in order to address key unanswered questions about the heat source and tectonics. Forward modeling, multidimensional inversions, and ideal body analysis of the gravity data, new electromagnetic sounding models, and arguments made from other geophysical data sets suggest that many of the geophysical anomalies have significant contributions from rock property and physical state variations in the upper 7 km and not from "magma' at greater depths. Regional tectonic and magmatic processes are analyzed to develop an updated scenario for pluton emplacement that differs substantially from earlier interpretations. In addition, a rationale is outlined for future exploration for geothermal resources in The Geysers-Clear Lake area. -from Authors

  17. Development And Application Of A Hydrothermal Model For The Salton Sea Geothermal Field, California

    Energy Technology Data Exchange (ETDEWEB)

    Kasameyer, P.; Younker, L.; Hanson, J.

    1984-01-01

    A simple lateral flow model adequately explains many of the features associated with the Salton Sea Geothermal Field. Earthquake swarms, a magnetic anomaly, and aspects of the gravity anomaly are all indirect evidence for the igneous activity which is the ultimate source of heat for the system. Heat is transferred from this area of intrusion by lateral spreading of hot water in a reservoir beneath an impermeable cap rock. A two dimensional analytic model encompassing this transport mechanism matches general features of the thermal anomaly and has been used to estimate the age of the presently observed thermal system. The age is calculated by minimizing the variance between the observed surface heat-flow data and the model. Estimates of the system age for this model range from 3,000 to 20,000 years.

  18. Geophysical survey, Paso Robles geothermal area, California, part of the resource assessment of low- and moderate-temperature geothermal resource areas in California

    Energy Technology Data Exchange (ETDEWEB)

    Chapman, R.H.; Chase, G.W.; Youngs, L.G.

    1980-11-10

    Some general background information concerning the geology and geothermal occurrences in the Southern Coast Ranges is included, as well as the more detailed information dealing with the Paso Robles area proper. Results for two geophysical methods that have been used in the area: the ground magnetic and gravity surveys, are discussed and interpreted.

  19. COTHERM: Modelling fluid-rock interactions in Icelandic geothermal systems

    Science.gov (United States)

    Thien, Bruno; Kosakowski, Georg; Kulik, Dmitrii

    2014-05-01

    Mineralogical alteration of reservoir rocks, driven by fluid circulation in natural or enhanced geothermal systems, is likely to influence the long-term performance of geothermal power generation. A key factor is the change of porosity due to dissolution of primary minerals and precipitation of secondary phases. Porosity changes will affect fluid circulation and solute transport, which, in turn, influence mineralogical alteration. This study is part of the Sinergia COTHERM project (COmbined hydrological, geochemical and geophysical modeling of geotTHERMal systems) that is an integrative research project aimed at improving our understanding of the sub-surface processes in magmatically-driven natural geothermal systems. We model the mineralogical and porosity evolution of Icelandic geothermal systems with 1D and 2D reactive transport models. These geothermal systems are typically high enthalphy systems where a magmatic pluton is located at a few kilometers depth. The shallow plutons increase the geothermal gradient and trigger the circulation of hydrothermal waters with a steam cap forming at shallow depth. We investigate two contrasting geothermal systems: Krafla, for which the water recharge consists of meteoritic water; and Reykjanes, for which the water recharge mainly consists of seawater. The initial rock composition is a fresh basalt. We use the GEM-Selektor geochemical modeling package [1] for calculation of kinetically controlled mineral equilibria between the rock and the ingression water. We consider basalt minerals dissolution kinetics according to Palandri & Kharaka [2]. Reactive surface areas are assumed to be geometric surface areas, and are corrected using a spherical-particle surface/mass relationship. For secondary minerals, we consider the partial equilibrium assuming that the primary mineral dissolution is slow, and the secondary mineral precipitation is fast. Comparison of our modeling results with the mineralogical assemblages observed in the

  20. Geothermal District Heating System City of Klamath Falls

    Energy Technology Data Exchange (ETDEWEB)

    Lienau, Paul J; Rafferty, Kevin

    1991-12-01

    The city of Klamath Falls became interested in the possibility of a establishing geothermal district heating system for downtown government buildings in January 1977. Since that time, the project has undergone some controversial and interesting developments that may be of educational value to other communities contemplating such a project. The purpose and content of this article is to identify the historical development of the project; including the design of the system, well owner objections to the project, aquifer testing, piping failure, and future expansion and marketing incentives. The shallow geothermal reservoir in Klamath falls extends for at least 6.8 miles in a northwest-southeast direction, as shown on Figure 1, with a width of about 2 miles. More than 550 thermal wells ranging in depth from about 10 to 2,000 ft, and obtaining or contacting water from 70 to 230oF, have been drilled into the reservoir. The system is not geologically homogeneous. Great variations in horizontal permeability and many vertical discontinuities exist because of stratigraphy and structure of the area. Basalt flows, eruptive centers, fluvial and lacustrine deposits, diatomite and pyroclastic materials alternate in the rock column. Normal faults with large throw (estimated up to 1,700 ft) are spaced less than 3,300 ft apart and appear to be the main avenue of vertical movement of hot fluids. In order to more effectively utilize this resource, the city of Klamath Falls decided in 1978 to apply for a federal grant (Program Opportunity Notice to cost share field experiment projects) to construct a geothermal district heating system that would deliver geothermal fluids to areas not located on the resource. In 1977, several Geo-Heat Center staff members visited Reykjavik, Iceland, to study the design of their geothermal district heating systems. This was in part the basis for the conceptual design and feasibility study (Lund, 1979) of a downtown commercial district. The main difference

  1. Revamping California's Education Finance System.

    Science.gov (United States)

    McFadden, Brett

    2003-01-01

    Describes reasons for California's budget deficits and their impact on school finance. Offers five possible solutions to the school funding crises: Restructure the state's tax and revenue system, restore school district revenue-sharing abilities, initiate a top-to-bottom mandate review, provide greater fiscal and program flexibility, and revamp…

  2. Sulfate mineralogy of fumaroles in the Salton Sea Geothermal Field, Imperial County, California

    Science.gov (United States)

    Adams, Paul M.; Lynch, David K.; Buckland, Kerry N.; Johnson, Patrick D.; Tratt, David M.

    2017-11-01

    The Salton Trough lies in the transition between the San Andreas Fault and oblique spreading centers and transform faults in the Gulf of California. The Salton Sea Geothermal Field is the northernmost expression of those spreading centers. In 2007 two ammonia-emitting fumarole fields that had been submerged beneath the Salton Sea were exposed for the first time in nearly 50 years. As the sea level continued to drop these fields have developed a number of boiling pools, mud pots, gryphons and a unique suite of ammonium sulfate minerals. These have been studied over time with long-wave infrared remote sensing coupled with ground truth surveys backed by laboratory analyses of the minerals. Many vents lie at the center of concentric rings of mineralization with systematic occurrence of different minerals from center to edge. Three semi-concentric zones (fumarole, transition and evaporite) have been defined with respect to ammonia-emitting vents and bubbling pools. The scale of these zones range from several meters, localized around individual vents, to that of the fumarole fields as a whole. The fumarole zone is closest to the vents and locally contains cavernous sulfur crystals and significant deposits of gypsum, mascagnite, boussingaultite and other ammonium sulfates. The transition zone comprises a dark brown surficial band of inconspicuous sodium nitrate underlain by anhydrite/bassanite that is thought to have formed by ammonia-oxidizing microbes interacting with the ammonium sulfates of the outer fumarole zone. The evaporite zone is the outermost and contains blödite, thenardite and glauberite, which are typical of the sulfates associated with the shoreline of the Salton Sea. Remote sensing has shown that the mineral zones have remained relatively stable from 2013 to 2017, with minor variations depending on rainfall, temperature and levels of agricultural runoff.

  3. 78 FR 77447 - California Wind Energy Association, First Solar, Inc. v. California Independent System Operator...

    Science.gov (United States)

    2013-12-23

    ... Energy Association, First Solar, Inc. v. California Independent System Operator Corporation, Southern...), California Wind Energy Association and First Solar, Inc. (collectively, Complainants) filed a formal complaint against the California Independent System Operator Corporation (CAISO) and Southern California...

  4. Health and safety impacts of nuclear, geothermal, and fossil-fuel electric generation in California. Volume 1. Health and safety impacts of nuclear, geothermal, and fossil-fuel electric generation in California

    International Nuclear Information System (INIS)

    Nero, A.V. Jr.

    1977-01-01

    This report presents an overview of a project on the health and safety impacts of nuclear, geothermal, and fossil-fuel electric generation in California. In addition to presenting an executive summary of the project, it sets forth the main results of the four tasks of the project: to review the health impacts (and related standards) of these forms of power generation, to review the status of standards related to plant safety (with an emphasis on nuclear power), to consider the role of the California Energy Resources Conservation and Development Commission in selection of standards, and to set forth methodologies whereby that Commission may review the health and safety aspects of proposed sites and facilities

  5. Environmental impacts of open loop geothermal system on groundwater

    Science.gov (United States)

    Kwon, Koo-Sang; Park, Youngyun; Yun, Sang Woong; Lee, Jin-Yong

    2013-04-01

    Application of renewable energies such as sunlight, wind, rain, tides, waves and geothermal heat has gradually increased to reduce emission of CO2 which is supplied from combustion of fossil fuel. The geothermal energy of various renewable energies has benefit to be used to cooling and heating systems and has good energy efficiency compared with other renewable energies. However, open loop system of geothermal heat pump system has possibility that various environmental problems are induced because the system directly uses groundwater to exchange heat. This study was performed to collect data from many documents such as papers and reports and to summarize environmental impacts for application of open loop system. The environmental impacts are classified into change of hydrogeological factors such as water temperature, redox condition, EC, change of microbial species, well contamination and depletion of groundwater. The change of hydrogeological factors can induce new geological processes such as dissolution and precipitation of some minerals. For examples, increase of water temperature can change pH and Eh. These variations can change saturation index of some minerals. Therefore, dissolution and precipitation of some minerals such as quartz and carbonate species and compounds including Fe and Mn can induce a collapse and a clogging of well. The well contamination and depletion of groundwater can reduce available groundwater resources. These environmental impacts will be different in each region because hydrogeological properties and scale, operation period and kind of the system. Therefore, appropriate responses will be considered for each environmental impact. Also, sufficient study will be conducted to reduce the environmental impacts and to improve geothermal energy efficiency during the period that a open loop system is operated. This work was supported by the Energy Efficiency and Resources of the Korea Institute of Energy Technology Evaluation and Planning

  6. Engineered Geothermal Systems Energy Return On Energy Investment

    Energy Technology Data Exchange (ETDEWEB)

    Mansure, A J

    2012-12-10

    Energy Return On Investment (EROI) is an important figure of merit for assessing the viability of energy alternatives. Too often comparisons of energy systems use efficiency when EROI would be more appropriate. For geothermal electric power generation, EROI is determined by the electricity delivered to the consumer compared to the energy consumed to construct, operate, and decommission the facility. Critical factors in determining the EROI of Engineered Geothermal Systems (EGS) are examined in this work. These include the input energy embodied into the system. Embodied energy includes the energy contained in the materials, as well as, that consumed in each stage of manufacturing from mining the raw materials to assembling the finished system. Also critical are the system boundaries and value of the energy heat is not as valuable as electrical energy. The EROI of an EGS depends upon a number of factors that are currently unknown, for example what will be typical EGS well productivity, as well as, reservoir depth, temperature, and temperature decline rate. Thus the approach developed is to consider these factors as parameters determining EROI as a function of number of wells needed. Since the energy needed to construct a geothermal well is a function of depth, results are provided as a function of well depth. Parametric determination of EGS EROI is calculated using existing information on EGS and US Department of Energy (DOE) targets and is compared to the minimum EROI an energy production system should have to be an asset rather than a liability.

  7. Multiparameter fiber optic sensing system for monitoring enhanced geothermal systems

    Energy Technology Data Exchange (ETDEWEB)

    Challener, William A

    2014-12-04

    The goal of this project was to design, fabricate and test an optical fiber cable which supports multiple sensing modalities for measurements in the harsh environment of enhanced geothermal systems. To accomplish this task, optical fiber was tested at both high temperatures and strains for mechanical integrity, and in the presence of hydrogen for resistance to darkening. Both single mode (SM) and multimode (MM) commercially available optical fiber were identified and selected for the cable based on the results of these tests. The cable was designed and fabricated using a tube-within-tube construction containing two MM fibers and one SM fiber, and without supporting gel that is not suitable for high temperature environments. Commercial fiber optic sensing instruments using Raman DTS (distributed temperature sensing), Brillouin DTSS (distributed temperature and strain sensing), and Raleigh COTDR (coherent optical time domain reflectometry) were selected for field testing. A microelectromechanical systems (MEMS) pressure sensor was designed, fabricated, packaged, and calibrated for high pressure measurements at high temperatures and spliced to the cable. A fiber Bragg grating (FBG) temperature sensor was also spliced to the cable. A geothermal well was selected and its temperature and pressure were logged. The cable was then deployed in the well in two separate field tests and measurements were made on these different sensing modalities. Raman DTS measurements were found to be accurate to ±5°C, even with some residual hydrogen darkening. Brillouin DTSS measurements were in good agreement with the Raman results. The Rayleigh COTDR instrument was able to detect some acoustic signatures, but was generally disappointing. The FBG sensor was used to determine the effects of hydrogen darkening, but drift over time made it unreliable as a temperature or pressure sensor. The MEMS sensor was found to be highly stable and accurate to better than its 0.1% calibration.

  8. Neutral sodium/bicarbonate/sulfate hot waters in geothermal systems

    Energy Technology Data Exchange (ETDEWEB)

    Mahon, W.A.J. (Dept. of Industrial and Scientific Research, Wairakei, New Zealand); Klyen, L.E.; Rhode, M.

    1980-03-01

    The least understood thermal water is a near neutral water which contains varying amounts of bicarbonate and sulfate as the major anions, low concentrations of chloride (< 30 ppM) and sodium as the major cation. In the past this water has been referred to as a sodium bicarbonate water but present studies suggest that the quantities of bicarbonate and sulfate in this water type are frequently of the same order. Of particular interest is the distribution and position of the sodium/bicarbonate/sulfate water in the same and different systems. Many hot springs in Indonesia, for example, discharge water of this composition. Present studies indicate that this water type can originate from high temperature reservoirs which form the secondary steam heated part of a normal high temperature geothermal system. The hydrological conditions producing these waters in geothermal systems are investigated and the relationship between the water type and vapor dominated systems is discussed. It is suggested that the major water type occurring in the so called vapor dominated parts of geothermal systems is this water. The water does not simply represent steam condensate, rather it consists essentially of meteoric water which has been steam heated. The water composition results from the interaction of carbon dioxide and hydrogen sulfide with meteoric water and the rocks confining this water in the aquifer.

  9. Geothermal system 'Toplets' and geothermal potential of Dojran region

    International Nuclear Information System (INIS)

    Karakashev, Deljo; Delipetrov, Marjan; Jovanov, Kosta

    2008-01-01

    The Toplets geothermal spring that expands into a wide geothermal net in the watershed of Lake Dojran along the geophysical exploration work carried out in the terrain, indicated the presence of a significant geothermal potential in the region. In the future it may become the major factor for the development of vegetable growing, the use of the medicinal properties of the mineral spas and tourism as well as the prosperity of the region. Water temperature in Lake Dojran amounts 15°C to 28°C during the year that is mach higher compared with the temperature of water lakes in neighbouring Greece. This indicates that beneath Lake Dojran there are other geothermal sources that replenish the lake with thermal water. Such manifestations of geothermal energy in the region along with other thermal phenomena speak for the presence of large reserves of geothermal energy in the Dojran depression. (Author)

  10. Geothermal system 'Toplets' and geothermal potential of Dojran region

    International Nuclear Information System (INIS)

    Karakashev, Deljo; Delipetrov, Marjan; Jovanov, Kosta

    2007-01-01

    The Toplets geothermal spring that expands into a wide geothermal net in the watershed of Lake Dojran along the geophysical exploration work carried out in the terrain, indicated the presence of a significant geothermal potential in the region. In the future it may become the major factor for the development of vegetable growing, the use of the medicinal properties of the mineral spas and tourism as well as the prosperity of the region. Water temperature in Lake Dojran amounts 15°C to 28°C during the year that is mach higher compared with the temperature of water lakes in neighbouring Greece. This indicates that beneath Lake Dojran there are other geothermal sources that replenish the lake with thermal water. Such manifestations of geothermal energy in the region along with other thermal phenomena speak for the presence of large reserves of geothermal energy in the Dojran depression. (Author)

  11. Conventional vs. unconventional enhanced (or engineered) geothermal systems

    Energy Technology Data Exchange (ETDEWEB)

    Dzebisashvili, K.; Breede, K.; Liu, X.; Falcone, G. [Technische Univ. Clausthal, Clausthal-Zellerfeld (Germany). ITE

    2013-08-01

    Enhanced (or Engineered) Geothermal Systems (EGS) have evolved from the Hot Dry Rock (HDR) concept, implemented for the first time at Fenton Hill in 1977, and subsequently through the Stimulated Geothermal System, the Deep Heat Mining and finally the Deep Earth Geothermal. All of these systems usually imply petro-thermal processes. The term EGS has evolved to include conduction dominated, low permeability resources in sedimentary and basement formations, as well as geopressured, magma, and low-grade, unproductive hydrothermal resources. Co-produced hot water from hydrocarbon wells has also been included by some in the definition of EGS, which constitutes a considerable divergence from the original concept. Four decades on from the first EGS implementation, this paper highlights the lessons learned from 'conventional' systems and contrasts the 'unconventional' solutions that have been proposed. Examples of unconventional EGS include single-well solutions, downhole heat exchangers, engineered well profiles and using circulation fluids other than water. Perhaps some of the ideas proposed in the past, which would be considered unconventional, have remained dormant or never made it to a commercial stage for field implementation, but they may yet open doors to the future generations of EGS. (orig.)

  12. 3D Geological Model for "LUSI" - a Deep Geothermal System

    Science.gov (United States)

    Sohrabi, Reza; Jansen, Gunnar; Mazzini, Adriano; Galvan, Boris; Miller, Stephen A.

    2016-04-01

    Geothermal applications require the correct simulation of flow and heat transport processes in porous media, and many of these media, like deep volcanic hydrothermal systems, host a certain degree of fracturing. This work aims to understand the heat and fluid transport within a new-born sedimentary hosted geothermal system, termed Lusi, that began erupting in 2006 in East Java, Indonesia. Our goal is to develop conceptual and numerical models capable of simulating multiphase flow within large-scale fractured reservoirs such as the Lusi region, with fractures of arbitrary size, orientation and shape. Additionally, these models can also address a number of other applications, including Enhanced Geothermal Systems (EGS), CO2 sequestration (Carbon Capture and Storage CCS), and nuclear waste isolation. Fractured systems are ubiquitous, with a wide-range of lengths and scales, making difficult the development of a general model that can easily handle this complexity. We are developing a flexible continuum approach with an efficient, accurate numerical simulator based on an appropriate 3D geological model representing the structure of the deep geothermal reservoir. Using previous studies, borehole information and seismic data obtained in the framework of the Lusi Lab project (ERC grant n°308126), we present here the first 3D geological model of Lusi. This model is calculated using implicit 3D potential field or multi-potential fields, depending on the geological context and complexity. This method is based on geological pile containing the geological history of the area and relationship between geological bodies allowing automatic computation of intersections and volume reconstruction. Based on the 3D geological model, we developed a new mesh algorithm to create hexahedral octree meshes to transfer the structural geological information for 3D numerical simulations to quantify Thermal-Hydraulic-Mechanical-Chemical (THMC) physical processes.

  13. Assessment of geothermal development in the Imperial Valley of California. Volume 1. Environment, health, and socioeconomics

    Energy Technology Data Exchange (ETDEWEB)

    Layton, D. (ed.)

    1980-07-01

    Utilization of the Imperial Valley's geothermal resources to support energy production could be hindered if environmental impacts prove to be unacceptable or if geothermal operations are incompatible with agriculture. To address these concerns, an integrated environmental and socioeconomic assessment of energy production in the valley was prepared. The most important impacts examined in the assessment involved air quality changes resulting from emissions of hydrogen sulfide, and increases in the salinity of the Salton Sea resulting from the use of agricultural waste waters for power plant cooling. The socioeconomics consequences of future geothermal development will generally be beneficial. (MHR)

  14. Modeling study of the natural state of the Heber geothermal field, California

    Energy Technology Data Exchange (ETDEWEB)

    Lippmann, M.J.; Bodvarsson, G.S.

    1983-06-01

    As a first step in simulating the behavior of the Heber field under exploitation, the system is modeled in its natural (pre-exploitation) state. Using Lawrence Berkeley Laboratory's (LBL) computer code PT and a radially symmetric model, a reasonable match between published and calculated temperature and pressure distributions is obtained. The results of the study indicate that the Heber geothermal system is created by the upflow of hot water through a central zone of higher permeability. The model shows that in its natural state the system is recharged at depth by a 15 MW(thermal) convective heat source. The existence of a radially symmetric convection pattern, whose axis coincides with that of the Heber anomaly is suggested. At the lower part of the ascending hot water plume, the deep recharge water mixes with colder water moving laterally towards the axis of the system. On the upper part, the rising plume spreads radially outward before reaching the bottom of the caprock, at 550 m depth. The model results suggest that the caprock is quite permeable, with convection controlling the temperature distribution. The low permeability of the upper zones in the outer region of the system may be due to mineral precipitation.

  15. Geothermal district heating system feasibility analysis, Thermopolis, Wyoming

    Energy Technology Data Exchange (ETDEWEB)

    Goering, S.W.; Garing, K.L.; Coury, G.; Mickley, M.C.

    1982-04-26

    The purpose of this study is to determine the technical and economic feasibility of constructing and operating a district heating system to serve the residential, commercial, and public sectors in Thermopolis. The project geothermal resource assessment, based on reviews of existing information and data, indicated that substantial hot water resources likely exist in the Rose Dome region 10 miles northeast of Thermopolis, and with quantities capable of supporting the proposed geothermal uses. Preliminary engineering designs were developed to serve the space heating and hot water heating demands for buildings in the Thermopolis-East Thermopolis town service area. The heating district design is based on indirect geothermal heat supply and includes production wells, transmission lines, heat exchanger units, and the closed loop distribution and collection system necessary to serve the individual customers. Three options are presented for disposal of the cooled waters-reinjection, river disposal, and agricultural reuse. The preliminary engineering effort indicates the proposed system is technically feasible. The design is sized to serve 1545 residences, 190 businesses, and 24 public buildings. The peak design meets a demand of 128.2 million Btu at production rates of 6400 gpm.

  16. Gas and Isotope Geochemistry of 81 Steam Samples from Wells in The Geysers Geothermal Field, Sonoma and Lake Counties, California

    Science.gov (United States)

    Lowenstern, Jacob B.; Janik, Cathy J.; Fahlquist, Lynne; Johnson, Linda S.

    1999-01-01

    The Geysers geothermal field in northern California, with about 2000-MW electrical capacity, is the largest geothermal field in the world. Despite its importance as a resource and as an example of a vapor-dominated reservoir, very few complete geochemical analyses of the steam have been published (Allen and Day, 1927; Truesdell and others, 1987). This report presents data from 90 steam, gas, and condensate samples from wells in The Geysers geothermal field in northern California. Samples were collected between 1978 and 1991. Well attributes include sampling date, well name, location, total depth, and the wellhead temperature and pressure at which the sample was collected. Geochemical characteristics include the steam/gas ratio, composition of noncondensable gas (relative proportions of CO2, H2S, He, H2, O2, Ar, N2, CH4, and NH3), and isotopic values for deltaD and delta18O of H2O, delta13C of CO2, and delta34S of H2S. The compilation includes 81 analyses from 74 different production wells, 9 isotopic analyses of steam condensate pumped into injection wells, and 5 complete geochemical analyses on gases from surface fumaroles and bubbling pools. Most samples were collected as saturated steam and plot along the liquid-water/steam boiling curve. Steam-togas ratios are highest in the southeastern part of the geothermal field and lowest in the northwest, consistent with other studies. Wells in the Northwest Geysers are also enriched in N2/Ar, CO2 and CH4, deltaD, and delta18O. Well discharges from the Southeast Geysers are high in steam/gas and have isotopic compositions and N2/Ar ratios consistent with recharge by local meteoric waters. Samples from the Central Geysers show characteristics found in both the Southeast and Northwest Geysers. Gas and steam characteristics of well discharges from the Northwest Geysers are consistent with input of components from a high-temperature reservoir containing carbonrich gases derived from the host Franciscan rocks. Throughout the

  17. Seismicity, focal mechanisms, and stress distribution in the Tres Virgenes volcanic and geothermal region, Baja California Sur, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Wong, Victor; Munguia, Luis [Centro de Investigacion Cientifica y de Educacion Superior de Ensenada (Mexico)

    2006-01-15

    In October 1993 we carried out a seismic monitoring in the Tres Virgenes volcanic region in order to record the background seismicity associated with the volcanic structures, the geothermal field and the tectonic features of the area. Hypocenters for 257 microearthquakes were located in the volcanic edifices and along the northwest right-lateral, strike-slip La Virgen fault. Focal depths range from close to the Earth surface to about 8 km. Shallow depths occur mainly in the volcanic edifices. Deeper seismic events occurred outside the volcanic area. The duration magnitudes of the located microearthquakes range between 1 and 3. The Vp/Vs ratio and the low-Q values estimated suggest heterogeneous material properties in the volcanic structures mainly toward the El Azufre fault and the El Aguajito Caldera, where hydrothermal activity has been reported. The P- and T-axes of focal mechanisms for 90 microearthquakes suggest that the region is under N-S compression and E-W extension, in agreement with the regional tectonic stress field of the NW-SE right-lateral strike-slip transform fault system of the Gulf of California. [Spanish] En octubre de 1993 se llevo a cabo un monitoreo sismico en la region volcanica Las Tres Virgenes con el proposito de registrar la actividad sismica asociada a las estructuras volcanicas, al campo geotermico y a la tectonica local. Se localizaron 257 microsismos con hipocentros en los edificios volcanicos y a lo largo de la falla de rumbo, lateral derecha conocida como falla La Virgen. La profundidad focal de los sismos varia desde los muy cercanos a la superficie de la Tierra hasta los 8 km. Las profundidades someras ocurren principalmente en los edificios volcanicos. Los sismos mas profundos ocurren fuera del area volcanica. La magnitud de duracion de los microsismos localizados varia entre 1 y 3. La razon Vp/Vs y los valores bajos de Q que se estimaron en la zona sugieren un material con propiedades heterogeneas bajo las estructuras

  18. Geological interpretation of Mount Ciremai geothermal system from remote sensing and magneto-teluric analysis

    OpenAIRE

    Sumintadireja, Prihadi; Saepuloh, Asep; Irawan, Dasapta E.; Irawan, Diky; Fadillah, Ahmad

    2014-01-01

    The exploration of geothermal system at Mount Ciremai has been started since the early 1980s and has just been studied carefully since the early 2000s. Previous studies have detected the potential of geothermal system and also the groundwater mechanism feeding the system. This paper will discuss the geothermal exploration based on regional scale surface temperature analysis with Landsat image to have a more detail interpretation of the geological setting and magneto-telluric or MT survey at p...

  19. Exergoenvironmental analysis for a geothermal district heating system: An application

    International Nuclear Information System (INIS)

    Keçebaş, Ali

    2016-01-01

    Energy sources are of great importance in relation to pollution of the world. The use of renewable energy resources and the creation of more efficient energy systems make great contributions to the prevention of greenhouse gases. Recently, many studies indicate that the energy conversion systems have many advantages in terms of technical and economic point of view. In near future, environmental impact is going to play an important role in the selection/design of such energy resources and systems. In this study, the Afyon GDHS (geothermal district heating system) having actual operating conditions is investigated at the component level in terms of environmental impact by using exergoenvironmental analysis. Moreover, the effects of ambient and wellhead temperatures on the environmental impacts of the system are discussed. The results show that a great part of total environmental impact of the system occurs from the exergy destructions of the components. Therefore, the environmental impacts can be reduced by improving their exergetic efficiencies instead of design changes of the system components. The environmental impacts of the system are reduced when the ambient temperature decreases and the wellhead temperature increases. Thus, it might not be necessary to conduct separately the exergoenvironmental analysis for different ambient temperatures. - Highlights: • Using exergoenvironmental analysis in a geothermal district heating for the first time. • Evaluating environmental impact of a geothermal district heating system. • Discussing the effects of ambient and wellhead temperatures on the environmental impact. • Total environmental impact of the system occurs from exergy destructions of components. • The exergoenvironmental analysis can be done only once for all the ambient temperatures.

  20. Economic study of low temperature geothermal energy in Lassen and Modoc Counties, California

    Energy Technology Data Exchange (ETDEWEB)

    1977-04-01

    The feasibility of using low cost, low temperature geothermal energy in job-producing industries to increase employment and encourage economic development was investigated. The study, encompassing all of Lassen and Modoc Counties, was to be site-specific, referencing candidate geothermal applications to known hot wells and springs as previously determined, or to new wells with specific characteristics as defined in the Scope of Work. The emphasis was to be placed on economically practical and readily achievable applications from known resources. Although both positive and negative findings were found in specific areas of investigation, it is felt that the overall long term prognosis for geothermal energy stimulus to industry in the area is excellent. The applications studied were; greenhouse heating, kiln drying, onion dehydration, feedlots, and aquaculture.

  1. Behavior of Rare Earth Element In Geothermal Systems; A New Exploration/Exploitation Tool

    Energy Technology Data Exchange (ETDEWEB)

    Scott A. Wood

    2002-01-28

    The goal of this four-year project was to provide a database by which to judge the utility of the rare earth elements (REE) in the exploration for and exploitation of geothermal fields in the United States. Geothermal fluids from hot springs and wells have been sampled from a number of locations, including: (1) the North Island of New Zealand (1 set of samples); (2) the Cascades of Oregon; (3) the Harney, Alvord Desert and Owyhee geothermal areas of Oregon; (4) the Dixie Valley and Beowawe fields in Nevada; (5) Palinpion, the Philippines: (6) the Salton Sea and Heber geothermal fields of southern California; and (7) the Dieng field in Central Java, Indonesia. We have analyzed the samples from all fields for REE except the last two.

  2. Behavior of Rare Earth Element In Geothermal Systems; A New Exploration/Exploitation Tool; FINAL

    International Nuclear Information System (INIS)

    Scott A. Wood

    2002-01-01

    The goal of this four-year project was to provide a database by which to judge the utility of the rare earth elements (REE) in the exploration for and exploitation of geothermal fields in the United States. Geothermal fluids from hot springs and wells have been sampled from a number of locations, including: (1) the North Island of New Zealand (1 set of samples); (2) the Cascades of Oregon; (3) the Harney, Alvord Desert and Owyhee geothermal areas of Oregon; (4) the Dixie Valley and Beowawe fields in Nevada; (5) Palinpion, the Philippines: (6) the Salton Sea and Heber geothermal fields of southern California; and (7) the Dieng field in Central Java, Indonesia. We have analyzed the samples from all fields for REE except the last two

  3. Exergoeconomic analysis of geothermal district heating systems: A case study

    International Nuclear Information System (INIS)

    Ozgener, Leyla; Hepbasli, Arif; Dincer, Ibrahim; Rosen, Marc A.

    2007-01-01

    An exergoeconomic study of geothermal district heating systems through mass, energy, exergy and cost accounting analyses is reported and a case study is presented for the Salihli geothermal district heating system (SGDHS) in Turkey to illustrate the present method. The relations between capital costs and thermodynamic losses for the system components are also investigated. Thermodynamic loss rate-to-capital cost ratios are used to show that, for the devices and the overall system, a systematic correlation appears to exist between capital cost and exergy loss (total or internal), but not between capital cost and energy loss or external exergy loss. Furthermore, a parametric study is conducted to determine how the ratio of thermodynamic loss rate to capital cost changes with reference temperature and to develop a correlation that can be used for practical analyses. The correlations may imply that devices in successful district heating systems such as the SGDHS are configured so as to achieve an overall optimal design, by appropriately balancing the thermodynamic (exergy-based) and economic (cost) characteristics of the overall systems and their devices

  4. Mapping temperature and radiant geothermal heat flux anomalies in the Yellowstone geothermal system using ASTER thermal infrared data

    Science.gov (United States)

    Vaughan, R. Greg; Lowenstern, Jacob B.; Keszthelyi, Laszlo P.; Jaworowski, Cheryl; Heasler, Henry

    2012-01-01

    The purpose of this work was to use satellite-based thermal infrared (TIR) remote sensing data to measure, map, and monitor geothermal activity within the Yellowstone geothermal area to help meet the missions of both the U.S. Geological Survey Yellowstone Volcano Observatory and the Yellowstone National Park Geology Program. Specifically, the goals were to: 1) address the challenges of remotely characterizing the spatially and temporally dynamic thermal features in Yellowstone by using nighttime TIR data from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and 2) estimate the temperature, geothermal radiant emittance, and radiant geothermal heat flux (GHF) for Yellowstone’s thermal areas (both Park wide and for individual thermal areas). ASTER TIR data (90-m pixels) acquired at night during January and February, 2010, were used to estimate surface temperature, radiant emittance, and radiant GHF from all of Yellowstone’s thermal features, produce thermal anomaly maps, and update field-based maps of thermal areas. A background subtraction technique was used to isolate the geothermal component of TIR radiance from thermal radiance due to insolation. A lower limit for the Yellowstone’s total radiant GHF was established at ~2.0 GW, which is ~30-45% of the heat flux estimated through geochemical (Cl-flux) methods. Additionally, about 5 km2 was added to the geodatabase of mapped thermal areas. This work provides a framework for future satellite-based thermal monitoring at Yellowstone as well as exploration of other volcanic / geothermal systems on a global scale.

  5. Drilling Addendum to Resource Assessment of Low- and Moderate-Temperature Geothermal Waters in Calistoga, Napa County, California

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Gary C.; Bacon, C. Forrest; Chapman, Rodger H.; Chase, Gordon W.; Majmundar, Hasmukhrai H.

    1981-05-01

    This addendum report presents the results of the California Division of Mines and Geology (CDMG) drilling program at Calistoga, California, which was the final geothermal-resource assessment investigation performed under terms of the second year contract (1979-80) between the U.S. Department of Energy (DOE) and the CDMG under the State Coupled Program. This report is intended to supplement information presented in CDMG's technical report for the project year, ''Resource Assessment of Low- and Moderate-Temperature Geothermal Waters in Calistoga, Napa County, California''. During the investigative phase of the CDMG's Geothermal Project, over 200 well-driller's reports were obtained from the Department of Water Resources (DWR). It was hoped that the interpretation and correlation of these logs would reveal the subsurface geology of the Upper Napa Valley and also provide a check for the various geophysical surveys that were performed in the course of the study. However, these DWR driller logs proved to be inadequate due to the brief, non-technical, and erroneous descriptions contained on the logs. As a result of the lack of useable drill-hole data, and because information was desired from,deeper horizons, it became evident that drilling some exploratory holes would be necessary in order to obtain physical evidence of the stratigraphy and aquifers in the immediate Calistoga area. Pursuant to this objective, a total of twelve sites were selected--four under jurisdiction of Napa County and eight under jurisdiction of the City of Calistoga. A moratorium is currently in existence within Napa County on most geothermal drilling, and environmental and time constraints precluded CDMG from obtaining the necessary site permits within the county. However, a variance was applied for and obtained from the City of Calistoga to allow CDMG to drill within the city limits. With this areal constraint and also funding limits in mind, six drilling sites

  6. Systems and methods for multi-fluid geothermal energy systems

    Science.gov (United States)

    Buscheck, Thomas A.

    2017-09-19

    A method for extracting geothermal energy from a geothermal reservoir formation. A production well is used to extract brine from the reservoir formation. At least one of nitrogen (N.sub.2) and carbon dioxide (CO.sub.2) may be used to form a supplemental working fluid which may be injected into a supplemental working fluid injection well. The supplemental working fluid may be used to augment a pressure of the reservoir formation, to thus drive a flow of the brine out from the reservoir formation.

  7. Geothermal pump down-hole energy regeneration system

    Science.gov (United States)

    Matthews, Hugh B.

    1982-01-01

    Geothermal deep well energy extraction apparatus is provided of the general kind in which solute-bearing hot water is pumped to the earth's surface from a subterranean location by utilizing thermal energy extracted from the hot water for operating a turbine motor for driving an electrical power generator at the earth 3 s surface, the solute bearing water being returned into the earth by a reinjection well. Efficiency of operation of the total system is increased by an arrangement of coaxial conduits for greatly reducing the flow of heat from the rising brine into the rising exhaust of the down-well turbine motor.

  8. Modeling of an Air Conditioning System with Geothermal Heat Pump for a Residential Building

    Directory of Open Access Journals (Sweden)

    Silvia Cocchi

    2013-01-01

    Full Text Available The need to address climate change caused by greenhouse gas emissions attaches great importance to research aimed at using renewable energy. Geothermal energy is an interesting alternative concerning the production of energy for air conditioning of buildings (heating and cooling, through the use of geothermal heat pumps. In this work a model has been developed in order to simulate an air conditioning system with geothermal heat pump. A ground source heat pump (GSHP uses the shallow ground as a source of heat, thus taking advantage of its seasonally moderate temperatures. GSHP must be coupled with geothermal exchangers. The model leads to design optimization of geothermal heat exchangers and to verify the operation of the geothermal plant.

  9. Geothermal direct heat use: market potential/penetration analysis for Federal Region IX (Arizona, California, Hawaii, Nevada)

    Energy Technology Data Exchange (ETDEWEB)

    Powell, W.; Tang, K. (eds.)

    1980-05-01

    A preliminary study was made of the potential for geothermal direct heat use in Arizona, California, Hawaii, and Nevada (Federal Region IX). The analysis for each state was performed by a different team, located in that state. For each state, the study team was asked to: (1) define the resource, based on the latest available data; (2) assess the potential market growth for geothermal energy; and (3) estimate the market penetration, projected to 2020. Each of the four states of interest in this study is unique in its own way. Rather than impose the same assumptions as to growth rates, capture rates, etc. on all of the study teams, each team was asked to use the most appropriate set of assumptions for its state. The results, therefore, should reflect the currently accepted views within each state. The four state reports comprise the main portion of this document. A brief regional overview section was prepared by the Jet Propulsion Laboratory, following completion of the state reports.

  10. An overview of the Awibengkok geothermal system, Indonesia

    Energy Technology Data Exchange (ETDEWEB)

    Stimac, James; Nordquist, Gregg; Suminar, Aquardi; Sirad-Azwar, Lutfhie [Chevron Geothermal Salak, Ltd., 11th Floor Sentral Senayan I, Jl. Asia Afrika No. 8, Jakarta 10270 (Indonesia)

    2008-06-15

    The Awibengkok (Salak) geothermal system is a liquid-dominated, fracture-controlled reservoir with benign chemistry and low-to-moderate non-condensable gas content. The geothermal system is hosted mainly by andesitic-to-rhyodacitic rocks, and floored by Miocene marine sedimentary rocks cut by igneous intrusions. The volcanic sequence is capped by an 8400-year-old phreatic explosion breccia, rhyolite fallout tuff (>8400 years and <40,000 years), rhyolite lavas, domes and related tuffs ({>=}40-120 ka), and dacite-to-rhyodate lavas and domes (185-280 ka) that were erupted across the eastern part of the field from NNE-trending vents controlled by a major fault. More regionally extensive basaltic-andesite to andesite volcanic centers are mostly between 180 and 1610 ka old. Surface and subsurface fault patterns, formation image logs and tracer studies indicate strongly anisotropic permeability aligned with the dominant N to NE fracture trend, dividing the field into a number of subcompartments that are locally connected by fractured aquifers and NW- and E-W-trending fractures. Shallow argillic alteration gives way with increasing depth and temperature to argillic-phyllic and propylitic zones, with the latter accounting for the bulk of the fluid produced from the geothermal system. The commercial Awibengkok reservoir is a moderate-to-high temperature (240-312 C) geothermal resource with high fracture permeability, moderate porosity (mean = 10.6%) and moderate-to-low matrix permeability (geometric mean = 0.026 md). The principal deep upflow zone, with fluid temperatures in the 275-312 C range, is located in the western part of the field. The ascending fluids move up along N- or NNE-trending structures that breach low-permeability tuff layers in the central and east-central parts of the field. Fluids in the central part of the reservoir are uniform in composition and temperature, representing the mixing of upflow and convective reflux. Fluids ascend and flow laterally to

  11. Geophysical survey, Paso Robles Geothermal area, California: Part of the Resource Assessment of Low- and Moderate-Temperature Geothermal Resource Areas in California; Part of the Second year Report, 1979-80 of the US Department of Energy-California State-Coupled Program for Reservoir Assessment and Confirmation

    Energy Technology Data Exchange (ETDEWEB)

    Chapman, Rodger H.; Chase, Gordon W.; Youngs, Les G.

    1980-11-10

    This report presents the details of new geophysical work for the Paso Robles geothermal area, California performed under terms of the second year contract, 1979-80 between the US Department of Energy (DOE) and the California Division of Mines and Geology (CDMG). The report contains two sections. The first section is to provide background for the reader and consists of a reprint from CDMG's first year report (1979-80) to DOE. It describes only the Paso Robles studies performed by CDMG in its first year effort. The second section provides new information developed by CDMG in its 1979-80 studies concerning the geophysical survey of the Paso Robles geothermal area. Included in the first section is some general background information concerning the geology and geothermal occurrences in the Southern Coast Ranges, as well as the more detailed information dealing with the Paso Robles area proper. The second section is concerned only with discussion and interpretation of results for two geophysical methods that have so far been used by CDMG in the area: the ground magnetic and gravity surveys. The CDMG studies of the Paso Robles area are not yet complete and additional studies using newly acquired resistivity equipment are planned for the near future, as are more complete surveys of existing wells and new studies of the geothermal aquifers present in the area. A final report to DOE on the Paso Robles area is planned following completion of those studies.

  12. National Geothermal Data System Hub Deployment Timeline (Appendix E-1-d)

    Energy Technology Data Exchange (ETDEWEB)

    Caudill, Christy [Executive Office of the State of Arizona (Arizona Geological Survey)

    2015-12-20

    Excel spreadsheet describing activity, spending, and development for the four data hubs (Arizona Geoloical Survey, Kentucky Geological Survey, Illinois Geological Survey, and Nevada Bureau of Mines and Geology) serving data for the National Geothermal Data System under the State Contributions to the National Geothermal Data System Project.

  13. Design of Tomato Drying System by Utilizing Brine Geothermal

    Science.gov (United States)

    Afuar, W.; Sibarani, B.; Abdurrahman, G.; Hendrarsakti, J.

    2016-09-01

    Cultivation of tomato plants in Indonesia has been started since 1961.Tomatoes generally will rot in three days if left on storage. Moreover, low quality tomatoes have cheaper price. After harvested, tomatoes need to be treated by drying process so it can last longer. Energy for drying tomatoes can be obtained by utilizing heat from geothermal brine. Purpose of this research is to design a tomato drying system by extracting heat of geothermal brine from separator with certain flow rate to heat up water by using a heat exchanger. Furthermore, this water will be used to heat up the surrounding air which is circulated by blower system to heat up the tomatoes chamber. Tomatoes drying process needs temperature range of 50-70°C to evaporate water content from 95.7% to 26%. After that treatment, the tomatoes are expected to have better durability. The objective of this study is to determine the quantity of hot brine which is needed for drying tomatoes and to design a drying system so that tomatoes can last longer.

  14. Enhanced Geothermal Systems (EGS) R&D Program

    Energy Technology Data Exchange (ETDEWEB)

    Entingh, Daniel J.

    1999-08-18

    The purpose of this workshop was to develop technical background facts necessary for planning continued research and development of Enhanced Geothermal Systems (EGS). EGS are geothermal reservoirs that require improvement of their permeability or fluid contents in order to achieve economic energy production. The initial focus of this R&D program is devising and testing means to extract additional economic energy from marginal volumes of hydrothermal reservoirs that are already producing commercial energy. By mid-1999, the evolution of the EGS R&D Program, begun in FY 1988 by the U.S. Department of Energy (DOE), reached the stage where considerable expertise had to be brought to bear on what technical goals should be pursued. The main purpose of this Workshop was to do that. The Workshop was sponsored by the Office of Geothermal Technologies of the Department of Energy. Its purpose and timing were endorsed by the EGS National Coordinating Committee, through which the EGS R&D Program receives guidance from members of the U.S. geothermal industry. Section 1.0 of this report documents the EGS R&D Program Review Session. There, managers and researchers described the goals and activities of the program. Recent experience with injection at The Geysers and analysis of downhole conditions at Dixie Valley highlighted this session. Section 2.0 contains a number of technical presentations that were invited or volunteered to illuminate important technical and economic facts and opportunities for research. The emphasis here was on fi.acture creation, detection, and analysis. Section 3.0 documents the initial general discussions of the participants. Important topics that emerged were: Specificity of defined projects, Optimizing cost effectiveness, Main technical areas to work on, Overlaps between EGS and Reservoir Technology R&D areas, Relationship of microseismic events to hydraulic fractures, and Defining criteria for prioritizing research thrusts. Sections 4.0 and 5.0 report

  15. Hydrogeochemistry of high-temperature geothermal systems in China: A review

    International Nuclear Information System (INIS)

    Guo, Qinghai

    2012-01-01

    As an important part of the Mediterranean-Himalayas geothermal belt, southern Tibet and western Yunnan are the regions of China where high-temperature hydrothermal systems are intensively distributed, of which Rehai, Yangbajing and Yangyi have been investigated systematically during the past several decades. Although much work has been undertaken at Rehai, Yangbajing and Yangyi to study the regional geology, hydrogeology, geothermal geology and geophysics, the emphasis of this review is on hydrogeochemical studies carried out in these geothermal fields. Understanding the geochemistry of geothermal fluids and their environmental impact is critical for sustainable exploitation of high-temperature hydrothermal resources in China. For comparison, the hydrogeochemistry of several similar high-temperature hydrothermal systems in other parts of the world are also included in this review. It has been confirmed by studies on Cl − and stable isotope geochemistry that magma degassing makes an important contribution to the geothermal fluids from Rehai, Yangbajing and Yangyi, though meteoric water is still the major source of recharge for these hydrothermal systems. However, the mechanisms of magma heat sources appear to be quite different in the three systems, as recorded by the 3 He/ 4 He ratios of escaping geothermal gases. A mantle-derived magma intrusion to shallow crust is present below Rehai, although the intruding magma has been heavily hybridized by crustal material. By contrast, the heat sources below Yangbajing and Yangyi are inferred to be remelted continental crust. Besides original sources, the geochemistry of characteristic constituents in the geothermal fluids have also been affected by temperature-dependent fluid–rock interactions, boiling and redox condition changes occurring in the upper part of hydrothermal systems, and mixing with cold near-surface waters. The geothermal fluids from Rehai, Yangbajing and Yangyi contain very high concentrations of some

  16. Revisiting the 'Buy versus Build' decision for publicly owned utilities in California considering wind and geothermal resources; TOPICAL

    International Nuclear Information System (INIS)

    Bolinger, Mark; Wiser, Ryan; Golove, William

    2001-01-01

    owned utility's decision to buy or build new renewable energy capacity-specifically wind or geothermal power-in California. To examine the economic aspects of this decision, we modified and updated a 20-year financial cash-flow model to assess the levelized cost of electricity under four supply options: (1) public utility ownership of new geothermal capacity, (2) public utility ownership of new wind capacity, (3) a PPA for new geothermal capacity, and (4) a PPA for new wind capacity

  17. Enhanced Geothermal Systems (EGS) well construction technology evaluation report.

    Energy Technology Data Exchange (ETDEWEB)

    Capuano, Louis, Jr. (Thermasource Inc.); Huh, Michael; Swanson, Robert (Thermasource Inc.); Raymond, David Wayne; Finger, John Travis; Mansure, Arthur James; Polsky, Yarom; Knudsen, Steven Dell

    2008-12-01

    Electricity production from geothermal resources is currently based on the exploitation of hydrothermal reservoirs. Hydrothermal reservoirs possess three ingredients critical to present day commercial extraction of subsurface heat: high temperature, in-situ fluid and high permeability. Relative to the total subsurface heat resource available, hydrothermal resources are geographically and quantitatively limited. A 2006 DOE sponsored study led by MIT entitled 'The Future of Geothermal Energy' estimates the thermal resource underlying the United States at depths between 3 km and 10 km to be on the order of 14 million EJ. For comparison purposes, total U.S. energy consumption in 2005 was 100 EJ. The overwhelming majority of this resource is present in geological formations which lack either in-situ fluid, permeability or both. Economical extraction of the heat in non-hydrothermal situations is termed Enhanced or Engineered Geothermal Systems (EGS). The technologies and processes required for EGS are currently in a developmental stage. Accessing the vast thermal resource between 3 km and 10 km in particular requires a significant extension of current hydrothermal practice, where wells rarely reach 3 km in depth. This report provides an assessment of well construction technology for EGS with two primary objectives: (1) Determining the ability of existing technologies to develop EGS wells. (2) Identifying critical well construction research lines and development technologies that are likely to enhance prospects for EGS viability and improve overall economics. Towards these ends, a methodology is followed in which a case study is developed to systematically and quantitatively evaluate EGS well construction technology needs. A baseline EGS well specification is first formulated. The steps, tasks and tools involved in the construction of this prospective baseline EGS well are then explicitly defined by a geothermal drilling contractor in terms of sequence, time and

  18. Development of an Internet based geothermal information system for Germany; Aufbau eines geothermischen Informationssystems fuer Deutschland

    Energy Technology Data Exchange (ETDEWEB)

    Schulz, R.; Agemar, T.; Alten, J.A.; Kuehne, K.; Maul, A.A.; Pester, S.; Wirth, W. [Inst. fuer Geowissenschaftliche Gemeinschaftsaufgaben (GGA), Hannover (Germany)

    2007-02-15

    The Leibniz Institute for Applied Geosciences (GGA-Institut) is setting up an internet based information system on geothermal resources in close collaboration with partners. For a start, the geothermal information system will contain data about hydrogeothermal resources only. The project aims at an improvement of quality in the planning of geothermal plants and at a minimization of exploration risks. The key parameters for this purpose are production rate (Q) and temperature (T). The basis for the estimation of subsurface hydraulic properties comes from the information system on hydrocarbons. This information system provides permeability and porosity values derived from the analyses of drilling cores. The IT targets will be realised by a relational database providing all data relevant to the project. A 3D model of the ground provides the basis for visualisation and calculation of geothermal resources. As a prototype, a data-recall facility of geothermal sites in Germany is available online. (orig.)

  19. Baseline studies in the desert ecosystem at East Mesa Geothermal Test Site, Imperial Valley, California

    Energy Technology Data Exchange (ETDEWEB)

    Romney, E.M.; Wallace, A.; Lunt, O.R.; Ackerman, T.A.; Kinnear, J.E.

    1977-09-01

    Baseline data reported herein for soil, vegetation, and small mammal components of the East Mesa desert ecosystem represent a collection period from October 1975 to September 1977. Inasmuch as changes in salt balance from geothermal brine sources are of potential impact upon the ecosystem, considerable analytical effort was given to the determination of element constituents in soil, plant, and animal samples. A preliminary synthesis of data was done to investigate the heterogeneity of element constituents among the sampled population and to summarize results. Findings indicate that periodic sampling and chemical analysis of vegetation around an industrialized geothermal energy source is probably the best way to monitor the surrounding ecosystem for assuring containment of any resource pollutants.

  20. Geothermal environmental studies, Heber Region, Imperial Valley, California. Environmental baseline data acquisition. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1977-02-01

    The Electric Power Research Institute (EPRI) has been studying the feasibility of a Low Salinity Hydrothermal Demonstration Plant as part of its Geothermal Energy Program. The Heber area of the Imperial Valley was selected as one of the candidate geothermal reservoirs. Documentation of the environmental conditions presently existing in the Heber area is required for assessment of environmental impacts of future development. An environmental baseline data acquisition program to compile available data on the environment of the Heber area is reported. The program included a review of pertinent existing literature, interviews with academic, governmental and private entities, combined with field investigations and meteorological monitoring to collect primary data. Results of the data acquisition program are compiled in terms of three elements: the physical, the biological and socioeconomic settings.

  1. Sperry Low Temperature Geothermal Conversion System, Phase 1 and Phase 2. Volume 3: Systems description

    Science.gov (United States)

    Matthews, H. B.

    The major fraction of hydrothermal resources with the prospect of economic usefulness for the generation of electricity are in the 300(0)F to 425(0)F temperature range. Cost effective conversion of the geothermal energy to electricity requires new ideas to improve conversion efficiency, enhance brine flow, reduce plant costs, increase plant availability, and shorten the time between investment and return. The problems addressed are those inherent in the geothermal environment, in the binary fluid cycle, in the difficulty of efficiently converting the energy of a low temperature resource, and in geothermal economics some of these problems are explained. The energy expended by the down hole pump; the difficulty in designing reliable down hole equipment; fouling of heat exchanger surfaces by geothermal fluids; the unavailability of condenser cooling water at most geothermal sites; the large portion of the available energy used by the feed pump in a binary system; the pinch effect, a loss in available energy in transferring heat from water to an organic fluid; flow losses in fluids that carry only a small amount of useful energy to begin with; high heat exchanger costs, the lower the temperature interval of the cycle, the higher the heat exchanger costs in $/kW; the complexity and cost of the many auxiliary elements of proposed geothermal plants; and the unfortunate cash flow vs. investment curve caused by the many years of investment required to bring a field into production before any income is realized.

  2. Economic study of low temperature geothermal energy in Lassen and Modoc counties, California

    Energy Technology Data Exchange (ETDEWEB)

    None

    1977-04-01

    The purpose of this study was to investigate the feasibility of using low cost, low temperature geothermal energy in job-producing industries to increase employment and encourage economic development. The study, encompassing all of Lassen and modoc Counties, was to be site-specific, referencing candidate geothermal applications to known hot wells and springs as previously determined, or to new wells with specific characteristics as defined in the Scope of Work. The emphasis was to be placed on economically practical and readily achievable applications from known resources, thus complimenting the recently completed ERDA-Susanville Study where a designated community was used as a ''laboratory'' in which land-use planning, institutional aspects, geological assessments, technical modeling and socioeconomic impacts were all examined in overview. During the course of the study, monthly progress reports were prepared and reviewed with the Commission so that emphasis on particular features of study could be changed as necessary to reflect updated findings and to redirect efforts into additional areas of potential promise as they became apparent. In this manner, a degree of flexibility was maintained which allowed a more comprehensive study than would have been otherwise possible. Although the report generates both positive and negative findings in specific areas of investigation, it is felt that the overall long term prognosis for geothermal energy stimulus to industry in the area is excellent.

