Environmental impact assessment of Kachchh tidal power project

International Nuclear Information System (INIS)

Yadav, Ramanand; Lal, B.B.

1995-01-01

The Kachchh tidal power development project is a single-basin, single -effect and ebb generation development by construction of a tidal power barrage of about 3.25 km length across Hansthal creek. The project may disturb the ecosystem of the region. The paper deals in detail the environmental impacts of the project on climate, water velocity, flow and sedimentation pattern, water quality, flora and fauna, fishery, tourism and recreation, wild life, public health and socio-economic conditions. (author). 4 refs., 1 fig., 2 tabs

Feasibility of tidal power development in the Bay of Fundy

Energy Technology Data Exchange (ETDEWEB)

1969-01-01

A committee was formed to carry out technical studies on the feasibility of a tidal power plant in the Bay of Fundy. Basic information was collected on the physical, geological, climatic, and tidal characteristics of the area to determine areas for more intense investigation. Studies were conducted on the possible effects of the plant on navigation, ground transportation, fisheries, and area development. Electric power marketing and transmission were also examined, as well as the basic concepts for extracting tidal energy. A number of potential sites were examined, and the three most promising sites were selected for preliminary design and cost estimates. Computerized models were used at appropriate stages in order to evaluate various tidal power schemes. This report presents a summary of the committee's investigations. It was seen that a site at the entrance to Cobequid Bay would have an economic advantage over the other sites considered. From the results of the design studies, it was concluded that a long period of construction, plus extensive capital investment, would be required. However, the lowest unit cost of output was calculated at 5.6 mills/kWh, substantially above the incremental cost of energy available from existing sources. Under current economic conditions, the tidal power plant would not be feasible. 4 figs., 1 tab.

Electrical Power Conversion of River and Tidal Power Generator

Energy Technology Data Exchange (ETDEWEB)

Muljadi, Eduard; Gevorgian, Vahan; Wright, Alan; Donegan, James; Marnagh, Cian; McEntee, Jarlath

2016-11-21

As renewable generation has become less expensive during recent decades, and it becomes more accepted by the global population, the focus on renewable generation has expanded to include new types with promising future applications, such as river and tidal generation. Although the utilization of power electronics and electric machines in industry is phenomenal, the emphasis on system design is different for various sectors of industry. In precision control, robotics, and weaponry, the design emphasis is on accuracy and reliability with less concern for the cost of the final product. In energy generation, the cost of energy is the prime concern; thus, capital expenditures (CAPEX) and operations and maintenance expenditures (OPEX) are the major design objectives. This paper describes the electrical power conversion aspects of river and tidal generation. Although modern power converter control is available to control the generation side, the design was chosen on the bases of minimizing the CAPEX and OPEX; thus, the architecture is simple and modular for ease of replacement and maintenance. The power conversion is simplified by considering a simple diode bridge and a DC-DC power converter to take advantage of abundant and low-cost photovoltaic inverters that have well-proven grid integration characteristics (i.e., the capability to produce energy with good power quality and control real power and voltage on the grid side).

Regulatory, design and methodological impacts in determining tidal-in-stream power resource potential

International Nuclear Information System (INIS)

Atwater, Joel F.; Lawrence, Gregory A.

2011-01-01

Tidal-in-Stream energy has been heralded by many as a significant potential source for clean power, a scheme where kinetic energy is extracted from tidal currents. A number of estimates have suggested that tidal power may become a sizeable fraction of overall electricity generation, however these estimates have been largely based on a resource assessment methodology that dramatically oversimplifies the physical phenomenon at play. This paper develops a model that considers the effect of energy extraction on the bulk flow, showing that tidal energy inventories that assess solely kinetic energy flux may represent both an order-of-magnitude overestimation of the resource and a significant oversimplification of regulatory impacts. The interplay between the characteristics of a flow and the regulatory and economic issues will likely limit tidal power generation to levels significantly below the physical maximums. Permitted flow reduction, turbine design and staging of development all have significant and predictable impacts on the extractible resource. Energy planners must therefore understand these relationships in order to appropriately assess the magnitude of generation that can be realistically be produced from tidal energy. - Research highlights: → Inventorying kinetic energy is not appropriate for assessing the tidal energy potential and may overestimate the resource by orders of magnitude. → The physical maximum for tidal power extraction is 38% of the total fluid power of a channel and causes a flow reduction of 42%. → Any amount of tidal power generation will reduce the flow rate in a channel. → Limiting the permitted reduction in flow significantly reduces the available resource. → Turbine efficiency is important as extraneous resistance depletes the resource without providing power generation.

The Rance tidal power plant is thirty years old

International Nuclear Information System (INIS)

Anon.

1996-01-01

The 240 MW Rance tidal power plant is sited between Dinard and Saint-Malo (Brittany, France) and was inaugurated in November 26, 1966. Its availability reaches 90% and the plant has worked about 160000 hours without any major incident or failure. It has provided more than 16 TWh and it provides each year about 600 GWh to the national network. Because its functioning introduces some modifications of the natural tide conditions in the Rance estuary, EdF applies specific procedures to limit its environmental impact. The paper recalls the basic principles of the tidal power and the characteristics of the Rance plant which is the biggest in the world and which produces electric power during both the flood and the ebb. The economical aspects of the project are also described and replaced in their historical context. Other future projects of tidal plants in UK, Canada and Argentina are evoked. (J.S.)

Tidal Energy System for On-Shore Power Generation

Energy Technology Data Exchange (ETDEWEB)

Bruce, Allan J

2012-06-26

Addressing the urgent need to develop LCOE competitive renewable energy solutions for US energy security and to replace fossil-fuel generation with the associated benefits to environment impacts including a reduction in CO2 emissions, this Project focused on the advantages of using hydraulic energy transfer (HET) in large-scale Marine Hydrokinetic (MHK) systems for harvesting off-shore tidal energy in US waters. A recent DOE resource assessment, identifies water power resources have a potential to meet 15% of the US electric supply by 2030, with MHK technologies being a major component. The work covered a TRL-4 laboratory proof-in-concept demonstration plus modeling of a 15MW full scale system based on an approach patented by NASA-JPL, in which submerged high-ratio gearboxes and electrical generators in conventional MHK turbine systems are replaced by a submerged hydraulic radial pump coupled to on-shore hydraulic motors driving a generator. The advantages are; first, the mean-time-between-failure (MTBF), or maintenance, can be extended from approximately 1 to 5 years and second, the range of tidal flow speeds which can be efficiently harvested can be extended beyond that of a conventional submerged generator. The approach uses scalable, commercial-off-the-shelf (COTS) components, facilitating scale-up and commercialization. All the objectives of the Project have been successfully met (1) A TRL4 system was designed, constructed and tested. It simulates a tidal energy turbine, with a 2-m diameter blade in up to a 2.9 m/sec flow. The system consists of a drive motor assembly providing appropriate torque and RPM, attached to a radial piston pump. The pump circulates pressurized, environmentally-friendly, HEES hydraulic fluid in a closed loop to an axial piston motor which drives an electrical generator, with a resistive load. The performance of the components, subsystems and system were evaluated during simulated tidal cycles. The pump is contained in a tank for

Environmental consequences of tidal power in a hyper-tidal muddy regime: the Severn estuary

International Nuclear Information System (INIS)

Kirby, R.

1997-01-01

Muddy hyper-tidal regimes, such as the Severn Estuary in the UK, are especially difficult for plants and animals. The difficulties stem from the semi-diurnal and semi-lunar energy fluctuations. On spring tides entrained fine sediment induces elevated suspended sediment concentrations such that photosynthesis is inhibited. On neap tides much of the entrained fine sediment is deposited on the sub-tidal bed over periods of several days to form ephemeral dense layers, which reach in excess of 100 G/l and rapidly become anaerobic on stagnation. Such occasional bed faunas as develop are characterised by very large numbers of immature individuals of a few species. One of the few organisms able to cope with the extreme conditions is the siliceous reef-building worn Sabellaria. Arising from the long term suppression in its calcareous fauna, erosion and winnowing of these Holocene clays fails to give rise to lag shell deposits, called chenier ridges, found elsewhere in eroding muddy inter-tidal systems. A tidal power barrage would shift the regime from hyper-tidal to macro-tidal decrease in turbidity would permit photosynthesis and phytoplankton growth, so stimulating the higher food chain. Ironically, perhaps, cleaning up the sewage discharges in the estuary, in the absence of barrage construction would lead to a wading bird crash whereas barrage construction would lead to an improved carrying capacity. (author)

Wind, Wave, and Tidal Energy Without Power Conditioning

Science.gov (United States)

Jones, Jack A.