  3. Microearthquake Study of the Salton Sea Geothermal Field, California: Evidence of Stress Triggering

    International Nuclear Information System (INIS)

    Holland, Austin A.

    2002-01-01

    A digital network of 24 seismograph stations was operated from September 15, 1987 to September 30, 1988, by Lawrence Livermore National Laboratory and Unocal as part of the Salton Sea Scientific Drilling Project to study seismicity related to tectonics and geothermal activity near the drilling site. More than 2001 microearthquakes were relocated in this study in order to image any pervasive structures that may exist within the Salton Sea geothermal field. First, detailed velocity models were obtained through standard 1-D inversion techniques. These velocity models were then used to relocate events using both single event methods and Double-Differencing, a joint hypocenter location method. An anisotropic velocity model was built from anisotropy estimates obtained from well logs within the study area. During the study period, the Superstition Hills sequence occurred with two moderate earthquakes of MS 6.2 and MS 6.6. These moderate earthquakes caused a rotation of the stress field as observed from the inversion of first motion data from microearthquakes at the Salton Sea geothermal field. Coulomb failure analysis also indicates that microearthquakes occurring after the Superstition Hills sequence are located within a region of stress increase suggesting stress triggering caused by the moderate earthquakes

  4. Synthetic Modeling of A Geothermal System Using Audio-magnetotelluric (AMT) and Magnetotelluric (MT)

    Science.gov (United States)

    Mega Saputra, Rifki; Widodo

    2017-04-01

    Indonesia has 40% of the world’s potential geothermal resources with estimated capacity of 28,910 MW. Generally, the characteristic of the geothermal system in Indonesia is liquid-dominated systems, which driven by volcanic activities. In geothermal exploration, electromagnetic methods are used to map structures that could host potential reservoirs and source rocks. We want to know the responses of a geothermal system using synthetic data of Audio-magnetotelluric (AMT) and Magnetotelluric (MT). Due to frequency range, AMT and MT data can resolve the shallow and deeper structure, respectively. 1-D models have been performed using AMT and MT data. The results indicate that AMT and MT data give detailed conductivity distribution of geothermal structure.

  5. Seismic Fracture Characterization Methodologies for Enhanced Geothermal Systems

    Energy Technology Data Exchange (ETDEWEB)

    Queen, John H. [Hi-Geophysical, Inc., Ponca, OK (United States)

    2016-05-09

    Executive Summary The overall objective of this work was the development of surface and borehole seismic methodologies using both compressional and shear waves for characterizing faults and fractures in Enhanced Geothermal Systems. We used both surface seismic and vertical seismic profile (VSP) methods. We adapted these methods to the unique conditions encountered in Enhanced Geothermal Systems (EGS) creation. These conditions include geological environments with volcanic cover, highly altered rocks, severe structure, extreme near surface velocity contrasts and lack of distinct velocity contrasts at depth. One of the objectives was the development of methods for identifying more appropriate seismic acquisition parameters for overcoming problems associated with these geological factors. Because temperatures up to 300º C are often encountered in these systems, another objective was the testing of VSP borehole tools capable of operating at depths in excess of 1,000 m and at temperatures in excess of 200º C. A final objective was the development of new processing and interpretation techniques based on scattering and time-frequency analysis, as well as the application of modern seismic migration imaging algorithms to seismic data acquired over geothermal areas. The use of surface seismic reflection data at Brady's Hot Springs was found useful in building a geological model, but only when combined with other extensive geological and geophysical data. The use of fine source and geophone spacing was critical in producing useful images. The surface seismic reflection data gave no information about the internal structure (extent, thickness and filling) of faults and fractures, and modeling suggests that they are unlikely to do so. Time-frequency analysis was applied to these data, but was not found to be significantly useful in their interpretation. Modeling does indicate that VSP and other seismic methods with sensors located at depth in wells will be the most

  6. Hawaii geothermal project

    Science.gov (United States)

    Kamins, R. M.

    1974-01-01

    Hawaii's Geothermal Project is investigating the occurrence of geothermal resources in the archipelago, initially on the Island of Hawaii. The state's interest in geothermal development is keen, since it is almost totally dependent on imported oil for energy. Geothermal development in Hawaii may require greater participation by the public sector than has been true in California. The initial exploration has been financed by the national, state, and county governments. Maximization of net benefits may call for multiple use of geothermal resources; the extraction of by-products and the application of treated effluents to agricultural and aquacultural uses.

  7. The hydrothermal evolution of the Kawerau geothermal system, New Zealand

    Science.gov (United States)

    Milicich, S. D.; Chambefort, I.; Wilson, C. J. N.; Charlier, B. L. A.; Tepley, F. J.

    2018-03-01

    Hydrothermal alteration zoning and processes provide insights into the evolution of heat source(s) and fluid compositions associated with geothermal systems. Traditional petrological techniques, combined with hydrothermal alteration studies, stable isotope analyses and geochronology can resolve the nature of the fluids involved in hydrothermal processes and their changes through time. We report here new findings along with previous unpublished works on alteration patterns, fluid inclusion measurements and stable isotope data to provide insights into the thermal and chemical evolution of the Kawerau geothermal system, New Zealand. These data indicate the presence of two hydrothermal events that can be coupled with chronological data. The earlier period of hydrothermal activity was initiated at 400 ka, with the heat driving the hydrothermal system inferred to be from the magmatic system that gave rise to rhyolite lavas and sills of the Caxton Formation. Isotopic data fingerprint fluids attributed to this event as meteoric, indicating that the magma primarily served as a heat source driving fluid circulation, and was not releasing magmatic fluids in sufficient quantity to affect the rock mineralogy and thus inferred fluid compositions. The modern Kawerau system was initiated at 16 ka with hydrothermal eruptions linked to shallow intrusion of magma at the onset of activity that gave rise to the Putauaki andesite cone. Likely associated with this later event was a pulse of magmatic CO2, resulting in large-scale deposition of hydrothermal calcite enriched in 18O. Meteoric water-dominated fluids subsequently overwhelmed the magmatic fluids associated with this 18O-rich signature, and both the fluid inclusion microthermometry and stable isotope data reflect a change to the present-day fluid chemistry of low salinity, meteoric-dominated waters.

  8. Hydrogen energy system in California

    International Nuclear Information System (INIS)

    Zweig, R.M.

    1995-01-01

    Results of experiences on the use of hydrogen as a clean burning fuel in California and results of the South Coast Air Quality Management district tests using hydrogen as a clean burning environmentally safe fuel are given. The results of Solar Hydrogen Projects in California and recent medical data documentation of human lung damage of patients living in air polluted urban areas are summarized

  9. Supporting Continuous Improvement in California's Education System

    Science.gov (United States)

    Darling-Hammond, Linda; Plank, David N.

    2015-01-01

    California's new accountability system originated in the radical decentralization of power and authority from Sacramento to local schools and their communities brought about by the Legislature's adoption of the Local Control Funding Formula (LCFF) in 2013. Under California's previous accountability policies and the federal "No Child Left…

  10. State-of-the-art of liquid waste disposal for geothermal energy systems: 1979. Report PNL-2404

    Energy Technology Data Exchange (ETDEWEB)

    Defferding, L.J.

    1980-06-01

    The state-of-the-art of geothermal liquid waste disposal is reviewed and surface and subsurface disposal methods are evaluated with respect to technical, economic, legal, and environmental factors. Three disposal techniques are currently in use at numerous geothermal sites around the world: direct discharge into surface waters; deep-well injection; and ponding for evaporation. The review shows that effluents are directly discharged into surface waters at Wairakei, New Zealand; Larderello, Italy; and Ahuachapan, El Salvador. Ponding for evaporation is employed at Cerro Prieto, Mexico. Deep-well injection is being practiced at Larderello; Ahuachapan; Otake and Hatchobaru, Japan; and at The Geysers in California. All sites except Ahuachapan (which is injecting only 30% of total plant flow) have reported difficulties with their systems. Disposal techniques used in related industries are also reviewed. The oil industry's efforts at disposal of large quantities of liquid effluents have been quite successful as long as the effluents have been treated prior to injection. This study has determined that seven liquid disposal methods - four surface and three subsurface - are viable options for use in the geothermal energy industry. However, additional research and development is needed to reduce the uncertainties and to minimize the adverse environmental impacts of disposal. (MHR)

  11. A new idea: The possibilities of offshore geothermal system in Indonesia marine volcanoes

    Science.gov (United States)

    Rahat Prabowo, Teguh; Fauziyyah, Fithriyani; Suryantini; Bronto, Sutikno

    2017-12-01

    High temperature geothermal systems in Indonesia are commonly associated with volcanic systems. It is believed that volcanoes are acting as the heat source for a geothermal system. Right now, most of the operating geothermal fields in the world are assosiating with volcanic settings which known as the conventional geothermal system. Volcanoes are created in active tectonic zone such as collision zone and MOR (mid oceanic ridge). The later is the one which formed the marine volcanoes on the sea floor. The advances of today’s technology in geothermal energy has created many ideas regarding a new kind of geothermal system, including the ideas of developing the utilization of marine volcanoes. These marine volcanoes are predicted to be hotter than the land system due to the shorter distance to the magma chamber. Seamounts like NEC, Banua Wuhu, and Kawio Barat in Indonesia Sea are good spots to be studied. Methods such as remote sensing using NOAA images, sonar, and MAPR are commonly used, eventhough these would be more accurate with more detailed techniques. This has become the challenge for all geothermal scientists to overcome for a better study result.

  12. THE PROBLEM OF ENERGY EFFICIENCY OF THE GEOTHERMAL CIRCULATION SYSTEM IN DIFFERENT MODES OF REINJECTION OF THE COOLANT

    OpenAIRE

    D. K. Djavatov; A. A. Azizov

    2017-01-01

    Aim. Advanced technologies are crucial for widespread use of geothermal energy to ensure its competitiveness with conventional forms of energy. To date, the basis for the development of geothermal energy is the technology of extracting the heat transfer fluids from the subsoil. There are the following ways to extract the coolant: freeflow; pumping and circular methods. Of greatest interest is the technology to harness the geothermal energy based on geothermal circulatory system (GCS). There i...

  13. ThermoGIS - An integrated web-based information system for geothermal exploration and governmental decision support for M

    NARCIS (Netherlands)

    Kramers, L.; Wees, J.D.A.M. van; Mijnlieff, H.F.; Kronimus, R.A.

    2010-01-01

    The use of geothermal energy through implementation of low enthalpy geothermal production systems for both electricity and heating has been growing rapidly in Europe. Geothermal activities can take considerable advantage of a wealth of existing oil and gas data. It is a major challenge to put this

  14. Tracer Methods for Characterizing Fracture Creation in Engineered Geothermal Systems

    Energy Technology Data Exchange (ETDEWEB)

    Rose, Peter [Energy & Geoscience Institute at the University of Utah, Salt Lake City, UT (United States); Harris, Joel [Univ. of Utah, Salt Lake City, UT (United States)

    2014-05-08

    The aim of this proposal is to develop, through novel high-temperature-tracing approaches, three technologies for characterizing fracture creation within Engineered Geothermal Systems (EGS). The objective of a first task is to identify, develop and demonstrate adsorbing tracers for characterizing interwell reservoir-rock surface areas and fracture spacing. The objective of a second task is to develop and demonstrate a methodology for measuring fracture surface areas adjacent to single wells. The objective of a third task is to design, fabricate and test an instrument that makes use of tracers for measuring fluid flow between newly created fractures and wellbores. In one method of deployment, it will be used to identify qualitatively which fractures were activated during a hydraulic stimulation experiment. In a second method of deployment, it will serve to measure quantitatively the rate of fluid flowing from one or more activated fracture during a production test following a hydraulic stimulation.

  15. Geothermal reservoir simulation of hot sedimentary aquifer system using FEFLOW®

    Science.gov (United States)

    Nur Hidayat, Hardi; Gala Permana, Maximillian

    2017-12-01

    The study presents the simulation of hot sedimentary aquifer for geothermal utilization. Hot sedimentary aquifer (HSA) is a conduction-dominated hydrothermal play type utilizing deep aquifer, which is heated by near normal heat flow. One of the examples of HSA is Bavarian Molasse Basin in South Germany. This system typically uses doublet wells: an injection and production well. The simulation was run for 3650 days of simulation time. The technical feasibility and performance are analysed in regards to the extracted energy from this concept. Several parameters are compared to determine the model performance. Parameters such as reservoir characteristics, temperature information and well information are defined. Several assumptions are also defined to simplify the simulation process. The main results of the simulation are heat period budget or total extracted heat energy, and heat rate budget or heat production rate. Qualitative approaches for sensitivity analysis are conducted by using five parameters in which assigned lower and higher value scenarios.

  16. Life Cycle Water Consumption and Water Resource Assessment for Utility-Scale Geothermal Systems: An In-Depth Analysis of Historical and Forthcoming EGS Projects

    Energy Technology Data Exchange (ETDEWEB)

    Clark, Corrie E. [Argonne National Lab. (ANL), Argonne, IL (United States); Harto, Christopher B. [Argonne National Lab. (ANL), Argonne, IL (United States); Schroeder, Jenna N. [Argonne National Lab. (ANL), Argonne, IL (United States); Martino, Louis E. [Argonne National Lab. (ANL), Argonne, IL (United States); Horner, Robert M. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2013-08-01

    and is much warmer than normal groundwater sources, for their cooling water needs; thus, while there is considerable geofluid loss at 2.7 gal/kWh, fresh water consumption during operations is similar to that of aircooled binary systems. Chapter 5 presents the assessment of water demand for future growth in deployment of utility-scale geothermal power generation. The approach combines the life cycle analysis of geothermal water consumption with a geothermal supply curve according to resource type, levelized cost of electricity (LCOE), and potential growth scenarios. A total of 17 growth scenarios were evaluated. In general, the scenarios that assumed lower costs for EGSs as a result of learning and technological improvements resulted in greater geothermal potential, but also significantly greater water demand due to the higher water consumption by EGSs. It was shown, however, that this effect could be largely mitigated if nonpotable water sources were used for belowground operational water demands. The geographical areas that showed the highest water demand for most growth scenarios were southern and northern California, as well as most of Nevada. In addition to water demand by geothermal power production, Chapter 5 includes data on water availability for geothermal development areas. A qualitative analysis is included that identifies some of the basins where the limited availability of water is most likely to affect the development of geothermal resources. The data indicate that water availability is fairly limited, especially under drought conditions, in most of the areas with significant near- and medium-term geothermal potential. Southern California was found to have the greatest potential for water-related challenges with its combination of high geothermal potential and limited water availability. The results of this work are summarized in Chapter 6. Overall, this work highlights the importance of utilizing dry cooling systems for binary and EGS systems and

  17. Performance analyses of a hybrid geothermal–fossil power generation system using low-enthalpy geothermal resources

    International Nuclear Information System (INIS)

    Liu, Qiang; Shang, Linlin; Duan, Yuanyuan

    2016-01-01

    Highlights: • Geothermal energy is used to preheat the feedwater in a coal-fired power unit. • The performance of a hybrid geothermal–fossil power generation system is analyzed. • Models for both parallel and serial geothermal preheating schemes are presented. • Effects of geothermal source temperatures, distances and heat losses are analyzed. • Power increase of the hybrid system over an ORC and tipping distance are discussed. - Abstract: Low-enthalpy geothermal heat can be efficiently utilized for feedwater preheating in coal-fired power plants by replacing some of the high-grade steam that can then be used to generate more power. This study analyzes a hybrid geothermal–fossil power generation system including a supercritical 1000 MW power unit and a geothermal feedwater preheating system. This study models for parallel and serial geothermal preheating schemes and analyzes the thermodynamic performance of the hybrid geothermal–fossil power generation system for various geothermal resource temperatures. The models are used to analyze the effects of the temperature matching between the geothermal water and the feedwater, the heat losses and pumping power during the geothermal water transport and the resource distance and temperature on the power increase to improve the power generation. The serial geothermal preheating (SGP) scheme generally generates more additional power than the parallel geothermal preheating (PGP) scheme for geothermal resource temperatures of 100–130 °C, but the SGP scheme generates slightly less additional power than the PGP scheme when the feedwater is preheated to as high a temperature as possible before entering the deaerator for geothermal resource temperatures higher than 140 °C. The additional power decreases as the geothermal source distance increases since the pipeline pumping power increases and the geothermal water temperature decreases due to heat losses. More than 50% of the power decrease is due to geothermal

  18. Fluid geochemistry and geothermometry applications of the Kangding high-temperature geothermal system in eastern Himalayas

    International Nuclear Information System (INIS)

    Guo, Qi; Pang, Zhonghe; Wang, Yingchun; Tian, Jiao

    2017-01-01

    High-temperature geothermal systems hold an enormous capacity for generating geothermal energy. The Kangding area is a typical high-temperature geothermal field in the Himalayan Geothermal Belt. Hydrogeochemical, gas geochemical and isotopic investigations were performed to identify and qualify the main hydrogeochemical processes affecting thermal water composition, including mixing and degassing, and then to estimate a reliable reservoir temperature. Nine water samples and four geothermal gas samples were collected and analysed for chemical and isotopic components. The results demonstrate the alkaline deep geothermal water is the mixtures of approximately 75% snow-melt water and 25% magmatic water. It is enriched in Na, K, F, Li and other trace elements, indicating the granite reservoir nature. The shallow geothermal water is the mixtures of approximately 30% upward flow of deep geothermal water and 70% meteoric cold water. High concentrations of Ca, Mg and HCO_3 indicate the limestone reservoir nature. There is no remarkable oxygen isotope shift in the geothermal water since the rapid circulation is difficult to trigger off strong water-rock interaction. CO_2 is the predominant geothermal gas, accounting for more than 97% of total gases in volume percentage. The concentration of CO_2 degassing ranged from 0.4 mol L"−"1 to 0.8 mol L"−"1 via geothermometrical modelling. As a result, the geothermal water pH increased from 6.0 to 9.0, and approximately 36% of the total SiO_2 re-precipitate. The sources of CO_2 are the metamorphism of limestone and magmatic degassing based on the composition of carbon isotope. The appropriate geothermometers of Na-K and Na-Li yield reservoir temperature of 280 °C. The geothermometrical modelling, developed to eliminate the effects of CO_2 degassing, yields temperature of 250 °C. The silica-enthalpy mixing model yields temperature of 270 °C with no steam separation before mixing. - Highlights: • Water and gas

  19. Uranium-thorium series radionuclides in brines and reservoir rocks from two deep geothermal boreholes in the Salton Sea geothermal field, southeastern California

    International Nuclear Information System (INIS)

    Zukin, J.G.; Hammond, D.E.; Ku, Tehlung; Elders, W.A.

    1987-01-01

    Naturally occurring U and Th series radionuclides have been analyzed in high temperature brines (∼ 300 degree C, 25 wt% dissolved solids) and associated rocks from two deep geothermal wells located on the northeastern margin of the Salton Sea Geothermal Field (SSGF). These data are part of a study of the SSGF as a natural analog of possible radionuclide behavior near a nuclear waste repository constructed in salt beds, and permit evaluation of some characteristics of water-rock interaction in the SSGF

  20. High-Temperature-High-Volume Lifting for Enhanced Geothermal Systems

    Energy Technology Data Exchange (ETDEWEB)

    Turnquist, Norman [GE Global Research, Munchen (Germany); Qi, Xuele [GE Global Research, Munchen (Germany); Raminosoa, Tsarafidy [GE Global Research, Munchen (Germany); Salas, Ken [GE Global Research, Munchen (Germany); Samudrala, Omprakash [GE Global Research, Munchen (Germany); Shah, Manoj [GE Global Research, Munchen (Germany); Van Dam, Jeremy [GE Global Research, Munchen (Germany); Yin, Weijun [GE Global Research, Munchen (Germany); Zia, Jalal [GE Global Research, Munchen (Germany)

    2013-12-20

    This report summarizes the progress made during the April 01, 2010 – December 30, 2013 period under Cooperative Agreement DE-EE0002752 for the U.S. Department of Energy entitled “High-Temperature-High-Volume Lifting for Enhanced Geothermal Systems.” The overall objective of this program is to advance the technology for well fluids lifting systems to meet the foreseeable pressure, temperature, and longevity needs of the Enhanced Geothermal Systems (EGS) industry for the coming ten years. In this program, lifting system requirements for EGS wells were established via consultation with industry experts and site visits. A number of artificial lift technologies were evaluated with regard to their applicability to EGS applications; it was determined that a system based on electric submersible pump (ESP) technology was best suited to EGS. Technical barriers were identified and a component-level technology development program was undertaken to address each barrier, with the most challenging being the development of a power-dense, small diameter motor that can operate reliably in a 300°C environment for up to three years. Some of the targeted individual component technologies include permanent magnet motor construction, high-temperature insulation, dielectrics, bearings, seals, thrust washers, and pump impellers/diffusers. Advances were also made in thermal management of electric motors. In addition to the overall system design for a full-scale EGS application, a subscale prototype was designed and fabricated. Like the full-scale design, the subscale prototype features a novel “flow-through-the-bore” permanent magnet electric motor that combines the use of high temperature materials with an internal cooling scheme that limits peak internal temperatures to <330°C. While the full-scale high-volume multi-stage pump is designed to lift up to 80 kg/s of process water, the subscale prototype is based on a production design that can pump 20 kg/s and has been modified

  1. University Campus Bielefeld. Geothermal systems built-up points; Hochschulcampus Bielefeld. Erdwaermesysteme in Bebauungsschwerpunkten

    Energy Technology Data Exchange (ETDEWEB)

    Kohlsch, Oliver; Heske, Claus [CDM Smith, Bochum (Germany); Bussmann, Werner [MEDIAfrac, Geeste (Germany)

    2012-07-01

    Three new buildings with greater geothermal plants are established on the area of the University Campus Bielefeld (Federal Republic of Germany). Due to the more than 100 geothermal probes as well as due to more than 400 energy piles within a radius of only 500 meter, extremely high demands are made on the planning of geothermal energy systems. The mutual interference of the different systems, the impacts on the surrounding buildings as well as the official requirements and the obligations on the later monitoring had to be considered.

  2. Geothermal Today - 1999

    Energy Technology Data Exchange (ETDEWEB)

    None

    2000-05-01

    U.S. Department of Energy 1999 Geothermal Energy Program Highlights The Hot Facts Getting into Hot Water Turning Waste water into Clean Energy Producing Even Cleaner Power Drilling Faster and Cheaper Program in Review 1999: The Year in Review JanuaryCal Energy announced sale of Coso geothermal power plants at China Lake, California, to Caithness Energy, for $277 million. U.S. Export-Import Bank completed a $50 million refinancing of the Leyte Geothermal Optimization Project in the Philippines. F

  3. Micro-seismicity and seismic moment release within the Coso Geothermal Field, California

    Science.gov (United States)

    Kaven, Joern; Hickman, Stephen H.; Davatzes, Nicholas C.

    2014-01-01

    We relocate 16 years of seismicity in the Coso Geothermal Field (CGF) using differential travel times and simultaneously invert for seismic velocities to improve our knowledge of the subsurface geologic and hydrologic structure. We expand on our previous results by doubling the number of relocated events from April 1996 through May 2012 using a new field-wide 3-D velocity model. Relocated micro-seismicity sharpens in many portions of the active geothermal reservoir, likely defining large-scale fault zones and fluid pressure compartment boundaries. However, a significant fraction of seismicity remains diffuse and does not cluster into sharply defined structures, suggesting that permeability is maintained within the reservoir through distributed brittle failure. The seismic velocity structure reveals heterogeneous distributions of compressional (Vp) and shear (Vs) wave speed, with Vs generally higher in the Main Field and East Flank and Vp remaining relatively uniform across the CGF, but with significant local variations. The Vp/Vs ratio appears to outline the two main producing compartments of the reservoir at depths below mean ground level of approximately 1 to 2.5 km, with a ridge of relatively high Vp/Vs separating the Main Field from the East Flank. Detailed analyses of spatial and temporal variations in earthquake relocations and cumulative seismic moment release in the East Flank reveal three regions with persistently high rates of seismic activity. Two of these regions exhibit sharp, stationary boundaries at the margins of the East Flank that likely represent barriers to fluid flow and advective heat transport. However, seismicity and moment release in a third region at the northern end of the East Flank spread over time to form an elongated NE to SW structure, roughly parallel both to an elongated cluster of seismicity at the southern end of the East Flank and to regional fault traces mapped at the surface. Our results indicate that high

  4. Exergoeconomic optimization of integrated geothermal system in Simav, Kutahya

    International Nuclear Information System (INIS)

    Arslan, Oguz; Kose, Ramazan

    2010-01-01

    The aim of this study is to investigate the integrated use of the geothermal resources in the Kutahya-Simav region, Turkey. Although geothermal energy has been in use for years in the others countries, the integrated use of the geothermal fluid is new in Turkey. The high temperature level of the geothermal fluid in the Simav field makes it possible to utilize it for electricity generation, space heating and balneology. In this regard, a multiple complex has been proposed there in order to use the energy of the geothermal fluid more efficiently. Therefore, the possibility of electricity generation by a binary cycle has been preliminarily researched. After the electricity generation process, the waste geothermal fluid has been conducted to residences and greenhouses later for heating purpose in the field. In this regard, twenty one different models have been formed and analyzed using exergy and LCC methods. As a conclusion, the pre-feasibility study indicates that utilization of this geothermal capacity for multiple uses would be an attractive investment for Simav region.

  5. Characterisation of induced fracture networks within an enhanced geothermal system using anisotropic electromagnetic modelling

    Czech Academy of Sciences Publication Activity Database

    MacFarlane, J.; Thiel, S.; Pek, Josef; Peacock, J.; Heinson, G.

    2014-01-01

    Roč. 288, November (2014), s. 1-7 ISSN 0377-0273 Institutional support: RVO:67985530 Keywords : geothermal systems * magnetotellurics * fluid injection Subject RIV: DE - Earth Magnetism, Geodesy, Geography Impact factor: 2.543, year: 2014

  6. National Geothermal Data System State Contributions by Data Type (Appendix A1-b)

    Energy Technology Data Exchange (ETDEWEB)

    Love, Diane [Executive Office of the State of Arizona (Arizona Geological Survey)

    2015-12-20

    Multipaged spreadsheet listing an inventory of data submissions to the State contributions to the National Geothermal Data System project by services, by state, by metadata compilations, metadata, and map count, including a summary of information.

  7. Integration of deep geothermal energy and woody biomass conversion pathways in urban systems

    International Nuclear Information System (INIS)

    Moret, Stefano; Peduzzi, Emanuela; Gerber, Léda; Maréchal, François

    2016-01-01

    Highlights: • Novel optimization-based methodology to integrate renewable energy systems in cities. • Multiperiod model including storage, heat integration and Life Cycle Assessment. • Case study: systematic assessment of deep geothermal and wood conversion pathways. • Identification of novel wood-geothermal hybrid systems leading to higher efficiencies. • Extensive Supplementary Material to ensure full reproducibility of the work. - Abstract: Urban systems account for about two-thirds of global primary energy consumption and energy-related greenhouse gas emissions, with a projected increasing trend. Deep geothermal energy and woody biomass can be used for the production of heat, electricity and biofuels, thus constituting a renewable alternative to fossil fuels for all end-uses in cities: heating, cooling, electricity and mobility. This paper presents a methodology to assess the potential for integrating deep geothermal energy and woody biomass in an urban energy system. The city is modeled in its entirety as a multiperiod optimization problem with the total annual cost as an objective, assessing as well the environmental impact with a Life Cycle Assessment approach. For geothermal energy, deep aquifers and Enhanced Geothermal Systems are considered for stand-alone production of heat and electricity, and for cogeneration. For biomass, besides direct combustion and cogeneration, conversion to biofuels by a set of alternative processes (pyrolysis, Fischer-Tropsch synthesis and synthetic natural gas production) is studied. With a scenario-based approach, all pathways are first individually evaluated. Secondly, all possible combinations between geothermal and biomass options are systematically compared, taking into account the possibility of hybrid systems. Results show that integrating these two resources generates configurations featuring both lower costs and environmental impacts. In particular, synergies are found in innovative hybrid systems using

  8. An evaluation of interferences in heat production from low enthalpy geothermal doublets systems

    DEFF Research Database (Denmark)

    Willems, Cees J. L.; Nick, Hamidreza M.; Weltje, Gert Jan

    2017-01-01

    Required distance between doublet systems in low enthalpy geothermal heat exploitation is often not fully elucidated. The required distance aims to prevent negative interference influencing the utilisation efficiency of doublet systems. Currently production licence areas are often issued based...... and minimal required production temperature. The results of this study can be used to minimize negative interference or optimise positive interference aiming at improving geothermal doublet deployment efficiency. (C) 2017 The Authors. Published by Elsevier Ltd....

  9. Enhanced Geothermal System Development of the AmeriCulture Leasehold in the Animas Valley; FINAL

    International Nuclear Information System (INIS)

    Duchane, David V; Seawright, Gary L; Sewright, Damon E; Brown, Don; Witcher, James c.; Nichols, Kenneth E.

    2001-01-01

    Working under the grant with AmeriCulture, Inc., and its team of geothermal experts, assembled a plan to apply enhanced geothermal systems (EGS) techniques to increase both the temperature and flow rate of the geothermal waters on its leasehold. AmeriCulture operates a commercial aquaculture facility that will benefit from the larger quantities of thermal energy and low cost electric power that EGS technology can provide. The project brought together a team of specialists that, as a group, provided the full range of expertise required to successfully develop and implement the project

  10. Enhanced Geothermal Systems (EGS) R&D Program: Monitoring EGS-Related Research

    Energy Technology Data Exchange (ETDEWEB)

    McLarty, Lynn; Entingh, Daniel; Carwile, Clifton

    2000-09-29

    This report reviews technologies that could be applicable to Enhanced Geothermal Systems development. EGS covers the spectrum of geothermal resources from hydrothermal to hot dry rock. We monitored recent and ongoing research, as reported in the technical literature, that would be useful in expanding current and future geothermal fields. The literature review was supplemented by input obtained through contacts with researchers throughout the United States. Technologies are emerging that have exceptional promise for finding fractures in nonhomogeneous rock, especially during and after episodes of stimulation to enhance natural permeability.

  11. Protocol for Addressing Induced Seismicity Associated with Enhanced Geothermal Systems

    Energy Technology Data Exchange (ETDEWEB)

    Majer, Ernie [Office of Energy Efficiency and Renewable Energy (EERE), Washington, DC (United States); Nelson, James [Office of Energy Efficiency and Renewable Energy (EERE), Washington, DC (United States); Robertson-Tait, Ann [Office of Energy Efficiency and Renewable Energy (EERE), Washington, DC (United States); Savy, Jean [Office of Energy Efficiency and Renewable Energy (EERE), Washington, DC (United States); Wong, Ivan [Office of Energy Efficiency and Renewable Energy (EERE), Washington, DC (United States)

    2012-01-01

    This Protocol is a living guidance document for geothermal developers, public officials, regulators and the general public that provides a set of general guidelines detailing useful steps to evaluate and manage the effects of induced seismicity related to EGS projects.

  12. Stable isotope studies of some low enthalpy geothermal systems in Kenya

    Science.gov (United States)

    Tole, Mwakio P.

    Oxygen and hydrogen isotope compositions of some low enthalpy geothermal systems in Kenya have been determined. Plots on δ 18O versus δD diagrams show that the compositions do not deviate appreciably from local meteoric water values. This would indicate that local meteoric waters are heated at depth and rise to the surface without much interaction with the country rocks. This is interpreted to be the case for the geothermal systems at Majimoto and Narosura, which have salinities of less than 350 ppm TDS and calculated reservoir temperatures of less than 110°C. The geothermal systems at Kapedo and Homa mountain which have high salinities (> 2 000 ppm TDS) and relatively higher calculated reservoir temperatures (> 150° C) are interpreted to have been operating for long periods of time, such that the rocks through which the present day geothermal waters are circulating have attained isotopic equilibrium with local meteoric waters.

  13. 3D characterization of a Great Basin geothermal system: Astor Pass, NV

    Science.gov (United States)

    Siler, D. L.; Mayhew, B.; Faulds, J. E.

    2012-12-01

    The Great Basin exhibits both anomalously high heat flow (~75±5 mWm-2) and active faulting and extension resulting in robust geothermal activity. There are ~430 known geothermal systems in the Great Basin, with evidence suggesting that undiscovered blind geothermal systems may actually represent the majority of geothermal activity. These systems employ discrete fault intersection/interaction areas as conduits for geothermal circulation. Recent studies show that steeply dipping normal faults with step-overs, fault intersections, accommodation zones, horse-tailing fault terminations and transtensional pull-aparts are the most prominent structural controls of Great Basin geothermal systems. These fault geometries produce sub-vertical zones of high fault and fracture density that act as fluid flow conduits. Structurally controlled fluid flow conduits are further enhanced when critically stressed with respect to the ambient stress conditions. The Astor Pass blind geothermal system, northwestern Nevada, lies along the boundary between the Basin and Range to the east and the Walker Lane to the west. Along this boundary, strain is transferred from dextral shear in the Walker Lane to west-northwest directed extension in the Basin and Range. As such, the Astor Pass area lies in a transtensional setting consisting of both northwest-striking, left-stepping dextral faults and more northerly striking normal faults. The Astor Pass tufa tower implies the presence of a blind geothermal system. Previous studies suggest that deposition of the Astor Pass tufa was controlled by the intersection of a northwest-striking dextral normal fault and north-northwest striking normal fault. Subsequent drilling (to ~1200 m) has revealed fluid temperatures of ~94°C, confirming the presence of a blind geothermal system at Astor Pass. Expanding upon previous work and employing additional detailed geologic mapping, interpretation of 2D seismic reflection data and analysis of well cuttings, a 3

  14. Geothermal energy

    International Nuclear Information System (INIS)

    Lemale, J.

    2009-01-01

    The geothermal energy, listed among the new and renewable energy sources, is characterized by a huge variety of techniques and applications. This book deals with the access to underground geothermal resources and with their energy valorization as well. After a presentation of the main geological, hydrogeological and thermal exploitation aspects of this resource, the book presents the different geothermal-related industries in detail, in particular the district heating systems, the aquifer-based heat pumps, the utilizations in the agriculture, fishery and balneology sectors, and the power generation. (J.S.)

  15. Geochemical features of the geothermal fluids from the Mapamyum non-volcanic geothermal system (Western Tibet, China)

    Science.gov (United States)

    Wang, Peng; Chen, Xiaohong; Shen, Licheng; Wu, Kunyu; Huang, Mingzhi; Xiao, Qiong

    2016-06-01

    Mapamyum geothermal field (MGF) in western Tibet is one of largest geothermal areas characterized by the occurrence of hydrothermal explosions on the Tibetan Plateau. The geochemical properties of hydrothermal water in the MGF system were investigated to trace the origin of the solutes and to determine the equilibrium temperatures of the feeding reservoir. The study results show that the geochemistry of hydrothermal waters in the MGF system is mainly of the Na-HCO3 type. The chemical components of hydrothermal waters are mainly derived from the minerals in the host rocks (e.g., K-feldspar, albite, Ca-montmorillonite, and Mg-montmorillonite). The hydrothermal waters are slightly supersaturated or undersaturated with respect to aragonite, calcite, dolomite, chalcedony and quartz (saturation indices close to 0), but are highly undersaturated with respect to gypsum and anhydrite (saturation indices < 0). Mixing models and Na-K-Mg ternary diagrams show that strong mixing between cold meteoric water and deeply-seated thermal fluids occurred during the upward flowing process. δD and δ18O data confirm that the meteoric water acts as the water source of the geothermal waters. An 220 °C equilibrated reservoir temperature of hydrothermal spring waters was calculated via both the Na-K-Mg ternary diagrams and the cationic chemical geothermometers. The logpCO2 of hydrothermal waters in the MGF system ranges from - 2.59 to - 0.57 and δ13C of the total dissolved inorganic carbon ranges from - 5.53‰ to - 0.94‰, suggesting that the carrier CO2 in hydrothermal water are mainly of a magmatic or metamorphic CO2 origin.

  16. Recovery Act: Geothermal Data Aggregation: Submission of Information into the National Geothermal Data System, Final Report DOE Project DE-EE0002852 June 24, 2014

    Energy Technology Data Exchange (ETDEWEB)

    Blackwell, David D. [SMU Geothermal Laboratory; Chickering Pace, Cathy [SMU Geothermal Laboratory; Richards, Maria C. [SMU Geothermal Laboratory

    2014-06-24

    The National Geothermal Data System (NGDS) is a Department of Energy funded effort to create a single cataloged source for a variety of geothermal information through a distributed network of databases made available via web services. The NGDS will help identify regions suitable for potential development and further scientific data collection and analysis of geothermal resources as a source for clean, renewable energy. A key NGDS repository or ‘node’ is located at Southern Methodist University developed by a consortium made up of: • SMU Geothermal Laboratory • Siemens Corporate Technology, a division of Siemens Corporation • Bureau of Economic Geology at the University of Texas at Austin • Cornell Energy Institute, Cornell University • Geothermal Resources Council • MLKay Technologies • Texas Tech University • University of North Dakota. The focus of resources and research encompass the United States with particular emphasis on the Gulf Coast (on and off shore), the Great Plains, and the Eastern U.S. The data collection includes the thermal, geological and geophysical characteristics of these area resources. Types of data include, but are not limited to, temperature, heat flow, thermal conductivity, radiogenic heat production, porosity, permeability, geological structure, core geophysical logs, well tests, estimated reservoir volume, in situ stress, oil and gas well fluid chemistry, oil and gas well information, and conventional and enhanced geothermal system related resources. Libraries of publications and reports are combined into a unified, accessible, catalog with links for downloading non-copyrighted items. Field notes, individual temperature logs, site maps and related resources are included to increase data collection knowledge. Additional research based on legacy data to improve quality increases our understanding of the local and regional geology and geothermal characteristics. The software to enable the integration, analysis, and

  17. Resource investigation of low- and moderate-temperature geothermal areas in Paso Robles, California

    Energy Technology Data Exchange (ETDEWEB)

    Campion, L.F.; Chapman, R.H.; Chase, G.W.; Youngs, L.G.

    1983-01-01

    Ninety-eight geothermal wells and springs were identified and plotted, and a geologic map and cross sections were compiled. Detailed geophysical, geochemical, and geological surveys were conducted. The geological and geophysical work delineated the basement highs and trough-like depressions that can exercise control on the occurrence of the thermal waters. The Rinconada fault was also evident. Cross sections drawn from oil well logs show the sediments conforming against these basement highs and filling the depressions. It is along the locations where the sediments meet the basement highs that three natural warm springs in the area occur. Deep circulation of meteoric waters along faults seems to be a reasonable source for the warm water. The Santa Margarita, Pancho Rico, and Paso Robles Formations would be the first permeable zones that abut the faults through which water would enter. Temperatures and interpretation of well logs indicate the warmest aquifer at the base of the Paso Robles Formation. Warm water may be entering higher up in the section, but mixing with water from cooler zones seems to be evident. Geothermometry indicates reservoir temperatures could be as high as 91/sup 0/C (196/sup 0/F).

  18. Applicability of `GREATEM' system in mapping geothermal regions in volcanic areas

    Science.gov (United States)

    Verma, S. K.; Mogi, T.; Abd Allah, S.

    2010-12-01

    The ‘GREATEM’ helicopter borne TEM system employs a long grounded cable as transmitter while a light weight receiver coil is flown below a helicopter. This arrangement greatly simplifies the flying logistics and speed of the survey. Also there is very little reduction in the anomaly amplitude when the survey altitude is increased. This is a great advantage particularly in volcanic regions usually having rough topography, as the ‘GREATEM’ survey can be done with helicopter flying at a safe height. Many volcanic areas have anomalous geothermal regions containing hydrothermal fluids. Eruption of volcanoes may cause changes in the thermal character and spatial distribution of these regions. Mapping of these regions is important as they may be associated with hazards. Sometimes, if the temperature is high and volume of the geothermal region is large, they can provide a good source of geothermal energy. Applicability of ‘GREATEM’ system in mapping geothermal regions in volcanic areas is studied by numerical modeling. We have considered a 3D conductor at a shallow depth (50 t0 100m), representing the anomalous geothermal region with dimensions of 500m X 500m X 500m. Different types of geological host environment are considered by varying their resistivities from 10 Ohm.m to 2000 Ohm.m. The ‘GREATEM’ response is analyzed as ‘Percentage Difference (PD)’ over the response produced by the host environment. It is found that the “GREATEM’ system can delineate the geothermal region well. Many geothermal regions are associated with a deeper (> 1 km) reservoir of much larger dimensions. In this situation also it is found that the ‘GREATEM’ system can pick up the response of the shallower geothermal region against the background response of different types of geological host environment containing the deeper reservoir (Figure 1).

  19. Integration of deep geothermal energy and woody biomass conversion pathways in urban systems

    OpenAIRE

    Moret, Stefano; Peduzzi, Emanuela; Gerber, Léda; Maréchal, François

    2016-01-01

    Urban systems account for about two-thirds of global primary energy consumption and energy-related greenhouse gas emissions, with a projected increasing trend. Deep geothermal energy and woody biomass can be used for the production of heat, electricity and biofuels, thus constituting a renewable alternative to fossil fuels for all end-uses in cities: heating, cooling, electricity and mobility. This paper presents a methodology to assess the potential for integrating deep geothermal energy and...

  20. Empirical Green's tensor retrieved from ambient noise cross-correlations at The Geysers geothermal field, Northern California

    Science.gov (United States)

    Nayak, Avinash; Taira, Taka'aki; Dreger, Douglas S.; Gritto, Roland

    2018-04-01

    We retrieve empirical Green's functions in the frequency range (˜0.2-0.9 Hz) for interstation distances ranging from ˜1 to ˜30 km (˜0.22 to ˜6.5 times the wavelength) at The Geysers geothermal field, Northern California, from coherency of ambient seismic noise being recorded by a variety of sensors (broad-band, short-period surface and borehole sensors, and one accelerometer). The applied methodology preserves the intercomponent relative amplitudes of the nine-component Green's tensor that allows us to directly compare noise-derived Green's functions (NGFs) with normalized displacement waveforms of complete single-force synthetic Green's functions (SGFs) computed with various 1-D and 3-D velocity models using the frequency-wavenumber integration method and a 3-D finite-difference wave propagation method, respectively. These comparisons provide an effective means of evaluating the suitability of different velocity models to different regions of The Geysers, and assessing the quality of the sensors and the NGFs. In the T-Tangential, R-Radial, Z-Vertical reference frame, the TT, RR, RZ, ZR and ZZ components (first component: force direction, second component: response direction) of NGFs show clear surface waves and even body-wave phases for many station pairs. They are also broadly consistent in phase and intercomponent relative amplitudes with SGFs for the known local seismic velocity structure that was derived primarily from body-wave traveltime tomography, even at interstation distances less than one wavelength. We also find anomalous large amplitudes in TR, TZ, RT and ZT components of NGFs at small interstation distances (≲4 km) that can be attributed to ˜10°-30° sensor misalignments at many stations inferred from analysis of longer period teleseismic waveforms. After correcting for sensor misalignments, significant residual amplitudes in these components for some longer interstation distance (≳8 km) paths are better reproduced by the 3-D velocity

  1. Seismic properties of fluid bearing formations in magmatic geothermal systems: can we directly detect geothermal activity with seismic methods?

    Science.gov (United States)

    Grab, Melchior; Scott, Samuel; Quintal, Beatriz; Caspari, Eva; Maurer, Hansruedi; Greenhalgh, Stewart

    2016-04-01

    Seismic methods are amongst the most common techniques to explore the earth's subsurface. Seismic properties such as velocities, impedance contrasts and attenuation enable the characterization of the rocks in a geothermal system. The most important goal of geothermal exploration, however, is to describe the enthalpy state of the pore fluids, which act as the main transport medium for the geothermal heat, and to detect permeable structures such as fracture networks, which control the movement of these pore fluids in the subsurface. Since the quantities measured with seismic methods are only indirectly related with the fluid state and the rock permeability, the interpretation of seismic datasets is difficult and usually delivers ambiguous results. To help overcome this problem, we use a numerical modeling tool that quantifies the seismic properties of fractured rock formations that are typically found in magmatic geothermal systems. We incorporate the physics of the pore fluids, ranging from the liquid to the boiling and ultimately vapor state. Furthermore, we consider the hydromechanics of permeable structures at different scales from small cooling joints to large caldera faults as are known to be present in volcanic systems. Our modeling techniques simulate oscillatory compressibility and shear tests and yield the P- and S-wave velocities and attenuation factors of fluid saturated fractured rock volumes. To apply this modeling technique to realistic scenarios, numerous input parameters need to be indentified. The properties of the rock matrix and individual fractures were derived from extensive literature research including a large number of laboratory-based studies. The geometries of fracture networks were provided by structural geologists from their published studies of outcrops. Finally, the physical properties of the pore fluid, ranging from those at ambient pressures and temperatures up to the supercritical conditions, were taken from the fluid physics

  2. Thermal Effect on Fracture Integrity in Enhanced Geothermal Systems

    Science.gov (United States)

    Zeng, C.; Deng, W.; Wu, C.; Insall, M.

    2017-12-01

    In enhanced geothermal systems (EGS), cold fluid is injected to be heated up for electricity generation purpose, and pre-existing fractures are the major conduits for fluid transport. Due to the relative cold fluid injection, the rock-fluid temperature difference will induce thermal stress along the fracture wall. Such large thermal stress could cause the failure of self-propping asperities and therefore change the fracture integrity, which could affect the heat recovery efficiency and fluid recycling. To study the thermal effect on fracture integrity, two mechanisms pertinent to thermal stress are proposed to cause asperity contact failure: (1) the crushing between two pairing asperities leads to the failure at contact area, and (2) the thermal spalling expedites this process. Finite element modeling is utilized to investigate both failure mechanisms by idealizing the asperities as hemispheres. In the numerical analysis, we have implemented meso-scale damage model to investigate coupled failure mechanism induced by thermomechanical stress field and original overburden pressure at the vicinity of contact point. Our results have shown that both the overburden pressure and a critical temperature determine the threshold of asperity failure. Since the overburden pressure implies the depth of fractures in EGS and the critical temperature implies the distance of fractures to the injection well, our ultimate goal is to locate a region of EGS where the fracture integrity is vulnerable to such thermal effect and estimate the influences.

  3. Uranium-thorium series radionuclides in brines and reservoir rocks from two deep geothermal boreholes in the Salton Sea Geothermal Field, southeastern California

    Science.gov (United States)

    Zukin, Jeffrey G.; Hammond, Douglas E.; Teh-Lung, Ku; Elders, Wilfred A.

    1987-10-01

    Naturally occurring U and Th series radionuclides have been analyzed in high temperature brines (~300°C, 25 wt% dissolved solids) and associated rocks from two deep geothermal wells located on the northeastern margin of the Salton Sea Geothermal Field (SSGF). These data are part of a study of the SSGF as a natural analog of possible radionuclide behavior near a nuclear waste repository constructed in salt beds, and permit evaluation of some characteristics of water-rock interaction in the SSGF. Rock/Brine concentration ratios ( Rc = (dpm/ g) rock/(dpm/ g) brine) were found to vary from near unity for isotopes of Ra, Pb and Rn to about 5 × 10 5 for 232Th. The high sorptivity of 232Th is closely followed by that of 238U and 234U ( Rc ~ 5 × 10 4), suggesting that U is retained in the +4 oxidation state by the reducing conditions in the brines. The relatively high solubility of 210Pb and 212Pb is attributed to formation of chloride complexes, while the high Ra solubility is attributed to chloride complexing, a lack of suitable adsorption sites due to the high brine salinity and temperature, and the reducing conditions that prevent MnO 2 and RaSO 4 from forming. The 228Ra /226Ra ratios in the brines are approximately equal to those of their parents ( 232Th /230Th ) in associated rocks, indicating that Ra equilibration in the brine-rock system is achieved within the mean life of 228Ra (8.3 years). The 224Ra /228Ra ratios in these brines are about 0.7, indicating that either (1) brine composition is not homogeneous and 224Ra decays in fracture zones deficient in Ra and Th as the brine travels to the wellhead or (2) Ra equilibration in the brine-host rock system is not complete within the mean life of 224Ra (5.2 days) because the desorption of 224Ra from the solid phase is impeded. The 228Ac /228Ra activity ratio in the SSGF brines studied is <0.1, and from this ratio the residence time of 228Ac in the brine before sorption onto solid surfaces is estimated to be <70

  4. Feasibility and Supply Analysis of U.S. Geothermal District Heating and Cooling System

    Science.gov (United States)

    He, Xiaoning

    Geothermal energy is a globally distributed sustainable energy with the advantages of a stable base load energy production with a high capacity factor and zero SOx, CO, and particulates emissions. It can provide a potential solution to the depletion of fossil fuels and air pollution problems. The geothermal district heating and cooling system is one of the most common applications of geothermal energy, and consists of geothermal wells to provide hot water from a fractured geothermal reservoir, a surface energy distribution system for hot water transmission, and heating/cooling facilities to provide water and space heating as well as air conditioning for residential and commercial buildings. To gain wider recognition for the geothermal district heating and cooling (GDHC) system, the potential to develop such a system was evaluated in the western United States, and in the state of West Virginia. The geothermal resources were categorized into identified hydrothermal resources, undiscovered hydrothermal resources, near hydrothermal enhanced geothermal system (EGS), and deep EGS. Reservoir characteristics of the first three categories were estimated individually, and their thermal potential calculated. A cost model for such a system was developed for technical performance and economic analysis at each geothermally active location. A supply curve for the system was then developed, establishing the quantity and the cost of potential geothermal energy which can be used for the GDHC system. A West Virginia University (WVU) case study was performed to compare the competiveness of a geothermal energy system to the current steam based system. An Aspen Plus model was created to simulate the year-round campus heating and cooling scenario. Five cases of varying water flow rates and temperatures were simulated to find the lowest levelized cost of heat (LCOH) for the WVU case study. The model was then used to derive a levelized cost of heat as a function of the population density

  5. A conceptual geochemical model of the geothermal system at Surprise Valley, CA

    Science.gov (United States)

    Fowler, Andrew P. G.; Ferguson, Colin; Cantwell, Carolyn A.; Zierenberg, Robert A.; McClain, James; Spycher, Nicolas; Dobson, Patrick

    2018-03-01

    Characterizing the geothermal system at Surprise Valley (SV), northeastern California, is important for determining the sustainability of the energy resource, and mitigating hazards associated with hydrothermal eruptions that last occurred in 1951. Previous geochemical studies of the area attempted to reconcile different hot spring compositions on the western and eastern sides of the valley using scenarios of dilution, equilibration at low temperatures, surface evaporation, and differences in rock type along flow paths. These models were primarily supported using classical geothermometry methods, and generally assumed that fluids in the Lake City mud volcano area on the western side of the valley best reflect the composition of a deep geothermal fluid. In this contribution, we address controls on hot spring compositions using a different suite of geochemical tools, including optimized multicomponent geochemistry (GeoT) models, hot spring fluid major and trace element measurements, mineralogical observations, and stable isotope measurements of hot spring fluids and precipitated carbonates. We synthesize the results into a conceptual geochemical model of the Surprise Valley geothermal system, and show that high-temperature (quartz, Na/K, Na/K/Ca) classical geothermometers fail to predict maximum subsurface temperatures because fluids re-equilibrated at progressively lower temperatures during outflow, including in the Lake City area. We propose a model where hot spring fluids originate as a mixture between a deep thermal brine and modern meteoric fluids, with a seasonally variable mixing ratio. The deep brine has deuterium values at least 3 to 4‰ lighter than any known groundwater or high-elevation snow previously measured in and adjacent to SV, suggesting it was recharged during the Pleistocene when meteoric fluids had lower deuterium values. The deuterium values and compositional characteristics of the deep brine have only been identified in thermal springs and

  6. Impact of enhanced geothermal systems on US energy supply in the twenty-first century.

    Science.gov (United States)

    Tester, Jefferson W; Anderson, Brian J; Batchelor, Anthony S; Blackwell, David D; DiPippo, Ronald; Drake, Elisabeth M; Garnish, John; Livesay, Bill; Moore, Michal C; Nichols, Kenneth; Petty, Susan; Toksoz, M Nafi; Veatch, Ralph W; Baria, Roy; Augustine, Chad; Murphy, Enda; Negraru, Petru; Richards, Maria

    2007-04-15

    Recent national focus on the value of increasing US supplies of indigenous renewable energy underscores the need for re-evaluating all alternatives, particularly those that are large and well distributed nationally. A panel was assembled in September 2005 to evaluate the technical and economic feasibility of geothermal becoming a major supplier of primary energy for US base-load generation capacity by 2050. Primary energy produced from both conventional hydrothermal and enhanced (or engineered) geothermal systems (EGS) was considered on a national scale. This paper summarizes the work of the panel which appears in complete form in a 2006 MIT report, 'The future of geothermal energy' parts 1 and 2. In the analysis, a comprehensive national assessment of US geothermal resources, evaluation of drilling and reservoir technologies and economic modelling was carried out. The methodologies employed to estimate geologic heat flow for a range of geothermal resources were utilized to provide detailed quantitative projections of the EGS resource base for the USA. Thirty years of field testing worldwide was evaluated to identify the remaining technology needs with respect to drilling and completing wells, stimulating EGS reservoirs and converting geothermal heat to electricity in surface power and energy recovery systems. Economic modelling was used to develop long-term projections of EGS in the USA for supplying electricity and thermal energy. Sensitivities to capital costs for drilling, stimulation and power plant construction, and financial factors, learning curve estimates, and uncertainties and risks were considered.

  7. Modeling of a deep-seated geothermal system near Tianjin, China.

    Science.gov (United States)

    Xun, Z; Mingyou, C; Weiming, Z; Minglang, L

    2001-01-01

    A geothermal field is located in deep-seated basement aquifers in the northeastern part of the North China Plain near Tianjin, China. Carbonate rocks of Ordovician and Middle and Upper Proterozoic age on the Cangxian Uplift are capable of yielding 960 to 4200 m3/d of 57 degrees C to 96 degrees C water to wells from a depth of more than 1000 m. A three-dimensional nonisothermal numerical model was used to simulate and predict the spatial and temporal evolution of pressure and temperature in the geothermal system. The density of the geothermal water, which appears in the governing equations, can be expressed as a linear function of pressure, temperature, and total dissolved solids. A term describing the exchange of heat between water and rock is incorporated in the governing heat transport equation. Conductive heat flow from surrounding formations can be considered among the boundary conditions. Recent data of geothermal water production from the system were used for a first calibration of the numerical model. The calibrated model was used to predict the future changes in pressure and temperature of the geothermal water caused by two pumping schemes. The modeling results indicate that both pressure and temperature have a tendency to decrease with time and pumping. The current withdrawal rates and a pumping period of five months followed by a shut-off period of seven months are helpful in minimizing the degradation of the geothermal resource potential in the area.