2013-01-01

Most present wind, wave, and tidal energy systems require expensive power conditioning systems that reduce overall efficiency. This new design eliminates power conditioning all, or nearly all, of the time. Wind, wave, and tidal energy systems can transmit their energy to pumps that send high-pressure fluid to a central power production area. The central power production area can consist of a series of hydraulic generators. The hydraulic generators can be variable displacement generators such that the RPM, and thus the voltage, remains constant, eliminating the need for further power conditioning. A series of wind blades is attached to a series of radial piston pumps, which pump fluid to a series of axial piston motors attached to generators. As the wind is reduced, the amount of energy is reduced, and the number of active hydraulic generators can be reduced to maintain a nearly constant RPM. If the axial piston motors have variable displacement, an exact RPM can be maintained for all, or nearly all, wind speeds. Analyses have been performed that show over 20% performance improvements with this technique over conventional wind turbines

On effects produced by tidal power plants upon environmental conditions in adjacent sea areas

International Nuclear Information System (INIS)

Nekrasov, A.V.; Romanenkov, D.A.

1997-01-01

Consideration is given to the change in natural (oceanographic) environmental conditions due to the transformation of the tidal oscillations structure resulting from erection and operation of tidal power plants (TPP). The relevant transformation of tidal movements encompasses practically all its main characteristics: amplitudes, phases and spectral composition of sea level oscillations, as well as the similar parameters of tidal currents and also the intensity and positioning of extremes zones. The changes in positioning and width of the inter-tidal zone, the inter-tidal zone regime, mutual arrangement of mixed, stratified and transient frontal zones, transportation of suspended matter and bottom sedimentation, owing to residual tidal currents, sea ice characteristics, air these changes can be estimated on the basis of mathematical predictive modelling of tidal characteristics transformed by a contemplated tidal power plant. Some results are presented for the Russian large-scale TPP projects in the White and Okhotsk seas. (author)

Estimating effects of tidal power projects and climate change on threatened and endangered marine species and their food web.

Science.gov (United States)

Busch, D Shallin; Greene, Correigh M; Good, Thomas P

2013-12-01

Marine hydrokinetic power projects will operate as marine environments change in response to increased atmospheric carbon dioxide concentrations. We considered how tidal power development and stressors resulting from climate change may affect Puget Sound species listed under the U.S. Endangered Species Act (ESA) and their food web. We used risk tables to assess the singular and combined effects of tidal power development and climate change. Tidal power development and climate change posed risks to ESA-listed species, and risk increased with incorporation of the effects of these stressors on predators and prey of ESA-listed species. In contrast, results of a model of strikes on ESA-listed species from turbine blades suggested that few ESA-listed species are likely to be killed by a commercial-scale tidal turbine array. We applied scenarios to a food web model of Puget Sound to explore the effects of tidal power and climate change on ESA-listed species using more quantitative analytical techniques. To simulate development of tidal power, we applied results of the blade strike model. To simulate environmental changes over the next 50 years, we applied scenarios of change in primary production, plankton community structure, dissolved oxygen, ocean acidification, and freshwater flooding events. No effects of tidal power development on ESA-listed species were detected from the food web model output, but the effects of climate change on them and other members of the food web were large. Our analyses exemplify how natural resource managers might assess environmental effects of marine technologies in ways that explicitly incorporate climate change and consider multiple ESA-listed species in the context of their ecological community. Estimación de los Efectos de Proyectos de Energía de las Mareas y el Cambio Climático sobre Especies Marinas Amenazadas y en Peligro y su Red Alimentaria. © 2013 Society for Conservation Biology No claim to original US government works.

Electrical Power Conversion of a River and Tidal Power Generator: Preprint

Energy Technology Data Exchange (ETDEWEB)

Muljadi, Eduard; Gevorgian, Vahan; Wright, Alan; Donegan, James; Marnagh, Cian; McEntee, Jarlath

2016-09-01

As renewable generation has become less expensive during recent decades, and it becomes more accepted by the global population, the focus on renewable generation has expanded to include new types with promising future applications, such as river and tidal generation. Although the utilization of power electronics and electric machines in industry is phenomenal, the emphasis on system design is different for various sectors of industry. In precision control, robotics, and weaponry, the design emphasis is on accuracy and reliability with less concern for the cost of the final product. In energy generation, the cost of energy is the prime concern; thus, capital expenditures (CAPEX) and operations and maintenance expenditures (OPEX) are the major design objectives. This paper describes the electrical power conversion aspects of river and tidal generation. Although modern power converter control is available to control the generation side, the design was chosen on the bases of minimizing the CAPEX and OPEX; thus, the architecture is simple and modular for ease of replacement and maintenance. The power conversion is simplified by considering a simple diode bridge and a DC-DC power converter to take advantage of abundant and low-cost photovoltaic inverters that have well-proven grid integration characteristics (i.e., the capability to produce energy with good power quality and control real power and voltage on the grid side).

77 FR 58370 - Pennamaquan Tidal Power LLC; Notice of Intent To File License Application, Filing of Pre...

Science.gov (United States)

2012-09-20

... Tidal Power LLC; Notice of Intent To File License Application, Filing of Pre-Application Document (PAD... Filed: July 19, 2012. d. Submitted By: Pennamaquan Tidal Power LLC (Pennamaquan Power). e. Name of Project: Pennamaquan Tidal Power Plant Project. f. Location: On the Pennamaquan River at the entrance to...

Complementary Power Control for Doubly Fed Induction Generator-Based Tidal Stream Turbine Generation Plants

Directory of Open Access Journals (Sweden)

Khaoula Ghefiri

2017-06-01

Full Text Available The latest forecasts on the upcoming effects of climate change are leading to a change in the worldwide power production model, with governments promoting clean and renewable energies, as is the case of tidal energy. Nevertheless, it is still necessary to improve the efficiency and lower the costs of the involved processes in order to achieve a Levelized Cost of Energy (LCoE that allows these devices to be commercially competitive. In this context, this paper presents a novel complementary control strategy aimed to maximize the output power of a Tidal Stream Turbine (TST composed of a hydrodynamic turbine, a Doubly-Fed Induction Generator (DFIG and a back-to-back power converter. In particular, a global control scheme that supervises the switching between the two operation modes is developed and implemented. When the tidal speed is low enough, the plant operates in variable speed mode, where the system is regulated so that the turbo-generator module works in maximum power extraction mode for each given tidal velocity. For this purpose, the proposed back-to-back converter makes use of the field-oriented control in both the rotor side and grid side converters, so that a maximum power point tracking-based rotational speed control is applied in the Rotor Side Converter (RSC to obtain the maximum power output. Analogously, when the system operates in power limitation mode, a pitch angle control is used to limit the power captured in the case of high tidal speeds. Both control schemes are then coordinated within a novel complementary control strategy. The results show an excellent performance of the system, affording maximum power extraction regardless of the tidal stream input.

On-Shore Central Hydraulic Power Generation for Wind and Tidal Energy

Science.gov (United States)

Jones, Jack A.; Bruce, Allan; Lim, Steven; Murray, Luke; Armstrong, Richard; Kimbrall, Richard; Cook-Chenault, Kimberly; DeGennaro, Sean

2012-01-01

Tidal energy, offshore wind energy, and onshore wind energy can be converted to electricity at a central ground location by means of converting their respective energies into high-pressure hydraulic flows that are transmitted to a system of generators by high-pressure pipelines. The high-pressure flows are then efficiently converted to electricity by a central power plant, and the low-pressure outlet flow is returned. The Department of Energy (DOE) is presently supporting a project led by Sunlight Photonics to demonstrate a 15 kW tidal hydraulic power generation system in the laboratory and possibly later submerged in the ocean. All gears and submerged electronics are completely eliminated. A second portion of this DOE project involves sizing and costing a 15 MW tidal energy system for a commercial tidal energy plant. For this task, Atlantis Resources Corporation s 18-m diameter demonstrated tidal blades are rated to operate in a nominal 2.6 m/sec tidal flow to produce approximately one MW per set of tidal blades. Fifteen units would be submerged in a deep tidal area, such as in Maine s Western Passage. All would be connected to a high-pressure (20 MPa, 2900 psi) line that is 35 cm ID. The high-pressure HEPG fluid flow is transported 500-m to on-shore hydraulic generators. HEPG is an environmentally-friendly, biodegradable, watermiscible fluid. Hydraulic adaptations to ORPC s cross-flow turbines are also discussed. For 15 MW of wind energy that is onshore or offshore, a gearless, high efficiency, radial piston pump can replace each set of top-mounted gear-generators. The fluid is then pumped to a central, easily serviceable generator location. Total hydraulic/electrical efficiency is 0.81 at full rated wind or tidal velocities and increases to 0.86 at 1/3 rated velocities.