  8. Geoelectrical Characterization of the Punta Banda System: A Possible Structural Control for the Geothermal Anomalies

    Science.gov (United States)

    Arango-Galvan, C.; Flores-Marquez, E.; Prol-Ledesma, R.; Working Group, I.

    2007-05-01

    The lack of sufficient drinking water in México has become a very serious problem, especially in the northern desert regions of the country. In order to give a real solution to this phenomenon the IMPULSA research program has been created to develope novel technologies based on desalination of sea and brackish water using renewable sources of energy to face the problem. The Punta Banda geothermal anomaly is located towards the northern part of Baja California Peninsula (Mexico). High water temperatures in some wells along the coast depicted a geothermal anomaly. An audiomagnetotelluric survey was carried out in the area as a preliminary study, both to understand the process generating these anomalous temperatures and to assess its potential exploitation to supply hot water to desalination plants. Among the electromagnetic methods, the audiomagnetotellurics (AMT) method is appropriated for deep groundwater and geothermal studies. The survey consisted of 27 AMT stations covering a 5 km profile along the Agua Blanca Fault. The employed array allowed us to characterize the geoelectrical properties of the main structures up to 500 m depth. Two main geoelectrical zones were identified: 1) a shallow low resistivity media located at the central portion of the profile, coinciding with the Maneadero valley and 2) two high resitivity structures bordering the conductive zone possibly related to NS faulting, already identified by previous geophysical studies. These results suggest that the main geothermal anomalies are controlled by the dominant structural regime in the zone.

  9. Orthogonal Test Analysis on Conditions Affecting Electricity Generation Performance of an Enhanced Geothermal System at Yangbajing Geothermal Field

    Directory of Open Access Journals (Sweden)

    Yuchao Zeng

    2017-12-01

    Full Text Available The main conditions affecting electricity generation performance of an enhanced geothermal system (EGS include reservoir porosity, reservoir permeability, rock heat conductivity, water production rate and injection temperature. Presently there is lack of systematic research the relative importance of the five aforementioned conditions. The orthogonal test method is a statistical approach to analyze multi-factor and multi-level influence on system performance. In this work, based on the geological data at Yangbajing geothermal field, we analyzed the five conditions affecting the electricity generation performance of EGS, and ranked the relative importance of the five factors. The results show that the order of the relative importance of the conditions on electric power is water production rate > injection temperature > reservoir porosity > rock heat conductivity > reservoir permeability; the order of the relative importance of the conditions on reservoir impedance is reservoir permeability > injection temperature > water production rate > reservoir porosity > rock heat conductivity; the order of the relative importance of the conditions on pump power is water production rate > reservoir permeability > injection temperature > reservoir porosity > rock heat conductivity, and; the order of the relative importance of the conditions on energy efficiency is water production rate > reservoir permeability > reservoir porosity > injection temperature > rock heat conductivity. The construction of an EGS reservoir should be located at a formation with higher reservoir porosity or rock heat conductivity, while the determination of reservoir permeability, water production rate and injection temperature should be based on the comprehensive target.

  10. An application of neural network in geophysical prospecting. Electrical resistivity at Las Virgenes geothermal field, Baja California Sur, Mexico; Una aplicacion de las redes neuronales a la prospeccion geofisica. Resistividad electrica en las Tres Virgenes, Baja California Sur, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Palma Guzman, Sergio Hugo [Comision Federal de Electricidad, Morelia, Michoacan (Mexico)

    2000-12-01

    The technology of the neural network is presented with geophysical focus in the Las Virgenes geothermal field, Baja California Sur, Mexico. The results obtained when extrapolating the associative data of the prospecting magnetoteluria and Vertical Electric Sounding, on the area of the geothermal wells to the rest of the area, allows to classify zones of interest for the geothermal exploitation. Also, the use of these associative parameters with the information of the stabilized temperature of the wells, they allow to predict temperatures for the rest of the area. [Spanish] Se presenta una aplicacion de la tecnologia de las redes neuronales con enfoque geofisico en el campo geotermico de Las Virgenes, Baja California Sur, Mexico. Los resultados obtenidos al extrapolar los datos asociativos de las prospecciones geoelectricas de magnetoteluria y sondeos electricos verticales, en la zona de los pozos geotermicos al resto del area, permiten clasificar zonas de interes para la explotacion geotermica. Tambien, la utilizacion de estos parametros asociativos con la informacion de la temperatura estabilizada de los pozos, permiten predecir temperaturas para la misma area.

  11. The use of petrology in Philippine geothermal system

    International Nuclear Information System (INIS)

    Reyes, A.G.

    1992-01-01

    Petrology is used in the various stages of exploration, development and exploitation of a geothermal area, often in conjunction with other fields of study. It is an effective operations tool for predicting syn- and post-drilling conditions in a well, for field and well maintenance, and to a small extent for monitoring fluids passing through the pipelines and steam turbines. Petrological data and interpretations are important in assessing an exploration area, and in formulating and developing strategy of a geothermal field. (auth.). 11 figs

  12. Development of an active solar humidification-dehumidification (HDH) desalination system integrated with geothermal energy

    International Nuclear Information System (INIS)

    Elminshawy, Nabil A.S.; Siddiqui, Farooq R.; Addas, Mohammad F.

    2016-01-01

    Highlights: • Productivity increases with increasing geothermal water flow rate up to 0.15 kg/s. • Geothermal energy increases productivity by 187–465% when used with solar energy. • Daytime experimental productivity (8AM-5PM) up to 104 L/m"2 was achieved. • Daily experimental productivity (24 h) up to 192 L/m"2 was achieved. • Fresh potable water can be produced at 0.003 USD/L using this desalination setup. - Abstract: This paper investigates the technical and economic feasibility of using a hybrid solar-geothermal energy source in a humidification-dehumidification (HDH) desalination system. The newly developed HDH system is a modified solar still with air blower and condenser used at its inlet and outlet respectively. A geothermal water tank in a temperature range 60–80 °C which imitates a low-grade geothermal energy source was used to supply heat to water inside the humidification chamber. The experiments were conducted in January 2015 under the climatological conditions of Madinah (latitude: 24°33′N, longitude: 39°36′0″E), Saudi Arabia to study the effect of geothermal water temperature and flow rate on the performance and productivity of proposed desalination system. Analytical model was also developed to compare the effect of solar energy and combined solar-geothermal energy on accumulated productivity. Daytime experimental accumulated productivity up to 104 L/m"2 and daily average gained output ratio (GOR) in the range 1.2–1.58 was achieved using the proposed desalination system. Cost of fresh water produced using the presented desalination system is 0.003 USD/L.

  13. The Role of Boron Chloride and noble gas isotope ratios in Taupo Volcanic Zone geothermal systems

    International Nuclear Information System (INIS)

    Hulston, J.R.

    1995-01-01

    The model of the geothermal system in which deep circulating groundwater con noble gases, at air saturated water concentrations, mixes with hot fluids of man origin at depth, is extended to include the effect of interaction of the ascending fluid with both solid and gaseous phases of basement (or other) rocks 'en route' the surface. It is demonstrated that this interaction is responsible for most of CO/sub 2/ in the Taupo Volcanic Zone (TVZ) geothermal systems. It is proposed th the modelling of this interaction might be accomplished by techniques similar to those used for the understanding of the oxygen isotope shift found in geothermal systems. The water rock interaction experiments of Ellis and Mahon (1964, 1967) provides some data on the kinetic rates for B and Cl dissolution from rocks like to be encountered in the geothermal system, but further information on the behaviour of B may be needed. If these problems can be overcome this modelling technique has promise for the estimation of the recharge of geothermal systems a hence the sustainability of these systems. (author). 17 refs., 4 figs

  14. The role of boron-chloride and noble gas isotope ratios in TVZ geothermal systems

    International Nuclear Information System (INIS)

    Hulston, J.R.

    1995-01-01

    The model of the geothermal system in which deep circulating groundwater containing noble gases, at air saturated water concentrations, mixes with hot fluids of mantle origin at depth, is extended to include the effect of interaction of the ascending fluid with both solid and gaseous phases of basement (or other) rocks en route to the surface. It is demonstrated that this interaction is responsible for most of the CO 2 in the Taupo Volcanic Zone (TVZ) geothermal systems. It is proposed that the modelling of this interaction might be accomplished by techniques similar to those used for the understanding of the oxygen isotope shift found in geothermal systems. The water rock interaction experiments of Ellis and Mahon (1964, 1967) provides some data on the kinetic rates for B and Cl dissolution from rocks likely to be encountered in the geothermal system, but further information on the behaviour of B may be needed. If these problems can be overcome this modelling technique has promise for the estimation of the recharge of geothermal systems and hence the sustainability of these systems. (author). 17 refs., 4 figs

  15. Geochemical and isotopic evidence on the recharge and circulation of geothermal water in the Tangshan Geothermal System near Nanjing, China: implications for sustainable development

    Science.gov (United States)

    Lu, Lianghua; Pang, Zhonghe; Kong, Yanlong; Guo, Qi; Wang, Yingchun; Xu, Chenghua; Gu, Wen; Zhou, Lingling; Yu, Dandan

    2018-01-01

    Geothermal resources are practical and competitive clean-energy alternatives to fossil fuels, and study on the recharge sources of geothermal water supports its sustainable exploitation. In order to provide evidence on the recharge source of water and circulation dynamics of the Tangshan Geothermal System (TGS) near Nanjing (China), a comprehensive investigation was carried out using multiple chemical and isotopic tracers (δ2H, δ18O, δ34S, 87Sr/86Sr, δ13C, 14C and 3H). The results confirm that a local (rather than regional) recharge source feeds the system from the exposed Cambrian and Ordovician carbonate rocks area on the upper part of Tangshan Mountain. The reservoir temperature up to 87 °C, obtained using empirical as well as theoretical chemical geothermometers, requires a groundwater circulation depth of around 2.5 km. The temperature of the geothermal water is lowered during upwelling as a consequence of mixing with shallow cold water up to a 63% dilution. The corrected 14C age shows that the geothermal water travels at a very slow pace (millennial scale) and has a low circulation rate, allowing sufficient time for the water to become heated in the system. This study has provided key information on the genesis of TGS and the results are instructive to the effective management of the geothermal resources. Further confirmation and even prediction associated with the sustainability of the system could be achieved through continuous monitoring and modeling of the responses of the karstic geothermal reservoir to hot-water mining.

  16. Generic Guide Specification for Geothermal Heat Pump Systems

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, WKT

    2000-04-12

    The attached Geothermal (Ground-Source) Heat Pump (GHP) Guide Specifications have been developed by Oak Ridge National Laboratory (ORNL) with the intent to assist federal agency sites and engineers in the preparation of construction specifications for GHP projects. These specifications have been developed in the industry-standard Construction Specification Institute (CSI) format and cover several of the most popular members of the family of GHP systems. These guide specifications are applicable to projects whether the financing is with conventional appropriations, arranged by GHP specialty ESCOs under the U.S. Department of Energy's Technology-Specific GHP Super ESPCs, arranged by utilities under Utility Energy Service Contracts (UESCs) or arranged by generalist ESCOs under the various regional ESPCs. These specifications can provide several benefits to the end user that will help ensure successful GHP system installations. GHP guide specifications will help to streamline the specification development, review, and approval process because the architecture and engineering (AE) firm will be working from the familiar CSI format instead of developing the specifications from other sources. The guide specifications help to provide uniformity, standardization, and consistency in both the construction specifications and system installations across multiple federal sites. This standardization can provide future benefits to the federal sites in respect to both maintenance and operations. GHP guide specifications can help to ensure that the agency is getting its money's worth from the GHP system by preventing the use of marginal or inferior components and equipment. The agency and its AE do not have to start from scratch when developing specifications and can use the specification as a template and/or a checklist in developing both the design and the contract documents. The guide specifications can save project costs by reducing the engineering effort required

  17. THE PROBLEM OF ENERGY EFFICIENCY OF THE GEOTHERMAL CIRCULATION SYSTEM IN DIFFERENT MODES OF REINJECTION OF THE COOLANT

    Directory of Open Access Journals (Sweden)

    D. K. Djavatov

    2017-01-01

    Full Text Available Aim. Advanced technologies are crucial for widespread use of geothermal energy to ensure its competitiveness with conventional forms of energy. To date, the basis for the development of geothermal energy is the technology of extracting the heat transfer fluids from the subsoil. There are the following ways to extract the coolant: freeflow; pumping and circular methods. Of greatest interest is the technology to harness the geothermal energy based on geothermal circulatory system (GCS. There is the problem of the right choice of technological parameters for geothermal systems to ensure their effective functioning.Methods. We consider the development of geothermal energy technology based on geothermal circulatory system, as this technology solves the dumping of the waste water containing environmentally harmful substances. In addition to the environmental issues, this technology makes it possible to intensify the process of production and the degree of extraction of thermal resources, which significantly increases the potential for geothermal heat resources in terms of the fuel and energy balance.Findings. Were carried out optimization calculations for Ternairsky deposits of thermal waters. In the calculations, was taken into account the temperature dependence of important characteristics, such as the density and heat capacity of the coolant.Conclusions. There is the critical temperature of the coolant injected, depending on the flow rate and the diameter of the well, ensuring the effective functioning of the geothermal circulatory systems

  18. Design of a novel geothermal heating and cooling system: Energy and economic analysis

    International Nuclear Information System (INIS)

    Angrisani, G.; Diglio, G.; Sasso, M.; Calise, F.; Dentice d’Accadia, M.

    2016-01-01

    Highlights: • A desiccant-based air handling unit is coupled with a geothermal source. • A TRNSYS model is developed to simulate both winter and summer period. • Sensitivity analysis is carried out in order to evaluate the effects of the design parameters. • Pay back period about 1.2 years and Primary Energy Savings higher than 90% were founded. • Economic and energetic performance increase with to the use of Domestic Hot Water. - Abstract: A dynamic simulation study in TRNSYS environment has been carried out to evaluate energy and economic performance of a novel heating and cooling system based on the coupling between a low or medium-enthalpy geothermal source and an Air Handling Unit, including a Desiccant Wheel. During summer season, a Downhole Heat Exchanger supplies heat to regenerate the desiccant material, while a certain amount of geothermal fluid is continuously extracted by the well in order to maintain high operating temperatures. Simultaneously, the extracted geothermal fluid drives an absorption chiller, producing chilled water to the cooling coil of the Air Handling Unit. Conversely, during the winter season, geothermal energy is used to cover a certain amount of the space heating demand. In both summer and winter operation modes, a geothermal energy is also used to supply Domestic Hot Water. A case study was analyzed, in which an existing low-enthalpy geothermal well (96 °C), located in Ischia (an island close to Naples, Southern Italy), is used to drive the geothermal system. Results showed that the performance of the proposed system is significantly affected by the utilization factor of Domestic Hot Water. In fact, considering a range of variation of such parameter between 5% and 100%, Primary Energy Saving increase from 77% to 95% and Pay-Back Period decreases from 14 years to 1.2 years, respectively. The simulations proved the technical and economic viability of the proposed system. In fact, a comparison with similar systems available

  19. Preliminary report on the Northern California Power Agency's Notice of Intention to seek certification for NCPA Geothermal Project No. 2

    Energy Technology Data Exchange (ETDEWEB)

    1978-01-01

    This preliminary report on the Northern California Power Agency (NCPA) geothermal power plant proposal has been prepared pursuant to California Public Resources Code Sections 25510, 25512, and 25540. It presents the preliminary Findings of fact and Conclusions adopted by the Commission Committee assigned to conduct proceedings on the Notice. In addition, the report contains a description of the proposed project, a summary of the proceedings to date, and local, state, and Federal government agency comments on the proposal. Finally, the report presents the Committee's view of those issues that require further consideration in future proceedings on the Notice. Pursuant to Public Resources Code Sections 25512 and 25540, the report presents preliminary Findings and Conclusions on: (1) conformity to the forecast of statewide and service area electric power demands; (2) the degree to which the proposed site and facility conform with applicable local, regional, state and Federal standards, ordinances, and laws; and (3) the safety and reliability of the facility.

  20. Western Sicily (Italy), a key area for understanding geothermal system within carbonate reservoirs

    Science.gov (United States)

    Montanari, D.; Bertini, G.; Botteghi, S.; Catalano, R.; Contino, A.; Doveri, M.; Gennaro, C.; Gianelli, G.; Gola, G.; Manzella, A.; Minissale, A.; Montegrossi, G.; Monteleone, S.; Trumpy, E.

    2012-12-01

    Oil exploration in western Sicily started in the late 1950s when several exploration wells were drilled, and continued with the acquisition of many seismic reflection profiles and the drilling of new wells in the1980s. The geological interpretation of these data mainly provided new insights for the definition of geometric relationships between tectonic units and structural reconstruction at depth. Although it has not produced completely satisfactory results for oil industry, this hydrocarbon exploration provided a great amount of data, resulting very suitable for geothermal resource assessment. From a geothermal point of view western Sicily is, indeed, a very promising area, with the manifestation at surface of several thermal springs, localized areas of high heat flux and thick carbonates units uninterruptedly developing from surface up top great depths. These available data were often collected with the modalities and purposes typical of oil exploration, not always the finest for geothermal exploration as in the case of temperature measurements. The multidisciplinary and integrated review of these data, specifically corrected for geothermal purposes, and the integration with new data acquired in particular key areas such as the Mazara Del Vallo site in the southern part of western Sicily, allowed us to better understand this medium-enthalpy geothermal system, to reconstruct the modalities and peculiarities of fluids circulation, and to evaluate the geothermal potentialities of western Sicily. We suggest that western Sicily can be taken as a reference for the understanding of geothermal systems developed at a regional scale within carbonate rocks. This study was performed within the framework of the VIGOR project (http://www.vigor-geotermia.it).

  1. Young (gold deposits and active geothermal systems of the Great Basin: Enigmas, questions, and exploration potential

    Science.gov (United States)

    Coolbaugh, Mark F.; Vikre, Peter G.; Faulds, James E.

    2011-01-01

    Young gold systems in the Great Basin (£ 7 Ma), though not as well studied as their older counterparts, comprise a rapidly growing and in some ways controversial group. The gold inventory for these systems has more than doubled in the last 5 years from roughly 370 tonnes (12 Moz) to 890 tonnes (29 Moz). Although these deposits are characterized by low grades, tonnages can be high and stripping ratios low, and they have been mined profitably, as exemplified by Florida Canyon and Hycroft. Active geothermal systems in the Great Basin also comprise a rapidly growing group, as evidenced by a number of recent discoveries of geothermal groundwater and a more than 50% increase in electricity production capacity from these systems in the last 5 years. Many young gold deposits are closely associated with active geothermal systems, suggesting that gold deposits may be forming today in the Great Basin. Measured or estimated geothermal reservoir temperatures commonly approach or exceed 200∞C, and other characteristics and processes (advanced argillic caps, hydrothermal eruption breccias) of these young deposits resemble those of nearby Tertiary precious metal deposits. Nonetheless, many young gold systems, especially in Nevada, are not associated with coeval igneous rocks. Similarly, almost all electricity-grade geothermal systems in Nevada are not associated with Quaternary silicic volcanic rocks, and have lower temperature gradients, lower 3He/4He ratios, and lower dissolved trace element concentrations than most magmatic-heated geothermal systems elsewhere in the world. The increasing economic significance of young gold deposits and active geothermal systems justifies more research to better understand their origins, particularly because in some aspects they remain enigmatic and controversial. Are young gold deposits in Nevada truly amagmatic, or have they received metal and fluid contributions from magmas deeper within the crust? Has gold in these deposits been

  2. [Geothermal system temperature-depth database and model for data analysis]. 5. quarterly technical progress report

    Energy Technology Data Exchange (ETDEWEB)

    Blackwell, D.D.

    1998-04-25

    During this first quarter of the second year of the contract activity has involved several different tasks. The author has continued to work on three tasks most intensively during this quarter: the task of implementing the data base for geothermal system temperature-depth, the maintenance of the WWW site with the heat flow and gradient data base, and finally the development of a modeling capability for analysis of the geothermal system exploration data. The author has completed the task of developing a data base template for geothermal system temperature-depth data that can be used in conjunction with the regional data base that he had already developed and is now implementing it. Progress is described.

  3. Proceedings of the second United Nations symposium on the development and use of geothermal resources held at San Francisco, California, May 20--29, 1975. Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    1976-01-01

    The 299 papers in the Proceedings are presented in three volumes and are divided into twelve sections, each section dealing with a different aspect of geothermal energy. Rapporturs' summaries of the contents of each section are grouped together in Vol. 1 of the Proceedings; a separate abstract was prepared for each summary. Volume 1 also contains ninety-eight papers under the following section headings: present status of resources development; geology, hydrology, and geothermal systems; and geochemical techniques in exploration. Separate abstracts were prepared for ninety-seven papers. One paper was previously abstracted for ERA and appeared as CONF-750525--17. (LBS)

  4. Geothermal Today: 2003 Geothermal Technologies Program Highlights (Revised)

    Energy Technology Data Exchange (ETDEWEB)

    2004-05-01

    This outreach publication highlights milestones and accomplishments of the DOE Geothermal Technologies Program for 2003. Included in this publication are discussions of geothermal fundamentals, enhanced geothermal systems, direct-use applications, geothermal potential in Idaho, coating technology, energy conversion R&D, and the GeoPowering the West initiative.

  5. The eastern Tibetan Plateau geothermal belt, western China: Geology, geophysics, genesis, and hydrothermal system

    Science.gov (United States)

    Tang, Xianchun; Zhang, Jian; Pang, Zhonghe; Hu, Shengbiao; Tian, Jiao; Bao, Shujing

    2017-10-01

    The eastern Tibetan Plateau geothermal belt (ETGB), which is located in 98-102°E, 28-32°N, belongs to the eastern part of the Mediterranean-Himalayan geothermal belt. Recently, about 248 natural hot springs have been found in the ETGB. > 60% of these springs have temperatures of > 40 °C, and 11 springs have temperature above the local water boiling point. Using the helium isotopic data, gravity, magnetic and seismic data, we analyzed the thermal structure and the relationship between hydrothermal activity and geothermal dynamics of the ETGB. Results show that: (1) the 248 springs can be divided into three geothermal fields: Kangding-Luhuo geothermal field (KGF), Litang-Ganzi geothermal field (LGF) and Batang-Xiangcheng geothermal field (BGF). The BGF and LGF have hot crust and warm mantle, and are characterized by the higher heat flux (66.26 mW/m2), and higher ratios of crust-derived heat flux to total flux (47.46-60.62%). The KGF has cool crust and hot mantle, and is characterized by the higher heat flux and lower Qc/Qm; (2) there is a relatively 4-6 m higher gravimetric geoid anomaly dome which is corresponding with the ETGB. And in hydrothermal activity areas of the BGF and LGF, there is a northwest - southeast-trending tensile stress area and the upper-middle crust uplift area; (3) an abnormal layer exists in the middle-lower crust at a depth of 13-30 km beneath the ETGB, and this layer is 8-10 km thick and is characterized by lower velocity (Vp 2.5), high conductivity ( 10 Ω·m) and high temperature (850-1000 °C). Finally, based on the heat source and geological and geophysical background, we propose Kangding-type and Batang-type hydrothermal system models in the ETGB.

  6. Geomagnetic Survey to Explore High-Temperature Geothermal System in Blawan-Ijen, East Java, Indonesia

    Directory of Open Access Journals (Sweden)

    Daud Yunus

    2018-01-01

    Full Text Available Ijen geothermal area is high-temperature geothermal system located in Bondowoso regency, East Java. It is categorized as caldera-hosted geothermal system which is covered by quaternary andesitic volcanic rocks with steep topography at the surrounding. Several surface thermal manifestations are found, such as altered rocks near Mt. Kukusan and a group of Blawan hotsprings in the northern part of the caldera. Geomagnetic survey was conducted at 72 stations which is distributed inside the caldera to delineate the existence of hydrothermal activity. Magnetic anomaly was obtained by reducing total magnetic measured on the field by IGRF and diurnal variation. Reduction to pole (RTP method was applied with geomagnetic inclination of about -32°. In general, the result shows that high magnetic anomaly is distributed at the boundary of study area, while low magnetic anomaly is observed in the centre. The low anomaly indicates demagnetized rock that probably caused by hydrothermal activity. It has a good correlation with surface alteration observed close to Mt. Kukusan as well as high temperature reservoir drilled in the centre of caldera. Accordingly, the low magnetic anomaly also presents the possibility of geothermal reservoir in Ijen geothermal area.

  7. Geomagnetic Survey to Explore High-Temperature Geothermal System in Blawan-Ijen, East Java, Indonesia

    Science.gov (United States)

    Daud, Yunus; Rosid, Syamsu; Fahmi, Fikri; Yunus, Faris Maulana; Muflihendri, Reza

    2018-02-01

    Ijen geothermal area is high-temperature geothermal system located in Bondowoso regency, East Java. It is categorized as caldera-hosted geothermal system which is covered by quaternary andesitic volcanic rocks with steep topography at the surrounding. Several surface thermal manifestations are found, such as altered rocks near Mt. Kukusan and a group of Blawan hotsprings in the northern part of the caldera. Geomagnetic survey was conducted at 72 stations which is distributed inside the caldera to delineate the existence of hydrothermal activity. Magnetic anomaly was obtained by reducing total magnetic measured on the field by IGRF and diurnal variation. Reduction to pole (RTP) method was applied with geomagnetic inclination of about -32°. In general, the result shows that high magnetic anomaly is distributed at the boundary of study area, while low magnetic anomaly is observed in the centre. The low anomaly indicates demagnetized rock that probably caused by hydrothermal activity. It has a good correlation with surface alteration observed close to Mt. Kukusan as well as high temperature reservoir drilled in the centre of caldera. Accordingly, the low magnetic anomaly also presents the possibility of geothermal reservoir in Ijen geothermal area.

  8. Quantifying the undiscovered geothermal resources of the United States

    Science.gov (United States)

    Williams, Colin F.; Reed, Marshall J.; DeAngelo, Jacob; Galanis, S. Peter

    2009-01-01

    In 2008, the U.S. Geological Survey (USGS) released summary results of an assessment of the electric power production potential from the moderate- and high-temperature geothermal resources of the United States (Williams et al., 2008a; USGS Fact Sheet 2008-3082; http://pubs.usgs.gov/fs/2008/3082). In the assessment, the estimated mean power production potential from undiscovered geothermal resources is 30,033 Megawatts-electric (MWe), more than three times the estimated mean potential from identified geothermal systems: 9057 MWe. The presence of significant undiscovered geothermal resources has major implications for future exploration and development activities by both the government and private industry. Previous reports summarize the results of techniques applied by the USGS and others to map the spatial distribution of undiscovered resources. This paper describes the approach applied in developing estimates of the magnitude of the undiscovered geothermal resource, as well as the manner in which that resource is likely to be distributed among geothermal systems of varying volume and temperature. A number of key issues constrain the overall estimate. One is the degree to which characteristics of the undiscovered resources correspond to those observed among identified geothermal systems. Another is the evaluation of exploration history, including both the spatial distribution of geothermal exploration activities relative to the postulated spatial distribution of undiscovered resources and the probability of successful discoveries from the application of standard geothermal exploration techniques. Also significant are the physical, chemical, and geological constraints on the formation and longevity of geothermal systems. Important observations from this study include the following. (1) Some of the largest identified geothermal systems, such as The Geysers vapor-dominated system in northern California and the diverse geothermal manifestations found in Yellowstone

  9. Geothermal district heating system in Tanggu, Tianjin, China

    International Nuclear Information System (INIS)

    Jinrong, C.

    1992-01-01

    Tanggu is a harbor and industrial area and is the location of Tianjin Harbor, Tianjin Bonded Area and Tianjin Economic Development Area. It covers an area of 859 km 2 and has a population of 430,000. Tanggu Geothermal Field is located at the western coast of Bohai Sea. This area belongs to the depression area of North China geologically. Neogene strata of Guantao Group is distributed widely in this region. Good permeability, large thickness, and high conductivity make it form a regional low-temperature porous reservoir. The reservoir is buried to a depth of 1,600 - 2,100 m. The total thickness of about 500 m can be divided into upper and lower sections including three aquifers. Geothermal space heating tests of Tanggu started in 1980. Up to the present, there are a total of 16 geothermal wells in Tanggu. Thirteen of them were drilled in the shallower aquifer. The total production rate of thermal water is 3.636 x 10 6 m 3 annually. The net production rate used for space heating is 3.10 x 10 6 m 3 from 11 wells. It has heated an area of 620 x 10 3 m 2 and has solved winter heating for 100 thousand people

  10. Three-Dimensional Geologic Characterization of a Great Basin Geothermal System: Astor Pass, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Mayhew, Brett; Siler, Drew L; Faulds, James E

    2013-09-30

    The Great Basin, western USA, exhibits anomalously high heat flow (~75±5 mWm-2) and active faulting and extension, resulting in ~430 known geothermal systems. Recent studies have shown that steeply dipping normal faults in transtensional pull-aparts are a common structural control of these Great Basin geothermal systems. The Astor Pass blind (no surface expression) geothermal system, Nevada, lies along the boundary between the Basin and Range to the east and the Walker Lane to the west. Across this boundary, strain is transferred from dextral shear in the Walker Lane to west-northwest directed extension in the Basin and Range, resulting in a transtensional setting consisting of both northwest-striking, left-stepping dextral faults and northerly striking normal faults. Previous studies indicate that Astor Pass was controlled by the intersection of a northwest-striking dextral normal fault and north-northwest striking normal-dextral fault bounding the western side of the Terraced Hills. Drilling (to ~1200 m) has revealed fluid temperatures of ~94°C, confirming a blind geothermal system. Expanding upon previous work and employing interpretation of 2D seismic reflection data, additional detailed geologic mapping, and well cuttings analysis, a 3-dimensional geologic model of the Astor Pass geothermal system was constructed. The 3D model indicates a complex interaction/intersection area of three discrete fault zones: a northwest-striking dextral-normal fault, a north-northwest-striking normal-dextral fault, and a north-striking west-dipping normal fault. These two discrete, critically-stressed intersection areas plunge moderately to steeply to the NW-NNW and probably act as conduits for upwelling geothermal fluids.

  11. Base-line data analysis of a developing geothermal system, Boise, Idaho

    Energy Technology Data Exchange (ETDEWEB)

    Waag, C.J.; Wood, S.H.

    1985-09-01

    The report covers a geothermal system and calculated aquifer transmissivities in the Boise Warm Springs Water District portion of the geothermal system range from 3500-25,000 gals/day/ft. Withdrawals during the 1984-1985 heating season stabilized drawdown at the pumpbowls, and water levels approached stability in observation wells as distant as 1675 ft (507.6m). In the near steady-state condition, recharge, and water from storage beyond the observation wells provided a maximum Q of 840 gpm.

  12. Conventional heating systems is heating with geothermal water, v. 15(60)

    International Nuclear Information System (INIS)

    Hadzhimishev, Dimitar; Gashteovski, Ljupcho; Shami, Jotso

    2007-01-01

    The Geothermal Energy (GE) is a new renewable energy source with many advantages and specifics. Present mainly application of GE is in agriculture. In Geothermal System Kochani the GE uses for district heating and industrial uses also. There are many problems to solve before using the geothermal energy for district heating: direct application feasibility for heating rooms and industrial using existing heating installation system (90/70°C); the level of heating needs covering without installation reconstruction; techno-economical justification of this reconstruction ; covering of pike heating needs. The answers of these enigmas you have in this written effort. The results were practically justified in about ten object in Kochani. (Author)

  13. Conventional heating systems is heating with geothermal water, v. 15(59)

    International Nuclear Information System (INIS)

    Hadzhimishev, Dimitar; Gashteovski, Ljupcho; Shami, Jotso

    2007-01-01

    The Geothermal Energy (GE) is a new renewable energy source with many advantages and specifics. Present mainly application of GE is in agriculture. In Geothermal System Kochani the GE uses for district heating and industrial uses also. There are many problems to solve before using the geothermal energy for district heating: direct application feasibility for heating rooms and industrial using existing heating installation system (90/70°C); the level of heating needs covering without installation reconstruction; techno-economical justification of this reconstruction ; covering of pike heating needs. The answers of these enigmas you have in this written effort. The results were practically justified in about ten object in Kochani. (Author)

  14. Dynamic modeling of а heating system using geothermal energy and storage tank

    Directory of Open Access Journals (Sweden)

    Milanović Predrag D.

    2012-01-01

    Full Text Available This paper analyzes a greenhouse heating system using geothermal energy and storage tank and the possibility of utilization of insufficient amount of heat from geothermal sources during the periods with low outside air temperatures. Crucial for these analyses is modelling of the necessary yearly energy requirements for greenhouse heating. The results of these analyses enable calculation of an appropriate storage tank capacity so that the energy efficiency of greenhouse heating system with geothermal energy could be significantly improved. [Acknowledgement. This work was supported by Ministry of Science and Technology Development of the Republic of Serbia through the National Energy Efficiency Program (Grant 18234 A. The authors are thankful to the stuff and management of the Company “Farmakom MB PIK 7. juli - Debrc” for their assistance during the realization of this project.

  15. Vertical distribution of potentially toxic elements in sediments impacted by intertidal geothermal hot springs (Bahia Concepcion, Gulf of California)

    Science.gov (United States)

    Leal-Acosta, M. L.; Shumilin, E.

    2016-12-01

    The intertidal geothermal hot springs (GHS) in Bahia Concepcion, Gulf of California are the source of potentially toxic elements to the adjacent marine environment surrounded by mangroves trees. The anoxic sediments enriched in organic carbon accumulate As, Hg and other heavy metals that can be bioavailable for the biota. To know the vertical distribution of these elements the geochemistry of a short sediment core was carried out. It was collected in June, 2010 in the mangrove area near to GHS (1 m) during a low tide, pushing manually a polypropylene tube into the sediments. The extracted sediment core was cut with plastic knife on 1 cm thick sub-samples, stored in plastic bags and transported on ice to the laboratory. The major and trace elements contents were determinate by ICP-MS after total digestion with stronger acids (HClO4-HNO3-HCl-HF). Certificate reference materials were used for the quality control of the method obtaining good recoveries for most of the elements (80-105%). The sediment core had high maximum contents of CaCO3 (70%) and total organic carbon (12%). The concentration of Hg along the core ranges from 650 to 74300 mg kg-1 and had more than three orders of magnitude above the reference values of 40 mg kg-1 for the Upper Continental Crust (UCC)1. In contrast, As ranges from 12 to 258 mg kg-1 resulting in more than one order of magnitude respect to UCC1 (1.7 mg kg-1). Similar pattern result for Mn, Cu, Pb, and Zn with the maximum values of 3200 mg kg-1, 42 mg kg-1, 12.4 mg kg-1, 71 mg kg-1 respectively that coincide with the maximum for As at the same core depth (4 cm). The Ca, Li, Co, Sb, U, and Mg also show high contents in comparison with the UCC1reference values. The maximum contents of Mo and Cd coincide with maximum concentration of sulfur (2%) at 6 to 8 cm. The enrichment factor calculated using Al as normalizing element showed Cd (7-280), As (26-329) and Hg (23-1196) as highly enriched mainly in the first centimeters of the sediment core

  16. Analysis of the apiclutural industry in relation to geothermal development and agriculture in the Imperial Valley, Imperial County, California

    Energy Technology Data Exchange (ETDEWEB)

    Atkins, E.L.

    1979-04-01

    PART I: Continuous exposure to 30 ppB H/sub 2/S increased lifespan of caged worker honey bees, Apis mellifera L., 33%; whereas, bees exposed > 13 days to 100 ppB and 300 ppB H/sub 2/S the lifespan was shortened 32% and 51%, respectively, over unexposed bees; bees exposed > 15 days to a combination of 300 ppB H/sub 2/S + 50 ppM CO/sub 2/ the lifespan was shortened 4.4% more that 300 ppB H/sub 2/S alone. The mean temperature and/or relative humidity did not exert a direct effect on the hazard to bees. A continuous exposure to 300 ppB SO/sub 2/ was detrimental to caged worker honey bees; and, a mean temperature of 27.2/sup 0/C was 75.7% more toxic than the same dosage at 16.7/sup 0/C. Worker bee lifespans exposed to 300 ppB SO/sub 2/ at 16.7/sup 0/C were shortened 13.5% and 79%, respectively, compared to unexposed bees. Therefore, both dosage and temperature exert direct effects on the hazards to bees. PART II: The status of the apicultural industry in Imperial County, California, was outlined giving a short characterization of the area in relation to the apicultural industry. Agriculture utilizes 500,000 intensely farmed acres which generated a 11-year average income of $370 million. Over 40 agricultural commodities are produced. The apicultural industry is intimately involved in 25% of the total gross agricultural income. In addition, most of the flora growing in the desert community which comprises the remainder of the county are very important to honey bees by providing sustaining nectar and/or pollen for brood rearing. The bee foraged flora provides substantial bee forage when colonies are located outside of the agriculutral area. It is concluded that geothermal resource development in the Imperial Valley is contemplated to have minimal effects on the apicultural industry.

  17. Health and safety impacts of nuclear, geothermal, and fossil-fuel electric generation in California. Volume 9. Methodologies for review of the health and safety aspects of proposed nuclear, geothermal, and fossil-fuel sites and facilities

    International Nuclear Information System (INIS)

    Nero, A.V.; Quinby-Hunt, M.S.

    1977-01-01

    This report sets forth methodologies for review of the health and safety aspects of proposed nuclear, geothermal, and fossil-fuel sites and facilities for electric power generation. The review is divided into a Notice of Intention process and an Application for Certification process, in accordance with the structure to be used by the California Energy Resources Conservation and Development Commission, the first emphasizing site-specific considerations, the second examining the detailed facility design as well. The Notice of Intention review is divided into three possible stages: an examination of emissions and site characteristics, a basic impact analysis, and an assessment of public impacts. The Application for Certification review is divided into five possible stages: a review of the Notice of Intention treatment, review of the emission control equipment, review of the safety design, review of the general facility design, and an overall assessment of site and facility acceptability

  18. National Geothermal Data System: an Exemplar of Open Access to Data

    Science.gov (United States)

    Allison, M. L.; Richard, S. M.; Blackman, H.; Anderson, A.

    2013-12-01

    The National Geothermal Data System's (NGDS - www.geothermaldata.org) formal launch in 2014 will provide open access to millions of datasets, sharing technical geothermal-relevant data across the geosciences to propel geothermal development and production. With information from all of the Department of Energy's sponsored development and research projects and geologic data from all 50 states, this free, interactive tool is opening new exploration opportunities and shortening project development by making data easily discoverable and accessible. We continue to populate our prototype functional data system with multiple data nodes and nationwide data online and available to the public. Data from state geological surveys and partners includes more than 5 million records online, including 1.48 million well headers (oil and gas, water, geothermal), 732,000 well logs, and 314,000 borehole temperatures and is growing rapidly. There are over 250 Web services and another 138 WMS (Web Map Services) registered in the system as of August, 2013. Companion projects run by Boise State University, Southern Methodist University, and USGS are adding millions of additional data records. The National Renewable Energy Laboratory is managing the Geothermal Data Repository which will serve as a system node and clearinghouse for data from hundreds of DOE-funded geothermal projects. NGDS is built on the US Geoscience Information Network data integration framework, which is a joint undertaking of the USGS and the Association of American State Geologists (AASG). NGDS is fully compliant with the White House Executive Order of May 2013, requiring all federal agencies to make their data holdings publicly accessible online in open source, interoperable formats with common core and extensible metadata. The National Geothermal Data System is being designed, built, deployed, and populated primarily with grants from the US Department of Energy, Geothermal Technologies Office. To keep this operational

  19. Environmental Impacts of a Multi-Borehole Geothermal System: Model Sensitivity Study

    Science.gov (United States)

    Krol, M.; Daemi, N.

    2017-12-01

    Problems associated with fossil fuel consumption has increased worldwide interest in discovering and developing sustainable energy systems. One such system is geothermal heating, which uses the constant temperature of the ground to heat or cool buildings. Since geothermal heating offers low maintenance, high heating/cooling comfort, and a low carbon footprint, compared to conventional systems, there has been an increasing trend in equipping large buildings with geothermal heating. However, little is known on the potential environmental impact geothermal heating can have on the subsurface, such as the creation of subsurface thermal plumes or changes in groundwater flow dynamics. In the present study, the environmental impacts of a closed-loop, ground source heat pump (GSHP) system was examined with respect to different system parameters. To do this a three-dimensional model, developed using FEFLOW, was used to examine the thermal plumes resulting from ten years of operation of a vertical closed-loop GSHP system with multiple boreholes. A required thermal load typical of an office building located in Canada was calculated and groundwater flow and heat transport in the geological formation was simulated. Consequently, the resulting thermal plumes were studied and a sensitivity analysis was conducted to determine the effect of different parameters like groundwater flow and soil type on the development and movement of thermal plumes. Since thermal plumes can affect the efficiency of a GSHP system, this study provides insight into important system parameters.

  20. Performance and Feasibility Study of a Standing Column Well (SCW System Using a Deep Geothermal Well

    Directory of Open Access Journals (Sweden)

    Jeong-Heum Cho

    2016-02-01

    Full Text Available Deep geothermal heat pump systems have considerable energy saving potential for heating and cooling systems that use stable ground temperature and groundwater as their heat sources. However, deep geothermal systems have several limitations for real applications such as a very high installation cost and a lack of recognition as heating and cooling systems. In this study, we performed a feasibility assessment of a Standing Column Well (SCW system using a deep geothermal well, based on a real-scale experiment in Korea. The results showed that the temperature of the heat source increased up to 42.04 °C in the borehole after the heating experiment, which is about 30 °C higher than that of normal shallow geothermal wells. Furthermore, the coefficient of performance (COP of the heat pump during 3 months of operation was 5.8, but the system COP was only 3.6 due to the relatively high electric consumption of the pump. Moreover, the payback period of the system using a deep well for controlled horticulture in a glass greenhouse was calculated as 6 years compared with using a diesel boiler system.

  1. Experimental evaluation of a non-azeotropic working fluid for geothermal heat pump system

    International Nuclear Information System (INIS)

    Zhao, L.

    2004-01-01

    Geothermal energy resources are found in many countries. A reasonable and efficient utilization of these resources has been a worldwide concern. The application of geothermal heat pump systems (GHPS) can help increase the efficiency of using geothermal energy and reduce the thermal pollution to the earth surface. However, this is only possible with a proper working fluid. In this paper, a non-azeotropic working fluid (R290/R600a/R123) is presented for a GHPS where geothermal water at 40-45 deg. C and heating network water at 70-80 deg. C serve as the low and high temperature heat sources. Experimental results show that the coefficient of performance (COP) of a GHPS using the working fluid is above 3.5 with the condensation temperature above 80 deg. C and the condensation pressure below 18 bar, while the temperature of the geothermal water is reduced from 40-46 deg. C to 31-36 deg. C

  2. A proposal to investigate higher enthalpy geothermal systems in the USA

    Science.gov (United States)

    Elders, W. A.

    2013-12-01

    After more than 50 years of development only ~3,400 MWe of electric power is currently being produced from geothermal resources in the USA. That is only about 0.33% of the country's total installed electrical capacity. In spite of the large demonstrated potential of geothermal resources, only ~2,500 MWe of new geothermal electrical capacity are under development, and the growth rate of this environmentally benign energy resource is overshadowed by the rapid increase in the installed capacity of wind and solar energy. Most of the new geothermal developments in the USA involve relatively small, moderate-temperature, geothermal systems. In contrast, development of higher enthalpy geothermal systems for power production has obvious advantages; specifically higher temperatures yield higher power outputs per well so that fewer wells are needed, leading to smaller environmental footprints for a given size of power plant. Disadvantages include that the fact that locations of suitable geothermal systems are restricted to young volcanic terrains, production of very high enthalpy fluids usually requires drilling deeper wells and may require enhanced geothermal (EGS) technology, and drilling deep into hot hostile environments is technologically challenging. However the potential for very favorable economic returns suggests that the USA should begin developing such a program. One approach to mitigating the cost issue is to form a consortium of industry, government and academia to share the costs and broaden the scope an investigation. An excellent example of such a collaboration is the Iceland Deep Drilling Project (IDDP) which is investigating the economic feasibility of producing electricity from supercritical geothermal reservoirs. This industry-government consortium planned to drill a deep well in the volcanic caldera of Krafla in NE Iceland. However drilling had to be terminated at 2.1 km depth when 900°C rhyolite magma flowed into the well. The resultant well was highly

  3. Selected data for low-temperature (less than 90{sup 0}C) geothermal systems in the United States: reference data for US Geological Survey Circular 892

    Energy Technology Data Exchange (ETDEWEB)

    Reed, M.J.; Mariner, R.H.; Brook, C.A.; Sorey, M.L.

    1983-12-15

    Supporting data are presented for the 1982 low-temperature geothermal resource assessment of the United States. Data are presented for 2072 geothermal sites which are representative of 1168 low-temperature geothermal systems identified in 26 States. The low-temperature geothermal systems consist of 978 isolated hydrothermal-convection systems, 148 delineated-area hydrothermal-convection systems, and 42 delineated-area conduction-dominated systems. The basic data and estimates of reservoir conditions are presented for each geothermal system, and energy estimates are given for the accessible resource base, resource, and beneficial heat for each isolated system.

  4. A three-dimensional coupled thermo-hydro-mechanical model for deformable fractured geothermal systems

    DEFF Research Database (Denmark)

    Salimzadeh, Saeed; Paluszny, Adriana; Nick, Hamidreza M.

    2018-01-01

    A fully coupled thermal-hydraulic-mechanical (THM) finite element model is presented for fractured geothermal reservoirs. Fractures are modelled as surface discontinuities within a three-dimensional matrix. Non-isothermal flow through the rock matrix and fractures are defined and coupled to a mec......A fully coupled thermal-hydraulic-mechanical (THM) finite element model is presented for fractured geothermal reservoirs. Fractures are modelled as surface discontinuities within a three-dimensional matrix. Non-isothermal flow through the rock matrix and fractures are defined and coupled....... The model has been validated against several analytical solutions, and applied to study the effects of the deformable fractures on the injection of cold water in fractured geothermal systems. Results show that the creation of flow channelling due to the thermal volumetric contraction of the rock matrix...

  5. Down-Hole Heat Exchangers: Modelling of a Low-Enthalpy Geothermal System for District Heating

    Directory of Open Access Journals (Sweden)

    M. Carlini

    2012-01-01

    Full Text Available In order to face the growing energy demands, renewable energy sources can provide an alternative to fossil fuels. Thus, low-enthalpy geothermal plants may play a fundamental role in those areas—such as the Province of Viterbo—where shallow groundwater basins occur and conventional geothermal plants cannot be developed. This may lead to being fuelled by locally available sources. The aim of the present paper is to exploit the heat coming from a low-enthalpy geothermal system. The experimental plant consists in a down-hole heat exchanger for civil purposes and can supply thermal needs by district heating. An implementation in MATLAB environment is provided in order to develop a mathematical model. As a consequence, the amount of withdrawable heat can be successfully calculated.

  6. Lithosphere tectonics and thermo-mechanical properties: An integrated modeling approach for enhanced geothermal systems exploration in Europe

    NARCIS (Netherlands)

    Wees, J.D. van; Cloetingh, S.; Ziegler, P.A.; Lenkey, L.; Beekman, F.; Tesauro, M.; Förster, A.; Norden, B.; Kaban, M.; Hardebol, N.; Voorde, M.T.; Willingshofer, E.; Cornu, T.; Bonté, D.

    2009-01-01

    For geothermal exploration and the development of enhanced geothermal systems (EGS) knowlegde of temperature at drillable depth is a prerequisite for site selection. Equally important is the thermo-mechanical signature of the lithosphere and crust which allow to obtain critical constraints for the

  7. Borehole heat exchangers: Longterm operational characteristics of a decentral geothermal heating system

    International Nuclear Information System (INIS)

    Rybach, L.; Eugster, W.J.; Hopkirk, R.J.; Kaelin, B.

    1992-01-01

    The heat pump-coupled borehole heat exchanger (BHE) is an efficient and small geothermal energy system for supplying heat typically to a single dwelling house. The long-term performance characteristics have been investigated by computer simulations. The numerical models were validated by measurements at instrumented BHE facilities. The results show the development of a new thermal equilibrium state after the first few years of BHE operation. The thermal influence is limited to the first few meters of the ground surrounding the BHE. The BHE could be scaled up in order to be installed in deep 'failed' holes (e.g. dry geothermal or hydrocarbon exploration holes)

  8. French know-how in the field of geothermal energy. District heating and electricity generation systems

    International Nuclear Information System (INIS)

    2012-08-01

    This brochure is aimed at presenting the French expertise, public and private, at international level in the field of geothermal energy (district heating and electricity generation systems). It presents a summary of the French public policy framework, measures to support Research and Development, innovation and training and offers from private companies. It has been designed by the ADEME in cooperation with the French ministry for Ecology and Sustainable Development, the French association of geothermal energy professionals, Ubifrance (the French Agency for international business development) and the French renewable energies union

  9. Numerical Analysis of Combined Well and Open-Closed Loops Geothermal (CWG) Systems

    Science.gov (United States)

    Park, Yu-Chul

    2016-04-01

    Open-loop geothermal heat pump (GHP) system and closed-loop heat pump systems have been used in Korea to reduce emission of greenhouse gases such as carbon dioxide (CO2). The GHP systems have the pros and cons, for example, the open-loop GHP system is good energy-efficient and the closed-loop GHP system requires minimum maintenance costs. The open-loop GHP system can be used practically only with large amount of groundwater supply. The closed-loop GHP system can be used with high costs of initial installation. The performance and efficiency of the GHP system depend on the characteristics of the GHP system itself in addition to the geologic conditions. To overcome the cons of open-loop or closed-loop GHP system, the combined well and open-closed loops geothermal (CWG) system was designed. The open-loop GHP system is surrounded with closed-loop GHP systems in the CWG system. The geothermal energy in closed-loop GHP systems is supplied by the groundwater pumped by the open-loop GHP system. In this study, 2 different types of the CWG systems (small aperture hybrid CWG system and large aperture CWG system) are estimated using numerical simulation models in the aspect of energy efficiency. This work was supported by the New & Renewable Energy Core Technology Program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP), granted financial resource from the Ministry of Trade, Industry & Energy, Republic of Korea. (No.20153030111120).

  10. Salton Sea Geothermal Field, California, as a near-field natural analog of a radioactive waste repository in salt

    International Nuclear Information System (INIS)

    Elders, W.A.; Cohen, L.H.

    1983-11-01

    Since high concentrations of radionuclides and high temperatures are not normally encountered in salt domes or beds, finding an exact geologic analog of expected near-field conditions in a mined nuclear waste repository in salt will be difficult. The Salton Sea Geothermal Field, however, provides an opportunity to investigate the migration and retardation of naturally occurring U, Th, Ra, Cs, Sr and other elements in hot brines which have been moving through clay-rich sedimentary rocks for up to 100,000 years. The more than thirty deep wells drilled in this field to produce steam for electrical generation penetrate sedimentary rocks containing concentrated brines where temperatures reach 365 0 C at only 2 km depth. The brines are primarily Na, K, Ca chlorides with up to 25% of total dissolved solids; they also contain high concentrations of metals such as Fe, Mn, Li, Zn, and Pb. This report describes the geology, geophysics and geochemistry of this system as a prelude to a study of the mobility of naturally occurring radionuclides and radionuclide analogs within it. The aim of this study is to provide data to assist in validating quantitative models of repository behavior and to use in designing and evaluating waste packages and engineered barriers. 128 references, 33 figures, 13 tables

  11. Salton Sea Geothermal Field, California, as a near-field natural analog of a radioactive waste repository in salt

    Science.gov (United States)

    Elders, W. A.; Cohen, L. H.

    1983-11-01

    Since high concentrations of radionuclides and high temperatures are not normally encountered in salt domes or beds, finding an exact geologic analog of expected near-field conditions in a mined nuclear waste repository in salt will be difficult. The Salton Sea Geothermal Field, however, provides an opportunity to investigate the migration and retardation of naturally occurring U, Th, Ra, Cs, Sr and other elements in hot brines which have been moving through clay-rich sedimentary rocks for up to 100,000 years. The more than thirty deep wells drilled in this field to produce steam for electrical generation penetrate sedimentary rocks containing concentrated brines where temperatures reach 3650C at only 2 km depth. The brines are primarily Na, K, Ca chlorides with up to 25% of total dissolved solids; they also contain high conentrations of metals such as Fe, Mn, Li, Zn, and Pb. This report describes the geology, geophysics and geochemistry of this system as a prelude to a study of the mobility of naturally occurring radionuclides and radionuclide analogs within it.

  12. Salton Sea Geothermal Field, California, as a near-field natural analog of a radioactive waste repository in salt

    Energy Technology Data Exchange (ETDEWEB)

    Elders, W.A.; Cohen, L.H.

    1983-11-01

    Since high concentrations of radionuclides and high temperatures are not normally encountered in salt domes or beds, finding an exact geologic analog of expected near-field conditions in a mined nuclear waste repository in salt will be difficult. The Salton Sea Geothermal Field, however, provides an opportunity to investigate the migration and retardation of naturally occurring U, Th, Ra, Cs, Sr and other elements in hot brines which have been moving through clay-rich sedimentary rocks for up to 100,000 years. The more than thirty deep wells drilled in this field to produce steam for electrical generation penetrate sedimentary rocks containing concentrated brines where temperatures reach 365/sup 0/C at only 2 km depth. The brines are primarily Na, K, Ca chlorides with up to 25% of total dissolved solids; they also contain high concentrations of metals such as Fe, Mn, Li, Zn, and Pb. This report describes the geology, geophysics and geochemistry of this system as a prelude to a study of the mobility of naturally occurring radionuclides and radionuclide analogs within it. The aim of this study is to provide data to assist in validating quantitative models of repository behavior and to use in designing and evaluating waste packages and engineered barriers. 128 references, 33 figures, 13 tables.

  13. World geothermal congress

    International Nuclear Information System (INIS)

    Povarov, O.A.; Tomarov, G.V.