75 FR 78236 - Pennamaquan Tidal Power, LLC; Notice of Preliminary Permit Application Accepted for Filing and...

Science.gov (United States)

2010-12-15

... Tidal Power, LLC; Notice of Preliminary Permit Application Accepted for Filing and Soliciting Comments, Motions To Intervene, and Competing Applications December 8, 2010. On November 22, 2010, Pennamaquan Tidal... Act (FPA), proposing to study the feasibility of the Pennamaquan Tidal Power Plant Project to be...

NATURE OF WAVE PROCESSES AND THEIR INTERACTION WITH Tidal power PLANTS

Directory of Open Access Journals (Sweden)

Alekseeva Ol'ga Aleksandrovna

2012-07-01

Full Text Available The author examines the nature of wave processes and their impact on the operation of tidal power plants. The article also has an overview of both operating and prospective tidal power plants in Russia and worldwide. Patterns of tidal fluctuations and the intensity of their driving forces are also considered in the article. The author discloses the origin of tides in terms of elementary physics and hydraulics. The author covers various aspects of formation of different types of inequality of tides caused by alterations in the mutual positions of the Sun and the Moon in relation to the Earth, variable declination of tide-generating luminaries (the Sun and the Moon in relation to the plane of the Earth equator, and variable distance between the luminaries and the Earth. The author analyzes wave-related phenomena, including refraction, diffraction and interference, their origin and influence onto the properties of waves. The author also covers the origin of advancing and standing waves, or waves of mixed origin, and the impact of the wind onto the characteristics of wave fluctuations. The author provides suggestions regarding potential methods of their control that can affect the essential concept of construction of tidal power plants.

Water Power Technologies Office 2017 Marine Energy Accomplishments

Energy Technology Data Exchange (ETDEWEB)

Water Power Technologies Office

2018-04-01

The U.S. Department of Energy's Water Power Technologies Office's marine and hydrokinetic portfolio has numerous projects that support industry advancement in wave, tidal, and ocean and river current technologies. In order to strengthen state-of-the-art technologies in these fields and bring them closer to commercialization, the Water Power Technologies Office funds industry, academia, and the national laboratories. A U.S. chapter on marine and hydrokinetic energy research and development was included in the Ocean Energy Systems' Technology Programme—an intergovernmental collaboration between countries, which operates under a framework established by the International Energy Agency. This brochure is an overview of the U.S. accomplishments and updates from that report.

Women's tidal power plant Forty candles for Kislaya Guba TPP

Energy Technology Data Exchange (ETDEWEB)

Chaineux, Marie-Claire [IDRECS, Brussels (Belgium); Charlier, Roger H. [Vrije Universiteit Brussel, Brussels (Belgium)

2008-12-15

Tidal energy has been used for centuries. Tidal current and rise and fall of tides were both put to work. They provided power for flour mills, saw mills, breweries, etc. Tide mills dotted several regions of Europe from The Netherlands to Spain and from Wales to England. Immigrants brought the technique to the 'New World' to the United States and Canada. But they could not withstand the development of more efficient power production and faded away. Though some subsisted well into the 20th century, most of those still in existence offer mainly a tourist interest. However, they may well be considered the forerunners of the power-generating tidal power stations. These are not numerous - except mini plants in China - but with the price of oil soaring a renewed interest as developed. Of all existing stations, the Kislaya Guba station has not the largest; but the only one completely built by women, and it celebrates this year its 40th birthday. (author)

75 FR 59256 - Eastport Tidal Power LLC; Notice of Competing Preliminary Permit Application Accepted for Filing...

Science.gov (United States)

2010-09-27

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Project No. 13830-000] Eastport Tidal... Comments and Motions To Intervene September 17, 2010. On August 9, 2010, Eastport Tidal Power LLC filed an... study the feasibility of the Half Moon Cove Tidal Power Plant Project to be located in Half Moon Cove...

Power Production and Economical Feasibility of Tideng Tidal Stream Power Converter

DEFF Research Database (Denmark)

Parmeggiani, Stefano; Frigaard, Peter; Kofoed, Jens Peter

This report is a product of the contract between Aalborg University and TIDENG (by Bent Hilleke) on the evaluation and development of the TIDENG Tidal Energy Conversion System (TECS). The work has focused on the evaluation of the yearly power production of the device and its economical feasibility...

The environmental aspects of a tidal power project in the upper reaches of the Bay Fundy

Energy Technology Data Exchange (ETDEWEB)

Gordon, D.C.; Longhurst, A.R.

1979-02-01

A recommendation for pre-investment design studies for a tidal power development in the Cumberland Basin region of the Bay of Fundy has been made by the Bay of Fundy Tidal Power Review Board and is backed by Canadian provincial and federal governments. A brief history of regional tidal power proposals is presented, and procedures for determining the environmental impacts of the project are outlined. Possible environmental consequences of tidal power development can be hypothesized, but the existing environmental data base is sparse. Investigations are presently being expanded by university and governmental scientists, and specific impact assessment studies will be commissioned if the project is authorized to proceed. (1 map, 11 references)

The development and application practice of neglected tidal energy in China

Energy Technology Data Exchange (ETDEWEB)

Liu, Li-qun; Liu, Chun-xia; Sun, Zhi-yi; Han, Ru-cheng [Department of Electronic and Information, Taiyuan University of Science and Technology, 030024 Taiyuan, Shanxi Province (China)

2011-02-15

Along the eastcoasts of China are large bodies of water, China has abundant ocean energy resource, such as the theory reserves of tidal resource is about 0.2 billion kW, as early as 1958, Jizhou tidal power station is the first tidal power station in China, which built in Shunde, Guangdong province, and more than 40 small tidal power stations are built in east coastal region in 1960s, and the total installed capacity is about 0.5 MW. But it is a pity, the application and development of tidal energy has not been regarded by the government and ordinary people due to the investment of power plant is big and the technology is not mature, so there are only several small tidal power stations in China, and Jiangxia tidal power station with an installed capacity of 3.2 MW is the most famous. Fortunately, with the rapid development of Chinese economic and society, the renewable and sustainable energy have been regarded by Chinese government, and the application and development of wind energy and solar energy is increasing in an incredible speed, and more and more specialists began to regard the application of tidal energy, and they thought that tidal energy can relieve the energy stress of east coastal region, and many layout of tidal energy exploitation is unfold in recently. This paper discusses the distribution zone and current developmental situation of tidal energy in China. Then, some application practice is described, such as tidal power station and tidal stream turbine. The policies and law of China central government and local governments are described in the following paragraph. At the end, the developmental prospect of tidal energy in future China and the development barriers and recommendations are introduced, respectively. (author)

Tidal Power in the UK and Worldwide to Reduce Greenhouse Gas Emissions

Directory of Open Access Journals (Sweden)

T. J. Hammons

2011-05-01

Full Text Available This paper discusses the role of Tidal Power in the UK in fulfilling the UK's requirements for reducing greenhouse gas emissions. Generating electricity from tidal range of the Severn Estuary has the potential to generate some 5% of UK electricity from a renewable indigenous resource. The paper focuses primarily on the proposed Severn Barrage considering potential benefits, conditions for sustainable development, energy policy context and compliance with environment legislation. UK tidal resource is reviewed: stream resource (that is KE contained in fast-flowing tidal currents, and tidal range resource (that refers to gravitation potential energy. The top tidal range and tidal stream sites in the UK with the resource (in TWh/year are indicated. A feasibility study for Tidal Range development in the Mersey Estuary is also summarised and other schemes including the Loughor Estuary (Wales, Duddon Estuary (located on the Cumbrian coast and the Thames Estuary proposals are reported. Also given is a strategic overview of the Severn Estuary resource, electric output and characteristics, carbon emissions (carbon payback and carbon reduction potential and physical implications of a barrage.

Lightweight steel tidal power barrages with minimal environmental impact: application to the Severn Barrage

Science.gov (United States)

Rainey, R. C. T.

2018-01-01

For tidal power barrages, a breast-shot water wheel, with a hydraulic transmission, has significant advantages over a conventional Kaplan turbine. It is better suited to combined operations with pumping that maintain the tidal range upstream of the barrage (important in reducing the environmental impact), and is much less harmful to fish. It also does not require tapered entry and exit ducts, making the barrage much smaller and lighter, so that it can conveniently be built in steel. For the case of the Severn Estuary, UK, it is shown that a barrage at Porlock would generate an annual average power of 4 GW (i.e. 35 TWh yr-1), maintain the existing tidal ranges upstream of it and reduce the tidal ranges downstream of it by only about 10%. The weight of steel required, in relation to the annual average power generated, compares very favourably with a recent offshore wind farm.

Lightweight steel tidal power barrages with minimal environmental impact: application to the Severn Barrage.