    2001-01-01

    The World geothermal congress took place in the period from 28 May up to 10 June 2000 in Japan. About 2000 men from 43 countries, including specialists in the area of developing geothermal fields, creating and operating geothermal electrical and thermal plants and various systems for the earth heat application, participated in the work of the Congress. It was noted at the Congress, that development of the geothermal power engineering in the world is characterized by the large-scale application of geothermal resources for the electrical energy generation [ru

  14. TOUGH2Biot - A simulator for coupled thermal-hydrodynamic-mechanical processes in subsurface flow systems: Application to CO2 geological storage and geothermal development

    Science.gov (United States)

    Lei, Hongwu; Xu, Tianfu; Jin, Guangrong

    2015-04-01

    Coupled thermal-hydrodynamic-mechanical processes have become increasingly important in studying the issues affecting subsurface flow systems, such as CO2 sequestration in deep saline aquifers and geothermal development. In this study, a mechanical module based on the extended Biot consolidation model was developed and incorporated into the well-established thermal-hydrodynamic simulator TOUGH2, resulting in an integrated numerical THM simulation program TOUGH2Biot. A finite element method was employed to discretize space for rock mechanical calculation and the Mohr-Coulomb failure criterion was used to determine if the rock undergoes shear-slip failure. Mechanics is partly coupled with the thermal-hydrodynamic processes and gives feedback to flow through stress-dependent porosity and permeability. TOUGH2Biot was verified against analytical solutions for the 1D Terzaghi consolidation and cooling-induced subsidence. TOUGH2Biot was applied to evaluate the thermal, hydrodynamic, and mechanical responses of CO2 geological sequestration at the Ordos CCS Demonstration Project, China and geothermal exploitation at the Geysers geothermal field, California. The results demonstrate that TOUGH2Biot is capable of analyzing change in pressure and temperature, displacement, stress, and potential shear-slip failure caused by large scale underground man-made activity in subsurface flow systems. TOUGH2Biot can also be easily extended for complex coupled process problems in fractured media and be conveniently updated to parallel versions on different platforms to take advantage of high-performance computing.

  15. National Geothermal Data System (USA): an Exemplar of Open Access to Data

    Science.gov (United States)

    Allison, M. Lee; Richard, Stephen; Blackman, Harold; Anderson, Arlene; Patten, Kim

    2014-05-01

    The National Geothermal Data System's (NGDS - www.geothermaldata.org) formal launch in April, 2014 will provide open access to millions of data records, sharing -relevant geoscience and longer term to land use data to propel geothermal development and production. NGDS serves information from all of the U.S. Department of Energy's sponsored development and research projects and geologic data from all 50 states, using free and open source software. This interactive online system is opening new exploration opportunities and potentially shortening project development by making data easily discoverable, accessible, and interoperable. We continue to populate our prototype functional data system with multiple data nodes and nationwide data online and available to the public. Data from state geological surveys and partners includes more than 6 million records online, including 1.72 million well headers (oil and gas, water, geothermal), 670,000 well logs, and 497,000 borehole temperatures and is growing rapidly. There are over 312 interoperable Web services and another 106 WMS (Web Map Services) registered in the system as of January, 2014. Companion projects run by Southern Methodist University and U.S. Geological Survey (USGS) are adding millions of additional data records. The DOE Geothermal Data Repository, currently hosted on OpenEI, is a system node and clearinghouse for data from hundreds of U.S. DOE-funded geothermal projects. NGDS is built on the US Geoscience Information Network (USGIN) data integration framework, which is a joint undertaking of the USGS and the Association of American State Geologists (AASG). NGDS complies with the White House Executive Order of May 2013, requiring all federal agencies to make their data holdings publicly accessible online in open source, interoperable formats with common core and extensible metadata. The National Geothermal Data System is being designed, built, deployed, and populated primarily with support from the US

  16. Assessing the prospective resource base for enhanced geothermal systems in Europe

    NARCIS (Netherlands)

    Limberger, Jon; Calcagno, Philippe; Manzella, Adelle; Trumpy, Eugenio; Boxem, Thijs; Pluymaekers, Maarten; van Wees, Jan-Diederik

    2014-01-01

    In this study the resource base for EGS (enhanced geothermal systems) in Europe was quantified and economically constrained, applying a discounted cash-flow model to different techno-economic scenarios for future EGS in 2020, 2030, and 2050. Temperature is a critical parameter that controls the

  17. Demonstration of a Variable Phase Turbine Power System for Low Temperature Geothermal Resources

    Energy Technology Data Exchange (ETDEWEB)

    Hays, Lance G

    2014-07-07

    A variable phase turbine assembly will be designed and manufactured having a turbine, operable with transcritical, two-phase or vapor flow, and a generator – on the same shaft supported by process lubricated bearings. The assembly will be hermetically sealed and the generator cooled by the refrigerant. A compact plate-fin heat exchanger or tube and shell heat exchanger will be used to transfer heat from the geothermal fluid to the refrigerant. The demonstration turbine will be operated separately with two-phase flow and with vapor flow to demonstrate performance and applicability to the entire range of low temperature geothermal resources. The vapor leaving the turbine is condensed in a plate-fin refrigerant condenser. The heat exchanger, variable phase turbine assembly and condenser are all mounted on single skids to enable factory assembly and checkout and minimize installation costs. The system will be demonstrated using low temperature (237F) well flow from an existing large geothermal field. The net power generated, 1 megawatt, will be fed into the existing power system at the demonstration site. The system will demonstrate reliable generation of inexpensive power from low temperature resources. The system will be designed for mass manufacturing and factory assembly and should cost less than $1,200/kWe installed, when manufactured in large quantities. The estimated cost of power for 300F resources is predicted to be less than 5 cents/kWh. This should enable a substantial increase in power generated from low temperature geothermal resources.

  18. Geothermal system boundary at the northern edge of Patuha Geothermal Field based on integrated study of volcanostratigraphy, geological field mapping, and cool springs contamination by thermal fluids

    Science.gov (United States)

    Suryantini; Rachmawati, C.; Abdurrahman, M.

    2017-12-01

    Patuha Geothermal System is a volcanic hydrothermal system. In this type of system, the boundary of the system is often determined by low resistivity (10 ohm.m) anomaly from Magnetotelluric (MT) or DC-Resistivity survey. On the contrary, during geothermal exploration, the system boundary often need to be determined as early as possible even prior of resistivity data available. Thus, a method that use early stage survey data must be developed properly to reduce the uncertainty of the geothermal area extent delineation at the time the geophysical data unavailable. Geological field mapping, volcanostratigraphy analysis and fluid chemistry of thermal water and cold water are the data available at the early stage of exploration. This study integrates this data to delineate the geothermal system boundary. The geological mapping and volcanostratigraphy are constructed to limit the extent of thermal and cold springs. It results that springs in the study area are controlled hydrologically by topography of Patuha Volcanic Crown (complex) or so called PVC, the current geothermal field and Masigit Volcanic Crown (complex) or so called MVC, the dormant volcano not associated with active geothermal system. Some of the cold springs at PVC are contaminated by subsurface steam heated outflow while others are not contaminated. The contaminated cold springs have several characteristics such as higher water temperature than ambient temperature at the time it was measured, higher total disolved solid (TDS), and lower pH. The soluble elements analysis support the early contamination indication by showing higher cation and anion, and positive oxygen shifting of stable isotope of these cool springs. Where as the uncontaminated spring shows similar characteristic with cool springs occur at MVC. The boundary of the system is delineated by an arbitrary line drawn between distal thermal springs from the upflow or contaminated cool springs with the cool uncontaminated springs. This boundary is

  19. Human Health Science Building Geothermal Heat Pump Systems

    Energy Technology Data Exchange (ETDEWEB)

    Leidel, James [Oakland Univ., Rochester, MI (United States)

    2014-12-22

    The grant objectives of the DOE grant funded project have been successfully completed. The Human Health Building (HHB) was constructed and opened for occupancy for the Fall 2012 semester of Oakland University. As with any large construction project, some issues arose which all were overcome to deliver the project on budget and on time. The facility design is a geothermal / solar-thermal hybrid building utilizing both desiccant dehumidification and variable refrigerant flow heat pumps. It is a cooling dominant building with a 400 ton cooling design day load, and 150 ton heating load on a design day. A 256 vertical borehole (320 ft depth) ground source heat pump array is located south of the building under the existing parking lot. The temperature swing and performance over 2013 through 2015 shows the ground loop is well sized, and may even have excess capacity for a future building to the north (planned lab facility). The HHB achieve a US Green Building Counsel LEED Platinum rating by collecting 52 of the total 69 available LEED points for the New Construction v.2 scoring checklist. Being Oakland's first geothermal project, we were very pleased with the building outcome and performance with the energy consumption approximately 1/2 of the campus average facility, on a square foot basis.

  20. Geothermal Program Review X: proceedings. Geothermal Energy and the Utility Market -- the Opportunities and Challenges for Expanding Geothermal Energy in a Competitive Supply Market

    Energy Technology Data Exchange (ETDEWEB)

    1992-01-01

    Each year the Geothermal Division of the US Department of Energy conducts an in-depth review of its entire geothermal R&D program. The conference serves several purposes: a status report on current R&D activities, an assessment of progress and problems, a review of management issues, and a technology transfer opportunity between DOE and the US geothermal city. This year`s conference, Program Review X, was held in San Francisco on March 24--26, 1992. The theme of the review, ``Geothermal Energy and the Utility Market -- The Opportunities and Challenges for Expanding Geothermal Energy in a Competitive Supply Market,`` focused on the needs of the electric utility sector. Geothermal energy, with its power capacity potential of 10 GWe by the year 2010, can provide reliable, enviromentally clean electricity which can help offset the projected increase in demand. Program Review X consisted of seven sessions including an opening session with presentations by Mr. Vikram Budhraja, Vice President of System Planning and Operations, Southern California Edison Company, and Mr. Richard Jaros, President and Chief Operating Officer, California Energy Company. The six technical sessions included presentations by the relevant field researchers covering DOE-sponsored R&D in hydrothermal, hot dry rock, and geopressured energy. Individual projects are processed separately for the data bases.

  1. Structural Controls of the Emerson Pass Geothermal System, Washoe County, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Ryan B [Nevada Bureau of Mines and Geology, University of Nevada, Reno; Faulds, James E [Nevada Bureau of Mines and Geology, University of Nevada, Reno

    2012-09-30

    We have conducted a detailed geologic study to better characterize a blind geothermal system in Emerson Pass on the Pyramid Lake Paiute Tribe Reservation, western Nevada. A thermal anomaly was discovered in Emerson Pass by use of 2 m temperature surveys deployed within a structurally favorable setting and proximal to surface features indicative of geothermal activity. The anomaly lies at the western edge of a broad left step at the northeast end of Pyramid Lake between the north- to north-northeast-striking, west-dipping, Fox and Lake Range normal faults. The 2-m temperature surveys have defined a N-S elongate thermal anomaly that has a maximum recorded temperature of ~60°C and resides on a north- to north-northeaststriking fault. Travertine mounds, chalcedonic silica veins, and silica cemented Pleistocene lacustrine gravels in Emerson Pass indicate a robust geothermal system active at the surface in the recent past. Structural complexity and spatial heterogeneities of the strain and stress field have developed in the step-over region, but kinematic data suggest a WNW-trending (~280° azimuth) extension direction. The geothermal system is likely hosted in Emerson Pass as a result of enhanced permeability generated by the intersection of two oppositely dipping, southward terminating north- to north-northwest-striking (Fox Range fault) and northnortheast- striking faults.

  2. Economic, environmental and social impacts of geothermal development, and energy savings and efficient use of power in Baja California, Mexico; Impactos economicos, ambientales y sociales del desarrollo geotermico y del ahorro y uso eficiente de la electricidad en Baja California, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Campbell R, Hector E.; Montero A, Gisela [Universidad Autonoma de Baja California, Instituto de Ingenieria, Mexicali, Baja California (Mexico)]. E-mail: hecr@iing.mxl.uabc.mx; Lambert A., Alejandro A. [Universidad Autonoma de Baja California, Facultad de Ingenieria, Mexicali, Baja California (Mexico)

    2011-01-15

    This essay of electrical planning for Baja California, Mexico, includes diagnosis of power production and consumption from 1994-2005, prospective to 2025 if historical trends are maintained, discussion of a systemic plan and its impact on the prospective through energy savings and energy efficient use, combined with an increase of the geothermal energy share. Diagnosis indicates that geothermal capacity in 1998 accounted for 57% of total electric capacity in Baja California, and by 2004 73% of this total electric capacity was based on natural gas, increasing energy dependence on fossil fuels. During this period, electric generation changed from a ratio of 2 to 1 (geothermal steam to fuel oil) to 1 to 1 (geothermal steam to natural gas). The unit cost of natural gas energy with an efficiency of 50% is 24 times the cost of the same unit of geothermal steam with 16% efficiency. Power generation, with fuel oil or simple cycle turbines firing natural gas, costs twice that of combined cycle turbines, while the costs are three times less with geothermal steam. In 2005, as a consequence of a minor contribution of geothermal energy to the power-generation total, production costs increased, reaching $122.80 USD/MWh. The replacement of fuel oil, as power fuel, decreased the SO{sub x} emissions from 4.16 kg/MWh to 0.19 kg/MWh. The combined-cycle fired by natural gas diminished the relative emissions of NO{sub x} and CO{sub 2} by 30%, but the 2.6 million tons of CO{sub x} given off each year did no vary significantly. Using geothermal energy avoids burning 20 million barrels of oil equivalent annually. The Prospective 2005-2025 indicates Baja California requires the installation of an additional 4500 MW to reach 7200 MW. The energy portfolio will become more dependent on natural gas increasing its share from 60% to 86%. Geothermal energy will decrease its share in installed capacity to 10%, eliminating the damping effect on the cost of production. SO{sub x} emissions will

  3. Geothermal life cycle assessment - part 3

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, J. L. [Argonne National Lab. (ANL), Argonne, IL (United States); Frank, E. D. [Argonne National Lab. (ANL), Argonne, IL (United States); Han, J. [Argonne National Lab. (ANL), Argonne, IL (United States); Elgowainy, A. [Argonne National Lab. (ANL), Argonne, IL (United States); Wang, M. Q. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2013-11-01

    A set of key issues pertaining to the environmental performance of geothermal electric power have been addressed. They include: 1) greenhouse gas emissions (GHG) from geothermal facilities, 2) the use of supercritical carbon dioxide (scCO2) as a geofluid for enhanced geothermal systems (EGS), 3) quantifying the impact of well field exploration on the life cycle of geothermal power, and finally 4) criteria pollutant emissions for geothermal and other electric power generation. A GHG emission rate (g/kWh) distribution as function of cumulative running capacity for California has been developed based on California and U. S. government data. The distribution is similar to a global distribution for compared geothermal technologies. A model has been developed to estimate life cycle energy of and CO2 emissions from a coupled pair of coal and EGS plants, the latter of which is powered by scCO2 captured from coal plant side. Depending on the CO2 capture rate on the coal side and the CO2 consumption rate on the EGS side, significant reductions in GHG emissions were computed when the combined system is compared to its conventional coal counterpart. In effect, EGS CO2 consumption acts as a sequestration mechanism for the coal plant. The effects CO2 emissions from the coupled system, prompt on the coal side and reservoir leakage on the EGS side, were considered as well as the subsequent decline of these emissions after entering the atmosphere over a time frame of 100 years. A model was also developed to provide better estimates of the impact of well field exploration on the life cycle performance of geothermal power production. The new estimates increase the overall life cycle metrics for the geothermal systems over those previously estimated. Finally, the GREET model has been updated to include the most recent criteria pollutant emissions for a range of renewable (including geothermal) and other power

  4. Geothermal applications on the Madison (Pahasapa) aquifer system in South Dakota. Final report, October 1, 1976--September 30, 1977

    Energy Technology Data Exchange (ETDEWEB)

    Gries, J.P.

    1977-09-01

    Pertinent geologic, hydrologic, and chemical data for the Madison Formation underlying western South Dakota are presented in text and in graphic form. A temperature anomaly in west central South Dakota makes 130 to 160/sup 0/F water available at depths of less than 3500 ft. A central geothermal space heating system designed for Midland, South Dakota indicates that by 1980 geothermal heat will be competitive with existing energy sources. Preliminary tests indicate the superiority of 304 or 316 stainless steel for fabrication of equipment to utilize the warm, corrosive Madison water. South Dakota has no statutes governing geothermal resources; under existing water law, geothermal water would be classified as a top priority domestic use. Suggestions are made for state legislation pertaining to the development of geothermal energy.

  5. ThermoGIS: An integrated web-based information system for geothermal exploration and governmental decision support for mature oil and gas basins

    NARCIS (Netherlands)

    Wees, J.-D. van; Juez-Larre, J.; Mijnlieff, H.; Kronimus, A.; Gessel, S. van; Kramers, L.; Obdam, A.; Verweij, H.; Bonté, D.

    2009-01-01

    In the recent years the use of geothermal energy through implementation of low enthalpy geothermal production systems for both electricity and heating have been growing rapidly in north-western Europe. Geothermal exploration and production takes largely place in sedimentary basins at depths from 2

  6. Long-term Sustainability of Fracture Conductivity in Geothermal Systems using Proppants

    Energy Technology Data Exchange (ETDEWEB)

    Earl D Mattson; Ghanashyam Neupane; Mitchell Plummer; Clay Jones; Joe Moore

    2016-02-01

    Long-term sustainability of fracture conductivity is critical for commercial success of engineered geothermal system (EGS) and hydrogeothermal field sites. The injection of proppants has been suggested as a means to enhance the conductivity in these systems. Several studies have examined the chemical behavior of proppants that are not at chemical equilibrium with the reservoir rock and water. These studies have suggested that in geothermal systems, geochemical reactions can lead to enhance proppant dissolution and deposition alteration minerals. We hypothesize that proppant dissolution will decrease the strength of the proppant and can potentially reduce the conductivity of the fracture. To examine the geomechanical strength of proppants, we have performed modified crushing tests of proppants and reservoir rock material that was subjected to geothermal reservoir temperature conditions. The batch reactor experiments heated crushed quartz monzonite rock material, proppants (either quartz sand, sintered bauxite or kryptospheres) with Raft River geothermal water to 250 ºC for a period of 2 months. Solid and liquid samples were shipped to University of Utah for chemical characterization with ICP-OES, ICP-MS, and SEM. A separate portion of the rock/proppant material was subjected to a modified American Petroleum Institute ISO 13503-2 proppant crushing test. This test is typically used to determine the maximum stress level that can be applied to a proppant pack without the occurrence of unacceptable proppant crushing. We will use the test results to examine potential changes in proppant/reservoir rock geomechanical properties as compared to samples that have not been subjected to geothermal conditions. These preliminary results will be used to screen the proppants for long term use in EGS and hot hydrogeothermal systems.

  7. State Geological Survey Contributions to the National Geothermal Data System- Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Allison, M. Lee [Executive Office of the State of Arizona, Tuczon (AZGS), AZ (United States).; Richard, Stephen M. [Executive Office of the State of Arizona, Tuczon (AZGS), AZ (United States).

    2015-03-13

    The State Geological Survey Contributions to the National Geothermal Data System project is built on the work of the project managed by Boise State University to design and build the National Geothermal Data System, by deploying it nationwide and populating it with data principally from State Geological Surveys through collaboration with the Association of American State Geologists (AASG). This project subsequently incorporated the results of the design-build and other DOE-funded projects in support of the NGDS. The NGDS (www.geothermaldata.org) provides free open access to millions of data records, images, maps, and reports, sharing relevant geoscience, production, and land use data in 30+ categories to propel geothermal development and production in the U.S. NGDS currently serves information gathered from hundreds of the U.S. Department of Energy sponsored development and research projects and geologic data feeds from 60+ data providers throughout all 50 states. These data are relevant to geothermal energy exploration and development, but also have broad applicability in other areas including natural resources (e.g., energy, minerals, water), natural hazards, and land use and management.

  8. Quantitative Analysis of Existing Conditions and Production Strategies for the Baca Geothermal System, New Mexico

    Science.gov (United States)

    Faust, Charles R.; Mercer, James W.; Thomas, Stephen D.; Balleau, W. Pete

    1984-05-01

    The Baca geothermal reservoir and adjacent aquifers in the Jemez Mountains of New Mexico comprise an integrated hydrogeologic system. Analysis of the geothermal reservoir either under natural conditions or subject to proposed development should account for the mass (water) and energy (heat) balances of adjacent aquifers as well as the reservoir itself. A three-dimensional model based on finite difference approximations is applied to this integrated system. The model simulates heat transport associated with the flow of steam and water through an equivalent porous medium. The Baca geothermal reservoir is dominated by flow in fractures and distinct strata, but at the scale of application the equivalent porous media concept is appropriate. The geothermal reservoir and adjacent aquifers are simulated under both natural conditions and proposed production strategies. Simulation of natural conditions compares favorably with observed pressure, temperature, and thermal discharge data. The history matching simulations show that the results used for comparison are most sensitive to vertical permeability and the area of an assumed high-permeability zone connecting the reservoir to a deep hydrothermal source. Simulations using proposed production strategies and optimistic estimates of certain hydrologic parameters and reservoir extent indicate that a 50-MW power plant could be maintained for a period greater than 30 years. This production, however, will result in significant decreases in the total water discharge to the Jemez River.

  9. Development of Models to Simulate Tracer Tests for Characterization of Enhanced Geothermal Systems

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Mark D.; Reimus, Paul; Vermeul, Vincent R.; Rose, Peter; Dean, Cynthia A.; Watson, Tom B.; Newell, D.; Leecaster, Kevin; Brauser, Eric

    2013-05-01

    A recent report found that power and heat produced from enhanced (or engineered) geothermal systems (EGSs) could have a major impact on the U.S energy production capability while having a minimal impact on the environment. EGS resources differ from high-grade hydrothermal resources in that they lack sufficient temperature distribution, permeability/porosity, fluid saturation, or recharge of reservoir fluids. Therefore, quantitative characterization of temperature distributions and the surface area available for heat transfer in EGS is necessary for the design and commercial development of the geothermal energy of a potential EGS site. The goal of this project is to provide integrated tracer and tracer interpretation tools to facilitate this characterization. This project was initially focused on tracer development with the application of perfluorinated tracer (PFT) compounds, non-reactive tracers used in numerous applications from atmospheric transport to underground leak detection, to geothermal systems, and evaluation of encapsulated PFTs that would release tracers at targeted reservoir temperatures. After the 2011 midyear review and subsequent discussions with the U.S. Department of Energy Geothermal Technology Program (GTP), emphasis was shifted to interpretive tool development, testing, and validation. Subsurface modeling capabilities are an important component of this project for both the design of suitable tracers and the interpretation of data from in situ tracer tests, be they single- or multi-well tests. The purpose of this report is to describe the results of the tracer and model development for simulating and conducting tracer tests for characterizing EGS parameters.

  10. Fractal analysis for heat extraction in geothermal system

    Directory of Open Access Journals (Sweden)

    Shang Xiaoji

    2017-01-01

    Full Text Available Heat conduction and convection play a key role in geothermal development. These two processes are coupled and influenced by fluid seepage in hot porous rock. A number of integer dimension thermal fluid models have been proposed to describe this coupling mechanism. However, fluid flow, heat conduction and convection in porous rock are usually non-linear, tortuous and fractal, thus the integer dimension thermal fluid flow models can not well describe these phenomena. In this study, a fractal thermal fluid coupling model is proposed to describe the heat conduction and flow behaviors in fractal hot porous rock in terms of local fractional time and space derivatives. This coupling equation is analytically solved through the fractal travelling wave transformation method. Analytical solutions of Darcy’s velocity, fluid temperature with fractal time and space are obtained. The solutions show that the introduction of fractional parameters is essential to describe the mechanism of heat conduction and convection.

  11. Development of an Enhanced Two-Phase Production System at the Geysers Geothermal Field; FINAL

    International Nuclear Information System (INIS)

    Steven Enedy

    2001-01-01

    A method was developed to enhance geothermal steam production from two-phase wells at THE Geysers Geothermal Field. The beneficial result was increased geothermal production that was easily and economically delivered to the power plant

  12. Temporal changes of static stress drop as a proxy for poroelastic effects at The Geysers geothermal field, California

    Science.gov (United States)

    Staszek, Monika; Orlecka-Sikora, Beata; Lasocki, Stanislaw; Kwiatek, Grzegorz; Leptokaropoulos, Konstantinos; Martinez-Garzon, Patricia

    2017-04-01

    One of the major environmental impacts of shale gas exploitation is triggered and induced seismicity. Due to the similarity of fluid injection process data from geothermal fields can be used as a proxy for shale gas exploitation associated seismicity. Therefore, in this paper we utilize 'The Geysers' dataset compiled within SHale gas Exploration and Exploitation induced Risks (SHEER) project. The dependence of earthquake static stress drops on pore pressure in the medium was previously suggested by Goertz-Allmann et al. (2011), who observed an increase of the static stress drop with the distance from injection well during reservoir stimulation at Deep Heat Mining project in Basel, Switzerland. Similar observation has been done by Kwiatek et al. (2014) in Berlín geothermal field, El Salvador. In this study, we use a high-quality data from The Geysers geothermal field to determine whether the static stress drops and the stress drop distributions change statistically significantly in time or not, and how such changes are correlated with the values of hypocenter depth, water injection rate, and distance from injection well. For the analyses we use a group of 354 earthquakes, which occurred in the proximity of Prati-9 and Prati-29 injection wells. Spectral parameters of these earthquakes were determined using mesh spectral ratio technique. Our results indicate that: (1) the static stress drop variation in time is statistically significant, (2) median static stress drop is inversely related to median injection rate. Therefore, it is highly expected that static stress drop is influenced by pore pressure in underground fluid injection conditions. References: Goertz-Allmann B., Goertz A., Wiemer S. (2011), Stress drop variations of induced earthquakes at the Basel geothermal site. Geophysical Research Letters, 38, L09308, doi:10.1029/2011GL047498. Kwiatek G., Bulut F., Bohnhoff M., Dresen G. (2014), High-resolution analysis of seismicity induced at Berlin geothermal field

  13. Mapping the Geothermal System Using AMT and MT in the Mapamyum (QP Field, Lake Manasarovar, Southwestern Tibet

    Directory of Open Access Journals (Sweden)

    Lanfang He

    2016-10-01

    Full Text Available Southwestern Tibet plays a crucial role in the protection of the ecological environment and biodiversity of Southern Asia but lacks energy in terms of both power and fuel. The widely distributed geothermal resources in this region could be considered as potential alternative sources of power and heat. However, most of the known geothermal fields in Southwestern Tibet are poorly prospected and currently almost no geothermal energy is exploited. Here we present a case study mapping the Mapamyum (QP geothermal field of Southwestern Tibet using audio magnetotellurics (AMT and magnetotellurics (MT methods. AMT in the frequency range 11.5–11,500 Hz was used to map the upper part of this geothermal reservoir to a depth of 1000 m, and MT in the frequency range 0.001–320 Hz was used to map the heat source, thermal fluid path, and lower part of the geothermal reservoir to a depth greater than 1000 m. Data from 1300 MT and 680 AMT stations were acquired around the geothermal field. Bostick conversion with electromagnetic array profiling (EMAP filtering and nonlinear conjugate gradient inversion (NLCGI was used for data inversion. The AMT and MT results presented here elucidate the geoelectric structure of the QP geothermal field, and provide a background for understanding the reservoir, the thermal fluid path, and the heat source of the geothermal system. We identified a low resistivity anomaly characterized by resistivity in the range of 1–8 Ω∙m at a depth greater than 7 km. This feature was interpreted as a potential reflection of the partially melted magma in the upper crust, which might correlate to mantle upwelling along the Karakorum fault. It is likely that the magma is the heat source of the QP geothermal system, and potentially provides new geophysical evidence to understand the occurrence of the partially melted magmas in the upper crust in Southwestern Tibet.

  14. Predictability of the California Current System

    Science.gov (United States)

    Miller, Arthur J.; Chereskin, T.; Cornuelle, B. D.; Niiler, P. P.; Moisan, J. R.; Lindstrom, Eric (Technical Monitor)

    2001-01-01

    The physical and biological oceanography of the Southern California Bight (SCB), a highly productive subregion of the California Current System (CCS) that extends from Point Conception, California, south to Ensenada, Mexico, continues to be extensively studied. For example, the California Cooperative Oceanic Fisheries Investigations (CalCOFI) program has sampled this region for over 50 years, providing an unparalleled time series of physical and biological data. However, our understanding of what physical processes control the large-scale and mesoscale variations in these properties is incomplete. In particular, the non-synoptic and relatively coarse spatial sampling (70km) of the hydrographic grid does not completely resolve the mesoscale eddy field (Figure 1a). Moreover, these unresolved physical variations exert a dominant influence on the evolution of the ecosystem. In recent years, additional datasets that partially sample the SCB have become available. Acoustic Doppler Current Profiler (ADCP) measurements, which now sample upper-ocean velocity between stations, and sea level observations along TOPEX tracks give a more complete picture of the mesoscale variability. However, both TOPEX and ADCP are well-sampled only along the cruise or orbit tracks and coarsely sampled in time and between tracks. Surface Lagrangian drifters also sample the region, although irregularly in time and space. SeaWiFS provides estimates of upper-ocean chlorophyll-a (chl-alpha), usually giving nearly complete coverage for week-long intervals, depending on cloud coverage. Historical ocean color data from the Coastal Zone Color Scanner (CZCS) has been used extensively to determine phytoplankton patterns and variability, characterize the primary production across the SCB coastal fronts, and describe the seasonal and interannual variability in pigment concentrations. As in CalCOFI, these studies described much of the observed structures and their variability over relatively large space and

  15. A Materials and Equipment Review of Selected U.S. Geothermal District Heating Systems

    Energy Technology Data Exchange (ETDEWEB)

    Rafferty, K D [P.E.

    0000-12-30

    Geothermal district heating systems are now quite common in the western U.S. A recent survey identified a total of 17 such systems. The performance of materials and equipment in 13 of these systems is reviewed in this paper. Specific areas covered include: production facilities, central plants, distribution, customer connection, metering and disposal. Those areas: characterized by the highest incidence of problems include: production well pumps, customer branch piping and energy metering.

  16. Hydrogeochemical evaluation of conventional and hot dry rock geothermal resource potential in the Clear Lake region, California

    Energy Technology Data Exchange (ETDEWEB)

    Goff, F.; Adams, A.I.; Trujillo, P.E.; Counce, D.

    1993-05-01

    Chemistry, stable isotope, and tritium contents of thermal/mineral waters in the Clear Lake region were used to evaluate conventional and hot dry rock (HDR) geothermal potential for electrical generation. Thermal/mineral waters of the Clear Lake region are broadly classified as thermal meteoric and connate types based on chemical and isotopic criteria. Ratios of conservative components such as B/Cl are extremely different among all thermal/mineral waters of the Clear Lake region except for clusters of waters emerging from specific areas such as the Wilbur Springs district and the Agricultural Park area south of Mt. Konocti. In contrast ratios of conservative components in large, homogeneous geothermal reservoirs are constant. Stable isotope values of Clear Lake region waters show a mixing trend between thermal meteoric and connate (generic) end-members. The latter end-member has enriched {delta}D as well as enriched {delta}{sup 18}O, from typical high-temperature geothermal reservoir waters. Tritium data indicate most Clear Lake region waters are mixtures of old and young fluid components. Subsurface equilibration temperature of most thermal/mineral waters of the Clear Lake region is {le}150{degree}C based on chemical geothermometers but it is recognized that Clear Lake region waters are not typical geothermal fluids and that they violate rules of application of many geothermometers. The combined data indicate that no large geothermal reservoir underlies the Clear Lake region and that small localized reservoirs have equilibration temperatures {le}150{degree}C (except for Sulphur Bank mine). HDR technologies are probably the best way to commercially exploit the known high-temperatures existing beneath the Clear Lake region particularly within and near the main Clear Lake volcanic field.

  17. Recent trends in the development of heat exchangers for geothermal systems

    Science.gov (United States)

    Franco, A.; Vaccaro, M.

    2017-11-01

    The potential use of geothermal resources has been a remarkable driver for market players and companies operating in the field of geothermal energy conversion. For this reason, medium to low temperature geothermal resources have been the object of recent rise in consideration, with strong reference to the perspectives of development of Organic Rankine Cycle (ORC) technology. The main components of geothermal plants based on ORC cycle are surely the heat exchangers. A lot of different heat exchangers are required for the operation of ORC plants. Among those it is surely of major importance the Recovery Heat Exchanger (RHE, typically an evaporator), in which the operating fluid is evaporated. Also the Recuperator, in regenerative Organic Rankine Cycle, is of major interest in technology. Another important application of the heat exchangers is connected to the condensation, according to the possibility of liquid or air cooling media availability. The paper analyzes the importance of heat exchangers sizing and the connection with the operation of ORC power plants putting in evidence the real element of innovation: the consideration of the heat exchangers as central element for the optimum design of ORC systems.

  18. Fracture Characterization in Enhanced Geothermal Systems by Wellbore and Reservoir Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Horne, Roland N.; Li, Kewen; Alaskar, Mohammed; Ames, Morgan; Co, Carla; Juliusson, Egill; Magnusdottir, Lilja

    2012-06-30

    This report highlights the work that was done to characterize fractured geothermal reservoirs using production data. That includes methods that were developed to infer characteristic functions from production data and models that were designed to optimize reinjection scheduling into geothermal reservoirs, based on these characteristic functions. The characterization method provides a robust way of interpreting tracer and flow rate data from fractured reservoirs. The flow-rate data are used to infer the interwell connectivity, which describes how injected fluids are divided between producers in the reservoir. The tracer data are used to find the tracer kernel for each injector-producer connection. The tracer kernel describes the volume and dispersive properties of the interwell flow path. A combination of parametric and nonparametric regression methods were developed to estimate the tracer kernels for situations where data is collected at variable flow-rate or variable injected concentration conditions. The characteristic functions can be used to calibrate thermal transport models, which can in turn be used to predict the productivity of geothermal systems. This predictive model can be used to optimize injection scheduling in a geothermal reservoir, as is illustrated in this report.

  19. Strategies for Detecting Hidden Geothermal Systems by Near-Surface Gas Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Lewicki, Jennifer L.; Oldenburg, Curtis M.

    2004-12-15

    ''Hidden'' geothermal systems are those systems above which hydrothermal surface features (e.g., hot springs, fumaroles, elevated ground temperatures, hydrothermal alteration) are lacking. Emissions of moderate to low solubility gases (e.g., CO2, CH4, He) may be one of the primary near-surface signals from these systems. Detection of anomalous gas emissions related to hidden geothermal systems may therefore be an important tool to discover new geothermal resources. This study investigates the potential for CO2 detection and monitoring in the subsurface and above ground in the near-surface environment to serve as a tool to discover hidden geothermal systems. We focus the investigation on CO2 due to (1) its abundance in geothermal systems, (2) its moderate solubility in water, and (3) the wide range of technologies available to monitor CO2 in the near-surface environment. However, monitoring in the near-surface environment for CO2 derived from hidden geothermal reservoirs is complicated by the large variation in CO2 fluxes and concentrations arising from natural biological and hydrologic processes. In the near-surface environment, the flow and transport of CO2 at high concentrations will be controlled by its high density, low viscosity, and high solubility in water relative to air. Numerical simulations of CO2 migration show that CO2 concentrations can reach very high levels in the shallow subsurface even for relatively low geothermal source CO2 fluxes. However, once CO2 seeps out of the ground into the atmospheric surface layer, surface winds are effective at dispersing CO2 seepage. In natural ecological systems in the absence of geothermal gas emissions, near-surface CO2 fluxes and concentrations are primarily controlled by CO2 uptake by photosynthesis, production by root respiration, and microbial decomposition of soil/subsoil organic matter, groundwater degassing, and exchange with the atmosphere. Available technologies for monitoring CO2 in

  20. Potential for a significant deep basin geothermal system in Tintic Valley, Utah

    Science.gov (United States)

    Hardwick, C.; Kirby, S.

    2014-12-01

    The combination of regionally high heat flow, deep basins, and permeable reservoir rocks in the eastern Great Basin may yield substantial new geothermal resources. We explore a deep sedimentary basin geothermal prospect beneath Tintic Valley in central Utah using new 2D and 3D models coupled with existing estimates of heat flow, geothermometry, and shallow hydrologic data. Tintic Valley is a sediment-filled basin bounded to the east and west by bedrock mountain ranges where heat-flow values vary from 85 to over 240 mW/m2. Based on modeling of new and existing gravity data, a prominent 30 mGal low indicates basin fill thickness may exceed 2 km. The insulating effect of relatively low thermal conductivity basin fill in Tintic Valley, combined with typical Great Basin heat flow, predict temperatures greater than 150 °C at 3 km depth. The potential reservoir beneath the basin fill is comprised of Paleozoic carbonate and clastic rocks. The hydrology of the Tintic Valley is characterized by a shallow, cool groundwater system that recharges along the upper reaches of the basin and discharges along the valley axis and to a series of wells. The east mountain block is warm and dry, with groundwater levels just above the basin floor and temperatures >50 °C at depth. The west mountain block contains a shallow, cool meteoric groundwater system. Fluid temperatures over 50 °C are sufficient for direct-use applications, such as greenhouses and aquaculture, while temperatures exceeding 140°C are suitable for binary geothermal power plants. The geologic setting and regionally high heat flow in Tintic Valley suggest a geothermal resource capable of supporting direct-use geothermal applications and binary power production could be present.

  1. Geothermal energy

    International Nuclear Information System (INIS)

    Rummel, F.; Kappelmeyer, O.; Herde, O.A.

    1992-01-01

    Objective of this brochure is to present the subject Geothermics and the possible use of geothermal energy to the public. The following aspects will be refered to: -present energy situation -geothermal potential -use of geothermal energy -environemental aspects -economics. In addition, it presents an up-dated overview of geothermal projects funded by the German government, and a list of institutions and companies active in geothermal research and developments. (orig./HP) [de

  2. Dynamic Modeling and Simulation of Deep Geothermal Electric Submersible Pumping Systems

    Directory of Open Access Journals (Sweden)

    Julian Kullick

    2017-10-01

    Full Text Available Deep geothermal energy systems employ electric submersible pumps (ESPs in order to lift geothermal fluid from the production well to the surface. However, rough downhole conditions and high flow rates impose heavy strain on the components, leading to frequent failures of the pump system. As downhole sensor data is limited and often unrealible, a detailed and dynamical model system will serve as basis for deeper understanding and analysis of the overall system behavior. Furthermore, it allows to design model-based condition monitoring and fault detection systems, and to improve controls leading to a more robust and efficient operation. In this paper, a detailed state-space model of the complete ESP system is derived, covering the electrical, mechanical and hydraulic subsystems. Based on the derived model, the start-up phase of an exemplary yet realistic ESP system in the Megawatt range—located at a setting depth of 950 m and producing geothermal fluid of 140 ∘ C temperature at a rate of 0.145 m 3 s − 1 —is simulated in MATLAB/Simulink. The simulation results show that the system reaches a stable operating point with realistic values. Furthermore, the effect of self-excitation between the filter capacitor and the motor inductor can clearly be observed. A full set of parameters is provided, allowing for direct model implementation and reproduction of the presented results.

  3. The Economics of Connecting of Small Buildings to Geothermal District Heating Systems

    Energy Technology Data Exchange (ETDEWEB)

    Rafferty, Kevin

    2003-03-01

    Many of the communities co-located with geothermal resources are very small and as a result the buildings they contain tend to be small as well. Generally, small buildings (10,000 ft2) use heating systems which are not hot water based. Since geothermal district heating systems deliver hot water, the costs associated with the conversion of small building heating systems to use hot water for heating is an issue of great influence in terms of the potential development of such systems. This paper examines the typical retrofit costs associated with conversion of small buildings and the level of savings necessary to attract the interest of owners. In general, the prospects for connection of such buildings based only on energy savings is not positive.

  4. The economics of connecting of small buildings to geothermal district heating systems

    Energy Technology Data Exchange (ETDEWEB)

    Rafferty, Kevin

    2001-01-01

    Many of the communities co-located with geothermal resources are very small and as a result the buildings they contain tend to be small as well. Generally, small buildings (10,000 ft2) use heating systems which are not hot water based. Since geothermal district heating systems deliver hot water, the costs associated with the conversion of small building heating systems to use hot water for heating is an issue of great influence in terms of the potential development of such systems. This paper examines the typical retrofit costs associated with conversion of small buildings and the level of savings necessary to attract the interest of owners. In general, the prospects for connection of such buildings based only on energy savings is not positive.

  5. Heat Recovery from Multiple-Fracture Enhanced Geothermal Systems: The Effect of Thermoelastic Fracture Interactions

    DEFF Research Database (Denmark)

    Vik, Hedda Slatlem; Salimzadeh, Saeed; Nick, Hamid

    2018-01-01

    This study investigates the effect of thermoelastic interactions between multiple parallel fractures on energy production from a multiple-fracture enhanced geothermal system. A coupled thermo-hydro-mechanical finite element model has been developed that accounts for non-isothermal fluid flow within...... increased to maximise the net energy production from the system. Otherwise, the multiple-fracture system fails to improve the energy recovery from the geothermal reservoir, as initially intended....... aperture in the adjacent fracture, and facilitates the creation of favourable flow pathways between the injection and production wells. These flow paths reduce the energy production from the system. The effects of fracture spacing, reservoir temperature gradient and mechanical properties of the rock matrix...

  6. Geothermal energy and the utility market -- the opportunities and challenges for expanding geothermal energy in a competitive supply market: Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    1992-01-01

    Each year the Geothermal Division of the US Department of Energy conducts an in-depth review of its entire geothermal R D program. The conference serves several purposes: a status report on current R D activities, an assessment of progress and problems, a review of management issues, and a technology transfer opportunity between DOE and the US geothermal city. This year's conference, Program Review X, was held in San Francisco on March 24--26, 1992. The theme of the review, Geothermal Energy and the Utility Market -- The Opportunities and Challenges for Expanding Geothermal Energy in a Competitive Supply Market,'' focused on the needs of the electric utility sector. Geothermal energy, with its power capacity potential of 10 GWe by the year 2010, can provide reliable, enviromentally clean electricity which can help offset the projected increase in demand. Program Review X consisted of seven sessions including an opening session with presentations by Mr. Vikram Budhraja, Vice President of System Planning and Operations, Southern California Edison Company, and Mr. Richard Jaros, President and Chief Operating Officer, California Energy Company. The six technical sessions included presentations by the relevant field researchers covering DOE-sponsored R D in hydrothermal, hot dry rock, and geopressured energy. Individual projects are processed separately for the data bases.

  7. Geochemistry of sericite and chlorite in well 14-2 Roosevelt Hot Springs geothermal system and in mineralized hydrothermal systems

    Energy Technology Data Exchange (ETDEWEB)

    Ballantyne, J.M.

    1980-06-01

    Chemical compositions of chlorite and sericite from one production well in the Roosevelt geothermal system have been determined by electron probe methods and compared with compositions of chlorite and sericite from porphyry copper deposits. Modern system sericite and chlorite occur over a depth interval of 2 km and a temperature interval of 250/sup 0/C.

  8. The role of helium and other noble gases in the modelling of geothermal systems

    International Nuclear Information System (INIS)

    Hulston, J.R.

    1994-01-01

    A model of the geothermal system in which deep circulating groundwater containing noble gases at air saturated water concentrations mixes with hot fluids of mantle origin at depth is described. It is proposed that the 3 He/heat ratio should be similar to that observed in mid-ocean ridge systems, in which case the 3 He to atmospheric argon ratio in geothermal discharges would be an indicator o the likely heat content of a system. As a first test of this hypothesis the noble gas results of Mazor et al. (1990) have been presented as the 3 He/heat ratios for Wairakei and early Mokai wells and fumaroles. Their simplified boiling model has been used to correct for the effects of gas-water separation which occurs in underground boiling. At Wairakei, the resultant range of 3 He/heat values is 140-8500 atoms 3 He mW -1 s -1 , similar (except for the lowest values) to the range measured in mid ocean ridges. Further work is needed, but the available data show that the technique has promise for the modelling of deep geothermal systems and providing input to simulation models currently being used in reservoir engineering. The technique has potential to distinguish between stored heat systems and renewing systems. (author). 8 refs., 2 figs., 1 tab

  9. A time-lapse gravity survey of the Coso geothermal field, China Lake Naval Air Weapons Station, California

    Science.gov (United States)

    Phelps, Geoffrey; Cronkite-Ratcliff, Collin; Blake, Kelly

    2018-04-19

    We have conducted a gravity survey of the Coso geothermal field to continue the time-lapse gravity study of the area initiated in 1991. In this report, we outline a method of processing the gravity data that minimizes the random errors and instrument bias introduced into the data by the Scintrex CG-5 relative gravimeters that were used. After processing, the standard deviation of the data was estimated to be ±13 microGals. These data reveal that the negative gravity anomaly over the Coso geothermal field, centered on gravity station CER1, is continuing to increase in magnitude over time. Preliminary modeling indicates that water-table drawdown at the location of CER1 is between 65 and 326 meters over the last two decades. We note, however, that several assumptions on which the model results depend, such as constant elevation and free-water level over the study period, still require verification.

  10. Deformation near the Casa Diablo geothermal well field and related processes Long Valley caldera, Eastern California, 1993-2000

    Science.gov (United States)

    Howle, J.F.; Langbein, J.O.; Farrar, C.D.; Wilkinson, S.K.

    2003-01-01

    Regional first-order leveling lines, which extend from Lee Vining, CA, to Tom's Place, CA, have been surveyed periodically since 1957 by the U.S. Geological Survey (USGS), the National Geodetic Survey (NGS), and Caltrans. Two of the regional survey lines, or leveling networks, intersect at the Casa Diablo geothermal well field. These leveling networks, referenced to a distant bench mark (C916) near Lee Vining, provide time-series vertical control data of land-surface deformation that began around 1980. These data are also useful for delineating localized subsidence at Casa Diablo related to reservoir pressure and temperature changes owing to geothermal development that began in 1985. A comparison of differences in bench-mark elevations for five time periods between 1983 and 1997 shows the development and expansion of a subsidence bowl at Casa Diablo. The subsidence coincides spatially with the geothermal well field and temporally with the increased production rates and the deepening of injection wells in 1991, which resulted in an increase in the rate of pressure decline. The subsidence, superimposed on a broad area of uplift, totaled about 310 mm by 1997. The USGS established orthogonal tilt arrays in 1983 to better monitor deformation across the caldera. One tilt array (DBR) was established near what would later become the Casa Diablo geothermal well field. This array responded to magmatic intrusions prior to geothermal development, tilting away from the well field. With the start of geothermal fluid extraction in 1985, tilt at the DBR array reversed direction and began tilting into the well field. In 1991, geothermal power production was increased by a factor of four, and reservoir pressures began a period of steep decline. These changes caused a temporary three-fold increase in the tilt rate. The tilt rate became stable in 1993 and was about 40% lower than that measured in 1991-1992, but still greater than the rates measured during 1985-1990. Data from the

  11. Design and Implementation of Geothermal Energy Systems at West Chester University

    Energy Technology Data Exchange (ETDEWEB)

    Cuprak, Greg [West Chester Univ. of Pennsylvania, PA (United States)

    2016-11-02

    West Chester University has launched a comprehensive transformation of its campus heating and cooling systems from traditional fossil fuels (coal, oil and natural gas) to geothermal. This change will significantly decrease the institution’s carbon footprint and serve as a national model for green campus efforts. The institution has designed a phased series of projects to build a district geo-exchange system with shared well fields, central pumping station and distribution piping to provide the geo-exchange water to campus buildings as their internal building HVAC systems is changed to be able to use the geo-exchange water. This project addresses the US Department of Energy Office of Energy Efficiency and Renewable Energy (EERE) goal to invest in clean energy technologies that strengthen the economy, protect the environment, and reduce dependence on foreign oil. In addition, this project advances EERE’s efforts to establish geothermal energy as an economically competitive contributor to the US energy supply.

  12. Design and Implementation of Geothermal Energy Systems at West Chester University

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, James [West Chester Univ., West Chester (PA)

    2016-08-05

    West Chester University has launched a comprehensive transformation of its campus heating and cooling systems from traditional fossil fuels to geothermal. This change will significantly decrease the institution's carbon footprint and serve as a national model for green campus efforts. The institution has designed a phased series of projects to build a district geo-exchange system with shared well fields, central pumping station and distribution piping to provide the geo-exchange water to campus buildings as their internal building HVAC systems are changed to be able to use the geo-exchange water. This project addresses the US Department of Energy Office of Energy Efficiency and Renewable Energy (EERE) goal to invest in clean energy technologies that strengthen the economy, protect the environment, and reduce dependence on foreign oil. In addition, this project advances EERE's efforts to establish geothermal energy as an economically competitive contributor to the US energy supply.

  13. Energy Returned On Investment of Engineered Geothermal Systems Annual Report FY2011

    Energy Technology Data Exchange (ETDEWEB)

    Mansure, A.J.

    2011-12-31

    Energy Return On Investment (EROI) is an important figure of merit for assessing the viability of energy alternatives. For geothermal electric power generation, EROI is determined by the electricity delivered to the consumer compared to the energy consumed to construct, operate, and decommission the facility. Critical factors in determining the EROI of Engineered Geothermal Systems (EGS) are examined in this work. These include the input energy embodied into the system. The embodied energy includes the energy contained in the materials, as well as, that consumed in each stage of manufacturing from mining the raw materials to assembling the finished plant. Also critical are the system boundaries and value of the energy - heat is not as valuable as electrical energy.

  14. Geothermal and Trigeneration Systems as Innovative and EnvironmentallyFriendly Solutions for Telecommunication Plant Cooling

    Directory of Open Access Journals (Sweden)

    Paolo Trotta

    2016-12-01

    Full Text Available The paper deals with a model-based analysis of innovative cooling systems, to be deployed in telecommunication (TLC plants in consideration of their size, geographical location and typology (e.g. central Offices or data-centers. Environmentally friendly systems, such as geothermal heat pumps and trigeneration plants, were considered. The trade-off between the investment and operating costs was first analyzed, followed by a comparative evaluation of economic savings achievable via each candidate solution with respect to reference benchmarks, here represented by traditional air-water heat pump and conventional interaction with electrical grid. In this way, a preliminary macroscopic assessment of the best solutions was accomplished, according to the different scenarios (i.e. small or big TLC plant under investigation. A more detailed analysis, concerning the comparison between traditional and geothermal systems, was specifically carried out to evaluate savings as a function of the external temperature and, consequently, of geographical location.

  15. Geochemistry of thermal/mineral waters in the Clear Lake region, California, and implications for hot dry rock geothermal development

    Energy Technology Data Exchange (ETDEWEB)

    Goff, F.; Adams, A.I.; Trujillo, P.E.; Counce, D.; Mansfield, J.

    1993-02-01

    Thermal/mineral waters of the Clear Lake region are broadly classified as thermal meteoric and connote types based on chemical and isotopic criteria. Ratios of conservative components such as B/Cl are extremely different among all thermal/mineral waters of the Clear Lake region except for clusters of waters emerging from specific areas such as the Wilbur Springs district and the Agricultural Park area south of Mt. Konocti. In contrast, ratios of conservative components in large, homogeneous geothermal reservoirs are constant. Stable isotope values of Clear Lake region waters show a mixing trend between thermal meteoric and connote end-members. The latter end-member has enriched [delta]D as well as enriched d[sup l8]O, very different from typical high-temperature geothermal reservoir waters. Tritium data and modeling of ages indicate most Clear Lake region waters are 500 to > 10,000 yr., although mixing of old and young components is implied by the data. The age of end-member connate water is probably > 10,000 yr. Subsurface equilibration temperature of most thermal/mineral waters of the Clear Lake region is [le] 150[degrees]C based on chemical geothermometers but it is recognized that Clear Lake region waters are not typical geothermal fluids and that they violate rules of application of many geothermometers. The combined data indicate that no large geothermal reservoir underlies the Clear Lake region and that small localized reservoirs have equilibration temperatures [le] 150[degrees]C (except for Sulphur Bank Mine). Hot dry rock technologies are the best way to commercially exploit the known high temperatures existing beneath the Clear Lake region, particularly within the main Clear Lake volcanic field.

  16. Novel Geothermal Development of Deep Sedimentary Systems in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Joseph [Univ. of Utah, Salt Lake City, UT (United States); Allis, Rick [Utah Geological Survey, Salt Lake City, UT (United States)

    2017-10-11

    Economic and reservoir engineering models show that stratigraphic reservoirs have the potential to contribute significant geothermal power in the U.S. If the reservoir temperature exceeds about 150 – 200 °C at 2 – 4 km depth, respectively, and there is good permeability, then these resources can generate power with a levelized cost of electricity (LCOE) of close to 10 ¢/kWh (without subsidies) on a 100 MW power plant scale. There is considerable evidence from both groundwater geology and petroleum reservoir geology that relatively clean carbonates and sandstones have, and can sustain, the required high permeability to depths of at least 5 km. This paper identifies four attractive stratigraphic reservoir prospects which are all located in the eastern Great Basin, and have temperatures of 160 – 230 °C at 3 – 3.5 km depth. They are the Elko basins (Nevada), North Steptoe Valley (Nevada), Pavant Butte (Utah), and the Idaho Thrust Belt. The reservoir lithologies are Paleozoic carbonates in the first three, and Jurassic sandstone and carbonate in the Idaho Thrust Belt. All reservoir lithologies are known to have high permeability characteristics. At North Steptoe Valley and Pavant Butte, nearby transmission line options allow interconnection to the California power market. Modern techniques for drilling and developing tight oil and gas reservoirs are expected to have application to geothermal development of these reservoirs.

  17. Application of Fusion Gyrotrons to Enhanced Geothermal Systems (EGS)

    Science.gov (United States)

    Woskov, P.; Einstein, H.; Oglesby, K.

    2013-10-01

    The potential size of geothermal energy resources is second only to fusion energy. Advances are needed in drilling technology and heat reservoir formation to realize this potential. Millimeter-wave (MMW) gyrotrons and related technologies developed for fusion energy research could contribute to enabling EGS. Directed MMW energy can be used to advance rock penetration capabilities, borehole casing, and fracking. MMWs are ideally suited because they can penetrate through small particulate extraction plumes, can be efficiently guided long distances in borehole dimensions, and continuous megawatt sources are commercially available. Laboratory experiments with a 10 kW, 28 GHz CPI gyrotron have shown that granite rock can be fractured and melted with power intensities of about 1 kW/cm2 and minute exposure times. Observed melted rock MMW emissivity and estimated thermodynamics suggest that penetrating hot, hard crystalline rock formations may be economic with fusion research developed MMW sources. Supported by USDOE, Office of Energy Efficiency and Renewable Energy and Impact Technologies, LLC.

  18. Geothermal Power Supply Systems around the World and in Russia: State of the Art and Future Prospects

    Science.gov (United States)

    Butuzov, V. A.; Amerkhanov, R. A.; Grigorash, O. V.

    2018-05-01

    Solar and geothermal energy systems are shown to have received the widest use among all kinds of renewable sources of energy for heat supply purposes around the world. The power capacities and amounts of thermal energy generated by solar and geothermal heat supply systems around the world are presented by way of comparison. The thermal power capacity of solar heat supply systems installed around the world as of 2015 totaled 268.1 GW, and the thermal energy generated by them amounted to 225 TW h/year. The thermal power capacity of geothermal heat supply systems installed around the world totaled 70.3 GW, and the thermal energy generated by them amounted to 163 TW h/year. Information on the geothermal heat supply systems in the leading countries around the world based on the data reported at the World Geothermal Congress held in 2015 is presented. It is shown that China, with the installed thermal power capacities of its geothermal heat supply stations totaling 17.87 GW and the amount of thermal energy generated per annum equal to 48.435 TW h/year, is the world's leader in this respect. The structures of geothermal heat supply systems by the kinds of heat consumption used around the world are presented. The systems equipped with geothermal heat pumps accounted for 70.95% in the total installed capacity and for 55.3% in the total amount of generated heat. For systems that do not use heat pumps, those serving for pools account for the largest share amounting to 44.74% in installed capacity and to 45.43% in generated heat. A total of 2218 geothermal wells with the total length equal to 9534 km (with 38.7% of them for heat supply purposes) were drilled in 42 countries in the period from 2010 to 2014. In Russia, geothermal heat supply systems are in operation mainly in Dagestan, in Krasnodar krai, and in Kamchatka. The majority of these systems have been made without breaking the stream after the well outlet. A cyclic control arrangement is also used. The combined

  19. Geothermal source heat pump performance for a greenhouse heating system: an experimental study

    Directory of Open Access Journals (Sweden)

    Alexandros Sotirios Anifantis

    2016-09-01

    Full Text Available Greenhouses play a significant function in the modern agriculture economy even if require great amount of energy for heating systems. An interesting solution to alleviate the energy costs and environmental problems may be represented by the use of geothermal energy. The aim of this paper, based on measured experimental data, such as the inside greenhouse temperature and the heat pump performance (input and output temperatures of the working fluid, electric consumption, was the evaluation of the suitability of low enthalpy geothermal heat sources for agricultural needs such as greenhouses heating. The study was carried out at the experimental farm of the University of Bari, where a greenhouse was arranged with a heating system connected to a ground-source heat pump (GSHP, which had to cover the thermal energy request. The experimental results of this survey highlight the capability of the geothermal heat source to ensue thermal conditions suitable for cultivation in greenhouses even if the compressor inside the heat pump have operated continuously in a fluctuating state without ever reaching the steady condition. Probably, to increase the performance of the heat pump and then its coefficient of performance within GSHP systems for heating greenhouses, it is important to analyse and maximise the power conductivity of the greenhouse heating system, before to design an expensive borehole ground exchanger. Nevertheless, according to the experimental data obtained, the GSHP systems are effective, efficient and environmental friendly and may be useful to supply the heating energy demand of greenhouses.

  20. Health and safety impacts of nuclear, geothermal, and fossil-fuel electric generation in California. Volume 4. Radiological emergency response planning for nuclear power plants in California

    International Nuclear Information System (INIS)

    Yen, W.W.S.

    1977-01-01

    This report reviews the state of emergency response planning for nuclear power plants in California. Attention is given to the role of Federal agencies, particularly the Nuclear Regulatory Commission, in planning for both on and off site emergency measures and to the role of State and local agencies for off site planning. The relationship between these various authorities is considered. Existing emergency plans for nuclear power plants operating or being constructed in California are summarized. The developing role of the California Energy Resources Conservation and Development Commission is examined

  1. Thermal history of the Acoculco geothermal system, eastern Mexico: Insights from numerical modeling and radiocarbon dating

    Science.gov (United States)

    Canet, Carles; Trillaud, Frederic; Prol-Ledesma, Rosa María; González-Hernández, Galia; Peláez, Berenice; Hernández-Cruz, Berenice; Sánchez-Córdova, María M.

    2015-10-01

    Acoculco is a geothermal prospective area hosted by a volcanic caldera complex in the eastern Trans-Mexican Volcanic Belt. Surface manifestations are scarce and consist of gas discharges (CO2-rich) and acid-sulfate springs of low temperature, whereas hydrothermal explosive activity is profusely manifested by meter-scale craters and mounds of hydrothermal debris and breccias. Silicic alteration extends for several square kilometers around the zone with gas manifestations and explosive features, affecting surficial volcanic rocks, primarily tuffs and breccias. In the subsurface, an argillic alteration zone (ammonium illite) extends down to a depth of ∼ 600 m, and underneath it a propylitic zone (epidote-calcite-chlorite) occurs down to ∼ 1000 m. Thermal logs from an exploratory borehole (EAC-1, drilled in 1995 down to 1810 m) showed a conductive heat transfer regime under high geothermal gradient (∼ 140 °C/1000 m). In contrast, the thermal profile established from temperatures of homogenization of fluid inclusions-measured on core samples from the same drill hole-suggests that convection occurred in the past through the upper ~ 1400 m of the geothermal system. A drop in permeability due to the precipitation of alteration minerals would have triggered the cessation of the convective heat transfer regime to give place to a conductive one. With the purpose of determining when the transition of heat transfer regime occurred, we developed a 1D model that simulates the time-depth distribution of temperature. According to our numerical simulations, this transition happened ca. 7000 years ago; this date is very recent compared to the lifespan of the geothermal system. In addition, radiocarbon chronology indicates that the hydrothermal explosive activity postdates the end of the convective heat transfer regime, having dated at least three explosive events, at 4867-5295, 1049-1417 and 543-709 y cal. BP. Therefore, hydrothermal explosions arise from the self-sealing of

  2. A 100% renewable electricity generation system for New Zealand utilising hydro, wind, geothermal and biomass resources

    International Nuclear Information System (INIS)

    Mason, I.G.; Page, S.C.; Williamson, A.G.

    2010-01-01

    The New Zealand electricity generation system is dominated by hydro generation at approximately 60% of installed capacity between 2005 and 2007, augmented with approximately 32% fossil-fuelled generation, plus minor contributions from geothermal, wind and biomass resources. In order to explore the potential for a 100% renewable electricity generation system with substantially increased levels of wind penetration, fossil-fuelled electricity production was removed from an historic 3-year data set, and replaced by modelled electricity production from wind, geothermal and additional peaking options. Generation mixes comprising 53-60% hydro, 22-25% wind, 12-14% geothermal, 1% biomass and 0-12% additional peaking generation were found to be feasible on an energy and power basis, whilst maintaining net hydro storage. Wind capacity credits ranged from 47% to 105% depending upon the incorporation of demand management, and the manner of operation of the hydro system. Wind spillage was minimised, however, a degree of residual spillage was considered to be an inevitable part of incorporating non-dispatchable generation into a stand-alone grid system. Load shifting was shown to have considerable advantages over installation of new peaking plant. Application of the approach applied in this research to countries with different energy resource mixes is discussed, and options for further research are outlined.

  3. Prospecting for a Blind Geothermal System Utilizing Geologic and Geophysical Data, Seven Troughs Range, Northwestern Nevada

    Science.gov (United States)

    Forson, Corina

    To aid in the discovery and evaluation of blind resources, it is important to utilize geologic, geophysical, and geochemical techniques to find the required elements (e.g., heat source, fluid to transport the heat, and permeability in a reservoir) for geothermal energy production. Based on a regional low resistivity anomaly discovered through a reconnaissance magnetotelluric (MT) survey, detailed geologic mapping, structural analysis, and a 2 m temperature survey were conducted to delineate the most likely areas for blind geothermal activity in the Seven Troughs Range, Nevada. The Seven Troughs Range resides in the northwestern Basin and Range province 190 km northeast of Reno and 50 km northwest of Lovelock in western Nevada. There is no known geothermal system in the area. Mesozoic metasedimentary strata and intrusions dominate the northern and southern parts of the range but are nonconformably overlain by a thick sequence (~ 1.5 km) of Oligocene to Miocene volcanic and volcaniclastic rocks and Quaternary sediments in the central part of the range. The southern part of the range consists of a basement horst block bounded by two major range-front faults, with Holocene fault scarps marking the more prominent fault on the east side of the range. In contrast, several gently to moderately west-tilted fault blocks, with good exposures of the Tertiary volcanic strata and bounded by a series of steeply east-dipping normal faults, characterize the central part of the range. Kinematic analysis of faults in the range and regional relations indicate a west-northwest-trending extension direction. Accordingly, slip and dilation tendency analyses suggest that north-northeast striking faults are the most favorably oriented for reactivation and fluid flow under the current stress field. Two areas in the Seven Troughs Range have a favorable structural setting for generating permeability and channeling geothermal fluids to the near surface: 1) A major right step in the range

  4. Geothermal Direct Heat Applications Program Summary

    Energy Technology Data Exchange (ETDEWEB)

    None

    1981-09-25

    Because of the undefined risk in the development and use of geothermal energy as a thermal energy source, the Department of Energy Division of Geothermal Energy solicited competitive proposals for field experiments in the direct use of geothermal energy. Twenty-two proposals were selected for cost-shared funding with one additional project co-funded by the State of New Mexico. As expected, the critical parameter was developing a viable resource. So far, of the twenty resources drilled, fourteen have proved to be useful resources. These are: Boise, Idaho; Elko heating Company in Nevada; Pagosa Springs, Colorado; Philip School, Philip, South Dakota; St. Mary's Hospital, Pierre, South Dakota; Utah Roses near Salt Lake City; Utah State Prison, Utah; Warm Springs State Hospital, Montana; T-H-S Hospital, Marlin, Texas; Aquafarms International in the Cochella Valley, California; Klamath County YMCA and Klamath Falls in Oregon; Susanville, California and Monroe, utah. Monroe's 164 F and 600 gpm peak flow was inadequate for the planned project, but is expected to be used in a private development. Three wells encountered a resource insufficient for an economical project. These were Madison County at Rexburg, Idaho; Ore-Ida Foods at Ontario, Oregon and Holly Sugar at Brawley, California. Three projects have yet to confirm their resource. The Navarro College well in Corsicana, Texas is being tested; the Reno, Moana, Nevada well is being drilled and the El Centro, California well is scheduled to be drilled in January 1982. The agribusiness project at Kelly Hot Springs was terminated because a significant archeological find was encountered at the proposed site. The Diamond Ring Ranch in South Dakota, and the additional project, Carrie Tingley Hospital in Truth or Consequences, New Mexico both used existing wells. The projects that encountered viable resources have proceeded to design, construct, and in the most advanced projects, to operate geothermal systems for

  5. Geothermal energy worldwide

    International Nuclear Information System (INIS)

    Barbier, Enriko

    1997-01-01

    Geothermal energy, as a natural steam and hot water, has been exploited for decades in order to generate electricity as well as district heating and industrial processes. The present geothermal electrical installed capacity in the world is about 10.000 MWe and the thermal capacity in non-electrical uses is about 8.200 MWt. Electricity is produced with an efficiency of 10-17%, and the cost of the kWh is competitive with conventional energy sources. In the developing countries, where a total installed electrical power is still low, geothermal energy can play a significant role: in El Salvador, for example, 25% of electricity comes from geothermal spring, 20% in the Philippines and 8% in Kenya. Present technology makes it possible to control the environmental impact of geothermal exploitation. Geothermal energy could also be extracted from deep geopressured reservoirs in large sedimentary basins, hot dry rock systems and magma bodies. (author)

  6. Geothermal Energy

    International Nuclear Information System (INIS)

    Haluska, Oscar P.; Tangir, Daniel; Perri, Matias S.

    2002-01-01

    A general overview of geothermal energy is given that includes a short description of the active and stable areas in the world. The possibilities of geothermal development in Argentina are analyzed taking into account the geothermal fields of the country. The environmental benefits of geothermal energy are outlined

  7. Geothermal energy

    Energy Technology Data Exchange (ETDEWEB)

    Gasparovic, N

    1962-07-01

    Live steam, transformed steam, and steam produced by expansion flashing are outlined with respect to their use in the production of electricity. The capacity, pressure, and temperature of a steam must be determined empirically by exploratory drilling. These factors are dependent on time and on the extent of nearby drilling-activity. Particulars of geothermal-steam power-plants such as steam dryness, hot-water flashing, condensation, gas extraction, and corrosion are discussed in detail. All available data (as per 1962) concerning the costs of operation and construction of geothermal power plants are tabulated. For space-heating purposes, two basic systems are utilized. When little corrosion or precipitation is expected, an open system is used, otherwise, closed systems are necessary. The space-heating system of Reykjavik, Iceland is cited as an example. A brief description of industrial applications of geothermal energy, such as the extraction of NaCl, D/sub 2/O, or boric acid, is provided. Thirty-two references are given.

  8. Optimization of the exploitation system of a low enthalpy geothermal aquifer with zones of different transmissivities and temperatures

    International Nuclear Information System (INIS)

    Tselepidou, K.; Katsifarakis, K.L.

    2010-01-01

    Market penetration of renewable energy sources, such as geothermal energy, could be promoted even by small cost reductions, achieved through improved development design. This paper deals with optimization of the exploitation system of a low enthalpy geothermal aquifer, by means of the method of genetic algorithms, which has been successfully used in similar problems of groundwater resources management. With respect to water flow, the aquifer consists of two zones of different transmissivities, while from the thermal point of view it may bear any number of zones with different temperatures. The optimization process comprises the annual pumping cost of the required flow and the amortization cost of the pipe network, which carries the hot water from the wells to a central water tank, situated at the border of the geothermal field. Results show that application of the proposed methodology allows better planning of low enthalpy geothermal heating systems, which may be crucial in cases of marginal financial viability. (author)

  9. Simulation of water-rock interaction in the yellowstone geothermal system using TOUGHREACT

    International Nuclear Information System (INIS)

    Dobson, P.F.; Salah, S.; Spycher, N.; Sonnenthal, E.

    2003-01-01

    The Yellowstone geothermal system provides an ideal opportunity to test the ability of reactive transport models to accurately simulate water-rock interaction. Previous studies of the Yellowstone geothermal system have characterized water-rock interaction through analysis of rocks and fluids obtained from both surface and downhole samples. Fluid chemistry, rock mineralogy, permeability, porosity, and thermal data obtained from the Y-8 borehole in Upper Geyser Basin were used to constrain a series of reactive transport simulations of the Yellowstone geothermal system using TOUGHREACT. Three distinct stratigraphic units were encountered in the 153.4 m deep Y-8 drill core: volcaniclastic sandstone, perlitic rhyolitic lava, and nonwelded pumiceous tuff. The main alteration phases identified in the Y-8 core samples include clay minerals, zeolites, silica polymorphs, adularia, and calcite. Temperatures observed in the Y-8 borehole increase with depth from sub-boiling conditions at the surface to a maximum of 169.8 C at a depth of 104.1 m, with near-isothermal conditions persisting down to the well bottom. 1-D models of the Y-8 core hole were constructed to determine if TOUGHREACT could accurately predict the observed alteration mineral assemblage given the initial rock mineralogy and observed fluid chemistry and temperatures. Preliminary simulations involving the perlitic rhyolitic lava unit are consistent with the observed alteration of rhyolitic glass to form celadonite

  10. A review on energetic, exergetic and exergoeconomic aspects of geothermal district heating systems (GDHSs)

    International Nuclear Information System (INIS)

    Hepbasli, Arif

    2010-01-01

    Geothermal is a reliable and promising renewable energy. In 1892 the first geothermal district heating system (GDHS) began operations in Boise, Idaho, USA. Since then, a number of GDHSs installations have been made worldwide. Various investigations on the efficient utilization of geothermal energy resources have also been conducted to attain sustainable development. There is a link between exergy and sustainable development. In recent years, exergy analysis has been widely used in the design, simulation and performance assessment of thermal systems. Exergoeconomic analysis, which is a combination of exergy and economics, is nowadays considered a powerful tool to study and optimize various types of energy-related systems. The present study comprehensively reviews GDHSs in terms of three aspects, namely energetic, exergetic and exergoeconomic analyses and assessments, for the first time to the best of the author's knowledge. A brief historical development of the studies on GDHSs was given on the base of these three aspects first. Next, GDHSs analyzed were schematically presented and shortly described. The previously conducted studies on GDHSs were then reviewed and classified. Finally, the conclusions were presented. It is expected that this comprehensive study will be very beneficial to everyone involved or interested in the energetic, exergetic and exergoeconomic design, analysis and performance evaluation of GDHSs.

  11. The application of unmanned aerial systems (UAS) in geophysical investigations of geothermal systems

    Science.gov (United States)

    Glen, J. M.; Egger, A. E.; Ippolito, C.; Phelps, G. A.; Berthold, R.; Lee, R.; Spritzer, J. M.; Tchernychev, M.

    2012-12-01

    Investigations of geothermal systems typically involve ground-based geological and geophysical studies in order to map structures that control and facilitate fluid flow. The spatial extent of ground-based investigations can be limited, however, by surficial hot springs, dense foliage, and roadless or private lands. This can result in data gaps in key areas, particularly around active hydrothermal springs. Manned aircraft can provide access to these areas and can yield broad and uniform data coverage, but high-resolution surveys are costly and relatively inflexible to changes in the survey specifications that may arise as data are collected. Unmanned aerial systems (UAS) are well suited for conducting these surveys, but until recently, various factors (scientific instrumentation requirements, platform limitations, and size of the survey area) have required the use of large UAS platforms, rendering unmanned aerial surveys unsuitable for most investigations. We have developed and tested a new cesium magnetometer system to collect magnetic data using two different small-platform UAS that overcomes many of the challenges described above. We are deploying this new system in Surprise Valley, CA, to study the area's active geothermal field. Surprise Valley is ideally suited to testing UAS due to its low population density, accessible airspace, and broad playa that provides ample opportunity to safely land the aircraft. In combination with gravity and topographic data, magnetic data are particularly useful for identifying buried, intra-basin structures, especially in areas such as Surprise Valley where highly magnetic, dense mafic volcanic rocks are interbedded with and faulted against less magnetic, less dense sedimentary rock. While high-resolution gravity data must be collected at point locations on the ground, high-resolution magnetic data can be obtained by UAS that provide continuous coverage. Once acquired, the magnetic data obtained by the UAS will be combined with

  12. District heating systems - the necessary infrastructure for geothermal energy; Fern- und Nahwaermesysteme - notwendige Infrastruktur fuer die Geothermie

    Energy Technology Data Exchange (ETDEWEB)

    Schoenberg, I [Inst. fuer Umwelt-, Sicherheits- und Energietechnik e.V. (UMSICHT), Oberhausen (Germany)

    1997-12-01

    The contribution discusses the future chances of geothermal energy use with cost-optimized systems of geothermal energy + cogeneration + district heating and with the focus on innovation instead of state funding. (orig./AKF) [Deutsch] Der Beitrag bezieht sich auf die zukuenftigen Chancen der Geothermie, die eine kostenoptimierte Systemloesung Geothermie + KWK + Nah-/Fernwaerme sowie durch Mut zur Innovation und nicht durch Foerderung bestimmt werden. (orig./AKF)

  13. Tectonic Constraints on the Evolution of Geothermal Systems in the Central Andean Volcanic Zone (CAVZ)

    Science.gov (United States)

    Veloso, E. E.; Tardani, D.; Aron, F.; Elizalde, J. D.; Sanchez-Alfaro, P.; Godoy, B.

    2017-12-01

    South of 19°S, geothermal fields and Pliocene-to-Holocene volcanic centers of the Central Andean Volcanic Zone are spatially associated with distinct, large-scale fault systems disrupting the volcanic arc, which control the architecture and dynamics of the fluids reservoirs at shallow crustal levels. Based on an extensive compilation of structural, lithological and isotopic data, and satellite imagery band-ratio analyses, we produced detailed maps of 13 areas comprising 19 identified and/or potential geothermal fields, to examine if particular local-scale tectonic configurations are associated to fluids migrating from different crustal levels. We defined three main tectonic environments according to the specific, kilometer-scale structural arrangement and its spatial relation to the geothermal surface manifestations. T1, dominated by left-lateral, pure strike-slip motion on a NW-trending duplex-like geometry with geothermal fields located along the faults - in turn distributed into five major subparallel zones cutting across the orogenic belt between ca. 20° and 27°S. T2, dominated by shortening on a series of N-trending thrust faults and fault-propagated folds, cut and displaced by the above mentioned NW-trending faults, with geothermal fields hosted at fault intersections and at fold hinges. And T3, characterized by transtension accommodated by NW-to-WNW-trending left-lateral/normal faults, with hot-springs lying along the fault traces. Interestingly, each of the independently defined tectonic environments has distinctive helium (in fluids) and strontium (in lavas) isotopic signatures and estimated geothermal reservoir temperatures. T1 shows a large 4He contribution, low 87Sr/86Sr ratio and temperatures varying between ca. 220°-310°C; T3 low 4He and high 87Sr/86Sr ratio and temperature (260°-320°C); T2 isotopic values fall between T1 and T3, yet showing the lowest (130°-250°C) temperatures. We suggest that these particular isotopic signatures are due to

  14. Development of an Advanced Stimulation / Production Predictive Simulator for Enhanced Geothermal Systems

    Energy Technology Data Exchange (ETDEWEB)

    Pritchett, John W. [Leidos, Inc., San Diego, CA (United States)

    2015-04-15

    There are several well-known obstacles to the successful deployment of EGS projects on a commercial scale, of course. EGS projects are expected to be deeper, on the average, than conventional “natural” geothermal reservoirs, and drilling costs are already a formidable barrier to conventional geothermal projects. Unlike conventional resources (which frequently announce their presence with natural manifestations such as geysers, hot springs and fumaroles), EGS prospects are likely to appear fairly undistinguished from the earth surface. And, of course, the probable necessity of fabricating a subterranean fluid circulation network to mine the heat from the rock (instead of simply relying on natural, pre-existing permeable fractures) adds a significant degree of uncertainty to the prospects for success. Accordingly, the basic motivation for the work presented herein was to try to develop a new set of tools that would be more suitable for this purpose. Several years ago, the Department of Energy’s Geothermal Technologies Office recognized this need and funded a cost-shared grant to our company (then SAIC, now Leidos) to partner with Geowatt AG of Zurich, Switzerland and undertake the development of a new reservoir simulator that would be more suitable for EGS forecasting than the existing tools. That project has now been completed and a new numerical geothermal reservoir simulator has been developed. It is named “HeatEx” (for “Heat Extraction”) and is almost completely new, although its methodology owes a great deal to other previous geothermal software development efforts, including Geowatt’s “HEX-S” code, the STAR and SPFRAC simulators developed here at SAIC/Leidos, the MINC approach originally developed at LBNL, and tracer analysis software originally formulated at INEL. Furthermore, the development effort was led by engineers with many years of experience in using reservoir simulation software to make meaningful forecasts for real geothermal

  15. Geothermal cooling of EDP systems; Geothermische Kuehlung von EDV-Servern

    Energy Technology Data Exchange (ETDEWEB)

    Ganzer, Christoph; Wietfeldt, Dirk; Schulz, Lars [celler brunnenbau gmbh und co. kg, Celle (Germany)

    2011-07-01

    Renewable energies are the future. And, sometimes a clever idea is enough in order to explore new fields of application. In Celle (Federal Republic of Germany), four technology partners have come together and developed a solution for the cooling of server cabinets by means of geothermal energy. The geothermal probe system is filled with a coolant which circulates in a closed circuit. The coolant acts as a cold heat-transport medium so that the resulting temperature differences can be used to generate heat (or coldness). Thus, a PUE value of lower than 1.10 can be realized. More than 90 % of the saved energy reaches the server. In a traditional data center, this ratio only amounts 50 %.

  16. 3D Geothermal Modelling of the Mount Amiata Hydrothermal System in Italy

    Directory of Open Access Journals (Sweden)

    Paolo Fulignati

    2014-11-01

    Full Text Available In this paper we build a subsurface model that helps in visualizing and understanding the structural framework, geology and their interactions with the Mt. Amiata geothermal system. Modelling in 3D provides the possibility to interpolate the geometry of structures and is an effective way of understanding geological features. The 3D modelling approach appears to be crucial for further progress in the reconstruction of the assessment of the geothermal model of Mt. Amiata. Furthermore, this model is used as the basis of a 3D numerical thermo-fluid-dynamic model of the existing reservoir(s. The integration between borehole data and numerical modelling results allows reconstructing the temperature distribution in the subsoil of the Mt. Amiata area.

  17. Helium isotopes in geothermal systems: Iceland, The Geysers, Raft River and Steamboat Springs

    International Nuclear Information System (INIS)

    Torgersen, T.

    1982-01-01

    Helium isotope ratios have been measured in geothermal fluids from Iceland, The Geysers, Raft River, Steamboat Springs and Hawaii. These ratios have been interpreted in terms of the processes which supply He in distinct isotopic ratios and in terms of the processes which can alter the isotopic ratio. Using this interpretational scheme, Iceland is found to be an area of hot-spot magmatic He implying an active volcanic source although the data are suggestive of high-temperature weathering release of crustal He incorporated in the geothermal fluids. By comparison to fumarolic gases from Hawaii and Juan De Fuca and Cayman Trench basaltic glass samples, The Geysers contains MOR type magmatic He again implying an active volcanic source possibly a 'leaky' transform related to the San Andreas Fault System. Raft River contains only crustal He indicating no active volcanic sources. Steamboat Springs He isotope ratios are distinctly less than typical plate margin volcanics but must still have a magmatic source. (author)

  18. Health impacts of geothermal energy

    International Nuclear Information System (INIS)

    Layton, D.W.; Anspaugh, L.R.

    1982-01-01

    Geothermal resources are used to produce electrical energy and to supply heat for non-electric applications like residential heating and crop drying. The utilization of geothermal energy consists of the extraction of hot water or steam from an underground reservoir followed by different methods of surface processing along with the disposal of liquid, gaseous, and even solid wastes. The focus of this paper is on electric power production using geothermal resources greater than 150 0 C because this form of geothermal energy utilization has the most serious health-related consequences. Based on measurements and experience at existing geothermal power plants, atmospheric emissions of non-condensing gases such as hydrogen sulphide and benzene pose the greatest hazards to public health. Surface and ground waters contaminated by discharges of spent geothermal fluids constitute another health hazard. In this paper it is shown that hydrogen sulphide emissions from most geothermal power plants are apt to cause odour annoyances among members of the exposed public -some of whom can detect this gas at concentrations as low as 0.002 ppmv. A risk-assessment model is used to estimate the lifetime risk of incurring leukaemia from atmospheric benzene caused by 2000 MW(e) of geothermal development in California's Imperial Valley. Also assessed is the risk of skin cancer due to the ingestion of river water in New Zealand that is contaminated by waste geothermal fluids containing arsenic. Finally, data on the occurrence of occupational disease in the geothermal industry is briefly summarized. (author)

  19. Energy balance and economic feasibility of shallow geothermal systems for winery industry

    Science.gov (United States)

    Ruiz-Mazarrón, F.; Almoguera-Millán, J.; García-Llaneza, J.; Perdigones, A.

    2012-04-01

    The search of energy efficient solutions has not yet been accomplished in agro-food constructions, for which technical studies and orientations are needed to find energy efficient solutions adapted to the environment. The main objective of this investigation is to evaluate the effectiveness of using shallow geothermal energy for the winery industry. World wine production in 2009 stood at 27100 millions of litres [1]. World spends 320 billion Euros on wine a year, according to industry insiders. On average, it is estimated that producing 1 litre of wine sold in a 75 cl glass bottle costs around 0.5-1.2 Euros /litre [2]. The process of ageing the wine could substantially increase production costs. Considering the time required for the aging of wine (months or years) and the size of the constructions, the use of an air conditioning system implies a considerable increase in energy consumption. Underground wine cellars have been in use for centuries for making and ageing wine. Ground thermal inertia provides protection from outdoor temperature oscillation and maintains thermal stability without energy consumption [3]. Since the last century, production of wine has moved to buildings above ground that have several advantages: lower construction cost, more space, etc. Nevertheless, these constructions require a large energy consumption to maintain suitable conditions for the ageing and conservation of wine. This change of construction techniques is the cause of an increase in energy consumption in modern wineries. The use of shallow geothermal energy can be a good alternative to take advantage of the benefits of aboveground buildings and underground constructions simultaneously. Shallow geothermal systems can meet the needs of heating and cooling using a single installation, maintaining low energy consumption. Therefore, it could be a good alternative to conventional HVAC systems. The main disadvantage of geothermal systems is the high cost of investment required. This

  20. Geothermal absorption refrigeration for food processing industries. Final report, December 13, 1976--November 13, 1977

    Energy Technology Data Exchange (ETDEWEB)

    Harris, R.L.; Olson, G.K.; Mah, C.S.; Bujalski, J.H.

    1977-11-01

    The first step in the economic analysis of the integration of geothermally powered absorption refrigeration into a food processing plant was an evaluation of the potential geothermal sites in the Western United States. The evaluation covered availability of raw materials, transportation, adequate geothermal source, labor, and other requirements for food processing plants. Several attractive geothermal sites were identified--Raft River, Idaho; Sespe Hot Springs, California; Vale Hot Springs, Oregon; Weisler-Crane Creek, Idaho; Cosco Hot Springs, California; and the Imperial Valley, California. The most economically attractive food processing industry was then matched to the site based on its particular energy, raw material, and transportation requirements. The more promising food processors identified were for frozen potato or vegetable products, freeze-dried products, and meat processing. For the refrigeration temperature range of +32/sup 0/F to -40/sup 0/F and geothermal temperature range of 212/sup 0/F to 300/sup 0/F, an absorption refrigeration system had to be identified, designed, and evaluated. Both the conventional ammonia/water and an organic absorption refrigeration system using monochlorodifluoromethane (R-22) as the refrigerant and dimethyl formamide (DMF) as the absorbent were studied. In general, only a 60/sup 0/F to 100/sup 0/F temperature drop would be effectively used for refrigeration leaving the remainder of the allowable temperature drop available for other use. The economic evaluation of the geothermal system installed in a food processing plant required the comparison of several principal alternatives. These alternatives were evaluated for three different food processing plants located at their optimum geothermal site: a forzen potato product processing plant located at Raft River, Idaho; a freeze-dried product plant located at Sespe Hot Springs, California; a beef slaughter operation located in the Imperial Valley of California. (JGB)

  1. Sensitivity analysis of coupled processes and parameters on the performance of enhanced geothermal systems.

    Science.gov (United States)

    Pandey, S N; Vishal, Vikram

    2017-12-06

    3-D modeling of coupled thermo-hydro-mechanical (THM) processes in enhanced geothermal systems using the control volume finite element code was done. In a first, a comparative analysis on the effects of coupled processes, operational parameters and reservoir parameters on heat extraction was conducted. We found that significant temperature drop and fluid overpressure occurred inside the reservoirs/fracture that affected the transport behavior of the fracture. The spatio-temporal variations of fracture aperture greatly impacted the thermal drawdown and consequently the net energy output. The results showed that maximum aperture evolution occurred near the injection zone instead of the production zone. Opening of the fracture reduced the injection pressure required to circulate a fixed mass of water. The thermal breakthrough and heat extraction strongly depend on the injection mass flow rate, well distances, reservoir permeability and geothermal gradients. High permeability caused higher water loss, leading to reduced heat extraction. From the results of TH vs THM process simulations, we conclude that appropriate coupling is vital and can impact the estimates of net heat extraction. This study can help in identifying the critical operational parameters, and process optimization for enhanced energy extraction from a geothermal system.

  2. Origin and Distribution of Thiophenes and Furans in Gas Discharges from Active Volcanoes and Geothermal Systems

    Directory of Open Access Journals (Sweden)

    Franco Tassi

    2010-03-01

    Full Text Available The composition of non-methane organic volatile compounds (VOCs determined in 139 thermal gas discharges from 18 different geothermal and volcanic systems in Italy and Latin America, consists of C2–C20 species pertaining to the alkanes, alkenes, aromatics and O-, S- and N-bearing classes of compounds. Thiophenes and mono-aromatics, especially the methylated species, are strongly enriched in fluids emissions related to hydrothermal systems. Addition of hydrogen sulphide to dienes and electrophilic methylation involving halogenated radicals may be invoked for the formation of these species. On the contrary, the formation of furans, with the only exception of C4H8O, seems to be favoured at oxidizing conditions and relatively high temperatures, although mechanisms similar to those hypothesized for the production of thiophenes can be suggested. Such thermodynamic features are typical of fluid reservoirs feeding high-temperature thermal discharges of volcanoes characterised by strong degassing activity, which are likely affected by conspicuous contribution from a magmatic source. The composition of heteroaromatics in fluids naturally discharged from active volcanoes and geothermal areas can then be considered largely dependent on the interplay between hydrothermal vs. magmatic contributions. This implies that they can be used as useful geochemical tools to be successfully applied in both volcanic monitoring and geothermal prospection.

  3. Origin and distribution of thiophenes and furans in gas discharges from active volcanoes and geothermal systems.

    Science.gov (United States)

    Tassi, Franco; Montegrossi, Giordano; Capecchiacci, Francesco; Vaselli, Orlando

    2010-03-31

    The composition of non-methane organic volatile compounds (VOCs) determined in 139 thermal gas discharges from 18 different geothermal and volcanic systems in Italy and Latin America, consists of C(2)-C(20) species pertaining to the alkanes, alkenes, aromatics and O-, S- and N-bearing classes of compounds. Thiophenes and mono-aromatics, especially the methylated species, are strongly enriched in fluids emissions related to hydrothermal systems. Addition of hydrogen sulphide to dienes and electrophilic methylation involving halogenated radicals may be invoked for the formation of these species. On the contrary, the formation of furans, with the only exception of C(4)H(8)O, seems to be favoured at oxidizing conditions and relatively high temperatures, although mechanisms similar to those hypothesized for the production of thiophenes can be suggested. Such thermodynamic features are typical of fluid reservoirs feeding high-temperature thermal discharges of volcanoes characterised by strong degassing activity, which are likely affected by conspicuous contribution from a magmatic source. The composition of heteroaromatics in fluids naturally discharged from active volcanoes and geothermal areas can then be considered largely dependent on the interplay between hydrothermal vs. magmatic contributions. This implies that they can be used as useful geochemical tools to be successfully applied in both volcanic monitoring and geothermal prospection.

  4. Geologic and preliminary reservoir data on the Los Humeros Geothermal System, Puebla, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Ferriz, H.

    1982-01-01

    Exploratory drilling has confirmed the existence of a geothermal system in the Los Humeros volcanic center, located 180 km east of Mexico City. Volcanic activity in the area began with the eruption of andesites, followed by two major caldera-forming pyroclastic eruptions. The younger Los Potreros caldera is nested inside the older Los Humeros caldera. At later stages, basaltic andesite, dacite, and olivine basalt lavas erupted along the ring-fracture zones of both calderas. Geologic interpretation of structural, geophysical, and drilling data suggests that: (1) the water-dominated geothermal reservoir is hosted by the earliest andesitic volcanic pile, is bounded by the ring-fracture zone of the Los Potreros caldera, and is capped by the products of the oldest caldera-forming eruption; (2) permeability within the andesitic pile is provided by faults and fractures related to intracaldera uplift; (3) the geothermal system has potential for a large influx of meteoric water through portions of the ring-fracture zones of both calderas; and (4) volcanic centers with similar magmatic and structural conditions can be found in the eastern Cascades, USA.

  5. Analysis of influencing factors of production performance of enhanced geothermal system: A case study at Yangbajing geothermal field

    International Nuclear Information System (INIS)

    Zeng, Yuchao; Tang, Liansheng; Wu, Nengyou; Cao, Yifei

    2017-01-01

    Deep geological exploration indicates that there is a high-temperature fractured granite reservoir at depth of 950–1350 m in well ZK4001 in the north of Yangbajing geothermal field, with an average temperature of 248 °C and a pressure within 8.01–11.57 MPa. In this work we established a conceptual and numerical model of this granite reservoir, evaluated heat production and electricity generation potential from this fractured reservoir by means of numerical simulation, and analyzed main factors affecting the heat production performance. The results indicate that in the reference case the system attains an electric power of 29.5–25.1 MW, a reservoir impedance of 0.12–0.21MPa/(kg/s), a pump power of 0.7–1.6 MW and an energy efficiency of 41.1–15.7 during a 50 year period. Main factors affecting the electric power are water production rate and injection temperature. Main factors affecting the reservoir impedance are the reservoir permeability, the water production rate and the injection temperature. Main factors affecting the pump power are the reservoir permeability, the water production rate and the injection temperature. Main factors affecting the energy efficiency are the reservoir permeability, the water production rate and the injection temperature. Within certain ranges main measures to improve the reservoir performance are to increase the reservoir permeability or adopt more reasonable water production rate and injection temperature. - Highlights: • We established a numerical model of the 950–1350 m fractured granite reservoir. • Desirable electricity production performance can be obtained under suitable conditions. • The system attains an electric power of 29.5–25.1 MW with an efficiency of about 41.1–15.7. • Electric power mainly depends on water production rate and injection temperature. • Higher permeability within a certain range is favorable for electricity generation.

  6. Geothermal Energy Program overview

    International Nuclear Information System (INIS)

    1991-12-01

    The mission of the Geothermal Energy Program is to develop the science and technology necessary for tapping our nation's tremendous heat energy sources contained with the Earth. Geothermal energy is a domestic energy source that can produce clean, reliable, cost- effective heat and electricity for our nation's energy needs. Geothermal energy -- the heat of the Earth -- is one of our nation's most abundant energy resources. In fact, geothermal energy represents nearly 40% of the total US energy resource base and already provides an important contribution to our nation's energy needs. Geothermal energy systems can provide clean, reliable, cost-effective energy for our nation's industries, businesses, and homes in the form of heat and electricity. The US Department of Energy's (DOE) Geothermal Energy Program sponsors research aimed at developing the science and technology necessary for utilizing this resource more fully. Geothermal energy originates from the Earth's interior. The hottest fluids and rocks at accessible depths are associated with recent volcanic activity in the western states. In some places, heat comes to the surface as natural hot water or steam, which have been used since prehistoric times for cooking and bathing. Today, wells convey the heat from deep in the Earth to electric generators, factories, farms, and homes. The competitiveness of power generation with lower quality hydrothermal fluids, geopressured brines, hot dry rock, and magma ( the four types of geothermal energy) still depends on the technical advancements sought by DOE's Geothermal Energy Program

  7. Geochemical exploration of a promissory Enhanced Geothermal System (EGS): the Acoculco caldera, Mexico.

    Science.gov (United States)

    Peiffer, Loic; Romero, Ruben Bernard; Pérez-Zarate, Daniel; Guevara, Mirna; Santoyo Gutiérrez, Edgar

    2014-05-01

    The Acoculco caldera (Puebla, Mexico) has been identified by the Mexican Federal Electricity Company (in Spanish 'Comisión Federal de Electricidad', CFE) as a potential Enhanced Geothermal System (EGS) candidate. Two exploration wells were drilled and promising temperatures of ~300° C have been measured at a depth of 2000 m with a geothermal gradient of 11oC/100m, which is three times higher than the baseline gradient measured within the Trans-Mexican Volcanic Belt. As usually observed in Hot Dry Rock systems, thermal manifestations in surface are scarce and consist in low-temperature bubbling springs and soil degassing. The goals of this study were to identify the origin of these fluids, to estimate the soil degassing rate and to explore new areas for a future detailed exploration and drilling activities. Water and gas samples were collected for chemical and isotopic analysis (δ18O, δD, 3He/4He, 13C, 15N) and a multi-gas (CO2, CH4, H2S) soil survey was carried out using the accumulation chamber method. Springs' compositions indicate a meteoric origin and the dissolution of CO2 and H2S-rich gases, while gas compositions reveal a MORB-type origin mixed with some arc-type contribution. Gas geothermometry results are similar to temperatures measured during well drilling (260° C-300° C). Amongst all measured CO2 fluxes, only 5% (mean: 5543 g m-2 day-1) show typical geothermal values, while the remaining fluxes are low and correspond to biogenic degassing (mean: 18 g m-2 day-1). The low degassing rate of the geothermal system is a consequence of the intense hydrothermal alteration observed in the upper 800 m of the system which acts as an impermeable caprock. Highest measured CO2 fluxes (above > 600 g m-2 day-1) have corresponding CH4/CO2 flux ratios similar to mass ratios of sampled gases, which suggest an advective fluid transport. To represent field conditions, a numerical model was also applied to simulate the migration of CO2 towards the surface through a

  8. A Selection Method for Power Generation Plants Used for Enhanced Geothermal Systems (EGS

    Directory of Open Access Journals (Sweden)

    Kaiyong Hu

    2016-07-01

    Full Text Available As a promising and advanced technology, enhanced geothermal systems (EGS can be used to generate electricity using deep geothermal energy. In order to better utilize the EGS to produce electricity, power cycles’ selection maps are generated for people to choose the best system based on the geofluids’ temperature and dryness conditions. Optimizations on double-flash system (DF, flash-organic Rankine cycle system (FORC, and double-flash-organic Rankine cycle system (DFORC are carried out, and the single-flash (SF system is set as a reference system. The results indicate that each upgraded system (DF, FORC, and DFORC can produce more net power output compared with the SF system and can reach a maximum net power output under a given geofluid condition. For an organic Rankine cycle (ORC using R245fa as working fluid, the generated selection maps indicate that using the FORC system can produce more power than using other power cycles when the heat source temperature is below 170 °C. Either DF or DFORC systems could be an option if the heat source temperature is above 170 °C, but the DF system is more attractive under a relatively lower geofluid’s dryness and a higher temperature condition.

  9. Origin of sulphur compounds and application of isotope geothermometry in selected geothermal systems of China

    International Nuclear Information System (INIS)

    Pang Zhonghe

    2005-01-01

    Geothermal and groundwater samples from East of Heber (EH) Province in the North China Basin and South of Fujian (SF) Province in Southeast of China were studied using sulphur and water isotopes. EH is located in a Mesozoic-Cenozoic sedimentary basin while SF is composed of small fault-block basins formed in Quaternary period. These systems belong to non-volcanic geothermal environments. Samples were collected from exploratory and production geothermal wells: 11 wells in EH and 17 wells in SF. The samples were analyzed for oxygen-18 (δ 18 O) and deuterium (δ 2 H) in water, sulfur-34 (δ 34 S) and oxygen-18 ((δ 18 O) in aqueous sulphate (SO 4 ). Chemical composition of the water samples was also determined. Results show that aqueous sulphate in the saline thermal waters of SF is of marine origin. The aqueous sulphate in EH waters is of non-marine origin. Reservoir temperature estimated using the oxygen isotope geothermometer is not compatible to those by chemical geothermometers or by down-hole measurements in the sedimentary environment for EH, different from that for the SF samples where aqueous sulphate seems to have reached equilibrium with thermal waters in the main up-flow zone. (author)

  10. Accelerating Geothermal Research (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2014-05-01

    Geothermal research at the National Renewable Energy Laboratory (NREL) is advancing geothermal technologies to increase renewable power production. Continuous and not dependent on weather, the geothermal resource has the potential to jump to more than 500 gigawatts in electricity production, which is equivalent to roughly half of the current U.S. capacity. Enhanced geothermal systems have a broad regional distribution in the United States, allowing the potential for development in many locations across the country.

  11. Energetic and exergoeconomic assessment of a multi-generation energy system based on indirect use of geothermal energy

    International Nuclear Information System (INIS)

    Akrami, Ehsan; Chitsaz, Ata; Nami, Hossein; Mahmoudi, S.M.S.

    2017-01-01

    In this paper, a geothermal based multi-generation energy system, including organic Rankine cycle, domestic water heater, absorption refrigeration cycle and proton exchange membrane electrolyzer, is developed to generate electricity, heating, cooling and hydrogen. For this purpose, energetic, exergetic and exergoeconomic analysis are undertaken upon proposed system. Also, the effects of some important variables, i.e. geothermal water temperature, turbine inlet temperature and pressure, generator temperature, geothermal water mass flow rate and electrolyzer current density on the several parameters such as energy and exergy efficiencies of the proposed system, heating and cooling load, net electrical output power, hydrogen production, unit cost of each system products and total unit cost of the products are investigated. For specified conditions, the results show that energy and exergy efficiencies of the proposed multi-generation system are calculated about 34.98% and 49.17%, respectively. The highest and lowest total unit cost of the products estimated approximately 23.18 and 22.73 $/GJ, respectively, by considering that geothermal water temperature increases from 185 °C to 215 °C. - Highlights: • A multigeneration energy system based on geothermal energy is developed. • The energetic, exergetic and exergoeconomic analysis are undertaken upon proposed system. • The influences of several significant parameters are investigated. • The energy and exergy efficiencies of the entire system are calculated around 34.98% and 49.17%.

  12. Recirculation System for Geothermal Energy Recovery in Sedimentary Formations: Laboratory Experiments and Numerical Simulations

    Science.gov (United States)

    Elkhoury, J. E.; Detwiler, R. L.; Serajian, V.; Bruno, M. S.

    2012-12-01

    Geothermal energy resources are more widespread than previously thought and have the potential for providing a significant amount of sustainable clean energy worldwide. In particular, hot permeable sedimentary formations provide many advantages over traditional geothermal recovery and enhanced geothermal systems in low permeability crystalline formations. These include: (1) eliminating the need for hydraulic fracturing, (2) significant reduction in risk for induced seismicity, (3) reducing the need for surface wastewater disposal, (4) contributing to decreases in greenhouse gases, and (5) potential use for CO2 sequestration. Advances in horizontal drilling, completion, and production technology from the oil and gas industry can now be applied to unlock these geothermal resources. Here, we present experimental results from a laboratory scale circulation system and numerical simulations aimed at quantifying the heat transfer capacity of sedimentary rocks. Our experiments consist of fluid flow through a saturated and pressurized sedimentary disc of 23-cm diameter and 3.8-cm thickness heated along its circumference at a constant temperature. Injection and production ports are 7.6-cm apart in the center of the disc. We used DI de-aired water and mineral oil as working fluids and explored temperatures from 20 to 150 oC and flow rates from 2 to 30 ml/min. We performed experiments on sandstone samples (Castlegate and Kirby) with different porosity, permeability and thermal conductivity to evaluate the effect of hydraulic and thermal properties on the heat transfer capacity of sediments. The producing fluid temperature followed an exponential form with time scale transients between 15 and 45 min. Steady state outflow temperatures varied between 60% and 95% of the set boundary temperature, higher percentages were observed for lower temperatures and flow rates. We used the flow and heat transport simulator TOUGH2 to develop a numerical model of our laboratory setting. Given

  13. Opportunities to Align California's PreK-3 Education System

    Science.gov (United States)

    Policy Analysis for California Education, PACE, 2016

    2016-01-01

    "PreK-3 Alignment in California's Education System: Obstacles and Opportunities" by Rachel Valentino and Deborah J. Stipek reviews the opportunities and challenges that must be addressed to better align PreK-3 education in California. The report describes policies and practices that districts have implemented to strengthen alignment, and…

  14. Q&A: The Basics of California's School Finance System

    Science.gov (United States)

    EdSource, 2006

    2006-01-01

    In a state as large and complex as California, education financing can become as complicated as rocket science. This two-page Q&A provides a brief, easy-to-understand explanation of California's school finance system and introduces the issues of its adequacy and equity. A list of resources providing additional information is provided.

  15. A geothermal recycling system for cooling and heating in deep mines

    International Nuclear Information System (INIS)

    Guo, Pingye; He, Manchao; Zheng, Liange; Zhang, Na

    2017-01-01

    Highlights: • A geothermal recycling system for cooling and heating was presented in coal mines. • The COP of this cooling subsystem is 30% higher than that of others. • The COP is 20% higher with the parallel running of cooling and heating systems. - Abstract: In the operation of deep coal mines, cooling systems must be built (in most cases) because of the high-temperature working environment within such mines. Once the coal is mined, it is often used to supply heat for buildings and domestic hot water. In either instance, the energy consumed can create environmental pollution. As a potential solution to this problem, we present a geothermal recycling system for mines (GRSM) for parallel mine cooling and surface heating. The performance of this system is investigated based on the observed data. Compared with traditional cooling systems, the most obvious feature of this system is the removal of a cooling tower, which contributes to a 30% increase in performance. Moreover, the parallel running of cooling and heating systems can effectively recover waste heat, improving energy efficiency by 20%.

  16. Cooling performance and energy saving of a compression-absorption refrigeration system assisted by geothermal energy

    International Nuclear Information System (INIS)

    Kairouani, L.; Nehdi, E.

    2006-01-01

    The objectives of this paper are to develop a novel combined refrigeration system, and to discuss the thermodynamic analysis of the cycle and the feasibility of its practical development. The aim of this work was to study the possibility of using geothermal energy to supply vapour absorption system cascaded with conventional compression system. Three working fluids (R717, R22, and R134a) are selected for the conventional compression system and the ammonia-water pair for the absorption system. The geothermal temperature source in the range 343-349 K supplies a generator operating at 335 K. Results show that the COP of a combined system is significantly higher than that of a single stage refrigeration system. It is found that the COP can be improved by 37-54%, compared with the conventional cycle, under the same operating conditions, that is an evaporation temperature at 263 K and a condensation temperature of 308 K. For industrial refrigeration, the proposed system constitutes an alternative solution for reducing energy consumption and greenhouse gas emissions

  17. Selection of working fluids for a novel low-temperature geothermally-powered ORC based cogeneration system

    International Nuclear Information System (INIS)

    Guo, T.; Wang, H.X.; Zhang, S.J.

    2011-01-01

    Highlights: → Performances of a novel cogeneration system using low-temperature geothermal sources under disturbance conditions were investigated. → It aimed at identifying appropriate fluids yielding high PPR and QQR values. → Fluids group presenting higher normal boiling point values showed averagely 7.7% higher PPR with a larger variation than QQR values under disturbance conditions. → Smaller T P value, higher η t value, higher geothermal source parameters and lower heating supply parameters led to higher PPR values but lower QQR values. -- Abstract: A novel cogeneration system driven by low-temperature geothermal sources was investigated in this study. This system consists of a low-temperature geothermally-powered organic Rankine cycle (ORC) subsystem, an intermediate heat exchanger and a commercial R134a-based heat pump subsystem. The main purpose is to identify appropriate fluids which may yield high PPR (the ratio of power produced by the power generation subsystem to power consumed by the heat pump subsystem) value and QQR (the ratio of heat supplied to the user to heat produced by the geothermal source) value. Performances of the novel cogeneration system under disturbance conditions have also been studied. Results indicate that fluids group presenting higher normal boiling point values shows averagely 7.7% higher PPR values and R236ea and R245ca outstand among the group. ΔT P (pinch temperature difference in heat exchangers) and η t (turbine efficiency) values play more important roles on the variation of PPR values. QQR values change slightly with various ΔT P , η t and η rp (refrigerant pump efficiency) values while the variation range is larger under various geothermal source and heating supply parameters. Smaller ΔT P value, higher η t value, higher geothermal source parameters and lower heating supply parameters lead to higher PPR values but lower QQR values.

  18. Fracture Propagation and Permeability Change under Poro-thermoelastic Loads & Silica Reactivity in Enhanced Geothermal Systems

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad Ghassemi

    2009-10-01

    Geothermal energy is recovered by circulating water through heat exchange areas within a hot rock mass. Geothermal reservoir rock masses generally consist of igneous and metamorphic rocks that have low matrix permeability. Therefore, cracks and fractures play a significant role in extraction of geothermal energy by providing the major pathways for fluid flow and heat exchange. Therefore, knowledge of the conditions leading to formation of fractures and fracture networks is of paramount importance. Furthermore, in the absence of natural fractures or adequate connectivity, artificial fractures are created in the reservoir using hydraulic fracturing. Multiple fractures are preferred because of the large size necessary when using only a single fracture. Although the basic idea is rather simple, hydraulic fracturing is a complex process involving interactions of high pressure fluid injections with a stressed hot rock mass, mechanical interaction of induced fractures with existing natural fractures, and the spatial and temporal variations of in-situ stress. As a result, it is necessary to develop tools that can be used to study these interactions as an integral part of a comprehensive approach to geothermal reservoir development, particularly enhanced geothermal systems. In response to this need we have developed advanced poro-thermo-chemo-mechanical fracture models for rock fracture research in support of EGS design. The fracture propagation models are based on a regular displacement discontinuity formulation. The fracture propagation studies include modeling interaction of induced fractures. In addition to the fracture propagation studies, two-dimensional solution algorithms have been developed and used to estimate the impact of pro-thermo-chemical processes on fracture permeability and reservoir pressure. Fracture permeability variation is studied using a coupled thermo-chemical model with quartz reaction kinetics. The model is applied to study quartz precipitation

  19. The geological framework of the Wairakei-Tauhara Geothermal System, New Zealand

    Energy Technology Data Exchange (ETDEWEB)

    Rosenberg, Michael D.; Bignall, Greg; Rae, Andrew J. [GNS Science, Wairakei Research Centre, Private Bag 2000, Taupo (New Zealand)

    2009-03-15

    The geology of the Wairakei-Tauhara geothermal system has been revealed in increments over more than 50 years of field development. Only two major reviews of geo-scientific information have been completed; the first was made more than 40 years ago, the second (unpublished) was completed more than 25 years ago. This paper is an overview and update of the stratigraphic and structural framework of the system and its controls on fluid flow and hydrothermal alteration. We provide information on new areas of drilling exploration in the west of the Wairakei Geothermal Field and on the first production-focused drilling in 40 years at the Tauhara Geothermal Field. The lithology, thickness and extent of several units have been refined, while new units have been discovered by recent deep wells; five new members of the Waiora Formation are proposed. Nomenclature of formations and members is also updated. We review controls on fluid flow in the system and find that fault zones are likely up-flow channels, but their correlation with well feed points is equivocal, whereas intra- and inter-formational permeable zones are directly located by drilling and well completion data. New mineralogy data confirms an earlier known prograde trend of increasing hydrothermal alteration rank and intensity with depth. In the west of the Wairakei-Tauhara system thermal and chemical evolution has created a lower temperature and/or pH overprint on the older propylitic assemblage. Conditions at the eastern boundary of the system appear to have long-term stability. (author)

  20. Design of a geothermal monitoring network in a coastal area and the evaluation system

    Science.gov (United States)

    Ohan Shim, Byoung; Lee, Chulwoo; Park, Chanhee

    2016-04-01

    In Seockmodo Island (area of 48.2 km2) located at the northwest of South Korea, a renewable energy development project to install photovoltaic 136 kW and geothermal 516.3 kW is initiated. Since the 1990s, more than 20 deep geothermal wells for hot springs, greenhouse and aquaculture have been developed along coastal areas. The outflow water of each site has the pumping capacity between 300 and 4,800 m3/day with the salinity higher than 20,000 mg/l, and the maximum temperature shows 70 ?C. Because of the required additional well drillings, the increased discharge rate can cause serious seawater intrusion into freshwater aquifers, which supply groundwater for drinking and living purposes from 210 wells. In order to manage the situation, advanced management skills are required to maintain the balance between geothermal energy development and water resources protection. We designed real-time monitoring networks with monitoring stations for the sustainable monitoring of the temperature and salinity. Construction of borehole temperature monitoring for deep and shallow aquifer consists with the installation of automated temperature logging system and cellular telemetry for real-time data acquisition. The DTS (distributed temperature sensing) system and fiber optic cables will be installed for the logging system, which has enough temperature resolution and accuracy. The spatial distribution and the monitoring points can be determined by geological and hydrological situations associated with the locations of current use and planned facilities. The evaluation of the temperature and salinity variation will be conducted by the web-based monitoring system. The evaluation system will be helpful to manage the balance between the hot water development and the fresh water resources conservation.