Science.gov (United States)

Rainey, R C T

2018-01-01

For tidal power barrages, a breast-shot water wheel, with a hydraulic transmission, has significant advantages over a conventional Kaplan turbine. It is better suited to combined operations with pumping that maintain the tidal range upstream of the barrage (important in reducing the environmental impact), and is much less harmful to fish. It also does not require tapered entry and exit ducts, making the barrage much smaller and lighter, so that it can conveniently be built in steel. For the case of the Severn Estuary, UK, it is shown that a barrage at Porlock would generate an annual average power of 4 GW (i.e. 35 TWh yr -1 ), maintain the existing tidal ranges upstream of it and reduce the tidal ranges downstream of it by only about 10%. The weight of steel required, in relation to the annual average power generated, compares very favourably with a recent offshore wind farm.

Tidal power from the River Mersey

International Nuclear Information System (INIS)

1991-01-01

The studies described in this report relate to work carried out since those reported upon in the stage I Mersey Barrage Report on the possible construction of a tidal power barrage on the Mersey Estuary. The objectives of the work were to review basic engineering, re-assess cost and energy output, improve engineering configuration, quantify social, industrial and regional effects, determine preferred alignment, review the main environmental impacts, assess economic viability and financing and identify further study requirements. (UK)

Assessment of Power Potential of Tidal Currents and Impacts of Power Extraction on Flow Conditions in Indonesia

Science.gov (United States)

Orhan, Kadir; Mayerle, Roberto

2017-04-01

Climate change is an urgent and potentially irreversible threat to human societies and the planet and thus requires an effective and appropriate response, with a view to accelerating the reduction of global greenhouse gas emissions. At this point, a worldwide shift to renewable energy is crucial. In this study, a methodology comprising of the estimates of power yield, evaluation of the effects of power extraction on flow conditions, and near-field investigations to deliver wake characteristics, recovery and interactions is described and applied to several straits in Indonesia. Site selection is done with high-resolution, three-dimensional flow models providing sufficient spatiotemporal coverage. Much attention has been given to the meteorological forcing, and conditions at the open sea boundaries to adequately capture the density gradients and flow fields. Model verifications using tidal records show excellent agreement. Sites with adequate depth for the energy conversion using horizontal axis tidal turbines, average kinetic power density greater than 0.5 kW/m2, and surface area larger than 0.5km2 are defined as energy hotspots. Spatial variation of the average extractable electric power is determined, and annual tidal energy resource is estimated for the straits in question. The results showed that the potential for tidal power generation in Indonesia is likely to exceed previous predictions reaching around 4,800MW. Models with higher resolutions have been developed to assess the impacts of devices on flow conditions and to resolve near-field turbine wakes in greater detail. The energy is assumed to be removed uniformly by sub-grid scale arrays of turbines. An additional drag force resulting in dissipation of the pre-existing kinetic power from 10% to 60% within a flow cross-section is introduced to capture the impacts. k-ɛ model, which is a second order turbulence closure model is selected to involve the effects of the turbulent kinetic energy and turbulent

The distribution and tapping tidal energy

Directory of Open Access Journals (Sweden)

Zygmunt Kowalik

2004-09-01

Full Text Available Tidal power along tidal shores has been used for centuries to run small tidal mills. Generating electricity by tapping tidal power proved to be very successful only in the last century through the tidal power plant constructed in 1967 in La Rance, France. This used a large barrier to generate the sea level head necessary for driving turbines. Construction of such plants evolved very slowly because of prohibitive costs and concerns about the environmental impact. Developments in the construction of small, efficient and inexpensive underwater turbines admit the possibility of small scale operations that will use local tidal currents to bring electricity to remote locations. Since the generation of such electricity is concerned with the tidal energy in local water bodies, it is important to understand the site-specific energy balance, i.e., the energy flowing in through open boundaries, and the energy generated and dissipated within the local domain. The question is how to tap the tidal energy while keeping possible changes in the present tidal regimes to a minimum. The older approach of constructing barrages may still be quite useful in some locations. The basics of such tidal power plants constructed in a small bay are analyzed in order to understand the principal parameter for tidal plant evaluation, i.e., the power produced.     The new approach is to place turbines - devices similar to windmills - in the pathway of tidal currents. Theoretically, the amount of power available by such turbines for electricity generation is proportional to the water density and velocity cubed of the tidal flow. The naturally dissipated tidal power due to bottom friction forces is also proportional to the cube of the velocity. Because of this similarity, the exploitation of tidal energy can be directed to reinvesting the naturally dissipated power into tidal power for the generation of electricity. This approach to tidal power exploitation is better tuned

Assessment of Power Potential of Tidal Currents and Impacts of Power Extraction on Flow Speeds in Indonesia

Science.gov (United States)

Orhan, K.; Mayerle, R.