  1. Renewability of geothermal resources

    Energy Technology Data Exchange (ETDEWEB)

    O' Sullivan, Michael; Yeh, Angus [Department of Engineering Science, University of Auckland, Auckland (New Zealand); Mannington, Warren [Contact Energy Limited, Taupo (New Zealand)

    2010-12-15

    In almost all geothermal projects worldwide, the rate of extraction of heat energy exceeds the pre-exploitation rate of heat flow from depth. For example, current production of geothermal heat from the Wairakei-Tauhara system exceeds the natural recharge of heat by a factor of 4.75. Thus, the current rate of heat extraction from Wairakei-Tauhara is not sustainable on a continuous basis, and the same statement applies to most other geothermal projects. Nevertheless, geothermal energy resources are renewable in the long-term because they would fully recover to their pre-exploitation state after an extended shut-down period. The present paper considers the general issue of the renewability of geothermal resources and uses computer modeling to investigate the renewability of the Wairakei-Tauhara system. In particular, modeling is used to simulate the recovery of Wairakei-Tauhara after it is shut down in 2053 after a hundred years of production. (author)

  2. US National Geothermal Data System: Web feature services and system operations

    Science.gov (United States)

    Richard, Stephen; Clark, Ryan; Allison, M. Lee; Anderson, Arlene

    2013-04-01

    The US National Geothermal Data System is being developed with support from the US Department of Energy to reduce risk in geothermal energy development by providing online access to the body of geothermal data available in the US. The system is being implemented using Open Geospatial Consortium web services for catalog search (CSW), map browsing (WMS), and data access (WFS). The catalog now includes 2427 registered resources, mostly individual documents accessible via URL. 173 WMS and WFS services are registered, hosted by 4 NGDS system nodes, as well as 6 other state geological surveys. Simple feature schema for interchange formats have been developed by an informal community process in which draft content models are developed based on the information actually available in most data provider's internal datasets. A template pattern is used for the content models so that commonly used content items have the same name and data type across models. Models are documented in Excel workbooks and posted for community review with a deadline for comment; at the end of the comment period a technical working group reviews and discusses comments and votes on adoption. When adopted, an XML schema is implemented for the content model. Our approach has been to keep the focus of each interchange schema narrow, such that simple-feature (flat file) XML schema are sufficient to implement the content model. Keeping individual interchange formats simple, and allowing flexibility to introduce new content models as needed have both assisted in adoption of the service architecture. One problem that remains to be solved is that off-the-shelf server packages (GeoServer, ArcGIS server) do not permit configuration of a normative schema location to be bound with XML namespaces in instance documents. Such configuration is possible with GeoServer using a more complex deployment process. XML interchange format schema versions are indicated by the namespace URI; because of the schema location

  3. Comparative cost analyses: total flow vs other power conversion systems for the Salton Sea Geothermal Resource

    Energy Technology Data Exchange (ETDEWEB)

    Wright, G.W.

    1978-09-18

    Cost studies were done for Total Flow, double flash, and multistage flash binary systems for electric Energy production from the Salton Sea Geothermal Resource. The purpose was to provide the Department of energy's Division of Geothermal Energy with information by which to judge whether to continue development of the Total Flow system. Results indicate that the Total Flow and double flash systems have capital costs of $1,135 and $1,026 /kW with energy costs of 40.9 and 39.7 mills/kW h respectively. The Total Flow and double flash systems are not distinguishable on a cost basis alone; the multistage flash binary system, with capital cost of $1,343 /kW and energy cost of 46.9 mills/kW h, is significantly more expensive. If oil savings are considered in the total analysis, the Total Flow system could save 30% more oil than the double flash system, $3.5 billion at 1978 oil prices.

  4. Investigations on the improvement of the energy output of a Closed Loop Geothermal System (CLGS)

    Energy Technology Data Exchange (ETDEWEB)

    Schulz, Sven-Uwe

    2008-08-04

    The scope of this study are the development of an integrated simulation model for the estimation of the energy output of a deep Closed Loop Geothermal System (CLGS) and the discussion of several approaches to the enhancement of this output. Due to its closed character this kind of geothermal installation provides the opportunity of heat utilization even in dry and impermeable geological zones without any stimulation effort and the usage of external fluids. After a short introduction of the system itself and the limitations of other geothermal systems that are available, the investigations start with the description of the state-of-the-art with regard to the energy output analyses of the CLGS that have been done in the past. These are evaluated and their shortcomings are identified. The newly developed and introduced 3-dimensional approach of this study is a capable tool for the pre-feasibility phase of the project development of a CLGS. A geological/geothermal model summarizes selected relevant data and information about the project area in the form of a spatial data distribution. Thereby the formation boundaries are modelled as well as local in-homogeneities. The lithology can be modelled as well as the distribution of the thermal and physical properties of the rocks. The temperature distribution can be modelled using map or drill log data and be interpolated using geostatistical methods. After the combination of the geological/geothermal model and the technical model of the CLGS containing all relevant data with regard to the drill hole design, dimensions, casings and thermal properties of the installed materials, incl. the annuli, the thermal behaviour of the heat bearing fluid (HBF) flowing within the pipe system is simulated over time in connection with the simulation of the thermal behaviour of the surrounding rock mass. This core simulation is added by the afterwards processed scenario based energy supply simulation that calculates the amounts of energy

  5. Analysis of historical and current drawdown and production data from the Boise geothermal system. Research technical completion report

    Energy Technology Data Exchange (ETDEWEB)

    Waag, C.J.; Wood, S.H.

    1987-08-01

    Since 1982 withdrawals from the Boise Geothermal aquifer system have increased from less than 300 million to over 600 million gals/yr. Prior to 1983 the system appears to have been in or near equilibrium. Current production levels exceed the ability of the system to recover on an annual basis. Potentiometric levels within the aquifer are declining at increasing rates and a new equilibrium level is not evident. Thus, exploitation of the geothermal aquifer is currently outstripping knowledge and understanding of the aquifer. It is time to give serious consideration to placing a temporary moratorium on further development and production from the system until a better understanding of its capacity is achieved.

  6. Comparison of carbon dioxide emissions with fluid upflow, chemistry, and geologic structures at the Rotorua geothermal system, New Zealand

    International Nuclear Information System (INIS)

    Werner, Cynthia; Cardellini, Carlo

    2006-01-01

    During 2002 and 2003, carbon dioxide fluxes were measured across the Rotorua geothermal system in the Taupo Volcanic Zone (TVZ), New Zealand. The results of a 956-measurement survey and of modeling studies show that CO 2 fluxes could be used to determine the main hot fluid upflow areas in Rotorua, and perhaps in undeveloped geothermal regions. Elevated degassing was observed along inferred fault traces and structures, lending confidence to their existence at depth. Degassing was also observed along lineaments that were consistent with the alignment of basement faulting in the TVZ. Areas where elevated degassing was spatially extensive typically overlapped with known regions of hot ground; however, elevated CO 2 fluxes were also observed in isolated patches of non-thermal ground. The total emission rate calculated from sequential Gaussian simulation modeling of CO 2 fluxes across the geothermal system was 620td -1 from an 8.9-km 2 area. However, because approximately one-third of the geothermal system is known to extend beneath Lake Rotorua, we expect the emissions could be minimally on the order of 1000td -1 . Comparing the emission rate with geochemical analyses of geothermal fluids and estimated upflows suggests that the majority of deep carbon reaches the surface in the form of carbon dioxide gas, and that less than one tenth of the CO 2 emissions is dissolved in, or released from, the fluids at depth. Thus, the geothermal reservoir exerts very little control on deep degassing of CO 2 . Carbon isotopic analyses of soil gases suggest a primarily magmatic source for the origin of the CO 2 . The total Rotorua emission rate is comparable to those from active volcanoes such as at White Island, New Zealand, and, when normalized by geothermal area, is comparable to other volcanic and hydrothermal regions worldwide. (author)

  7. Energetic, exergetic, economic and environmental evaluations of geothermal district heating systems: An application

    International Nuclear Information System (INIS)

    Keçebaş, Ali

    2013-01-01

    Highlights: ► Applying exergy, economic, environment and sustainability analyses to the GDHSs. ► Assessing energy and exergy efficiencies, economic and environmental impacts. ► Calculating the energy and exergy efficiencies of 34.86% and 48.78%, respectively. ► Proposing GDHSs as the most economic heating system. ► Providing a significant contribution towards reducing the emissions of air pollution. - Abstract: This study deals with an energetic and exergetic analysis as well as economic and environmental evaluations of Afyon geothermal district heating system (AGDHS) in Afyon, Turkey. In the analysis, actual system data are used to assess the district heating system performance, energy and exergy efficiencies, specific exergy index, exergetic improvement potential and exergy losses. And, for economic and environmental evaluations, actual data are obtained from the Technical Departments. The energy and exergy flow diagrams are clearly drawn to illustrate how much destructions/losses take place in addition to the inputs and outputs. For system performance analysis and improvement, both energy and exergy efficiencies of the overall AGDHS are determined to be 34.86% and 48.78%, respectively. The efficiency improvements in heat and power systems can help achieving energy security in an environmentally acceptable way by reducing the emissions that might otherwise occur. Present application has shown that in Turkey, geothermal energy is much cheaper than the other energy sources, like fossil fuels, and makes a significant contribution towards reducing the emissions of air pollution.

  8. Energy Efficiency Evaluation and Economic Feasibility Analysis of a Geothermal Heating and Cooling System with a Vapor-Compression Chiller System

    OpenAIRE

    Imal, Muharrem; Yılmaz, Koray; Pınarbaşı, Ahmet

    2015-01-01

    Increasing attention has been given to energy utilization in Turkey. In this report, we present an energy efficiency evaluation and economic feasibility analysis of a geothermal heating and cooling system (GSHP) and a mechanical compression water chiller system (ACHP) to improve the energy utilization efficiency and reduce the primary energy demand for industrial use. Analyses of a mechanical water chiller unit, GSW 180, and geothermal heating and cooling system, EAR 431 SK, were conducted in ...

  9. Thermodynamic Optimization of a Geothermal- Based Organic Rankine Cycle System Using an Artificial Bee Colony Algorithm

    Directory of Open Access Journals (Sweden)

    Osman Özkaraca

    2017-10-01

    Full Text Available Geothermal energy is a renewable form of energy, however due to misuse, processing and management issues, it is necessary to use the resource more efficiently. To increase energy efficiency, energy systems engineers carry out careful energy control studies and offer alternative solutions. With this aim, this study was conducted to improve the performance of a real operating air-cooled organic Rankine cycle binary geothermal power plant (GPP and its components in the aspects of thermodynamic modeling, exergy analysis and optimization processes. In-depth information is obtained about the exergy (maximum work a system can make, exergy losses and destruction at the power plant and its components. Thus the performance of the power plant may be predicted with reasonable accuracy and better understanding is gained for the physical process to be used in improving the performance of the power plant. The results of the exergy analysis show that total exergy production rate and exergy efficiency of the GPP are 21 MW and 14.52%, respectively, after removing parasitic loads. The highest amount of exergy destruction occurs, respectively, in condenser 2, vaporizer HH2, condenser 1, pumps 1 and 2 as components requiring priority performance improvement. To maximize the system exergy efficiency, the artificial bee colony (ABC is applied to the model that simulates the actual GPP. Under all the optimization conditions, the maximum exergy efficiency for the GPP and its components is obtained. Two of these conditions such as Case 4 related to the turbine and Case 12 related to the condenser have the best performance. As a result, the ABC optimization method provides better quality information than exergy analysis. Based on the guidance of this study, the performance of power plants based on geothermal energy and other energy resources may be improved.

  10. Performance investigation of the Turkish geothermal district heating systems (GDHSs). Paper no. IGEC-1-066

    International Nuclear Information System (INIS)

    Ozgener, L.; Hepbasli, A.; Dincer, I.

    2005-01-01

    Various energy and exergy modeling techniques have been used by many investigators for energy-utilization assessments to minimize losses and maximize energy savings and hence financial savings. Furthermore, performance indices are employed to detect and to evaluate quantitatively the causes of the thermodynamic imperfection of the process under consideration such as exergy analysis. The present study evaluates the performances of the two geothermal district heating systems (GDHSs) installed in Turkey. The GDHSs considered are the Balcova GDHS in Izmir and Salihli GDHS in Manisa, while the exergetic improvement potential (ExIP) and specific exergy index (SExI) are used for the modeling of the entire systems and their essential components for performance evaluations and comparisons as well as possible energy and exergy efficiency improvements. The SExI is found to be 0.07 and 0.049 for the Balcova and Salihli GDHSs, respectively, representing that Balcova and Salihli geothermal fields fall into the medium and low quality geothermal resources according to the Lee's classification, respectively. The values for the ExIP are also obtained as follows: For the BGDHS with thirteen plate-type heat exchangers, fourth heat exchanger has the largest ExIP rate as 69.96 kW, followed by the first, second, and third heat exchangers at 20.07, 11.71, and 4.05 kW capacities, respectively, with the remaining ones under 3 kW, which does not present much potential for improvement. For the SGDHS, the ExIP rate is found to be 106.04 kW for the plate-type heat exchanger. On the other hand, in order to improve the system efficiency, water leaks in the distribution network should be prevented. (author)

  11. Geothermal energy

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    This chapter discusses the role of geothermal energy may have on the energy future of the US. The topics discussed in the chapter include historical aspects of geothermal energy, the geothermal resource, hydrothermal fluids, electricity production, district heating, process heating, geopressured brines, technology and costs, hot dry rock, magma, and environmental and siting issues

  12. Low-Temperature Enhanced Geothermal System using Carbon Dioxide as the Heat-Transfer Fluid

    Energy Technology Data Exchange (ETDEWEB)

    Eastman, Alan D. [GreenFire Energy, Emeryville, CA (United States)

    2014-07-24

    This report describes work toward a supercritical CO2-based EGS system at the St. Johns Dome in Eastern Arizona, including a comprehensive literature search on CO2-based geothermal technologies, background seismic study, geological information, and a study of the possible use of metal oxide heat carriers to enhance the heat capacity of sCO2. It also includes cost estimates for the project, and the reasons why the project would probably not be cost effective at the proposed location.

  13. Revisiting the Euganean Geothermal System (NE Italy) - insights from large scale hydrothermal modelling

    Science.gov (United States)

    Pola, Marco; Cacace, Mauro; Fabbri, Paolo; Piccinini, Leonardo; Zampieri, Dario; Dalla Libera, Nico

    2017-04-01

    As one of the largest and most extensive utilized geothermal system in northern Italy, the Euganean Geothermal System (EGS, Veneto region, NE Italy) has long been the subject of still ongoing studies. Hydrothermal waters feeding the system are of meteoric origin and infiltrate in the Veneto Prealps, to the north of the main geothermal area. The waters circulate for approximately 100 km in the subsurface of the central Veneto, outflowing with temperatures from 65°C to 86°C to the southwest near the cities of Abano Terme and Montegrotto Terme. The naturally emerging waters are mainly used for balneotherapeutic purposes, forming the famous Euganean spa district. This preferential outflow is thought to have a relevant structural component producing a high secondary permeability localized within an area of limited extent (approx. 25 km2). This peculiar structure is associated with a local network of fractures resulting from transtentional tectonics of the regional Schio-Vicenza fault system (SVFS) bounding the Euganean Geothermal Field (EGF). In the present study, a revised conceptual hydrothermal model for the EGS based on the regional hydrogeology and structural geology is proposed. Particularly, this work aims to quantify: (1) the role of the regional SVFS, and (2) the impact of the high density local fractures mesh beneath the EGF on the regional-to-local groundwater flow circulation at depths and its thermal configuration. 3D coupled flow and heat transport numerical simulations inspired by the newly developed conceptual model are carried out to properly quantify the results from these interactions. Consistently with the observations, the obtained results provide indication for temperatures in the EGF reservoir being higher than in the surrounding areas, despite a uniform basal regional crustal heat inflow. In addition, they point to the presence of a structural causative process for the localized outflow, in which deep-seated groundwater is preferentially

  14. Numerical simulations of heat transfer through fractured rock for an enhanced geothermal system development in Seokmodo, Korea

    Science.gov (United States)

    Shin, Jiyoun; Kim, Kyung-Ho; Hyun, Yunjung; Lee, Kang-Keun

    2010-05-01

    Estimating the expected capacity and efficiency of energy is a crucial issue in the construction of geothermal plant. It is the lasting temperature of extracted geothermal water that determines the effectiveness of enhanced geothermal systems (EGS), so the heat transfer processes in geothermal reservoirs under site-specific geologic conditions should be understood first. The construction of the first geothermal plant in Korea is under planning in Seokmodo, where a few flowing artesian wells showing relatively high water temperature of around 70°C were discovered lately. The site of interest is a part of the island region, consisting of the reclaimed land surrounded by the sea and small mountains. Geothermal gradient measures approximately 45°C/km and the geothermal water is as saline as seawater. Geologic structure in this region is characterized by the fractured granite. In this study, thermo-hydrological (TH) numerical simulations for the temperature evolution in a fractured geothermal reservoir under the supposed injection-extraction operating conditions were carried out using TOUGH2. Multiple porosity model which is useful to calculate the transient interporosity flow in TH coupled heat transfer problem was used in simulations. Several fracture planes which had been investigated in the field were assigned to have highly permeable properties in order to avoid the averaging approximation and describe the dominant flow through the fractures. This heterogeneous model showed the rise of relatively hot geothermal water in the densely fractured region. The temperature of the extracted geothermal water also increased slowly for 50 years due to the rising flow through the fractures. The most sensitive factor which affects the underground thermal distribution and temperature of geothermal water was permeability of the medium. Change in permeabilities of rock and fracture within the range of 1 order might cause such an extreme change in the temperature of geothermal

  15. Design and Implementation of Geothermal Energy Systems at West Chester University

    Energy Technology Data Exchange (ETDEWEB)

    Greg Cuprak

    2011-08-31

    West Chester University is launching a comprehensive transformation of its campus heating and cooling systems from traditional fossil fuels (coal, oil and natural gas) to geothermal. This change will significantly decrease the institution's carbon footprint and serve as a national model for green campus efforts. The institution is in the process of designing and implementing this project to build well fields, a pumping station and install connecting piping to provide the geothermal heat/cooling source for campus buildings. This project addresses the US Department of Energy Office of Energy Efficiency and Renewable Energy (EERE) goal to invest in clean energy technologies that strengthen the economy, protect the environment, and reduce dependence on foreign oil. In addition, this project advances EERE's efforts to establish geothermal energy as an economically competitive contributor to the US energy supply. For this grant, WCU will extend piping for its geo-exchange system. The work involves excavation of a trench approximately 8 feet wide and 10-12 feet deep located about 30 feet north of the curb along the north side of West Rosedale for a distance of approximately 1,300 feet. The trench will then turn north for the remaining distance (60 feet) to connect into the mechanical room in the basement of the Francis Harvey Green Library. This project will include crossing South Church Street near its intersection with West Rosedale, which will involve coordination with the Borough of West Chester. After installation of the piping, the trench will be backfilled and the surface restored to grass as it is now. Because the trench will run along a heavily-used portion of the campus, it will be accomplished in sections to minimize disruption to the campus as much as possible.

  16. A suite of benchmark and challenge problems for enhanced geothermal systems

    Energy Technology Data Exchange (ETDEWEB)

    White, Mark; Fu, Pengcheng; McClure, Mark; Danko, George; Elsworth, Derek; Sonnenthal, Eric; Kelkar, Sharad; Podgorney, Robert

    2017-11-06

    A diverse suite of numerical simulators is currently being applied to predict or understand the performance of enhanced geothermal systems (EGS). To build confidence and identify critical development needs for these analytical tools, the United States Department of Energy, Geothermal Technologies Office sponsored a Code Comparison Study (GTO-CCS), with participants from universities, industry, and national laboratories. A principal objective for the study was to create a community forum for improvement and verification of numerical simulators for EGS modeling. Teams participating in the study were those representing U.S. national laboratories, universities, and industries, and each team brought unique numerical simulation capabilities to bear on the problems. Two classes of problems were developed during the study, benchmark problems and challenge problems. The benchmark problems were structured to test the ability of the collection of numerical simulators to solve various combinations of coupled thermal, hydrologic, geomechanical, and geochemical processes. This class of problems was strictly defined in terms of properties, driving forces, initial conditions, and boundary conditions. The challenge problems were based on the enhanced geothermal systems research conducted at Fenton Hill, near Los Alamos, New Mexico, between 1974 and 1995. The problems involved two phases of research, stimulation, development, and circulation in two separate reservoirs. The challenge problems had specific questions to be answered via numerical simulation in three topical areas: 1) reservoir creation/stimulation, 2) reactive and passive transport, and 3) thermal recovery. Whereas the benchmark class of problems were designed to test capabilities for modeling coupled processes under strictly specified conditions, the stated objective for the challenge class of problems was to demonstrate what new understanding of the Fenton Hill experiments could be realized via the application of

  17. Geothermal Modesty

    International Nuclear Information System (INIS)

    Anon.

    2004-01-01

    This publication of the Areva Group, a world nuclear industry leader, provides information on the energy in many domains. This issue deals with the uses for radioactivity, the future of the green electricity, the energy policy of Rhone-alps region, the end of the nuclear in Belgium, the nuclear propulsion to explore the solar system, the involvement of the Unites States in the hydrogen development, the gas exportation of China. A special part is devoted to the possibility of the geothermal energy. (A.L.B.)

  18. Monitoring of Building Heating and Cooling Systems Based on Geothermal Heat Pump in Galicia (Spain

    Directory of Open Access Journals (Sweden)

    Franco D.

    2012-10-01

    Full Text Available In November 2009 was signed an agreement between Galicia’s Government and EnergyLab to develop a project related with the geothermal heatpumps (hereafter, GSHP technology. That project consisted in replacing the existing thermal equipment generators (diesel boilers and air-water heat pumps by GSHP systems in representative public buildings: two nursery schools, a university library, a health centre and a residential building. This new systems will reach the demands of existing heating, cooling and domestic hot water (hereafter, DHW. These buildings can serve as examples of energy and economic savings that can offer this technology. We will show detailed analysis of the GSHP facilities monitored, since the starting-up of them. Which includes: COP’s, EER’s, energy consumption, operating costs, operation hours of the system, economic and emissions comparative, geothermal exchange evolution graphs, environmental conditions evolution graphs (temperature and demands, etc. The results presented show an example of the important benefits of the GSHP technology and the significant savings that can offer its implementation for heating, cooling and DHW production.

  19. Groundwater recharge through wells in open loop geothermal system: problems and solutions - part 1

    Directory of Open Access Journals (Sweden)

    Giovanni Pietro Beretta

    2017-07-01

    Full Text Available In the two parts of this article, the problems related to the management of water wells as part of a low-enthalpy geothermal power plant by means of heat pumps (open loop system are described. In many cases, in absence of discharge in surface water and/or to ensure the conservation of the resource from a quantitative point of view, a doublet system constituted by a pumping and a recharge well is provided. The clogging phenomenon often occurs in this kind of plant, affecting wells with different functions and different thermal potential related to water withdrawal and reinjection into the ground. This phenomenon is due to the presence of air bubbles, suspended solids, bacterial growth and to the chemical-physical reactions that are described in the text. Besides acknowledging the activities for recharge wells management to avoid the fracturing of the drain and the cementation, is also suggested the procedure of in situ tests that are used to properly determine the optimal well discharge, which determines the efficiency and effectiveness of the geothermal system and its economic performance.It is finally shown a regional regulation on the water quality used in an open loop.

  20. The smectite to chlorite transition in the Chipilapa geothermal system, El Salvador

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, D. [Univ. of Bristol (United Kingdom). Dept. of Earth Sciences; Santana de Zamora, A. [Comision Ejecutiva Hidroelectrica del Rio Lempa (El Salvador)

    1999-04-01

    Clay mineralogical, X-ray diffraction and electron microprobe studies have been carried out on separated <2 {micro}m fractions from cutting and core material from three wells in the Chipilapa geothermal system in El Salvador. The data indicate that the smectite to chlorite transition is prevalent, but a secondary smectite to illite transition is also present. At depths approximately <750 m, smectite with very minor chlorite mixed-layers (approximately <15%) is dominant, and has a composition midway between a di- and tri-smectite. At {approximately}750 m there is a very clear distinction and sharp transition into discrete chlorite with very minor smectite mixed-layers (approximately <10%). Corrensite is recorded only as a rare and minor phase. Smectite occurs in abundance at temperatures up to {approximately}200 C, and the transition from a smectite-dominant to chlorite-dominant assemblage takes place over a narrow temperature range ({approximately}150 to 200 C). The stability range of smectite is very similar to that recorded in other geothermal systems, whereas the smectite to chlorite transition differs greatly from that recorded in other systems. The transition does not involve continuous chlorite/smectite mixed-layering but a marked step: It is the sharpest and most discontinuous stepped sequence of this mineralogical transition recorded.

  1. Building Better Buildings: Sustainable Building Activities in California Higher Education Systems.

    Science.gov (United States)

    Sowell, Arnold; Eichel, Amanda; Alevantis, Leon; Lovegreen, Maureen

    2003-01-01

    This article outlines the activities and recommendations of California's sustainable building task force, discusses sustainable building activities in California's higher education systems, and highlights key issues that California is grappling with in its implementation of sustainable building practices. (EV)

  2. Geothermal spas

    International Nuclear Information System (INIS)

    Woodruff, J.L.; Takahashi, P.K.

    1990-01-01

    The spa business, part of the health and fitness industry that has sprung up in recent years, is highly successful world-wide. The most traditional type of spa is the geothermal spa, found in geothermal areas around the world. In Japan, for example, some 2,000 geothermal spas and resorts generate $6 billion annually. Hawaii has an ideal environment for geothermal spas, and several locations in the islands could supply warm mineral water for spa development. Hawaii receives about 6 million visitors annually, a high percentage of whom are familiar with the relaxing and therapeutic value of geothermal spas, virtually guaranteeing the success of this industry in Hawaii. Presently, Hawaii does not have a single geothermal spa. This paper reports that the geothermal spa business is an industry whose time has come, an industry that offers very promising investment opportunities, and one that would improve the economy while expanding the diversity of pleasurable vacation options in Hawaii

  3. Stable isotope geochemistry of the Tongonan geothermal system, Leyte, Philippines

    International Nuclear Information System (INIS)

    Hulston, J.R.; Stewart, M.K.

    1982-01-01

    Stable isotope and geochemical data on samples from natural features, shallow wells and deep wells collected over a number of years from the Tongonan area of Leyte have been evaluated. The variations in the isotopic compositions of the thermal waters are used to describe natural processes occurring within the system. The effect of the ''excess enthalpy'' of the deep wells on the isotope data is formulated. Water from the deep Tongonan wells shows an oxygen-18 shift of 5 per mille, which is larger than at Wairakei and Broadlands, probably in part because of the high temperatures at Tongonan. Recent measurements indicate that the deuterium shift is very much smaller than previously thought. Isotopic measurements of methane in the gases suggests differing flows from the Eastern and Central Philippine faults

  4. Quality label 'Geothermal energy source' (quality-assurance system)

    International Nuclear Information System (INIS)

    Eugster, W. J.

    2005-01-01

    The design of borehole heat exchanger (BHE) plants is covered only marginally through the existing quality labels. And only for small and simple systems. Especially the middle and large sized BHE plants are excluded from the labels. And exactly those plants may be very difficult to treat and to handle. Two concepts of quality control are proposed. On one hand a quality label, which is based on an object sheet, that is both, a planning help and a quality proof. There is no duty for the heating/ventilation/air-conditioning (HVAC) engineers to acquire such a quality label. The label is based on a self quality declaration of the engineers. Therefore a controlling system is needed which induces costs to the labelled engineers. A market penetration of around 20% is predicted for the first three years. The second concept is based on a clear definition of the actual state of the art in designing a BHE plant in a formal standard by the Swiss Engineers and Architects Society (SIA). This concept is proposed for realisation. Nearly 90% of the Swiss BHE drilling market is penetrated by the labelled drilling companies which have agreed to demand from their HVAC engineers (planners) to apply the future SIA standard, either by their general drilling and delivery conditions or by a special agreement. This fact guarantees a fast spreading and application of such a new SIA standard. A collateral information offensive for the HVAC engineers working in the design of BHE plants needs to be stated in any way. This method is not only very cheap but also guarantees a fast and a broad market penetration which must have nearly the same grade as the quality label for drilling companies. But of course, the new standard has to be elaborated first, what should be possible within approximately one year. (author)

  5. Sustainable Approaches for Stormwater Quality Improvements with Experimental Geothermal Paving Systems

    Directory of Open Access Journals (Sweden)

    Kiran Tota-Maharaj

    2015-01-01

    Full Text Available This research assesses the next generation of permeable pavement systems (PPS incorporating ground source heat pumps (geothermal paving systems. Twelve experimental pilot-scaled pavement systems were assessed for its stormwater treatability in Edinburgh, UK. The relatively high variability of temperatures during the heating and cooling cycle of a ground source heat pump system embedded into the pavement structure did not allow the ecological risk of pathogenic microbial expansion and survival. Carbon dioxide monitoring indicated relatively high microbial activity on a geotextile layer and within the pavement structure. Anaerobic degradation processes were concentrated around the geotextile zone, where carbon dioxide concentrations reached up to 2000 ppm. The overall water treatment potential was high with up to 99% biochemical oxygen demand removal. The pervious pavement systems reduced the ecological risk of stormwater discharges and provided a low risk of pathogen growth.

  6. Development of a Deep-Penetrating, Compact Geothermal Heat Flow System for Robotic Lunar Geophysical Missions

    Science.gov (United States)

    Nagihara, Seiichi; Zacny, Kris; Hedlund, Magnus; Taylor, Patrick T.

    2012-01-01

    Geothermal heat flow measurements are a high priority for the future lunar geophysical network missions recommended by the latest Decadal Survey of the National Academy. Geothermal heat flow is obtained as a product of two separate measurements of geothermal gradient and thermal conductivity of the regolith/soil interval penetrated by the instrument. The Apollo 15 and 17 astronauts deployed their heat flow probes down to 1.4-m and 2.3-m depths, respectively, using a rotary-percussive drill. However, recent studies show that the heat flow instrument for a lunar mission should be capable of excavating a 3-m deep hole to avoid the effect of potential long-term changes of the surface thermal environment. For a future robotic geophysical mission, a system that utilizes a rotary/percussive drill would far exceed the limited payload and power capacities of the lander/rover. Therefore, we are currently developing a more compact heat flow system that is capable of 3-m penetration. Because the grains of lunar regolith are cohesive and densely packed, the previously proposed lightweight, internal hammering systems (the so-called moles ) are not likely to achieve the desired deep penetration. The excavation system for our new heat flow instrumentation utilizes a stem which winds out of a pneumatically driven reel and pushes its conical tip into the regolith. Simultaneously, gas jets, emitted from the cone tip, loosen and blow away the soil. Lab tests have demonstrated that this proboscis system has much greater excavation capability than a mole-based heat flow system, while it weighs about the same. Thermal sensors are attached along the stem and at the tip of the penetrating cone. Thermal conductivity is measured at the cone tip with a short (1- to 1.5-cm long) needle sensor containing a resistance temperature detector (RTD) and a heater wire. When it is inserted into the soil, the heater is activated. Thermal conductivity of the soil is obtained from the rate of temperature

  7. Final Report to DOE EERE – Geothermal Technologies Program Project Title: Monitoring and modeling of fluid flow in a developing enhanced geothermal system (EGS) reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Fehler, Michael [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

    2017-04-19

    The primary objective of this project was to improve our ability to predict performance of an Enhanced Geothermal System (EGS) reservoir over time by relating, in a quantitative manner, microseismic imaging with fluid and temperature changes within the reservoir. Historically, microseismic data have been used qualitatively to place bounds on the growth of EGS reservoirs created by large hydraulic fracturing experiments. Previous investigators used an experimentally based fracture opening relationship (fracture aperture as a function of pressure), the spatial extent of microseismic events, and some assumptions about fracture frequency to determine the size of an EGS reservoir created during large pumping tests. We addressed a number of issues (1) locating microearthquakes that occur during hydraulic fracturing, (2) obtaining more information about a reservoir than the microearthquake locations from the microearthquake data, for example, information about the seismic velocity structure of the reservoir or the scattering of seismic waves within the reservoir, (3) developing an improved methodology for estimating properties of fractures that intersect wellbores in a reservoir, and (4) developing a conceptual model for explaining the downward growth of observed seismicity that accompanies some hydraulic injections into geothermal reservoirs. We used two primary microseismic datasets for our work. The work was motivated by a dataset from the Salak Geothermal Field in Indonesia where seismicity accompanying a hydraulic injection was observed to migrate downward. We also used data from the Soultz EGS site in France. We also used Vertical Seismic Profiling data from a well in the United States. The work conducted is of benefit for characterizing reservoirs that are created by hydraulic fracturing for both EGS and for petroleum recovery.

  8. Modelling ground movements at Campi Flegrei caldera (Italy): the role of the shallow geothermal system

    Science.gov (United States)

    Troiano, Antonio; Giulia di Giuseppe, Maria; Petrillo, Zaccaria; Troise, Claudia; de Natale, Giuseppe

    2010-05-01

    Campi Flegrei caldera is characterized by large ground movements, well known since Roman times. Superimposed to a general secular subsidence occurring at a rate of 1.5-2.0 cm/year, an episode of sharp uplift is in progress since 1969, with peak rates up to 1 m/year (in 1982-1984), similar to another episode which culminated with the 1538 eruption. Peak uplift episodes are often followed by some amount of subsidence, which prevent a simple interpretation in terms of purely magmatic inflation phenomena. Such up and down episodes of ground deformations are rather common at large calderas, like in Yellowstone (USA), Long Valley (USA), etc. Here we propose an interpretation based on a mixed mechanical-fluid-dynamical model, in which part of the uplift is generated by increase of water pressure in the shallow geothermal system, as a response to rapid inflow of magmatic fluids exsolved from a deeper magma chamber. We use the program THOUGH2 to model the changes of temperature and pressure in the geothermal system due to the magmatic fluids inflow. Changes in pressure in the caldera volume are then used to compute ground deformations. This way, a theoretical time evolution of ground deformation has been obtained, which compares well with the observed one, if appropriate values of permeability are used. We discuss the implication of such a model for eruption forecast purposes, and the extent at which the required values of permeability can be really representative of the real medium.

  9. Creation of an Enhanced Geothermal System through Hydraulic and Thermal Stimulation

    Energy Technology Data Exchange (ETDEWEB)

    Rose, Peter Eugene [Energy and Geoscience Institute at the University of Utah

    2013-04-15

    This report describes a 10-year DOE-funded project to design, characterize and create an Engineered Geothermal System (EGS) through a combination of hydraulic, thermal and chemical stimulation techniques. Volume 1 describes a four-year Phase 1 campaign, which focused on the east compartment of the Coso geothermal field. It includes a description of the geomechanical, geophysical, hydraulic, and geochemical studies that were conducted to characterize the reservoir in anticipation of the hydraulic stimulation experiment. Phase 1 ended prematurely when the drill bit intersected a very permeable fault zone during the redrilling of target stimulation well 34-9RD2. A hydraulic stimulation was inadvertently achieved, however, since the flow of drill mud from the well into the formation created an earthquake swarm near the wellbore that was recorded, located, analyzed and interpreted by project seismologists. Upon completion of Phase 1, the project shifted focus to a new target well, which was located within the southwest compartment of the Coso geothermal field. Volume 2 describes the Phase 2 studies on the geomechanical, geophysical, hydraulic, and geochemical aspects of the reservoir in and around target-stimulation well 46A-19RD, which is the deepest and hottest well ever drilled at Coso. Its total measured depth exceeding 12,000 ft. It spite of its great depth, this well is largely impermeable below a depth of about 9,000 ft, thus providing an excellent target for stimulation. In order to prepare 46A-19RD for stimulation, however, it was necessary to pull the slotted liner. This proved to be unachievable under the budget allocated by the Coso Operating Company partners, and this aspect of the project was abandoned, ending the program at Coso. The program then shifted to the EGS project at Desert Peak, which had a goal similar to the one at Coso of creating an EGS on the periphery of an existing geothermal reservoir. Volume 3 describes the activities that the Coso team

  10. Economic performances optimization of the transcritical Rankine cycle systems in geothermal application

    International Nuclear Information System (INIS)

    Yang, Min-Hsiung; Yeh, Rong-Hua

    2015-01-01

    Highlights: • The optimal economic performance of the TRC system are investigated. • In economic evaluations, R125 performs the most satisfactorily, followed by R41 and CO 2 . • The TRC system with CO 2 has the largest averaged temperature difference. • Economic optimized pressures are always lower than thermodynamic optimized operating pressures. - Abstract: The aim of this study is to investigate the economic optimization of a TRC system for the application of geothermal energy. An economic parameter of net power output index, which is the ratio of net power output to the total cost, is applied to optimize the TRC system using CO 2 , R41 and R125 as working fluids. The maximum net power output index and the corresponding optimal operating pressures are obtained and evaluated for the TRC system. Furthermore, the analyses of the corresponding averaged temperature differences in the heat exchangers on the optimal economic performances of the TRC system are carried out. The effects of geothermal temperatures on the thermodynamic and economic optimizations are also revealed. In both optimal economic and thermodynamic evaluations, R125 performs the most satisfactorily, followed by R41 and CO 2 in the TRC system. In addition, the TRC system operated with CO 2 has the largest averaged temperature difference in the heat exchangers and thus has potential in future application for lower-temperature heat resources. The highest working pressures obtained from economic optimization are always lower than those from thermodynamic optimization for CO 2 , R41, and R125 in the TRC system

  11. Fiscal 1995 survey of promotion of the geothermal development. Report on a usage feasibility test of a small scale geothermal binary cycle power generation system; 1995 nendo chinetsu kaihatsu sokushin chosa. Chusho chinetsu binary hatsuden system jissho shiken hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    In this survey, studies for popularization and practical utilization of small and medium size geothermal binary cycle power systems which assesses low and medium temperature geothermal resources were conducted, and studies for development of the system to be introduced for practical use and for promotion of the popularization were made. A study was carried out of preconditions and various conditions of a demonstrative test plant (100kW class, 500kW class) in view of the initial cost of the actual plant, and an analysis was made of the power generation cost. Acceptability of the demonstrative test plant (100kW class) was examined to analyze problems on the introduction. A thermodynamic analysis was made of the output of geothermal binary cycle power generation. Analysis/evaluation of the results of the 100kW demonstrative test plant were carried out in view of the operation results of the plant of the same kind, and checks/reviews were conducted of performance and reliability of the system, equipment simplification, etc. Inspection of the system was made in the stage of design/manufacture of the 500kW demonstrative test plant. Concerning the spread/expansion of the system, studied were multiple stage geothermal utilization and PR promotion method. 14 refs., 62 figs., 55 tabs.

  12. Energy efficiency model for small/medium geothermal heat pump systems

    Directory of Open Access Journals (Sweden)

    Staiger Robert

    2015-06-01

    Full Text Available Heating application efficiency is a crucial point for saving energy and reducing greenhouse gas emissions. Today, EU legal framework conditions clearly define how heating systems should perform, how buildings should be designed in an energy efficient manner and how renewable energy sources should be used. Using heat pumps (HP as an alternative “Renewable Energy System” could be one solution for increasing efficiency, using less energy, reducing the energy dependency and reducing greenhouse gas emissions. This scientific article will take a closer look at the different efficiency dependencies of such geothermal HP (GHP systems for domestic buildings (small/medium HP. Manufacturers of HP appliances must document the efficiency, so called COP (Coefficient of Performance in the EU under certain standards. In technical datasheets of HP appliances, these COP parameters give a clear indication of the performance quality of a HP device. HP efficiency (COP and the efficiency of a working HP system can vary significantly. For this reason, an annual efficiency statistic named “Seasonal Performance Factor” (SPF has been defined to get an overall efficiency for comparing HP Systems. With this indicator, conclusions can be made from an installation, economy, environmental, performance and a risk point of view. A technical and economic HP model shows the dependence of energy efficiency problems in HP systems. To reduce the complexity of the HP model, only the important factors for efficiency dependencies are used. Dynamic and static situations with HP´s and their efficiency are considered. With the latest data from field tests of HP Systems and the practical experience over the last 10 years, this information will be compared with one of the latest simulation programs with the help of two practical geothermal HP system calculations. With the result of the gathered empirical data, it allows for a better estimate of the HP system efficiency, their

  13. A complementary geothermal application

    International Nuclear Information System (INIS)

    Bedard, R.

    1998-01-01

    A geothermal project for air conditioning and heating at four health centres in Quebec was presented. The four health centres are: le centre Dominique-Tremblay, le centre Cardinal-Villeneuve, le centre Louis-Hebert, et le centre Francois-Charon. The investment made to install the geothermal heating and cooling system, the cost of operating the system, and energy savings resulting from the investment were discussed

  14. Probabilistic 3-D time-lapse inversion of magnetotelluric data: application to an enhanced geothermal system

    Science.gov (United States)

    Rosas-Carbajal, M.; Linde, N.; Peacock, J.; Zyserman, F. I.; Kalscheuer, T.; Thiel, S.

    2015-12-01

    Surface-based monitoring of mass transfer caused by injections and extractions in deep boreholes is crucial to maximize oil, gas and geothermal production. Inductive electromagnetic methods, such as magnetotellurics, are appealing for these applications due to their large penetration depths and sensitivity to changes in fluid conductivity and fracture connectivity. In this work, we propose a 3-D Markov chain Monte Carlo inversion of time-lapse magnetotelluric data to image mass transfer following a saline fluid injection. The inversion estimates the posterior probability density function of the resulting plume, and thereby quantifies model uncertainty. To decrease computation times, we base the parametrization on a reduced Legendre moment decomposition of the plume. A synthetic test shows that our methodology is effective when the electrical resistivity structure prior to the injection is well known. The centre of mass and spread of the plume are well retrieved. We then apply our inversion strategy to an injection experiment in an enhanced geothermal system at Paralana, South Australia, and compare it to a 3-D deterministic time-lapse inversion. The latter retrieves resistivity changes that are more shallow than the actual injection interval, whereas the probabilistic inversion retrieves plumes that are located at the correct depths and oriented in a preferential north-south direction. To explain the time-lapse data, the inversion requires unrealistically large resistivity changes with respect to the base model. We suggest that this is partly explained by unaccounted subsurface heterogeneities in the base model from which time-lapse changes are inferred.

  15. Comparative Analysis of Power Plant Options for Enhanced Geothermal Systems (EGS

    Directory of Open Access Journals (Sweden)

    Mengying Li

    2014-12-01

    Full Text Available Enhanced geothermal systems (EGS extract heat from underground hot dry rock (HDR by first fracturing the HDR and then circulating a geofluid (typically water into it and bringing the heated geofluid to a power plant to generate electricity. This study focuses on analysis, examination, and comparison of leading geothermal power plant configurations with a geofluid temperature from 200 to 800 °C, and also analyzes the embodied energy of EGS surface power plants. The power generation analysis is focused on flash type cycles for using subcritical geofluid (<374 °C and expansion type cycles for using supercritical geofluid (>374 °C. Key findings of this study include: (i double-flash plants have 24.3%–29.0% higher geofluid effectiveness than single-flash ones, and 3%–10% lower specific embodied energy; (ii the expansion type plants have geofluid effectiveness > 750 kJ/kg, significantly higher than flash type plants (geofluid effectiveness < 300 kJ/kg and the specific embodied energy is lower; (iii to increase the turbine outlet vapor fraction from 0.75 to 0.90, we include superheating by geofluid but that reduces the geofluid effectiveness by 28.3%; (iv for geofluid temperatures above 650 °C, double-expansion plants have a 2% higher geofluid effectiveness and 5%–8% lower specific embodied energy than single-expansion ones.

  16. Dating and tracing of fluids using 129I and 36Cl: results from geothermal fluids, oil field brines and formation waters

    International Nuclear Information System (INIS)

    Fehn, U.; Moran, J.E.; Teng, R.T.D.; Rao, U.

    1994-01-01

    Preliminary results are presented for 129 I/I and 36 Cl/Cl ratios in formation waters from the KTB project in Germany, geothermal waters from the Salton Sea Geothermal System in California and oilfield brines from the Anadarko Basin in Oklahoma. The results demonstrate the use of these isotopic systems to determine residence times, source formations and pathways of fluids in different geologic situations. ((orig.))

  17. Exploration of the enhanced geothermal system (EGS) potential of crystalline rocks for district heating (Elbe Zone, Saxony, Germany)

    Science.gov (United States)

    Förster, Andrea; Förster, Hans-Jürgen; Krentz, Ottomar

    2018-01-01

    This paper addresses aspects of a baseline geothermal exploration of the thermally quiescent Elbe Zone (hosting the cities of Meissen and Dresden) for a potential deployment of geothermal heat in municipal heating systems. Low-permeable to impermeable igneous and metamorphic rocks constitute the major rock types at depth, implying that an enhanced geothermal system needs to be developed by creating artificial flow paths for fluids to enhance the heat extraction from the subsurface. The study includes the development of geological models for two areas on the basis of which temperature models are generated at upper crustal scale. The models are parameterized with laboratory-measured rock thermal properties (thermal conductivity k, radiogenic heat production H). The uncertainties of modelled temperature caused by observed variations of k and H and inferred mantle heat flow are assessed. The study delineates highest temperatures within the intermediate (monzonite/syenite unit) and mafic rocks (diorite/monzodiorite unit) forming the deeper portions of the Meissen Massif and, specifically for the Dresden area, also within the low-metamorphic rocks (slates/phyllites/quartzites) of the Elbtalschiefergebirge. Boreholes 3-4 km deep need to be drilled to reach the envisioned economically favourable temperatures of 120 °C. The metamorphic and mafic rocks exhibit low concentrations of U and Th, thus being advantageous for a geothermal use. For the monzonite/syenite unit of high heat production ( 6 µW m-3) in the Meissen Massif, the mobilization of Th and U into the geothermal working fluid is assumed to be minor, although their various radioactive decay products will be omnipresent during geothermal use.

  18. A Study on the Efficiency Improvement of Multi-Geothermal Heat Pump Systems in Korea Using Coefficient of Performance

    Directory of Open Access Journals (Sweden)

    Young-Ju Jung

    2016-05-01

    Full Text Available The Korean government is fostering a renewable energy industry as a means of handling the energy crisis. Among the renewable energy systems available, geothermal energy has been highlighted as highly efficient, safely operable and relatively unaffected by outdoors air conditions. Despite the increasing use of renewable energy, the devices using renewables may not be operating appropriately. This study examined current problems in the operation of a geothermal heat pump (GHP system. The efficiency of a geothermal heat pump system to studied to maximize the operation plan. Our study modelled the target building and analyzed the energy using TRNSYS, which is a dynamic energy simulation tool, to apply the coefficient of performance (COP and evaluate the operation method. As a result, the GHP total energy consumption from the COP control method was reduced by 46% compared to the current operation. The proposed control method was evaluated after applying the system to a building. The results showed that efficient operation of a geothermal heat pump system is possible.

  19. Geothermal well log interpretation state of the art. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Sanyal, S.K.; Wells, L.E.; Bickham, R.E.

    1980-01-01

    An in-depth study of the state of the art in Geothermal Well Log Interpretation has been made encompassing case histories, technical papers, computerized literature searches, and actual processing of geothermal wells from New Mexico, Idaho, and California. A classification scheme of geothermal reservoir types was defined which distinguishes fluid phase and temperature, lithology, geologic province, pore geometry, salinity, and fluid chemistry. Major deficiencies of Geothermal Well Log Interpretation are defined and discussed with recommendations of possible solutions or research for solutions. The Geothermal Well Log Interpretation study and report has concentrated primarily on Western US reservoirs. Geopressured geothermal reservoirs are not considered.

  20. Towards a de-carbonized energy system in North-Eastern Morocco: Prospective Geothermal Resource

    OpenAIRE

    Rimi, Abdelkrim; Zarhloule, Yassine; Barkaoui, Alae Eddine; Correia, António; Carneiro, Júlio; Verdoya, Massimo; Lucazeau, Francis

    2012-01-01

    Geothermal data has been indicating promising potentialities in the north-eastern Morocco. This paper presents new temperature data, recently recorded in water boreholes located in the Berkane and Oujda areas. Generally, the observed temperature gradients are rather high. One hole near Berkane, revealed an average geothermal gradient of more than 110 °C/km at depths greater than 300 m. This result confirms the geothermal gradient estimated in a mining borehole located about 30 km west of the ...

  1. Enhanced Geothermal Systems Research and Development: Models of Subsurface Chemical Processes Affecting Fluid Flow

    Energy Technology Data Exchange (ETDEWEB)

    Moller, Nancy; Weare J. H.

    2008-05-29

    Successful exploitation of the vast amount of heat stored beneath the earth’s surface in hydrothermal and fluid-limited, low permeability geothermal resources would greatly expand the Nation’s domestic energy inventory and thereby promote a more secure energy supply, a stronger economy and a cleaner environment. However, a major factor limiting the expanded development of current hydrothermal resources as well as the production of enhanced geothermal systems (EGS) is insufficient knowledge about the chemical processes controlling subsurface fluid flow. With funding from past grants from the DOE geothermal program and other agencies, we successfully developed advanced equation of state (EOS) and simulation technologies that accurately describe the chemistry of geothermal reservoirs and energy production processes via their free energies for wide XTP ranges. Using the specific interaction equations of Pitzer, we showed that our TEQUIL chemical models can correctly simulate behavior (e.g., mineral scaling and saturation ratios, gas break out, brine mixing effects, down hole temperatures and fluid chemical composition, spent brine incompatibilities) within the compositional range (Na-K-Ca-Cl-SO4-CO3-H2O-SiO2-CO2(g)) and temperature range (T < 350°C) associated with many current geothermal energy production sites that produce brines with temperatures below the critical point of water. The goal of research carried out under DOE grant DE-FG36-04GO14300 (10/1/2004-12/31/2007) was to expand the compositional range of our Pitzer-based TEQUIL fluid/rock interaction models to include the important aluminum and silica interactions (T < 350°C). Aluminum is the third most abundant element in the earth’s crust; and, as a constituent of aluminosilicate minerals, it is found in two thirds of the minerals in the earth’s crust. The ability to accurately characterize effects of temperature, fluid mixing and interactions between major rock-forming minerals and hydrothermal and

  2. Geothermal energy

    International Nuclear Information System (INIS)

    Laplaige, Ph.; Lemale, J.

    2008-01-01

    Geothermal energy is a renewable energy source which consists in exploiting the heat coming from the Earth. It covers a wide range of techniques and applications which are presented in this article: 1 - the Earth, source of heat: structure of the Earth, geodynamic model and plate tectonics, origin of heat, geothermal gradient and terrestrial heat flux; 2 - geothermal fields and resources; 3 - implementation of geothermal resources: exploration, main characteristic parameters, resource exploitation; 4 - uses of geothermal resources: power generation, thermal uses, space heating and air conditioning heat pumps, district heating, addition of heat pumps; 5 - economical aspects: power generation, heat generation for district heating; 6 - environmental aspects: conditions of implementation, impacts as substitute to fossil fuels; 7 - geothermal energy in France: resources, organisation; 8 - conclusion. (J.S.)

  3. Characteristics of Southern California coastal aquifer systems

    Science.gov (United States)

    Edwards, B.D.; Hanson, R.T.; Reichard, E.G.; Johnson, T.A.

    2009-01-01

    Most groundwater produced within coastal Southern California occurs within three main types of siliciclastic basins: (1) deep (>600 m), elongate basins of the Transverse Ranges Physiographic Province, where basin axes and related fluvial systems strike parallel to tectonic structure, (2) deep (>6000 m), broad basins of the Los Angeles and Orange County coastal plains in the northern part of the Peninsular Ranges Physiographic Province, where fluvial systems cut across tectonic structure at high angles, and (3) shallow (75-350 m), relatively narrow fluvial valleys of the generally mountainous southern part of the Peninsular Ranges Physiographic Province in San Diego County. Groundwater pumped for agricultural, industrial, municipal, and private use from coastal aquifers within these basins increased with population growth since the mid-1850s. Despite a significant influx of imported water into the region in recent times, groundwater, although reduced as a component of total consumption, still constitutes a significant component of water supply. Historically, overdraft from the aquifers has caused land surface subsidence, flow between water basins with related migration of groundwater contaminants, as well as seawater intrusion into many shallow coastal aquifers. Although these effects have impacted water quality, most basins, particularly those with deeper aquifer systems, meet or exceed state and national primary and secondary drinking water standards. Municipalities, academicians, and local water and governmental agencies have studied the stratigraphy of these basins intensely since the early 1900s with the goals of understanding and better managing the important groundwater resource. Lack of a coordinated effort, due in part to jurisdictional issues, combined with the application of lithostratigraphic correlation techniques (based primarily on well cuttings coupled with limited borehole geophysics) have produced an often confusing, and occasionally conflicting

  4. Geochemical implications of production and storage control by coupling a direct-use geothermal system with heat networks

    NARCIS (Netherlands)

    Daniilidis, Alexandros; Scholten, Tjardo; Hooghiem, Joram; Persis, Claudio De; Herber, Rien

    2017-01-01

    This paper outlines a method in which the heat production of a geothermal system is controlled in relation to the demand from a district-heating network. A model predictive control strategy is designed, which uses volume measurements in the storage tank, and predictions of the demand, to regulate

  5. Geothermal Program Review XII: proceedings. Geothermal Energy and the President's Climate Change Action Plan

    Energy Technology Data Exchange (ETDEWEB)

    1994-12-31

    Geothermal Program Review XII, sponsored by the Geothermal Division of US Department of Energy, was held April 25--28, 1994, in San Francisco, California. This annual conference is designed to promote effective technology transfer by bringing together DOE-sponsored researchers; utility representatives; geothermal energy developers; suppliers of geothermal goods and services; representatives from federal, state, and local agencies; and others with an interest in geothermal energy. In-depth reviews of the latest technological advancements and research results are presented during the conference with emphasis on those topics considered to have the greatest potential to impact the near-term commercial development of geothermal energy.

  6. Evaluation of the environmental sustainability of a micro CHP system fueled by low-temperature geothermal and solar energy

    International Nuclear Information System (INIS)

    Ruzzenenti, Franco; Bravi, Mirko; Tempesti, Duccio; Salvatici, Enrica; Manfrida, Giampaolo; Basosi, Riccardo

    2014-01-01

    Highlights: • Binary, ORC technology avoids CO 2 , but raises questions about environmental impact. • We proposed a micro-size system that combines geothermal energy with solar energy. • The small scale and the solar energy input edges the energy profitability. • The system’s performance is appreciable if applied to existing wells. • The feasibility of exploiting abandoned wells is preliminarily evaluated. - Abstract: In this paper we evaluate the environmental sustainability of a small combined heat and power (CHP) plant operating through an Organic Rankine Cycle (ORC). The heat sources of the system are from geothermal energy at low temperature (90–95 °C) and solar energy. The designed system uses a solar field composed only of evacuated, non-concentrating solar collectors, and work is produced by a single turbine of 50 kW. The project addresses an area of Tuscany, but it could be reproduced in areas where geothermal energy is extensively developed. Therefore, the aim is to exploit existing wells that are either unfit for high-enthalpy technology, abandoned or never fully developed. Furthermore, this project aims to aid in downsizing the geothermal technology in order to reduce the environmental impact and better tailor the production system to the local demand of combined electric and thermal energy. The environmental impact assessment was performed through a Life Cycle Analysis and an Exergy Life Cycle Analysis. According to our findings the reservoir is suitable for a long-term exploitation of the designed system, however, the sustainability and the energy return of this latter is edged by the surface of the heat exchanger and the limited running hours due to the solar plant. Therefore, in order to be comparable to other renewable resources or geothermal systems, the system needs to develop existing wells, previously abandoned

  7. Assessment of the State-Of-The-Art of Numerical Simulation of Enhanced Geothermal Systems

    International Nuclear Information System (INIS)

    None

    1999-01-01

    The reservoir features of importance in the operation of enhanced geothermal systems are described first (Section 2). The report then reviews existing reservoir simulators developed for application to HDR reservoirs (Section 3), hydrothermal systems (Section 4), and nuclear waste isolation (Section 5), highlighting capabilities relevant to the evaluation and assessment of EGS. The report focuses on simulators that include some representation of flow in fractures, only mentioning other simulators, such as general-purpose programs or groundwater models (Section 6). Following these detailed descriptions, the report summarizes and comments on the simulators (Section 7), and recommends a course of action for further development (Section 8). The references are included in Section 9. Appendix A contains contractual information, including a description of the original and revised scope of work for this study. Appendix B presents comments on the draft report from DOE reviewer(s) and the replies of the authors to those comments. [DJE-2005

  8. Assessment of the State-Of-The-Art of Numerical Simulation of Enhanced Geothermal Systems

    Energy Technology Data Exchange (ETDEWEB)

    None

    1999-11-01

    The reservoir features of importance in the operation of enhanced geothermal systems are described first (Section 2). The report then reviews existing reservoir simulators developed for application to HDR reservoirs (Section 3), hydrothermal systems (Section 4), and nuclear waste isolation (Section 5), highlighting capabilities relevant to the evaluation and assessment of EGS. The report focuses on simulators that include some representation of flow in fractures, only mentioning other simulators, such as general-purpose programs or groundwater models (Section 6). Following these detailed descriptions, the report summarizes and comments on the simulators (Section 7), and recommends a course of action for further development (Section 8). The references are included in Section 9. Appendix A contains contractual information, including a description of the original and revised scope of work for this study. Appendix B presents comments on the draft report from DOE reviewer(s) and the replies of the authors to those comments. [DJE-2005

  9. Michrohole Arrays Drilled with Advanced Abrasive Slurry Jet Technology to Efficiently Exploit Enhanced Geothermal Systems

    Energy Technology Data Exchange (ETDEWEB)

    Oglesby, Kenneth [Impact Technologies, Tulsa, OK (United States); Finsterle, Stefan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Zhang, Yingqi [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Pan, Lehua [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Dobson, Parick [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Mohan, Ram [Univ. of Tulsa, OK (United States); Shoham, Ovadia [Univ. of Tulsa, OK (United States); Felber, Betty [Impact Technologies, Tulsa, OK (United States); Rychel, Dwight [Impact Technologies, Tulsa, OK (United States)

    2014-03-12

    This project had two major areas of research for Engineered/ Enhanced Geothermal System (EGS) development - 1) study the potential benefits from using microholes (i.e., bores with diameters less than 10.16 centimeters/ 4 inches) and 2) study FLASH ASJ to drill/ install those microbores between a well and a fracture system. This included the methods and benefits of drilling vertical microholes for exploring the EGS reservoir and for installing multiple (forming an array of) laterals/ directional microholes for creating the in-reservoir heat exchange flow paths. Significant benefit was found in utilizing small microbore sized connecting bores for EGS efficiency and project life. FLASH ASJ was deemed too complicated to optimally work in such deep reservoirs at this time.

  10. Advanced Heat/Mass Exchanger Technology for Geothermal and Solar Renewable Energy Systems

    Energy Technology Data Exchange (ETDEWEB)

    Greiner, Miles [Univ. of Nevada, Reno, NV (United States); Childress, Amy [Univ. of Nevada, Reno, NV (United States); Hiibel, Sage [Univ. of Nevada, Reno, NV (United States); Kim, Kwang [Univ. of Nevada, Reno, NV (United States); Park, Chanwoo [Univ. of Nevada, Reno, NV (United States); Wirtz, Richard [Univ. of Nevada, Reno, NV (United States)

    2014-12-16

    Northern Nevada has abundant geothermal and solar energy resources, and these renewable energy sources provide an ample opportunity to produce economically viable power. Heat/mass exchangers are essential components to any energy conversion system. Improvements in the heat/mass exchange process will lead to smaller, less costly (more efficient) systems. There is an emerging heat transfer technology, based on micro/nano/molecular-scale surface science that can be applied to heat/mass exchanger design. The objective is to develop and characterize unique coating materials, surface configurations and membranes capable of accommodating a 10-fold increase in heat/mass exchanger performance via phase change processes (boiling, condensation, etc.) and single phase convective heat/mass transfer.

  11. Geothermal energy

    OpenAIRE

    Manzella A.

    2017-01-01

    Geothermal technologies use renewable energy resources to generate electricity and direct use of heat while producing very low levels of greenhouse-gas (GHG) emissions. Geothermal energy is the thermal energy stored in the underground, including any contained fluid, which is available for extraction and conversion into energy products. Electricity generation, which nowadays produces 73.7 TWh (12.7 GW of capacity) worldwide, usually requires geothermal resources temperatures of over 100 °C. Fo...

  12. Modelling of Thermal Behavior of Borehole Heat Exchangers of Geothermal Heat Pump Heating Systems

    Directory of Open Access Journals (Sweden)

    Gornov V.F.

    2016-01-01

    Full Text Available This article reports results of comparing the accuracy of the software package “INSOLAR.GSHP.12”, modeling non-steady thermal behavior of geothermal heat pump heating systems (GHCS and of the similar model “conventional” using finite difference methods for solving spatial non-steady problems of heat conductivity. The software package is based on the method of formulating mathematical models of thermal behavior of ground low-grade heat collection systems developed by INSOLAR group of companies. Equations of mathematical model of spatial non-steady thermal behavior of ground mass of low-grade heat collection system obtained by the developed method have been solved analytically that significantly reduced computing time spent by the software complex “INSOLAR.GSHP.12” for calculations. The method allows to turn aside difficulties associated with information uncertainty of mathematical models of the ground thermal behavior and approximation of external factors affecting the ground. Use of experimentally obtained information about the ground natural thermal behavior in the software package allows to partially take into account the whole complex of factors (such as availability of groundwater, their velocity and thermal behavior, structure and arrangement of ground layers, the Earth’s thermal background, precipitation, phase transformations of moisture in the pore space, and more, significantly influencing the formation of thermal behavior of the ground mass of a low-grade geothermal heat collection system. Numerical experiments presented in the article confirmed the high convergence of the results obtained through the software package “INSOLAR.GSHP.12” with solutions obtained by conventional finite-difference methods.

  13. Geothermal energy

    International Nuclear Information System (INIS)

    Le Du, H.; Bouchot, V.; Lopez, S.; Bialkowski, A.; Colnot, A.; Rigollet, C.; Sanjuan, B.; Millot, R.; Brach, M.; Asmundsson, R.; Giroud, N.

    2010-01-01

    Geothermal energy has shown a revival for several years and should strongly develop in a near future. Its potentiality is virtually unexhaustible. Its uses are multiple and various: individual and collective space heating, heat networks, power generation, heat storage, heat exchanges etc.. Re-launched by the demand of renewable energy sources, geothermal energy has become credible thanks to the scientific works published recently which have demonstrated its economical and technical relevance. Its image to the public is changing as well. However, lot of work remains to do to make geothermal energy a real industry in France. Several brakes have to be removed rapidly which concern the noise pollution of geothermal facilities, the risk of bad results of drillings, the electricity costs etc. This dossier gives an overview of today's main research paths in the domain of geothermal energy: 1 - geothermal energy in France: historical development, surface and deep resources, ambitions of the French national energy plan (pluri-annual investment plan for heat generation, incentives, regional 'climate-air-energy' schemes), specific regulations; 2 - geothermal energy at the city scale - sedimentary basins: Ile-de-France 40 years of Dogger reservoir exploitation, potentialities of clastic reservoirs - the Chaunoy sandstones example; 3 - geothermal power generation: conventional reservoirs - the Bouillante model (Guadeloupe, French Indies); the Soultz-sous-Forets pilot plant (Bas-Rhin, France); the supercritical reservoirs - the Krafla geothermal area (Iceland). (J.S.)

  14. Temporal variability of secondary processes in alkaline geothermal waters associated to granitic rocks: the Caldes de Boí geothermal system (Spain)

    Energy Technology Data Exchange (ETDEWEB)

    Asta, M.; Gimeno, M.J.; Auqué, L.F.; Galve, J.P.; Gómez, J.; Acero, P.; Lapuente, P.

    2017-11-01

    The Caldes de Boí geothermal waters show important differences in pH (6.5–9.6) and temperature (15.9ºC–52ºC) despite they have a common origin and a very simple circuit at depth (4km below the recharge area level). Thes differences are the result of secondary processes such as conductive cooling, mixing with colder shallower waters, and input of external CO2, which affect each spring to a different extent in the terminal part of the thermal circuit. In this paper, the secondary processes that control the geochemical evolution of this system have been addressed using a geochemical dataset spanning over 20 years and combining different approaches: classical geochemical calculations and geochemical modelling. Mixing between a cold and a thermal end-member, cooling and CO2 exchange are the processes affecting the spring waters with different intensity over time. These differences in the intensity of the secondary processes could be controlled by the effect of climate and indirectly by the geomorphological and hydrogeological setting of the different springs. Infiltration recharging the shallow aquifer is dominant during the rainy seasons and the extent of the mixing process is greater, at least in some springs.Moreover, significant rainfall can produce a decrease in the ground temperature favouring the conductive cooling. Finally, the geomorphological settings of the springs determine the thickness and the hydraulic properties of the saturated layer below them and, therefore, they affect the extent of the mixing process between the deep thermal waters and the shallower cold waters. The understanding of the compositional changes in the thermal waters and the main factors that could affect them is a key issue to plan the future management of the geothermal resources of the Caldes de Boí system. Here, we propose to use a simple methodology to assess the effect of those factors, which could affect the quality of the thermal waters for balneotherapy at long

  15. Temporal variability of secondary processes in alkaline geothermal waters associated to granitic rocks: the Caldes de Boí geothermal system (Spain)

    International Nuclear Information System (INIS)

    Asta, M.; Gimeno, M.J.; Auqué, L.F.; Galve, J.P.; Gómez, J.; Acero, P.; Lapuente, P.

    2017-01-01

    The Caldes de Boí geothermal waters show important differences in pH (6.5–9.6) and temperature (15.9ºC–52ºC) despite they have a common origin and a very simple circuit at depth (4km below the recharge area level). Thes differences are the result of secondary processes such as conductive cooling, mixing with colder shallower waters, and input of external CO2, which affect each spring to a different extent in the terminal part of the thermal circuit. In this paper, the secondary processes that control the geochemical evolution of this system have been addressed using a geochemical dataset spanning over 20 years and combining different approaches: classical geochemical calculations and geochemical modelling. Mixing between a cold and a thermal end-member, cooling and CO2 exchange are the processes affecting the spring waters with different intensity over time. These differences in the intensity of the secondary processes could be controlled by the effect of climate and indirectly by the geomorphological and hydrogeological setting of the different springs. Infiltration recharging the shallow aquifer is dominant during the rainy seasons and the extent of the mixing process is greater, at least in some springs.Moreover, significant rainfall can produce a decrease in the ground temperature favouring the conductive cooling. Finally, the geomorphological settings of the springs determine the thickness and the hydraulic properties of the saturated layer below them and, therefore, they affect the extent of the mixing process between the deep thermal waters and the shallower cold waters. The understanding of the compositional changes in the thermal waters and the main factors that could affect them is a key issue to plan the future management of the geothermal resources of the Caldes de Boí system. Here, we propose to use a simple methodology to assess the effect of those factors, which could affect the quality of the thermal waters for balneotherapy at long

  16. Intertidal geothermal hot springs as a source of trace elements to the coastal zone: A case study from Bahía Concepción, Gulf of California.

    Science.gov (United States)

    Leal-Acosta, María Luisa; Shumilin, Evgueni; Mirlean, Nicolai; Baturina, Elena Lounejeva; Sánchez-Rodríguez, Ignacio; Delgadillo-Hinojosa, Francisco; Borges-Souza, José

    2018-03-01

    We investigated the influence of the intertidal geothermal hot spring (GHS) on the biogeochemistry of trace elements in Santispac Bight, Bahía Concepción (Gulf of California). The geothermal fluids were enriched in As and Hg mainly in ionic form. The suspended particulate matter of the GHS had elevated enrichment factor (EF) >1 of As, Bi, Cd, Co, Cu, Mn, Mo, Sb, Sn, Sr, Ti, U and Zn. The sediment core from GHS1 had high concentration of As, Hg, C org , S, V, Mo, and U and the extremely high EF of these elements at 8cm of the core. The maximum bioaccumulation of As and Hg was in seaweeds Sargassum sinicola collected near the GHS2. The results confirm the input of trace elements to the coastal zone in Bahía Concepción from geothermal fluids and the evident modification of the chemical composition of the adjacent marine environment. Copyright © 2018 Elsevier Ltd. All rights reserved.

  17. Interaction of processes may explain induced seismicity after shut-in in Enhanced Geothermal Systems

    Science.gov (United States)

    De Simone, Silvia; Carrera, Jesus; Vilarrasa, Victor

    2015-04-01

    Deep fluid injection is a necessary operation in several engineering sectors, like geothermal energy production, natural gas storage, CO2 storage, etc. The seismicity associated to these activities has, in some occasions, reached unexpected magnitude, raising public concern. Moreover, the occurrence of such seismicity after the injection shut-in pointed out the incompleteness of the knowledge and the inability of fully managing these processes. On the other hand, the growing attention toward clean energy makes it clear that we cannot abandon these procedures, which have a huge potential. Therefore, deeply understanding the mechanisms that induce seismicity is crucial. In this study we consider hydraulic stimulation of deep geothermal systems and analyze the mechanisms that may induce or trigger seismicity. Given that the basic mechanism is fluid pressure increase, secondary triggering processes have been studied. In detail, we attempt to identify the potential mechanisms that may trigger seismicity in the post-injection phase, when the overpressure decreases. These mechanisms have been investigated with a coupled and uncoupled approach, in order to understand the individual effects of each one and the effects of the interactions between them on the reservoir stability. Besides fluid overpressure, another relevant process is the temperature variation. Indeed, in the case of enhanced geothermal systems, the temperature contrast between the injected cold fluid and the deep hot reservoir is great and induces thermal stress, which sensibly affects the in-situ stress field. Therefore, we have studied overpressure and temperature effects by means of analytic solutions and by means of hydro-mechanical and thermo-hydro-mechanical numerical simulations. Results show that in fractured rocks the spatial variability of hydraulic and mechanic parameters provokes no isotropic variation of the tensional field, in response to pressure and temperature perturbations. Another

  18. Quartz dissolution and silica deposition in hot-dry-rock geothermal systems

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, B.A.

    1982-07-01

    The kinetics of quartz dissolution control the produced fluid dissolved silica concentration in geothermal systems in which the downhole residence time is finite. The produced fluid of the Phase I, Run Segment 5 experimental Hot Dry Rock (HDR) geothermal system at Fenton Hill, NM, was undersaturated with respect to quartz in one pass through the reservoir, suggesting that the rate of granite dissolution governed the outlet dissolved silica concentration in this system. The literature data for the rate of quartz dissolution in water from 65 to 625/sup 0/C is correlated using an empirical rate law which is first order in quartz surface area and degree of undersaturation of the fluid. The Arrhenius plot (ln k vs T/sup -1/) is linear over eight orders of magnitude of the rate constant, verifying the validity of the proposed rate expression. Carefully performed quartz dissolution experiments in the present study duplicated the literature data and completed the data base in the temperature range from 150 to 250/sup 0/C. Identical experiments using crushed granite indicate that the rate of quartz dissolution in the presence of granite could be as much as 1 to 2 orders of magnitude faster than the rates observed in the pure quartz experiments. A temperature dependent HDR reservoir model incorporates the quartz dissolution rate law to simulate the dissolved silica behavior during the Fenton Hill Run Segment 5 experiment. For this low-permeability, fracture-dominated reservoir, the assumptions of one-dimensional plug flow through a vertically-inclined rectangular fracture and one-dimensional rock heat conduction perpendicular to the direction of flow are employed. These simplifications lead to an analytical solution for the temperature field in the reservoir.

  19. SHAFT-79, 2 Phase Flow in Porous Media for Geothermic Energy System

    International Nuclear Information System (INIS)

    Pruess, K.; Schroeder, R.C.

    1981-01-01

    1 - Description of problem or function: SHAFT79 (Simultaneous Heat And Fluid Transport) is an integrated finite difference program for computing two-phase non-isothermal flow in porous media. Although designed for simulating production and injection in geothermal reservoirs, it is, or can be readily modified to be, applicable to other two-phase problems. SHAFT79 solves coupled mass and energy balance equations based on the following major assumptions: the physical system is a system of porous rock saturated with a one-component fluid in liquid and vapor form; all rock properties, except porosity, i.e., density, specific heat, thermal conductivity, and absolute permeability are independent of temperature, pressure, or vapor saturation: and liquid, vapor, and rock matrix are at the same temperature and pressure at all times. Capillary pressure is neglected. 2 - Method of solution: The solution method is an explicit-implicit integrated finite difference approach which allows a flexible geometric description because it does not distinguish between one-, two-, or three-dimensional regular or irregular geometries. The non-linear finite difference equations are solved using the Newton- Raphson method. In SHAFT79 a fluid table is used to provide the equilibrium thermodynamic properties of the fluid filling the void space - temperature, pressure, vapor saturation, heat conductivity, liquid and vapor viscosities, densities, specific interval energies - as functions of fluid density and fluid specific internal energy. All thermodynamic information including derivatives is obtained from the fluid table by bivariate interpolation. 3 - Restrictions on the complexity of the problem: SHAFT79 has been developed only for systems of water and rock. The fluid table covers most of the equation of state of water substance in the temperature range of 5 to 400 degrees C and the pressure range of 0.5 to 220 bar, which is adequate for most geothermal applications

  20. SHAFT-79, 2 Phase Flow in Porous Media for Geothermic Energy System

    Energy Technology Data Exchange (ETDEWEB)

    Pruess, K; Schroeder, R C [Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720 (United States)

    1981-11-20

    1 - Description of problem or function: SHAFT79 (Simultaneous Heat And Fluid Transport) is an integrated finite difference program for computing two-phase non-isothermal flow in porous media. Although designed for simulating production and injection in geothermal reservoirs, it is, or can be readily modified to be, applicable to other two-phase problems. SHAFT79 solves coupled mass and energy balance equations based on the following major assumptions: the physical system is a system of porous rock saturated with a one-component fluid in liquid and vapor form; all rock properties, except porosity, i.e., density, specific heat, thermal conductivity, and absolute permeability are independent of temperature, pressure, or vapor saturation: and liquid, vapor, and rock matrix are at the same temperature and pressure at all times. Capillary pressure is neglected. 2 - Method of solution: The solution method is an explicit-implicit integrated finite difference approach which allows a flexible geometric description because it does not distinguish between one-, two-, or three-dimensional regular or irregular geometries. The non-linear finite difference equations are solved using the Newton- Raphson method. In SHAFT79 a fluid table is used to provide the equilibrium thermodynamic properties of the fluid filling the void space - temperature, pressure, vapor saturation, heat conductivity, liquid and vapor viscosities, densities, specific interval energies - as functions of fluid density and fluid specific internal energy. All thermodynamic information including derivatives is obtained from the fluid table by bivariate interpolation. 3 - Restrictions on the complexity of the problem: SHAFT79 has been developed only for systems of water and rock. The fluid table covers most of the equation of state of water substance in the temperature range of 5 to 400 degrees C and the pressure range of 0.5 to 220 bar, which is adequate for most geothermal applications

  1. Geothermal energy

    International Nuclear Information System (INIS)

    Kappelmeyer, O.

    1991-01-01

    Geothermal energy is the natural heat of the earth. It represents an inexhaustible source of energy. In many countries, which are mostly located within the geothermal belts of the world, geothermal energy is being used since many decades for electricity generation and direct heating applications comprising municipal, industrial and agricultural heating. Outside the geothermal anomalous volcanic regions, hot ground water from deep rock formations at temperatures above 70 o C is used for process heat and space heating. Low prices for gas and oil hinder the development of geothermal plants in areas outside positive geothermal anomalies; the cost of drilling to reach depths, where temperatures are above 50 o C to 70 o C, is high. The necessary total investment per MW th installed capacity is in the order of 5 Mio- DM/MW th (3 Mio $/MW th ). Experience shows, that an economic break even with oil is reached at an oil price of 30$ per barrel or if an adequate bonus for the clean, environmentally compatible production of geothermal heat is granted. Worldwide the installed electric capacity of geothermal power plants is approximately 6 000 MW e . About 15 000 MW th of thermal capacity is being extracted for process heat and space heat. The importance of the terrestrial heat as an energy resource would be substantially increased, if the heat, stored in the hot crystalline basement could be extracted at economical production costs. Geothermal energy is a competitive energy source in areas with high geothermal gradients (relative low cost for drilling) and would be competitive in areas with normal geothermal gradients, if a fair compensation for environmental implications from fossil and nuclear power production would be granted. (author) 2 figs., 1 tab., 6 refs

  2. Modeling the response of the geothermal system at Lihir Island, Papua New Guinea to mine dewatering

    Energy Technology Data Exchange (ETDEWEB)

    Menzies, A.J. [GeothermEx, Inc., Richmond, CA (United States); Forth, J.L. [Lihir Management Company, Brisbane (Australia)

    1995-03-01

    Lihir Gold, Ltd., with RTZ Corporation, Niugini Mining Ltd. and the Government of Papua New Guinea as major shareholders, plans to mine two contiguous gold orebodies located in the Luise Caldera, Lihir Island, Papua New Guinea. Niugini Mining Ltd. first discovered the deposit, which is believed to be the largest undeveloped gold deposit in the world, in 1982 and detailed exploration was later conducted by Kennecott Corporation (an RTZ subsidiary) who also prepared the plan for mining the deposit. The gold was deposited in the caldera breccias by rising hot fluids from a still active geothermal system to form the orebody which is to be mined in a 2 km x 1.5 km open pit that will ultimately reach a depth of about 220 m below sea level.

  3. Detectability of geothermal areas using Skylab X-5 data

    Science.gov (United States)

    Siegal, B. S.; Kahle, A. B.; Goetz, A. F. H.; Gillespie, A. R.; Abrams, M. J.

    1975-01-01

    The results are presented of a study which was undertaken to determine if data from a single near-noon pass of Skylab could be used to detect geothermal areas. The size and temperature requirements for a geothermally heated area to be seen by Skylab S-192 MSS X-5 thermal sensor were calculated. This sensor obtained thermal data with the highest spatial resolution of any nonmilitary satellite system. Only very large hot areas could be expected to be unambiguously recognized with a single data set from this instrument. The study area chosen was The Geysers geothermal field in Sonoma County, California, the only geothermal area of significant size scanned by Skylab. Unfortunately, 95% of the Skylab thermal channel data was acquired within 3 hours of local noon. For The Geysers area only daytime X-5 data were available. An analysis of the thermal channel data (10.2 to 12.5 um) revealed that ground temperatures determined by Skylab were normally distributed. No anomalous hot spots were apparent. Computer enhancement techniques were used to delineate the hottest 100 and 300 ground areas (pixel, 75 m by 75 m) within the study region. It was found that the Skylab MSS with the X-5 thermal detector does not have sufficient spatial resolution to locate unambiguously from daytime data any but the largest and hottest convectively created geothermal features, which in general are prominent enough to have been previously recognized.

  4. Submarine geothermal resources

    Science.gov (United States)

    Williams, D.L.

    1976-01-01

    Approximately 20% of the earth's heat loss (or 2 ?? 1012 cal/s) is released through 1% of the earth's surface area and takes the form of hydrothermal discharge from young (Pleistocene or younger) rocks adjacent to active seafloor-spreading centers and submarine volcanic areas. This amount is roughly equivalent to man's present gross energy consumption rate. A sub-seafloor geothermal reservoir, to be exploitable under future economic conditions, will have to be hot, porous, permeable, large, shallow, and near an energy-deficient, populated land mass. Furthermore, the energy must be recoverable using technology achievable at a competitive cost and numerous environmental, legal and institutional problems will have to be overcome. The highest-temperature reservoirs should be found adjacent to the zones of the seafloor extension or volcanism that are subject to high sedimentation rates. The relatively impermeable sediments reduce hydrothermal-discharge flow rates, forcing the heat to be either conducted away or released by high-temperature fluids, both of which lead to reservoir temperatures that can exceed 300??C. There is evidence that the oceanic crust is quite permeable and porous and that it was amenable to deep (3-5 km) penetration by seawater at least some time in the early stages of its evolution. Most of the heat escapes far from land, but there are notable exceptions. For example, in parts of the Gulf of California, thermal gradients in the bottom sediments exceed 1??C/m. In the coastal areas of the Gulf of California, where electricity and fresh water are at a premium, this potential resource lies in shallow water (characteristics of these systems before they can be considered a viable resource. Until several of the most promising areas are carefully defined and drilled, the problem will remain unresolved. ?? 1976.

  5. Hydrochemistry and geothermometrical modeling of low-temperature Panticosa geothermal system (Spain)

    Science.gov (United States)

    Asta, Maria P.; Gimeno, Maria J.; Auqué, Luis F.; Gómez, Javier; Acero, Patricia; Lapuente, Pilar

    2012-08-01

    The chemical characteristics of the low-temperature geothermal system of Panticosa (Spain) were investigated in order to determine the water temperature at the reservoir and to identify the main geochemical processes that affect the water composition during the ascent of the thermal waters. In general, the studied waters are similar to other geothermal systems in the Pyrenees, belonging to the group of granite-related alkaline thermal waters (high pH, low total dissolved solids, very low magnesium concentration, and sodium as the dominant cation). According to the alkaline pH of these waters, they have a very low CO2 partial pressure, bicarbonate is the dominant anion and silica is partially ionized as H3SiO4-. The unusually active acid-base pairs (HCO3-/CO32 - and, mainly, H4SiO4/H3SiO4-) act as homogeneous pH buffers and contribute to the total alkalinity in these alkaline waters. On the basis of the study of the conservative elements, a mixing process between a hot and a cold end-member has been identified. Additionally, in order to determinate the water temperature at the reservoir, several geothermometric techniques have been applied, including both geothermometrical modeling and classical geothermometrical calculations. The geothermometrical modeling seems to indicate that thermal waters re-equilibrate with respect to calcite and kaolinite during their ascent to the surface. Modeling results suggest that these thermal waters would be in equilibrium with respect to albite, K-feldspar, quartz, calcite, kaolinite and zoisite at a similar temperature of 90 ± 20 °C in the reservoir, which is in good agreement with the results obtained by applying the classical geothermometers.

  6. The California All-sky Meteor Surveillance (CAMS) System

    Science.gov (United States)

    Gural, P. S.

    2011-01-01

    A unique next generation multi-camera, multi-site video meteor system is being developed and deployed in California to provide high accuracy orbits of simultaneously captured meteors. Included herein is a description of the goals, concept of operations, hardware, and software development progress. An appendix contains a meteor camera performance trade study made for video systems circa 2010.

  7. Sandia National Laboratories, California Environmental Management System program manual.

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, Barbara L.

    2013-04-01

    The Sandia National Laboratories, California (SNL/CA) Environmental Management System (EMS) Program Manual documents the elements of the site EMS Program. The SNL/CA EMS Program conforms to the International Standard on Environmental Management Systems, ISO 14001:2004 and Department of Energy (DOE) Order 436.1.

  8. Sandia National Laboratories, California Environmental Management System program manual

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, Barbara L.

    2014-04-01

    The Sandia National Laboratories, California (SNL/CA) Environmental Management System (EMS) Program Manual documents the elements of the site EMS Program. The SNL/CA EMS Program conforms to the International Standard on Environmental Management Systems, ISO 14001:2004 and Department of Energy (DOE) Order 436.1.

  9. Sustaining the National Geothermal Data System: Considerations for a System Wide Approach and Node Maintenance, Geothermal Resources Council 37th Annual Meeting, Las Vegas, Nevada, September 29-October 2, 2013

    Energy Technology Data Exchange (ETDEWEB)

    Allison, Lee [Arizona Geological Survey; Chickering, Cathy [Southern Methodist University; Anderson, Arlene [U. S. Department of Energy, Geothermal Technologies Office; Richard, Stephen M. [Arizona Geological Survey

    2013-09-23

    Since the 2009 American Recovery and Reinvestment Act the U.S. Department of Energy’s Geothermal Technologies Office has funded $33.7 million for multiple data digitization and aggregation projects focused on making vast amounts of geothermal relevant data available to industry for advancing geothermal exploration. These projects are collectively part of the National Geothermal Data System (NGDS), a distributed, networked system for maintaining, sharing, and accessing data in an effort to lower the levelized cost of electricity (LCOE). Determining “who owns” and “who maintains” the NGDS and its data nodes (repositories in the distributed system) is yet to be determined. However, the invest- ment in building and populating the NGDS has been substantial, both in terms of dollars and time; it is critical that this investment be protected by ensuring sustainability of the data, the software and systems, and the accessibility of the data. Only then, will the benefits be fully realized. To keep this operational system sustainable will require four core elements: continued serving of data and applications; maintenance of system operations; a governance structure; and an effective business model. Each of these presents a number of challenges. Data being added to the NGDS are not strictly geothermal but data considered relevant to geothermal exploration and develop- ment, including vast amounts of oil and gas and groundwater wells, among other data. These are relevant to a broader base of users. By diversifying the client base to other users and other fields, the cost of maintaining core infrastructure can be spread across an array of stakeholders and clients. It is presumed that NGDS will continue to provide free and open access to its data resources. The next-phase NGDS operation should be structured to eventually pursue revenue streams to help off-set sustainability expenses as necessary and appropriate, potentially including income from: grants and contracts

  10. Sensitivity analysis of system parameters on the performance of the Organic Rankine Cycle system for binary-cycle geothermal power plants

    International Nuclear Information System (INIS)

    Liu, Xiaomin; Wang, Xing; Zhang, Chuhua

    2014-01-01

    The main purpose of this paper is to analyze the sensitivity of system parameters to the performance of the Organic Rankine Cycle (ORC) system quantitatively. A thermodynamic model of the ORC system for binary-cycle geothermal power plants has been developed and verified. The system parameters, such as working fluid, superheat temperature, pinch temperature difference in evaporator and condenser, evaporating temperature, the isentropic efficiencies of the cycle pump and radial inflow turbine are selected as six factors for orthogonal design. The order of factors sensitivity on performance indices of the net power output of the ORC system, the thermal efficiency, the size parameter of radial inflow turbine, the power decrease factor of the pump and the total heat transfer capacity are determined by the range obtained from the orthogonal design. At different geothermal temperatures, the ranges of the six factors corresponding to performance indices are analyzed respectively. The results show that the geothermal temperature influences the range of the factors to the net power output, SP factor of radial inflow turbine, and the total heat transfer capacity, but it has no effect for the range of the factors for the thermal efficiency and the power decrease factor of the pump. The evaporating temperature is always the primary or secondary factor that influence the thermodynamic and economic performance of the ORC system. This study would provide useful references for determining the proper design variables in the performance optimization of the ORC system at different geothermal temperatures. - Highlights: • Evaporating temperature has significant effect on performance of ORC system. • Order of system parameters' sensitivity to the performance of ORC is revealed. • Effect of system parameters on performance indices vary with geothermal temperature. • Geothermal temperature has no effect on range of six factors to the size of turbine

  11. Geothermal heat can cool, too

    International Nuclear Information System (INIS)

    Wellstein, J.

    2008-01-01

    This article takes a look at how geothermal energy can not only be used to supply heating energy, but also be used to provide cooling too. The article reports on a conference on heating and cooling with geothermal energy that was held in Duebendorf, Switzerland, in March 2008. The influence of climate change on needs for heating and cooling and the need for additional knowledge and data on deeper rock layers is noted. The seasonal use of geothermal systems to provide heating in winter and cooling in summer is discussed. The planning of geothermal probe fields and their simulation is addressed. As an example, the geothermal installations under the recently renewed and extended 'Dolder Grand' luxury hotel in Zurich are quoted. The new SIA 384/6 norm on geothermal probes issued by the Swiss Association of Architects SIA is briefly reviewed.

  12. Direct Use Applications of Geothermal Resources at Desert Hot Springs, California. Final Report, May 23, 1977--July 31, 1978. Volume I. Summary of Findings

    Energy Technology Data Exchange (ETDEWEB)

    None

    1978-07-01

    The geothermal resources underlying the City of Desert Hot Springs were described in terms of anticipated geophysical, geochemical, and hydrological characteristics, based upon existing well log data, geologic surveys, and limited wellflow tests. The needs of the City were determined on the basis of its general plan, the City's 1976 census, load survey and a public acceptance survey. Then a broad range of potential nonelectric applications was surveyed in individual as well as energy cascading systems to identify the matchup of the resource and needs of the city. Applications investigated included space conditioning, space/water heating, car wash, agriculture/horticulture, and aquaculture operations. The list of applications so derived was assessed in light of technological, socio-economic, environmental, institutional, and market considerations to determine target opportunities for DHS as well as on a broad regional basis. Those systems which survived the initial screening were subjected to detailed parametric studies focused on determining tradeoffs among performance, cost, size, compatibility with off-the-shelf hardware, etc. A detailed analysis of the engineering and economic aspects of the most promising systems was then performed. Factors considered included technological problems and risks, status of supporting technologies, net energy ratios, costs, market, displacement of fossil fuels, and economic benefit to the community.

  13. Broadband Magnetotelluric Investigations of Crustal Resistivity Structure in North-Eastern Alberta: Implications for Engineered Geothermal Systems

    Science.gov (United States)

    Liddell, M. V.; Unsworth, M. J.; Nieuwenhuis, G.

    2013-12-01

    Greenhouse gas emissions from hydrocarbon consumption produce profound changes in the global climate, and the implementation of alternative energy sources is needed. The oilsands industry in Alberta (Canada) is a major producer of greenhouse gases as natural gas is burnt to produce the heat required to extract and process bitumen. Geothermal energy could be utilized to provide this necessary heat and has the potential to reduce both financial costs and environmental impacts of the oilsands industry. In order to determine the geothermal potential the details of the reservoir must be understood. Conventional hydrothermal reservoirs have been detected using geophysical techniques such as magnetotellurics (MT) which measures the electrical conductivity of the Earth. However, in Northern Alberta the geothermal gradient is relatively low, and heat must be extracted from deep inside the basement rocks using Engineered Geothermal Systems (EGS) and therefore an alternative exploration technique is required. MT can be useful in this context as it can detect fracture zones and regions of elevated porosity. MT data were recorded near Fort McMurray with the goal of determining the geothermal potential by understanding the crustal resistivity structure beneath the Athabasca Oilsands. The MT data are being used to locate targets of significance for geothermal exploration such as regions of low resistivity in the basement rocks which can relate to in situ fluids or fracture zones which can facilitate efficient heat extraction or het transport. A total of 93 stations were collected ~500m apart on two profiles stretching 30 and 20km respectively. Signals were recorded using Phoenix Geophysics V5-2000 systems over frequency bands from 1000 to 0.001 Hz, corresponding to depths of penetration approximately 50m to 50km. Groom-Bailey tensor decomposition and phase tensor analysis shows a well defined geoelectric strike direction that varied along the profile from N60°E to N45

  14. Probabilistic 3-D time-lapse inversion of magnetotelluric data: Application to an enhanced geothermal system

    Science.gov (United States)

    Rosas-Carbajal, Marina; Linde, Nicolas; Peacock, Jared R.; Zyserman, F. I.; Kalscheuer, Thomas; Thiel, Stephan

    2015-01-01

    Surface-based monitoring of mass transfer caused by injections and extractions in deep boreholes is crucial to maximize oil, gas and geothermal production. Inductive electromagnetic methods, such as magnetotellurics, are appealing for these applications due to their large penetration depths and sensitivity to changes in fluid conductivity and fracture connectivity. In this work, we propose a 3-D Markov chain Monte Carlo inversion of time-lapse magnetotelluric data to image mass transfer following a saline fluid injection. The inversion estimates the posterior probability density function of the resulting plume, and thereby quantifies model uncertainty. To decrease computation times, we base the parametrization on a reduced Legendre moment decomposition of the plume. A synthetic test shows that our methodology is effective when the electrical resistivity structure prior to the injection is well known. The centre of mass and spread of the plume are well retrieved.We then apply our inversion strategy to an injection experiment in an enhanced geothermal system at Paralana, South Australia, and compare it to a 3-D deterministic time-lapse inversion. The latter retrieves resistivity changes that are more shallow than the actual injection interval, whereas the probabilistic inversion retrieves plumes that are located at the correct depths and oriented in a preferential north-south direction. To explain the time-lapse data, the inversion requires unrealistically large resistivity changes with respect to the base model. We suggest that this is partly explained by unaccounted subsurface heterogeneities in the base model from which time-lapse changes are inferred.

  15. Energy Efficiency Evaluation and Economic Feasibility Analysis of a Geothermal Heating and Cooling System with a Vapor-Compression Chiller System

    Directory of Open Access Journals (Sweden)

    Muharrem Imal

    2015-09-01

    Full Text Available Increasing attention has been given to energy utilization in Turkey. In this report, we present an energy efficiency evaluation and economic feasibility analysis of a geothermal heating and cooling system (GSHP and a mechanical compression water chiller system (ACHP to improve the energy utilization efficiency and reduce the primary energy demand for industrial use. Analyses of a mechanical water chiller unit, GSW 180, and geothermal heating and cooling system, EAR 431 SK, were conducted in experimental working areas of the office buildings in a cigarette factory in Mersin, Turkey. The heating and cooling loads of the cigarette factory building were calculated, and actual thermal data were collected and analyzed. To calculate these loads, the cooling load temperature difference method was used. It was concluded that the geothermal heating and cooling system was more useful and productive and provides substantial economic benefits.

  16. Economic viability of geothermal energy usage in comparison to renewable and conventional energy systems

    International Nuclear Information System (INIS)

    Schaumann, G.

    2002-01-01

    This comprehensive lecture given by Prof. Dr. Gunter Schaumann in Bad Duerkheim, Germany, discusses the use of geothermal energy in relationship to other forms of renewable energy sources and conventional energy technologies used to provide heat, power and motive force. The characteristics of geothermal energy from various sources and examples of its possible use are discussed. In particular, the paper deals with deep geothermal energy, which can provide heating energy for district heating schemes, if necessary with the help of heat pumps. The prospects of such a use of geothermal energy in the next 50 years in various suitable regions in Germany is discussed and the associated prerequisites are listed. The present situation concerning the use of geothermal energy in Germany is examined. An example of a geothermal heating power station that also features a gas-fired combined heat and power installation, a heat pump and a peak-load boiler is given. Also, the generation of electrical power using the Organic Rankine Cycle is discussed. The factors influencing the economic viability of geothermal power stations are discussed in detail and the resulting energy prices are compared with conventional plants. The paper gives details of the calculation of investment and energy costs for heat and power generation and presents figures based on exemplary installations

  17. Geochemical study of water-rock interaction processes on geothermal systems of alkaline water in granitic massif

    International Nuclear Information System (INIS)

    Buil gutierrez, B.; Garcia Sanz, S.; Lago San Jose, M.; Arranz Yague, E.; Auque Sanz, L.

    2002-01-01

    The study of geothermal systems developed within granitic massifs (with alkaline waters and reducing ORP values) is a topic of increasing scientific interest. These systems are a perfect natural laboratory for studying the water-rock interaction processes as they are defined by three main features: 1) long residence time of water within the system, 2) temperature in the reservoir high enough to favour reaction kinetics and finally, 3) the comparison of the chemistry of the incoming and outgoing waters of the system allows for the evaluation of the processes that have modified the water chemistry and its signature, The four geothermal systems considered in this paper are developed within granitic massifs of the Spanish Central Pyrenes; these systems were studied from a geochemical point of view, defining the major, trace and REE chemistry of both waters and host rocks and then characterizing the composition and geochemical evolution of the different waters. Bicarbonate-chloride-sodic and bicarbonate-sodic compositions are the most representative of the water chemistry in the deep geothermal system, as they are not affected by secondary processes (mixing, conductive cooling, etc). (Author)

  18. Detection and Characterization of Natural and Induced Fractures for the Development of Enhanced Geothermal Systems

    Energy Technology Data Exchange (ETDEWEB)

    Toksoz, M. Nafi [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Dept. of Earth, Atmospheric and Planetary Sciences

    2013-04-06

    The objective of this 3-year project is to use various geophysical methods for reservoir and fracture characterization. The targeted field is the Cove Fort-Sulphurdale Geothermal Field in Utah operated by ENEL North America (ENA). Our effort has been focused on 1) understanding the regional and local geological settings around the geothermal field; 2) collecting and assembling various geophysical data sets including heat flow, gravity, magnetotelluric (MT) and seismic surface and body wave data; 3) installing the local temporary seismic network around the geothermal site; 4) imaging the regional and local seismic velocity structure around the geothermal field using seismic travel time tomography; and (5) determining the fracture direction using the shear-wave splitting analysis and focal mechanism analysis. Various geophysical data sets indicate that beneath the Cove Fort-Sulphurdale Geothermal Field, there is a strong anomaly of low seismic velocity, low gravity, high heat flow and high electrical conductivity. These suggest that there is a heat source in the crust beneath the geothermal field. The high-temperature body is on average 150 °C – 200 °C hotter than the surrounding rock. The local seismic velocity and attenuation tomography gives a detailed velocity and attenuation model around the geothermal site, which shows that the major geothermal development target is a high velocity body near surface, composed mainly of monzonite. The major fracture direction points to NNE. The detailed velocity model along with the fracture direction will be helpful for guiding the geothermal development in the Cove Fort area.

  19. National Geothermal Data System: Open Access to Geoscience Data, Maps, and Documents

    Science.gov (United States)

    Caudill, C. M.; Richard, S. M.; Musil, L.; Sonnenschein, A.; Good, J.

    2014-12-01

    The U.S. National Geothermal Data System (NGDS) provides free open access to millions of geoscience data records, publications, maps, and reports via distributed web services to propel geothermal research, development, and production. NGDS is built on the US Geoscience Information Network (USGIN) data integration framework, which is a joint undertaking of the USGS and the Association of American State Geologists (AASG), and is compliant with international standards and protocols. NGDS currently serves geoscience information from 60+ data providers in all 50 states. Free and open source software is used in this federated system where data owners maintain control of their data. This interactive online system makes geoscience data easily discoverable, accessible, and interoperable at no cost to users. The dynamic project site http://geothermaldata.org serves as the information source and gateway to the system, allowing data and applications discovery and availability of the system's data feed. It also provides access to NGDS specifications and the free and open source code base (on GitHub), a map-centric and library style search interface, other software applications utilizing NGDS services, NGDS tutorials (via YouTube and USGIN site), and user-created tools and scripts. The user-friendly map-centric web-based application has been created to support finding, visualizing, mapping, and acquisition of data based on topic, location, time, provider, or key words. Geographic datasets visualized through the map interface also allow users to inspect the details of individual GIS data points (e.g. wells, geologic units, etc.). In addition, the interface provides the information necessary for users to access the GIS data from third party software applications such as GoogleEarth, UDig, and ArcGIS. A redistributable, free and open source software package called GINstack (USGIN software stack) was also created to give data providers a simple way to release data using

  20. Quantification of exploitable shallow geothermal energy by using Borehole Heat Exchanger coupled Ground Source Heat Pump systems

    International Nuclear Information System (INIS)

    Hein, Philipp; Zhu, Ke; Bucher, Anke; Kolditz, Olaf; Pang, Zhonghe; Shao, Haibing

    2016-01-01

    Highlights: • The amount of technically exploitable shallow geothermal energy was quantified. • Therefore, a comprehensive numerical borehole heat exchanger model was employed. • The concept of equivalent temperature drop is introduced. • For one BHE, an equivalent temperature drop of 1.8–2.8 °C over 30 years is realistic • The average extractable energy amount evaluates to be 3.5–5.4 kW h m"−"2 a"−"1. - Abstract: In previous studies, the amount of exploitable shallow geothermal energy was estimated by assuming a uniform temperature drop of 2–6 °C in the aquifer. In this work, a more comprehensive numerical model has been employed to evaluate the available amount of shallow geothermal energy by using Borehole Heat Exchanger coupled Ground Source Heat Pump systems. Numerical experiments have been performed by simulating the long-term evolution of the subsurface temperature field, which is subject to the operation of borehole heat exchangers and varying parameters like subsurface thermal conductivity and groundwater flow velocity. The concept of equivalent temperature drop is proposed as an auxiliary quantity for the subsurface. With the help of this parameter, a procedure has been established to quantify the amount of shallow geothermal potential. Following this approach, a realistic equivalent temperature reduction is found to be from −1.8 to −4.4 °C in the subsurface over a period of 30 years. This can be translated to an annual extractable geothermal energy value in a unit surface area, and it ranges from 3.5 to 8.6 kW h m"−"2 a"−"1. The exact value is site specific and heavily depends on the soil thermal conductivity, groundwater velocity, and borehole arrangement.

  1. Numerical simulations of heat transfer considering hydraulic discontinuity for an enhanced geothermal system development in Seokmo Island, Korea

    Science.gov (United States)

    Shin, J.; Kim, K.; Hyun, Y.; Lee, K.; Lee, T.

    2011-12-01

    The construction of the first geothermal plant in Korea is under planning in Seokmo Island, where a few artesian wells showing relatively high water temperature of around 70 degrees were discovered lately. Geologic structure in this region is characterized by the fractured granite. Numerical simulations for the temperature evolution in a fractured geothermal reservoir in Seokmo Island under the supposed injection-extraction operating conditions were carried out using TOUGH2. A MINC model including a hydraulic discontinuity in Seokmo Island region, which reflected the analysis from several geophysical explorations and drilled rock core, was generated. Supposing the N05°E, NW83° fracture zone containing the pumping range, the numerical simulation results show that temperature of the extracted geothermal water decreases after 15 years of operation, which decreases the overall efficiency of the expected geothermal plant. This is because the colder water from the injection well, which is 400 m apart, begins to flow into the more permeable fracture zone from the 15th year, resulting in a decrease in temperature near the pumping well. Temperature distribution calculated from the simulation also shows a rise of relatively hot geothermal water along the fracture plane. All of the results are different from the non-fracture MINC model, which shows a low temperature contour in concentric circle shape around the injection well and relatively consistent extracting temperature. This demonstrates that the distribution and the structure of fracture system influence the major mass and heat flow mechanisms in geologic medium. Therefore, an intensive geologic investigation for the fractures including their structure, permeability and connecting relation is important. Acknowledgement This study was financially supported by KIGAM, KETEP and BK21.

  2. Capital cost models for geothermal power plants and fluid transmission systems. [GEOCOST

    Energy Technology Data Exchange (ETDEWEB)

    Schulte, S.C.

    1977-09-01

    The GEOCOST computer program is a simulation model for evaluating the economics of developing geothermal resources. The model was found to be both an accurate predictor of geothermal power production facility costs and a valid designer of such facilities. GEOCOST first designs a facility using thermodynamic optimization routines and then estimates costs for the selected design using cost models. Costs generated in this manner appear to correspond closely with detailed cost estimates made by industry planning groups. Through the use of this model, geothermal power production costs can be rapidly and accurately estimated for many alternative sites making the evaluation process much simpler yet more meaningful.

  3. Geothermal Field Investigations of Turkey

    Science.gov (United States)

    Sayın, N.; Özer, N.

    2017-12-01

    Geothermal energy is a type of energy that are found in the accessible depth of the crust, in the reservoirs by way of the permeable rocks, specially in heated fluid. Geothermal system is made of 3 main components; heat source, reservoir, and fluid bearing heat. Geothermal system mechanism is comprise of fluid transmission. Convection current (heat transmission) is caused by heating and causes the fluid in the system to expand. Heated fluid with low density show tendency to rise in system. Geothermal system occurs with variable geophysics and geochemical properties. Geophysical methods can determine structural properties of shallow and deep reservoirs with temperature, mineralization, gas amount, fluid movement, faulting, and sudden change in lithostratigraphic strata. This study revealed possible reservoir structures and showed examples of geophysics and gas measuring results in Turkey which is wealthy in regard to Geothermal sources.

  4. Recovery act. Development of design and simulation tool for hybrid geothermal heat pump system

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Shaojie [ClimateMaster, Inc., Oklahoma City, OK (United States); Ellis, Dan [ClimateMaster, Inc., Oklahoma City, OK (United States)

    2014-05-29

    The ground source heat pump (GSHP) system is one of the most energy efficient HVAC technologies in the current market. However, the heat imbalance may degrade the ability of the ground loop heat exchanger (GLHX) to absorb or reject heat. The hybrid GSHP system, which combines a geothermal well field with a supplemental boiler or cooling tower, can balance the loads imposed on the ground loop heat exchangers to minimize its size while retaining superior energy efficiency. This paper presents a recent simulation-based study with an intention to compare multiple common control strategies used in hybrid GSHP systems, including fixed setpoint, outside air reset, load reset, and wetbulb reset. A small office in Oklahoma City conditioned by a hybrid GSHP system was simulated with the latest version of eQUEST 3.7[1]. The simulation results reveal that the hybrid GSHP system has the excellent capability to meet the cooling and heating setpoints during the occupied hours, balance thermal loads on the ground loop, as well as improve the thermal comfort of the occupants with the undersized well field.

  5. Cost modelling of electricity producing hot dry rock (HDR) geothermal systems in the UK

    International Nuclear Information System (INIS)

    Doherty, P.S.

    1992-03-01

    A detailed and comprehensive cost model for Hot Dry Rock (HDR) electricity producing systems has been developed in this study. The model takes account of the major aspects of the HDR system, parameterized in terms of the main physical and cost parameters of the resource and the utilization system. A doublet configuration is assumed, and the conceptual HDR system which is defined in the study is based upon the UK Department of Energy (DEn) HDR geothermal R and D programme. The model has been used to calculate the costs of HDR electricity for a UK defined base case which represents a consensus view of what might be achieved in Cornwall in the long term. At 14.2 p/kWh (1988 costs) this cost appears to be unacceptably high. A wide-ranging sensitivity study has also been carried out on the main resource, geometrical, and operational parameters of the HDR system centred around the UK base case. The sensitivity study shows the most important parameters to be thermal gradient and depth. (Author)

  6. Geothermal energy

    International Nuclear Information System (INIS)

    Vuataz, F.-D.

    2005-01-01

    This article gives a general overview of the past and present development of geothermal energy worldwide and a more detailed one in Switzerland. Worldwide installed electrical power using geothermal energy sources amounts to 8900 MW el . Worldwide utilization of geothermal energy for thermal applications amounts to 28,000 MW th . The main application (56.5%) is ground-coupled heat pumps, others are thermal spas and swimming pools (17.7%), space heating (14.9%), heating of greenhouses (4.8%), fish farming (2.2%), industrial uses (1,8%), cooling and melting of snow (1.2%), drying of agricultural products (0.6 %). Switzerland has become an important user of geothermal energy only in the past 25 years. Earlier, only the exploitation of geothermal springs (deep aquifers) in Swiss thermal baths had a long tradition, since the time of the Romans. Today, the main use of geothermal energy is as a heat source for heat pumps utilizing vertical borehole heat exchangers of 50 to 350 meters length. 35,000 installations of this type with heating powers ranging from a few kW to 1000 kW already exist, representing the highest density of such installations worldwide. Other developments are geostructures and energy piles, the use of groundwater for heating and cooling, geothermal district heating, the utilization of draining water from tunnels and the project 'Deep Heat Mining' allowing the combined production of heat and electric power

  7. Evaluation of Oil-Industry Stimulation Practices for Engineered Geothermal Systems

    Energy Technology Data Exchange (ETDEWEB)

    Peter Van Dyke; Leen Weijers; Ann Robertson-Tait; Norm Warpinski; Mike Mayerhofer; Bill Minner; Craig Cipolla

    2007-10-17

    Geothermal energy extraction is typically achieved by use of long open-hole intervals in an attempt to connect the well with the greatest possible rock mass. This presents a problem for the development of Enhanced (Engineered) Geothermal Systems (EGS), owing to the challenge of obtaining uniform stimulation throughout the open-hole interval. Fluids are often injected in only a fraction of that interval, reducing heat transfer efficiency and increasing energy cost. Pinnacle Technologies, Inc. and GeothermEx, Inc. evaluated a variety of techniques and methods that are commonly used for hydraulic fracturing of oil and gas wells to increase and evaluate stimulation effectiveness in EGS wells. Headed by Leen Weijers, formerly Manager of Technical Development at Pinnacle Technologies, Inc., the project ran from August 1, 2004 to July 31, 2006 in two one-year periods to address the following tasks and milestones: 1) Analyze stimulation results from the closest oil-field equivalents for EGS applications in the United States (e.g., the Barnett Shale in North Texas) (section 3 on page 8). Pinnacle Technologies, Inc. has collected fracture growth data from thousands of stimulations (section 3.1 on page 12). This data was further evaluated in the context of: a) Identifying techniques best suited to developing a stimulated EGS fracture network (section 3.2 on page 29), and b) quantifying the growth of the network under various conditions to develop a calibrated model for fracture network growth (section 3.3 on page 30). The developed model can be used to design optimized EGS fracture networks that maximize contact with the heat source and minimize short-circuiting (section 3.4 on page 38). 2) Evaluate methods used in oil field applications to improve fluid diversion and penetration and determine their applicability to EGS (section 4 on page 50). These methods include, but are not limited to: a) Stimulation strategies (propped fracturing versus water fracturing versus injecting

  8. Funding California Schools: The Revenue Limit System. Technical Appendices

    Science.gov (United States)

    Weston, Margaret

    2010-01-01

    This document presents the technical appendices accompanying the report, "Funding California Schools: The Revenue Limit System." Included are: (1) Revenue Limit Calculation and Decomposition; (2) Data and Methods; and (3) Base Funding Alternative Simulation Results. (Contains 5 tables and 26 footnotes.) [For the main report,…

  9. Geothermal prospection in the Greater Geneva Basin (Switzerland and France): Architecture of the new Information System

    Science.gov (United States)

    Favre, Stéphanie; Brentini, Maud; Giuliani, Gregory; Lehmann, Anthony

    2017-04-01

    Growing interests on the subsurface resources can be noted while issues concerning sustainable territorial development are rising too (Blunier et al. 2007). Among these resources, geothermal energy is developing in Geneva and regions and asks questions on subsurface resources management especially in terms of data. The GEothermie 2020 program offers the possibility to reprocess old data (Rusillon et al., 2017; Clerc et al., 2016) and collect new ones in order to increase geological knowledge on the Greater Geneva Basin. To better valorize these data, an Information System (IS) is required for the geological survey of Geneva (GESDEC). However, existing IT infrastructures are not able to meet all their needs. This research aims to develop a geological IS for 2D and 3D data. To fit to the needs of the GESDEC, three aspects will be studied: 1) architecture, 2) tools and 3) data workflow. A case study will validate the Information System designed. The first step of this study was to establish the state of the art on the current geological data management practices in Europe, Switzerland and in Geneva. To evaluate IS, short structured questions have been sent to all European geological surveys as well as an adapted version for the cantonal and federal Swiss institutes. Concerning the database and GIS development aspects, an analysis of the GESDEC's needs and constraints allowed expanding the existing data model (Brentini and Favre 2014). Different database and GIS tools were compared and tested. Possibilities for these tools to communicate with GST, a 3D data viewer and manager (Gabriel et al. 2015), were also taken in account. These developments took place in parallel with discussions with stakeholders involved and various experts in the field of information management, geology and geothermal energy to support reflexions on the data workflows. Questionnaire results showed that the development of a geological IS differs largely from a country to another although their

  10. Baseline System Costs for 50.0 MW Enhanced Geothermal System -- A Function of: Working Fluid, Technology, and Location, Location, Location

    Energy Technology Data Exchange (ETDEWEB)

    Dunn, Paul [Gas Equipment Engineering Corp., Milford, CT (United States); Selman, Nancy [Gas Equipment Engineering Corp., Milford, CT (United States); Volpe, Anthony Della [Gas Equipment Engineering Corp., Milford, CT (United States); Moss, Deborah [Gas Equipment Engineering Corp., Milford, CT (United States); Mobley, Rick [Plasma Energy Services, LLC, Putnam, CT (United States); Dickey, Halley [Turbine Air Systems, Houston, TX (United States); Unruh, Jeffery [Fugro NV/Wm. Lettis & Associates, Houston, TX (United States); Hitchcock, Chris [Fugro NV/Wm. Lettis & Associates, Houston, TX (United States); Tanguay, Jasmine [Conservation Law Foundation/CLF Ventures, Boston, MA (United States); Larsen, Walker [Conservation Law Foundation/CLF Ventures, Boston, MA (United States); Sanyal, Sabir [GeothermEx, Inc., San Pablo, CA (United States); Butler, Steven [GeothermEx, Inc., San Pablo, CA (United States); Stacey, Robert [GeothermEx, Inc., San Pablo, CA (United States); Robertson-Tait, Ann [GeothermEx, Inc., San Pablo, CA (United States); Pruess, Karsten [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Gutoski, Greg [Fairbanks Morse Engines (FME), Beloit, WI (United States); Fay, Jamie M. [Fort Point Associates, Boston, MA (United States); Stitzer, John T. [Fort Point Associates, Boston, MA (United States); Oglesby, Ken [Impact Technologies LLC, Tulsa, OK (United States)

    2012-04-30

    Substantial unexploited opportunity exists for the US, and the world, in Enhanced Geothermal Systems (EGS). As a result of US DOE investment, new drilling technology, new power generation equipment and cycles enable meaningful power production, in a compact and modular fashion; at lower and lower top side EGS working fluid temperatures and in a broader range of geologies and geographies. This cost analysis effort supports the expansion of Enhanced Geothermal Systems (EGS), furthering DOE strategic themes of energy security and sub goal of energy diversity; reducing the Nation's dependence on foreign oil while improving the environment.

  11. Incentive Pass-through for Residential Solar Systems in California

    Energy Technology Data Exchange (ETDEWEB)

    Dong, C. G. [Univ. of Texas, Austin, TX (United States); Wiser, Ryan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Rai, Varun [Univ. of Texas, Austin, TX (United States)

    2014-10-01

    The deployment of solar photovoltaic (PV) systems has grown rapidly over the last decade, partly because of various government incentives. In the United States, among the largest and longest-running incentives have been those established in California. Building on past research, this report addresses the still-unanswered question: to what degree have the direct PV incentives in California been passed through from installers to consumers? This report helps address this question by carefully examining the residential PV market in California (excluding a certain class of third-party-owned PV systems) and applying both a structural-modeling approach and a reduced-form regression analysis to estimate the incentive pass-through rate. The results suggest an average pass-through rate of direct incentives of nearly 100%, though with regional differences among California counties. While these results could have multiple explanations, they suggest a relatively competitive market and well-functioning subsidy program. Further analysis is required to determine whether similar results broadly apply to other states, to other customer segments, to all third-party-owned PV systems, or to all forms of financial incentives for solar (considering not only direct state subsidies, but also utility electric bill savings and federal tax incentives).

  12. The chemistry and isotopic composition of waters in the low-enthalpy geothermal system of Cimino-Vico Volcanic District, Italy

    DEFF Research Database (Denmark)

    Battistel, Maria; Hurwitz, Shaul; Evans, William C.

    2016-01-01

    Geothermal energy exploration is based in part on interpretation of the chemistry, temperature, and discharge rate of thermal springs. Here we present the major element chemistry and the δD, δ18O, 87Sr/86Sr and δ11B isotopic ratio of groundwater from the low-enthalpy geothermal system near the city...... and tortuous ascent enhances extraction of boron but also promotes conductive cooling, partially masking the heat present in the reservoir. Overall data from this study is consistent with previous studies that concluded that the geothermal system has a large energy potential....... of Viterbo in the Cimino-Vico volcanic district of west-Central Italy. The geothermal system hosts many thermal springs and gas vents, but the resource is still unexploited. Water chemistry is controlled by mixing between low salinity,HCO3-rich fresh waters (

  13. Performance of desiccant air conditioning system with geothermal energy under different climatic conditions

    International Nuclear Information System (INIS)

    El-Agouz, S.A.; Kabeel, A.E.

    2014-01-01

    Highlights: • The performance of the hybrid air conditioning system is studied. • The influence of important operating parameters are estimated. • The ventilation, makeup and mix cycles are investigated at different climate. • The highest COP of the hybrid air conditioning system is 1.03. • The hybrid system provides a human thermal comfort at different climates. - Abstract: Energy saving still and continue a major seek in our life, due to the continuous increase in energy consumptions. So, a desiccant air conditioning system with geothermal energy is conducted in the current study. The thermal analysis of air conditioning system with its different components desiccant wheel, solar collector, heat exchanger, ground heat exchanger and water spray evaporative cooler is presented. Three different air conditioning cycles are simulated in the current study for different zones like: hot-dry zone, warm-dry zone, hot-humid zone and the warm-humid zone. The results show that the desiccant air conditioning system successfully provides a better thermal comfort condition in different climates. This hybrid system significantly decreases the supplied air temperature from 12.7 to 21.7 °C at different climate zones. When ω in , air and T Reg increasing, COP decreases and the ventilation cycle provides the better COP. The highest COP value of the desiccant air conditioning system is about 1.03 while the lowest value is about 0.15. The SHR of makeup cycle is higher than that ventilation cycle at warm and hot-humid zone and vice versa at warm and hot-dry zone. The highest SHR value of the desiccant air conditioning system is about 0.99 while the lowest value is about 0.2. The T sup,air , ω sup,air , COP and SHR isolines may easily be used for pre-evaluating of various cooling cycles in different climates. The hybrid system provides a human thermal comfort at different climates

  14. IMPACT OF GEOTHERMAL GRADIENT ON GROUND SOURCE HEAT PUMP SYSTEM MODELING

    OpenAIRE

    Tomislav Kurevija; Domagoj Vulin; Marija Macenić

    2014-01-01

    ndisturbed ground temperature is one of the most crucial thermogeological parameters needed for shallow geothermal resources assessment. Energy considered to be geothermal is energy stored in the ground at depths where solar radiation has no effect. At depth where undisturbed ground temperature occurs there is no influence of seasonal variations in air temperature from surface. Exact temperature value, and depth where it occurs, is functionally dependent on surface climate parameters and ther...

  15. Feasibility study of a hybrid renewable energy system with geothermal and solar heat sources for residential buildings in South Korea

    International Nuclear Information System (INIS)

    Kim, Young Ju; Woo, Nam Sub; Jang, Sung Cheol; Choi, Jeong Ju

    2013-01-01

    This study investigates the economic feasibility of a hybrid renewable energy system (HRES) that uses geothermal and solar heat sources for water heating, space heating, and space cooling in a residential building in Korea. A small-scale HRES consists of a geothermal heat pump for heating and cooling, solar collectors for hot water, a gas-fired backup boiler, and incidental facilities. To determine whether the Hares will produce any economic benefits for homeowners, an economic analysis is conducted to compare the Hares with conventional methods of space heating and cooling in Korea. The payback period of a small-scale Hares is predicted as a maximum of 9 yrs by life cycle costing based on a performance index compared with conventional systems. However, the payback period of large-scale HRES above 400 RT is 6 yrs to 7 yrs.

  16. Feasibility study of a hybrid renewable energy system with geothermal and solar heat sources for residential buildings in South Korea

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Ju; Woo, Nam Sub [Korea Institute of Geoscience and Mineral Resources, Daejeon (Korea, Republic of); Jang, Sung Cheol [Mechatronics Department of the Korea Aviation Polytechnic College, Sacheon (Korea, Republic of); Choi, Jeong Ju [Dong-A University, Busan (Korea, Republic of)

    2013-08-15

    This study investigates the economic feasibility of a hybrid renewable energy system (HRES) that uses geothermal and solar heat sources for water heating, space heating, and space cooling in a residential building in Korea. A small-scale HRES consists of a geothermal heat pump for heating and cooling, solar collectors for hot water, a gas-fired backup boiler, and incidental facilities. To determine whether the Hares will produce any economic benefits for homeowners, an economic analysis is conducted to compare the Hares with conventional methods of space heating and cooling in Korea. The payback period of a small-scale Hares is predicted as a maximum of 9 yrs by life cycle costing based on a performance index compared with conventional systems. However, the payback period of large-scale HRES above 400 RT is 6 yrs to 7 yrs.

  17. The Acoculco caldera magmas: genesis, evolution and relation with the Acoculco geothermal system

    Science.gov (United States)

    Sosa-Ceballos, G.; Macías, J. L.; Avellán, D.

    2017-12-01

    The Acoculco Caldera Complex (ACC) is located at the eastern part of the Trans Mexican Volcanic Belt; México. This caldera complex have been active since 2.7 Ma through reactivations of the system or associated magmatism. Therefore the ACC is an excellent case scenario to investigate the relation between the magmatic heat supply and the evolution processes that modified magmatic reservoirs in a potential geothermal field. We investigated the origin and the magmatic processes (magma mixing, assimilation and crystallization) that modified the ACC rocks by petrography, major oxides-trace element geochemistry, and isotopic analysis. Magma mixing is considered as the heat supply that maintain active the magmatic system, whereas assimilation yielded insights about the depth at which processes occurred. In addition, we performed a series of hydrothermal experiments in order to constrain the storage depth for the magma tapped during the caldera collapse. Rocks from the ACC were catalogued as pre, syn and post caldera. The post caldera rocks are peralkaline rhyolites, in contrast to all other rocks that are subalkaline. Our investigation is focus to investigate if the collapse modified the plumbing system and the depth at which magmas stagnate and recorded the magmatic processes.

  18. The Future of Geothermal Energy

    Energy Technology Data Exchange (ETDEWEB)

    Kubik, Michelle [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

    2006-01-01

    A comprehensive assessment of enhanced, or engineered, geothermal systems was carried out by an 18-member panel assembled by the Massachusetts Institute of Technology (MIT) to evaluate the potential of geothermal energy becoming a major energy source for the United States.

  19. Investigations on installation of the heat exchange system in geothermal wells; Chinetsu koseinai netsukokan system donyu ni kansuru chosa

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    The heat exchange system in geothermal wells is a system that replaces the air source heat pump and uses underground beds or groundwater as a heat source to heat rooms by collecting underground heat in winter, and cool rooms in summer by operating a heat media circuit in reverse direction through the action of a reverse flow valve to discharge heat underground. This paper describes feasibility investigations on the system including its technical trend for introducing the system technology. Technological and economic discussions were given by classifying the intra-well heat exchange device in its installation direction (horizontal loop type and vertical installation type), underground heat exchange media (antifreeze solution/water cyclic system and direct expansion system), and underground heat transfer (heat conduction system and heat convection system). As a result of discussing each system, it was concluded that the following two systems are promising: A = vertical installation, antifreeze solution/water cyclic and heat conduction system, and B = vertical installation, antifreeze solution/water cyclic and heat convection system. Since the system B was found to have better efficiency and economy among both systems, it is necessary to verify an intra-well heat exchange system and operation methods that suit the system B effectively. 21 refs., 8 tabs.

  20. California air transportation study: A transportation system for the California Corridor of the year 2010

    Science.gov (United States)

    1989-01-01

    To define and solve the problems of transportation in the California Corrider in the year 2010, the 1989 California Polytechnic State University Aeronautical Engineering Senior Design class determined future corridor transportation needs and developed a system to meet the requirements. A market study, which included interpreting travel demand and gauging the future of regional and national air travel in and out of the corridor, allowed the goals of the project to be accurately refined. Comprehensive trade-off studies of several proposed transporation systems were conducted to determine which components would form the final proposed system. Preliminary design and further analysis were performed for each resulting component. The proposed system consists of three vehicles and a special hub or mode mixer, the Corridor Access Port (CAP). The vehicles are: (1) an electric powered aircraft to serve secondary airports and the CAP; (2) a high speed magnetic levitation train running through the CAP and the high population density areas of the corridor; and (3) a vertical takeoff and landing tilt rotor aircraft to serve both intercity and intrametropolitan travelers from the CAP and city vertiports. The CAP is a combination and an extension of the hub, mode mixer, and Wayport concepts. The CAP is an integrated part of the system which meets the travel demands in the corridor, and interfaces with interstate and international travel.

  1. Play-fairway analysis for geothermal resources and exploration risk in the Modoc Plateau region

    Science.gov (United States)

    Siler, Drew; Zhang, Yingqi; Spycher, Nicolas F.; Dobson, Patrick; McClain, James S.; Gasperikova, Erika; Zierenberg, Robert A.; Schiffman, Peter; Ferguson, Colin; Fowler, Andrew; Cantwell, Carolyn

    2017-01-01

    The region surrounding the Modoc Plateau, encompassing parts of northeastern California, southern Oregon, and northwestern Nevada, lies at an intersection between two tectonic provinces; the Basin and Range province and the Cascade volcanic arc. Both of these provinces have substantial geothermal resource base and resource potential. Geothermal systems with evidence of magmatic heat, associated with Cascade arc magmatism, typify the western side of the region. Systems on the eastern side of the region appear to be fault controlled with heat derived from high crustal heat flow, both of which are typical of the Basin and Range. As it has the potential to host Cascade arc-type geothermal resources, Basin and Range-type geothermal resources, and/or resources with characteristics of both provinces, and because there is relatively little current development, the Modoc Plateau region represents an intriguing potential for undiscovered geothermal resources. It remains unclear however, what specific set(s) of characteristics are diagnostic of Modoc-type geothermal systems and how or if those characteristics are distinct from Basin and Range-type or Cascade arc-type geothermal systems. In order to evaluate the potential for undiscovered geothermal resources in the Modoc area, we integrate a wide variety of existing data in order to evaluate geothermal resource potential and exploration risk utilizing ‘play-fairway’ analysis. We consider that the requisite parameters for hydrothermal circulation are: 1) heat that is sufficient to drive circulation, and 2) permeability that is sufficient to allow for fluid circulation in the subsurface. We synthesize data that indicate the extent and distribution of these parameters throughout the Modoc region. ‘Fuzzy logic’ is used to incorporate expert opinion into the utility of each dataset as an indicator of either heat or permeability, and thus geothermal favorability. The results identify several geothermal prospects, areas that

  2. Use of Geothermal Energy for Electric Power Generation

    Energy Technology Data Exchange (ETDEWEB)

    Mashaw, John M.; Prichett, III, Wilson (eds.)

    1980-10-23

    The National Rural Electric Cooperative Association and its 1,000 member systems are involved in the research, development and utilization of many different types of supplemental and alternative energy resources. We share a strong commitment to the wise and efficient use of this country's energy resources as the ultimate answer to our national prosperity and economic growth. WRECA is indebted to the United States Department of Energy for funding the NRECA/DOE Geothermal Workshop which was held in San Diego, California in October, 1980. We would also like to express our gratitude to each of the workshop speakers who gave of their time, talent and experience so that rural electric systems in the Western U. S. might gain a clearer understanding of the geothermal potential in their individual service areas. The participants were also presented with practical, expert opinion regarding the financial and technical considerations of using geothermal energy for electric power production. The organizers of this conference and all of those involved in planning this forum are hopeful that it will serve as an impetus toward the full utilization of geothermal energy as an important ingredient in a more energy self-sufficient nation. The ultimate consumer of the rural electric system, the member-owner, expects the kind of leadership that solves the energy problems of tomorrow by fully utilizing the resources at our disposal today.

  3. Geothermal energy

    Directory of Open Access Journals (Sweden)

    Manzella A.

    2017-01-01

    Full Text Available Geothermal technologies use renewable energy resources to generate electricity and direct use of heat while producing very low levels of greenhouse-gas (GHG emissions. Geothermal energy is the thermal energy stored in the underground, including any contained fluid, which is available for extraction and conversion into energy products. Electricity generation, which nowadays produces 73.7 TWh (12.7 GW of capacity worldwide, usually requires geothermal resources temperatures of over 100 °C. For heating, geothermal resources spanning a wider range of temperatures can be used in applications such as space and district heating (and cooling, with proper technology, spa and swimming pool heating, greenhouse and soil heating, aquaculture pond heating, industrial process heating and snow melting. Produced geothermal heat in the world accounts to 164.6 TWh, with a capacity of 70.9 GW. Geothermal technology, which has focused for decades on extracting naturally heated steam or hot water from natural hydrothermal reservoirs, is developing to more advanced techniques to exploit the heat also where underground fluids are scarce and to use the Earth as a potential energy battery, by storing heat. The success of the research will enable energy recovery and utilization from a much larger fraction of the accessible thermal energy in the Earth’s crust.

  4. Geothermal energy

    Science.gov (United States)

    Manzella, A.

    2017-07-01

    Geothermal technologies use renewable energy resources to generate electricity and direct use of heat while producing very low levels of greenhouse-gas (GHG) emissions. Geothermal energy is the thermal energy stored in the underground, including any contained fluid, which is available for extraction and conversion into energy products. Electricity generation, which nowadays produces 73.7 TWh (12.7 GW of capacity) worldwide, usually requires geothermal resources temperatures of over 100 °C. For heating, geothermal resources spanning a wider range of temperatures can be used in applications such as space and district heating (and cooling, with proper technology), spa and swimming pool heating, greenhouse and soil heating, aquaculture pond heating, industrial process heating and snow melting. Produced geothermal heat in the world accounts to 164.6 TWh, with a capacity of 70.9 GW. Geothermal technology, which has focused for decades on extracting naturally heated steam or hot water from natural hydrothermal reservoirs, is developing to more advanced techniques to exploit the heat also where underground fluids are scarce and to use the Earth as a potential energy battery, by storing heat. The success of the research will enable energy recovery and utilization from a much larger fraction of the accessible thermal energy in the Earth's crust.

  5. Geothermal studies in China

    International Nuclear Information System (INIS)

    Wang Ji-Yang; Chen Mo-Xiang; Wang Ji-An; Deng Xiao; Wang Jun; Shen Hsien-Chieh; Hsiung Liang-Ping; Yan Shu-Zhen; Fan Zhi-Cheng; Liu Xiu-Wen

    1981-01-01

    Geothermal studies have been conducted in China continuosly since the end of the 1950's with renewed activity since 1970. Three areas of research are defined: (1) fundamental theoretical research of geothermics, including subsurface temperatures, terrestrial heat flow and geothermal modeling; (2) exploration for geothermal resources and exploitation of geothermal energy; (3) geothermal studies in mines. (orig./ME)

  6. Heat extraction and power production forecast of a prospective Enhanced Geothermal System site in Songliao Basin, China

    International Nuclear Information System (INIS)

    Huang, Xiaoxue; Zhu, Jialing; Niu, Chengke; Li, Jun; Hu, Xia; Jin, Xianpeng

    2014-01-01

    As a promising advanced technology, Enhanced Geothermal System (EGS) utilizing deep geothermal energy has gained increasing attention. Production performance of a prospective EGS site in Songliao Basin was evaluated through mathematical modeling. Firstly, numerical simulation of heat extraction process in the fractured reservoir was carried out. To take account of the flow process in wellbores, reservoir-wellbore coupled simulation was undertaken through indirect coupling of TOUGH2 with the wellbore simulator HOLA, in which dynamic treatment of the wellbottom pressure was enabled. Power production performance was then investigated through thermodynamic modeling of an electricity generation system using the output from the reservoir-wellbore coupled simulation. The results suggest that the desirable thermal efficiency and gross power output could be obtained initially, whereas the decrease in production arising from thermal depletion of the reservoir is significant at later stages of operation. Meanwhile, the power consumption of the injection pump takes up an increasing amount of the generated power. It can be inferred from the comparison between simulations with and without coupling that a downhole pump could improve the hydraulic performance notably with little sacrifice of the thermal performance. - Highlights: • An Enhanced Geothermal System based on field data in Songliao Basin is modelled. • We apply reservoir-wellbore and thermodynamic modeling for production evaluation. • Commercial objective is attained at the early stages, and decreases heavily afterward. • Mass flow rate decreases due to wellbottom pressure variation as enthalpy decreases. • Hydraulic performance is improved under the constant wellbottom pressure

  7. Geophysical Methods for Monitoring Temperature Changes in Shallow Low Enthalpy Geothermal Systems

    Directory of Open Access Journals (Sweden)

    Thomas Hermans

    2014-08-01

    Full Text Available Low enthalpy geothermal systems exploited with ground source heat pumps or groundwater heat pumps present many advantages within the context of sustainable energy use. Designing, monitoring and controlling such systems requires the measurement of spatially distributed temperature fields and the knowledge of the parameters governing groundwater flow (permeability and specific storage and heat transport (thermal conductivity and volumetric thermal capacity. Such data are often scarce or not available. In recent years, the ability of electrical resistivity tomography (ERT, self-potential method (SP and distributed temperature sensing (DTS to monitor spatially and temporally temperature changes in the subsurface has been investigated. We review the recent advances in using these three methods for this type of shallow applications. A special focus is made regarding the petrophysical relationships and on underlying assumptions generally needed for a quantitative interpretation of these geophysical data. We show that those geophysical methods are mature to be used within the context of temperature monitoring and that a combination of them may be the best choice regarding control and validation issues.

  8. Geothermal System as the Cause of the 1979 Landslide Tsunami in Lembata Island, Indonesia

    Directory of Open Access Journals (Sweden)

    Yudhicara Yudhicara

    2015-05-01

    Full Text Available DOI:10.17014/ijog.2.2.91-99A tsunami landslide which caused hundreds casualties and lots of damage took place on Lembata Island in 1979. In order to understand the characteristics of the landslide mechanism, a field survey was conducted in 2013 which sampled both the origin soil and landslide material, and the water from hotspring around the landslide site. The physical properties of the soil obtained show that the original soil has dominantly coarser grain than the landslide material (80.5% coarser grain compared to 11.8% coarse grain respectively which indicates that the soil has become finer and softer. Hot spring analysis indicated that the mineral content of the water was 99.48% SO4. This shows that magmatism processes are involved which caused the soil to become acidic and may have fragilised the system. Results of X-ray Diffraction Mineralogy Analysis (XRD show that the original soil is composed of minerals of cristobalite, quartz, and albite, while the landslide material consists of clay minerals such as quartz, saponite, chabazite, silicon oxide, and coesite which are typical minerals in a hydrothermal environment. Based on these results, it can be concluded that the area was influenced by an active geothermal system that could be the main source mechanism behind this disastrous event. 

  9. Seasonal thermal energy storage in shallow geothermal systems: thermal equilibrium stage

    Directory of Open Access Journals (Sweden)

    Nowamooz Hossein

    2016-01-01

    Full Text Available This paper is dedicated to the study of seasonal heat storage in shallow geothermal installations in unsaturated soils for which hydrothermal properties such as degree of saturation and thermal conductivity vary with time throughout the profile. In the model, a semi-analytical model which estimates time-spatial thermal conductivity is coupled with a 2D cylindrical heat transfer modeling using finite difference method. The variation of temperature was obtained after 3 heating and cooling cycles for the different types of loads with maximum thermal load of qmax = 15 W.m−1 with variable angular frequency (8 months of heating and 4 months of cooling.and constant angular frequency (6 months of heating and 6 months of cooling to estimate the necessary number of cycles to reach the thermal equilibrium stage. The results show that we approach a thermal equilibrium stage where the same variation of temperature can be observed in soils after several heating and cooling cycles. Based on these simulations, the necessary number of cycles can be related to the total applied energy on the system and the minimum number of cycles is for a system with the total applied energy of 1.9qmax.

  10. Effects of geothermal energy utilization on stream biota and water quality at The Geysers, California. Final report. [Big Sulphur, Little Sulphur, Squaw, and Pieta Creeks

    Energy Technology Data Exchange (ETDEWEB)

    LeGore, R.S.

    1975-01-01

    The discussion is presented under the following section headings: biological studies, including fish, insects, and microbiology; stream hydrology; stream water quality, including methods and results; the contribution of tributaries to Big Sulphur Creek, including methods, results, and tributary characterization; standing water at wellheads; steam condensate quality; accidental discharges; trout spawning bed quality; major conclusions; list of references; and appendices. It is concluded that present operational practices at Geysers geothermal field do not harm the biological resources in adjacent streams. The only effects of geothermal development observed during the study were related to operational accidents. (JGB)

  11. Cost modelling of electricity-producing hot dry rock (HDR) geothermal systems in the United Kingdom

    International Nuclear Information System (INIS)

    Doherty, P.; Harrison, R.

    1995-01-01

    A detailed and comprehensive cost model for Hot Dry Rock (HDR) electricity producing systems has been developed in this study. The model takes account of the major aspects of the HDR system, parameterized in terms of the main physical and cost parameters of the resource and the utilization system. A doublet configuration is assumed, and the conceptual HDR system which is defined in the study is based upon the UK Department of Energy (DEn) HDR geothermal R and D programme. The model has been used to calculate the costs of HDR electricity for a UK defined base case which represents a consensus view of what might be achieved in Cornwall in the long term. At 14.2 p/kWh (1988 costs) this cost appears to be unacceptably high. A wide-ranging sensitivity study has also been carried out on the main resource, geometrical, and operational parameters of the HDR system centred around the UK base case. The sensitivity study shows the most important parameters to be thermal gradient and depth. The geometrical arrangement and the shape of the reservoir constitute major uncertainties in HDR systems. Their effect on temperature has a major influence on system performance, and therefore a range of theoretically possible geometries have been studied and the importance of geometrical effects on HDR electricity costs assessed. The most cost effective HDR arrangement in terms of optimized volumes and flow rates has been investigated for a world-wide range of thermal settings. The main conclusions from this study suggests that for HDR electricity to be economic, thermal gradients of 55 o C/km and above, well depths of 5 km or less, and production fluid temperatures of 210 o C and above are required. (UK)

  12. Development of geothermal resources

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-09-01

    This paper describes the geothermal development promotion survey project. NEDO is taking the lead in investigation and development to reduce risks for private business entities and promote their development. The program is being moved forward by dividing the surveys into three ranks of A, B and C from prospects of geothermal resource availability and the state of data accumulation. The survey A lacks number of data, but covers areas as wide as 100 to 300 km{sup 2}, and studies possible existence of high-temperature geothermal energy. The survey B covers areas of 50 to 70 km{sup 2}, investigates availability of geothermal resources, and assesses environmental impacts. The survey C covers areas of 5 to 10 km{sup 2}, and includes production well drilling and long-term discharge tests, other than those carried out by the surveys A and B. Results derived in each fiscal year are evaluated and judged to establish development plans for the subsequent fiscal year. This paper summarizes development results on 38 areas from among 45 areas surveyed since fiscal 1980. Development promotion surveys were carried out over seven areas in fiscal 1994. Development is in progress not only on utilization of high-temperature steam, but also on binary cycle geothermal power generation utilizing hot waters of 80 to 150{degree}C. Fiscal 1994 has carried out discussions for spread and practical use of the systems (particularly on economic effects), and development of small-to-medium scale binary systems. 2 figs., 1 tab.

  13. Update on subsidence at the Wairakei-Tauhara geothermal system, New Zealand

    International Nuclear Information System (INIS)

    Allis, Rick; Bromley, Chris; Currie, Steve

    2009-01-01

    The total subsidence at the Wairakei field as a result of 50 years of geothermal fluid extraction is 15 ± 0.5 m. Subsidence rates in the center of the subsidence bowl have decreased from over 450 mm/year during the 1970s to 80-90 mm/year during 2000-2007. The location of the bowl, adjacent to the original liquid outflow zone of the field, has not changed significantly. Subsidence at the Tauhara field due to Wairakei production was not as well documented in the early years but appeared later and has been less intense than at Wairakei. Total subsidence of 2.6 ± 0.5 m has also occurred close to the original liquid outflow zone of this field, and maximum subsidence rates in this area today are in the 80-100 mm/year range. In the western part of the Wairakei field, near the area of hot upflow, subsidence rates have approximately doubled during the last 20 years to 30-50 mm/year. This increase appears to be have been caused by declining pressure in the underlying steam zone in this area, which is tapped by some production wells. At Tauhara field, two areas of subsidence have developed since the 1990s with rates of 50-65 mm/year. Although less well-determined, this subsidence may also be caused by declining pressure in shallow steam zones. The cause of the main subsidence bowls in the Wairakei-Tauhara geothermal system is locally high-compressibility rocks within the Huka Falls Formation (HFF), which are predominantly lake sediments and an intervening layer of pumice breccia. At Wairakei, casing deformation suggests the greatest compaction is at 150-200 m depth. The cause of the large compressibility is inferred to be higher clay content in the HFF due to intense hydrothermal alteration close to the natural fluid discharge areas. Future subsidence is predicted to add an additional 2-4 m to the Wairakei bowl, and 1-2 m elsewhere, but these estimates depend on the assumed production-injection scenarios. (author)

  14. Thermodynamic and economic evaluations of a geothermal district heating system using advanced exergy-based methods

    International Nuclear Information System (INIS)

    Tan, Mehmet; Keçebaş, Ali

    2014-01-01

    Highlights: • Evaluation of a GDHS using advanced exergy-based methods. • Comparison of the results of the conventional and advanced exergy-based methods. • The modified exergetic efficiency and exergoeconomic factor are found as 45% and 13%. • Improvement and total cost-savings potentials are found to be 3% and 14%. • All the pumps have the highest improvement potential and total cost-savings potential. - Abstract: In this paper, a geothermal district heating system (GDHS) is comparatively evaluated in terms of thermodynamic and economic aspects using advanced exergy-based methods to identify the potential for improvement, the interactions among system components, and the direction and potential for energy savings. The actual operational data are taken from the Sarayköy GDHS, Turkey. In the advanced exergetic and exergoeconomic analyses, the exergy destruction and the total operating cost within each component of the system are split into endogenous/exogenous and unavoidable/avoidable parts. The advantages of these analyses over conventional ones are demonstrated. The results indicate that the advanced exergy-based method is a more meaningful and effective tool than the conventional one for system performance evaluation. The exergetic efficiency and the exergoeconomic factor of the overall system for the Sarayköy GDHS were determined to be 43.72% and 5.25% according to the conventional tools and 45.06% and 12.98% according to the advanced tools. The improvement potential and the total cost-savings potential of the overall system were also determined to be 2.98% and 14.05%, respectively. All of the pumps have the highest improvement potential and total cost-savings potential because the pumps were selected to have high power during installation at the Sarayköy GDHS

  15. Seismic Technology Adapted to Analyzing and Developing Geothermal Systems Below Surface-Exposed High-Velocity Rocks Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Hardage, Bob A. [Univ. of Texas, Austin, TX (United States). Bureau of Economic Geology; DeAngelo, Michael V. [Univ. of Texas, Austin, TX (United States). Bureau of Economic Geology; Ermolaeva, Elena [Univ. of Texas, Austin, TX (United States). Bureau of Economic Geology; Hardage, Bob A. [Univ. of Texas, Austin, TX (United States). Bureau of Economic Geology; Remington, Randy [Univ. of Texas, Austin, TX (United States). Bureau of Economic Geology; Sava, Diana [Univ. of Texas, Austin, TX (United States). Bureau of Economic Geology; Wagner, Donald [Univ. of Texas, Austin, TX (United States). Bureau of Economic Geology; Wei, Shuijion [Univ. of Texas, Austin, TX (United States). Bureau of Economic Geology

    2013-02-01

    applications by inserting into this report a small part of the interpretation we have done with 3C3D data across Wister geothermal field in the Imperial Valley of California. This interpretation shows that P-SV data reveal faults (and by inference, also fractures) that cannot be easily, or confidently, seen with P-P data, and that the combination of P-P and P-SV data allows VP/VS velocity ratios to be estimated across a targeted reservoir interval to show where an interval has more sandstone (the preferred reservoir facies). The conclusion reached from this investigation is that S-wave seismic technology can be invaluable to geothermal operators. Thus we developed a strong interest in understanding the direct-S modes produced by vertical-force sources, particularly vertical vibrators, because if it can be demonstrated that direct-S modes produced by vertical-force sources can be used as effectively as the direct-S modes produced by horizontal-force sources, geothermal operators can acquire direct-S data across many more prospect areas than can be done with horizontal-force sources, which presently are limited to horizontal vibrators. We include some of our preliminary work in evaluating direct-S modes produced by vertical-force sources.

  16. Numerical Study on CO2-Brine-Rock Interaction of Enhanced Geothermal Systems with CO2 as Heat Transmission Fluid

    Directory of Open Access Journals (Sweden)

    Wan Yuyu

    2016-01-01

    Full Text Available Enhanced Geothermal Systems (EGS with CO2 instead of water as heat transmission fluid is an attractive concept for both geothermal resources development and CO2 geological sequestration. Previous studies show that CO2 has lots of favorable properties as heat transmission fluid and also can offer geologic storage of CO2 as an ancillary benefit. However, after CO2 injection into geological formations, chemical reaction between brine and rock can change chemical characteristics of saline and properties of rock such as porosity and permeability. Is this advantage or disadvantage for EGS operating? To answer this question, we have performed chemically reactive transport modeling to investigate fluid-rock interactions and CO2 mineral carbonation of Enhanced Geothermal Systems (EGS site at Desert Peak (Nevada operated with CO2. The simulation results show that (1 injection CO2 can create a core zone fulfilled with CO2 as main working domain for EGS, and (2 CO2 storage can induced self-enhancing alteration of EGS.

  17. Victorian first for geothermal

    International Nuclear Information System (INIS)

    Wallace, Paula

    2014-01-01

    AGL Limited (AGL) will assist Maroondah Sports Club to save hundreds of thousands of dollars on its energy bills over the next decade by commencing work to install Victoria's first GeoAir geothermal cooling and heating system. Utilising the earth's constant temperature, the new GeoAir geothermal system provides a renewable source of energy that will save the club up to $12,000 in the first year and up to $150,000 over the next 10 years

  18. Ground source geothermal heat. Ground source heat pumps and underground thermal energy storage systems. Proceedings; Oberflaechennahe Geothermie. Erdgekoppelte Waermepumpen und unterirdische thermische Energiespeicher. Tagungsband

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-07-01

    At the ninth international user forum on shallow geothermal heat on 28th and 29th April, 2009, at BadStaffelstein (Federal Republic of Germany), the following lectures were held: (1) Information system on shallow geothermal heat for Bavaria (Marcellus Schulze); (2) Calculation of the spreading of temperature anomalies in groundwater as an instrument of planning of heat pump systems (Wolfgang Rauch); (3) Comparison of models for simulation of deep geothermal probes (Markus Proell); (4) Impact of the geometry of boreholes and probes on heat transport (Manfred Reuss); (5) Thermal respond tests and temperature depth profiles - Experience from research and practice (Markus Kuebert); (6) A model of simulation for the investigation of the impact of different heat transfer fluids on the efficiency of ground source heat pump devices (Roland Koenigsdorff); (7) The research project EWSplus - Investigations for quality assurance of geothermal probes (Mathieu Riegger); (8) Quality management of plants for the utilization of shallow geothermal heat with geothermal probes - the example of Baden-Wuerttemberg (Bruno Lorinser, Ingrid Stober); (9) Not every heat pump contributes to climate protection (Falk Auer); (10) Field measurements of heat pumps in residential buildings with modern standard and in older buildings (Marek Miara); (11) System technology for a great annual performance factor (Werner Schenk); (12) Modification of older geothermal heat probe devices for use with modern heat pumps (Klaus Friedrich Staerk); (13) Energy-efficient modernisation of a pensioners' condominium from the 1970s with solar-geothermal-air (Michael Guigas); (14) Evaluation and optimization of operation of seasonal storage systems in the foundations of office buildings (Herdis Kipry); (15) Evaluation of an innovative heating and cooling concept with rain water vessels, thermo-active building components and phase change materials in a residential building (Doreen Kalz); (16) Contracts for ground

  19. Insights to Engineered Geothermal System Performance Using Gringarten-Witherspoon-Ohnishi Analytical Solutions and Fracture Network Models

    Science.gov (United States)

    Doe, T.; McLaren, R.; Finilla, A.

    2017-12-01

    An enduring legacy of Paul Witherspoon and his students and colleagues has been both the development of geothermal energy and the bases of modern fractured-rock hydrogeology. One of the seminal contributions to the geothermal field was Gringarten, Witherspoon, and Ohnishi's analytical models for enhanced geothermal systems. Although discrete fracture network (DFN) modeling developed somewhat independently in the late 1970s, Paul Witherspoon's foresight in promoting underground in situ testing at the Stripa Mine in Sweden was a major driver in Lawrence Berkeley Laboratory's contributions to its development.This presentation looks extensions of Gringarten's analytical model into discrete fracture network modeling as a basis for providing further insights into the challenges and opportunities of engineered geothermal systems. The analytical solution itself has many insightful applications beyond those presented in the original paper. The definition of dimensionless time by itself shows that thermal breakthrough has a second power dependence on surface area and on flow rate. The fracture intensity also plays a strong role, as it both increases the surface area and decrease his flow rate per fracture. The improvement of EGS performance with fracture intensity reaches a limit where thermal depletion of the rock lags only slightly behind the thermal breakthrough of cold water in the fracture network.Simple network models, which couple a DFN generator (FracMan) with a hydrothermally coupled flow solver (HydroGeoSphere) expand on Gringarten's concepts to show that realistic heterogeneity of spacing and transmissivity significantly degrades EGS performance. EGS production in networks of stimulated fractures initially follows Gringarten's type curves, with a later deviation is the smaller rock blocks thermally deplete and the entire stimulated volume acts as a single sink. Three-dimensional models of EGS performance show the critical importance of the relative magnitudes of

  20. Decreasing of energy consumption for space heating in existing residential buildings; Combined geothermal and gas district heating systems

    International Nuclear Information System (INIS)

    Rosca, Marcel

    2000-01-01

    The City of Oradea, Romania, has a population of about 230 000 inhabitants. Almost 70% of the total heat demand, including industrial, is supplied by a classical East European type district heating system. The heat is supplied by two low grade coal fired co-generation power plants. The oldest distribution networks and substitutions, as well as one power plant, are 35 years old and require renovation or even reconstruction. The geothermal reservoir located under the city supplies at present 2,2% of the total heat demand. By generalizing the reinjection, the production can be increased to supply about 8% of the total heat demand, without any significant reservoir pressure or temperature decline over 25 years. Another potential energy source is natural gas, a main transport pipeline running close to the city. Two possible scenarios are envisaged to replace the low grade coal by natural gas and geothermal energy as heat sources for Oradea. In one scenario, the geothermal energy supplies the heat for tap water heating and the base load for space heating in a limited number of substations, with peak load being produced by natural gas fired boilers. In the other scenario, the geothermal energy is only used for tap water heating. In both scenarios, all substations are converted into heat plants, natural gas being the main energy source. The technical, economic, and environmental assessment of the two proposed scenarios are compared with each other, as well as with the existing district heating system. Two other possible options, namely to renovate and convert the existing co-generation power plants to natural gas fired boilers or to gas turbines, are only briefly discussed, being considered unrealistic, at least for the short and medium term future. (Author)

  1. Copahue Geothermal System: A Volcanic Environment with Rich Extreme Prokaryotic Biodiversity.

    Science.gov (United States)

    Urbieta, María Sofía; Porati, Graciana Willis; Segretín, Ana Belén; González-Toril, Elena; Giaveno, María Alejandra; Donati, Edgardo Rubén

    2015-07-08

    The Copahue geothermal system is a natural extreme environment located at the northern end of the Cordillera de los Andes in Neuquén province in Argentina. The geochemistry and consequently the biodiversity of the area are dominated by the activity of the Copahue volcano. The main characteristic of Copahue is the extreme acidity of its aquatic environments; ponds and hot springs of moderate and high temperature as well as Río Agrio. In spite of being an apparently hostile location, the prokaryotic biodiversity detected by molecular ecology techniques as well as cultivation shows a rich and diverse environment dominated by acidophilic, sulphur oxidising bacteria or archaea, depending on the conditions of the particular niche studied. In microbial biofilms, found in the borders of the ponds where thermal activity is less intense, the species found are completely different, with a high presence of cyanobacteria and other photosynthetic species. Our results, collected during more than 10 years of work in Copahue, have enabled us to outline geomicrobiological models for the different environments found in the ponds and Río Agrio. Besides, Copahue seems to be the habitat of novel, not yet characterised autochthonous species, especially in the domain Archaea.

  2. Copahue Geothermal System: A Volcanic Environment with Rich Extreme Prokaryotic Biodiversity

    Directory of Open Access Journals (Sweden)

    María Sofía Urbieta

    2015-07-01

    Full Text Available The Copahue geothermal system is a natural extreme environment located at the northern end of the Cordillera de los Andes in Neuquén province in Argentina. The geochemistry and consequently the biodiversity of the area are dominated by the activity of the Copahue volcano. The main characteristic of Copahue is the extreme acidity of its aquatic environments; ponds and hot springs of moderate and high temperature as well as Río Agrio. In spite of being an apparently hostile location, the prokaryotic biodiversity detected by molecular ecology techniques as well as cultivation shows a rich and diverse environment dominated by acidophilic, sulphur oxidising bacteria or archaea, depending on the conditions of the particular niche studied. In microbial biofilms, found in the borders of the ponds where thermal activity is less intense, the species found are completely different, with a high presence of cyanobacteria and other photosynthetic species. Our results, collected during more than 10 years of work in Copahue, have enabled us to outline geomicrobiological models for the different environments found in the ponds and Río Agrio. Besides, Copahue seems to be the habitat of novel, not yet characterised autochthonous species, especially in the domain Archaea.

  3. Convective heat transfer of supercritical CO_2 in a rock fracture for enhanced geothermal systems

    International Nuclear Information System (INIS)

    Zhang, Le; Jiang, Peixue; Wang, Zhenchuan; Xu, Ruina

    2017-01-01

    Highlights: • Contrasting experiments between a rough and a smooth fracture were performed. • A numerical model of rough fracture was reconstructed based on CT scanning data. • Heat transfer in rough fracture was affected by channeling and disturbance effects. - Abstract: Convective heat transfer characteristics of supercritical pressure fluid in a rock fracture are important for building an accurate heat transfer model of enhanced geothermal systems. This paper presents experimental investigations of laminar convection heat transfer of supercritical pressure CO_2 in an artificial smooth parallel-plate fracture and a rough and tortuous fracture that was created using the Brazilian technique. Hot rock with a relatively high initial temperature reserves more heat, which can ensure a larger heat extraction rate for a longer time when cold fluid flows through the fracture. Compared with the smooth parallel-plate fracture, CO_2 flowing through the rough and tortuous fracture with an equivalent hydraulic aperture extracted less heat from the hot rock due to the less efficient heat exchange in a rough fracture caused by channeling effect. This was illustrated by numerical simulation results of the reconstructed fracture based on micro-computed tomography scan data. The overall Nusselt number obtained from the numerical results was larger in a rough fracture with a larger Reynolds number due to disturbance effect on the boundary layer development. The heat transfer performance in a rough fracture is therefore influenced by interactions of the channeling and disturbance effects caused by the tortuous flow path.

  4. Land subsidence in the Cerro Prieto Geothermal Field, 1 Baja California, Mexico, from 1994 to 2005. An integrated analysis of DInSAR, levelingand geological data.

    Energy Technology Data Exchange (ETDEWEB)

    Sarychikhina, O; Glowacka, E; Mellors, R; Vidal, F S

    2011-03-03

    Cerro Prieto is the oldest and largest Mexican geothermal field in operation and has been producing electricity since 1973. The large amount of geothermal fluids extracted to supply steam to the power plants has resulted in considerable deformation in and around the field. The deformation includes land subsidence and related ground fissuring and faulting. These phenomena have produced severe damages to infrastructure such as roads, irrigation canals and other facilities. In this paper, the technique of Differential Synthetic Aperture Radar Interferometry (DInSAR) is applied using C-band ENVISAR ASAR data acquired between 2003 and 2006 to determine the extent and amount of land subsidence in the Mexicali Valley near Cerro Prieto Geothermal Field. The DInSAR results were compared with published data from precise leveling surveys (1994- 1997 and 1997-2006) and detailed geological information in order to improve the understanding of temporal and spatial distributions of anthropogenic subsidence in the Mexicali Valley. The leveling and DInSAR data were modeled to characterize the observed deformation in terms of fluid extraction. The results confirm that the tectonic faults control the spatial extent of the observed subsidence. These faults likely act as groundwater flow barriers for aquifers and reservoirs. The shape of the subsiding area coincides with the Cerro Prieto pull-apart basin. In addition, the spatial pattern of the subsidence as well as changes in rate are highly correlated with the development of the Cerro Prieto Geothermal Field.

  5. IMPACT OF GEOTHERMAL GRADIENT ON GROUND SOURCE HEAT PUMP SYSTEM MODELING

    Directory of Open Access Journals (Sweden)

    Tomislav Kurevija

    2014-07-01

    Full Text Available ndisturbed ground temperature is one of the most crucial thermogeological parameters needed for shallow geothermal resources assessment. Energy considered to be geothermal is energy stored in the ground at depths where solar radiation has no effect. At depth where undisturbed ground temperature occurs there is no influence of seasonal variations in air temperature from surface. Exact temperature value, and depth where it occurs, is functionally dependent on surface climate parameters and thermogeologic properties of ground. After abovementioned depth, increase of ground temperature is solely dependent on geothermal gradient. Accurately determined value of undisturbed ground temperature is beneficial for proper sizing of borehole heat exchangers. On practical example of building which is being heated and cooled with shallow geothermal resource, influences of undisturbed ground temperature and geothermal gradient, on size of borehole heat exchanger are going to be presented. Sizing of borehole heat exchanger was calculated with commercial software Ground Loop Designer (GLD, which uses modified line source and cylinder source solutions of heat conduction in solids.

  6. Synthesis of gravity, magnetic and thermal studies at the Las Tres Virgenes geothermal zone, Baja California Sur, Mexico. Sintesis de los estudios de gravimetria, magnetometria y termometria en la zona geotermica de Las Tres Virgenes, Baja California Sur, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Estrada, Gerardo (Departamento de Exploracion, Gerencia de Proyectos Geotermoelectricos de la Comision Federal de Electricidad, Morelia (Mexico)); Gonzalez Lopez, Macario (Residencia General de Cerro Prieto, Mexicali (Mexico))

    1998-01-15

    Las Tres Virgenes geothermal zone is located in the NE-SW central sector of a sigmoidal basin that regionally has a NW-SE trend. In the local deepest zone there is a NE-SE granodioritic basement horst acting as hydrologic barrier, that makes the fluids flow up. After moving in a direction parallel to the local horst, waters continue its regional SE-NW movement controlled by regional tectonics. The flanks of the granodioritic basement horst, and local N-S faulting act as fluid paths in the hydrothermal zone, but regional NW-SE regional faults determine the general flow direction. Both regional and local tectonics show magnetic evidences of the emplacement of magmatic bodies of intermediate to basic composition. Those along NW-SE trends are more noticeable but we consider they are not the present day heat source. Intermediate magmatism along NE-SW local trend seems to be less extensive but it is younger, so, we consider it constitutes the heat source of the hydrothermal system. Thermal data suggest that the heat source is located below the volcanic chain toward the S or SW of the wells, phenomena related with the general displacement of magmatism from NE to SW along the volcanic chain. However, recent intensive faulting permits a higher permeability in the northern sector in which there are slightly smaller temperatures but at shallower depths and with higher flow rates.

  7. Hydrothermal alteration of Hercynian granites, its significance to the evolution of geothermal systems in granitic rocks

    Energy Technology Data Exchange (ETDEWEB)

    Marques, Jose M.; Matias, Maria J.; Basto, Maria J.; Aires-Barros, Luis A. [Instituto Superior Tecnico, Centro de Petrologia e Geoquimica, Universidade Tecnica de Lisboa, Av. Rovisco Pais, 1049-001 Lisbon (Portugal); Carreira, Paula M. [Instituto Tecnologico e Nuclear, Estrada Nacional n 10, 2686 - 953 Sacavem (Portugal); Goff, Fraser E. [Earth and Planetary Sciences Department, Univ. of New Mexico, Albuquerque, NM 87131 (United States)

    2010-06-15

    We discuss geochemical and isotopic ({sup 18}O/{sup 16}O, {sup 2}H/{sup 1}H and {sup 87}Sr/{sup 86}Sr) data recording the hydrothermal alteration of northern Portuguese Hercynian granites by Na-HCO{sub 3}-CO{sub 2}-rich mineral waters. Whole-rock samples from drill cores of Vilarelho da Raia granite have {delta}{sup 18}O values in the +11.47 to +10.10 permille range. The lower values correspond to highly fractured granite samples displaying vein and pervasive alteration. In the pervasive alteration stage, which probably results from a convective hydrothermal system set up by the intrusion of the granites, the metamorphic waters are in equilibrium with hydrous minerals. In contrast, the vein alteration of these granitic rocks was caused by water of meteoric origin. The oxygen ratios between water (W) and rock (R), the so-called W/R ratios, obtained for the open system (where the heated water is lost from the system by escape to the surface) range between 0.05 and 0.11, suggesting that the recrystallization of the veins was influenced by a small flux of meteoric water. Stable isotope analyses performed on the cores show that the vein alteration stage relates to post-emplacement tectonic stresses acting on the granite, probably of late Hercynian age. Our results are consistent with the existence of two separate alteration events (pervasive and vein) caused by hydrothermal waters of different isotopic characteristics. The studies presented in this paper should be viewed as a natural analogue that uses the alteration features observed in a fossil geothermal system at Vilarelho da Raia to assess possible water-rock reactions presently occurring at depth in granitic rocks of the nearby Chaves area. (author)

  8. Geothermal overviews of the western United States

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, D.N.; Axtell, L.H. (comps.)

    1972-01-01

    This compendium presents data on geothermal resources for all those western states with geothermal potential. Individual sections, which have been processed separately for inclusion in the EDB data base, are devoted to each of the following states: Arizona, California, Colorado, Hawaii, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, Washington, and Wyoming. A separate section is also devoted to the U.S. Bureau of Reclamation Imperial Valley Project. Maps and references are included for each section. (JGB)

  9. Identification the geothermal system using 1-D audio-magnetotelluric inversion in Lamongan volcano field, East Java, Indonesia

    Science.gov (United States)

    Ilham, N.; Niasari, S. W.

    2018-04-01

    Tiris village, Probolinggo, East Java, is one of geothermal potential areas in Indonesia. This area is located in a valley flank of Mount Lamongan and Argopuro volcanic complex. This research aimed to identify a geothermal system at Tiris area, particularly the fluid pathways. The geothermal potential can be seen from the presence of warm springs with temperature ranging 35-45°C. The warm spring locations are aligned in the same orientation with major fault structure in the area. The fault structure shows dominant northwest-southeast orientation. We used audio-magnetotelluric data in the frequency range of 10 Hz until 92 kHz. The total magnetotelluric sites are 6. From the data analysis, most of the data orientation were 2-D with geo-electrical direction north-south. We used 1-D inversion using Newton algorithm. The 1-D inversion resulted in low resistive anomaly that corresponds to Lamongan lavas. Additionally, the depth of the resistor are different between the area to the west (i.e. 75 m) and to the east (i.e. 25 m). This indicates that there is a fault around the aligned maar (e.g. Ranu Air).

  10. Geothermal handbook

    Science.gov (United States)

    1976-01-01

    The Bureau of Land Management offered over 400,000 hectares (one million acres) for geothermal exploration and development in 1975, and figure is expected to double this year. The Energy Research and Development Administration hopes for 10-15,000 megawatts of geothermal energy by 1985, which would require, leasing over 16.3 million hectares (37 million acres) of land, at least half of which is federal land. Since there is an 8 to 8-1/2 year time laf between initial exploration and full field development, there would have to be a ten-fold increase in the amount of federal land leased within the next three years. Seventy percent of geothermal potential, 22.3 million hectares (55 million acres), is on federal lands in the west. The implication for the Service are enormous and the problems immediate. Geothermal resource are so widespread they are found to some extent in most biomes and ecosystems in the western United States. In most cases exploitation and production of geothermal resources can be made compatible with fish and wildlife management without damage, if probable impacts are clearly understood and provided for before damage has unwittingly been allowed to occur. Planning for site suitability and concern with specific operating techniques are crucial factors. There will be opportunities for enhancement: during exploration and testing many shallow groundwater bodies may be penetrated which might be developed for wildlife use. Construction equipment and materials needed for enhancement projects will be available in areas heretofore considered remote projects will be available in areas heretofore considered remote by land managers. A comprehensive knowledge of geothermal development is necessary to avoid dangers and seize opportunities. This handbook is intended to serve as a working tool in the field. It anticipated where geothermal resource development will occur in the western United States in t