2016-12-01

A methodology comprising of the estimates of power yield, evaluation of the effects of power extraction on flow conditions, and near-field investigations to deliver wake characteritics, recovery and interactions is described and applied to several straits in Indonesia. Site selection is done with high-resolution, three-dimensional flow models providing sufficient spatiotemporal coverage. Much attention has been given to the meteorological forcing, and conditions at the open sea boundaries to adequately capture the density gradients and flow fields. Model verification using tidal records shows excellent agreement. Sites with adequate depth for the energy conversion using horizontal axis tidal turbines, average kinetic power density greater than 0.5 kW/m2, and surface area larger than 0.5km2 are defined as energy hotspots. Spatial variation of the average extractable electric power is determined, and annual tidal energy resource is estimated for the straits in question. The results showed that the potential for tidal power generation in Indonesia is likely to exceed previous predictions reaching around 4,800MW. To assess the impact of the devices, flexible mesh models with higher resolutions have been developed. Effects on flow conditions, and near-field turbine wakes are resolved in greater detail with triangular horizontal grids. The energy is assumed to be removed uniformly by sub-grid scale arrays of turbines, and calculations are made based on velocities at the hub heights of the devices. An additional drag force resulting in dissipation of the pre-existing kinetic power from %10 to %60 within a flow cross-section is introduced to capture the impacts. It was found that the effect of power extraction on water levels and flow speeds in adjacent areas is not significant. Results show the effectivess of the method to capture wake characteritics and recovery reasonably well with low computational cost.

Numerical Simulation of an Oscillatory-Type Tidal Current Powered Generator Based on Robotic Fish Technology

Directory of Open Access Journals (Sweden)

Ikuo Yamamoto

2017-10-01

Full Text Available The generation of clean renewable energy is becoming increasingly critical, as pollution and global warming threaten the environment in which we live. While there are many different kinds of natural energy that can be harnessed, marine tidal energy offers reliability and predictability. However, harnessing energy from tidal flows is inherently difficult, due to the harsh environment. Current mechanisms used to harness tidal flows center around propeller-based solutions but are particularly prone to failure due to marine fouling from such as encrustations and seaweed entanglement and the corrosion that naturally occurs in sea water. In order to efficiently harness tidal flow energy in a cost-efficient manner, development of a mechanism that is inherently resistant to these harsh conditions is required. One such mechanism is a simple oscillatory-type mechanism based on robotic fish tail fin technology. This uses the physical phenomenon of vortex-induced oscillation, in which water currents flowing around an object induce transverse motion. We consider two specific types of oscillators, firstly a wing-type oscillator, in which the optimal elastic modulus is being sort. Secondly, the optimal selection of shape from 6 basic shapes for a reciprocating oscillating head-type oscillator. A numerical analysis tool for fluid structure-coupled problems—ANSYS—was used to select the optimum softness of material for the first type of oscillator and the best shape for the second type of oscillator, based on the exhibition of high lift coefficients. For a wing-type oscillator, an optimum elastic modulus for an air-foil was found. For a self-induced vibration-type mechanism, based on analysis of vorticity and velocity distribution, a square-shaped head exhibited a lift coefficient of more than two times that of a cylindrically shaped head. Analysis of the flow field clearly showed that the discontinuous flow caused by a square-headed oscillator results in

The influence of waves on the tidal kinetic energy resource at a tidal stream energy site

International Nuclear Information System (INIS)

Guillou, Nicolas; Chapalain, Georges; Neill, Simon P.

2016-01-01

Highlights: • We model the influence of waves on tidal kinetic energy in the Fromveur Strait. • Numerical results are compared with field data of waves and currents. • The introduction of waves improve predictions of tidal stream power during storm. • Mean spring tidal stream potential is reduced by 12% during extreme wave conditions. • Potential is reduced by 7.8% with waves forces and 5.3% with enhanced friction. - Abstract: Successful deployment of tidal energy converters relies on access to accurate and high resolution numerical assessments of available tidal stream power. However, since suitable tidal stream sites are located in relatively shallow waters of the continental shelf where tidal currents are enhanced, tidal energy converters may experience effects of wind-generated surface-gravity waves. Waves may thus influence tidal currents, and associated kinetic energy, through two non-linear processes: the interaction of wave and current bottom boundary layers, and the generation of wave-induced currents. Here, we develop a three-dimensional tidal circulation model coupled with a phase-averaged wave model to quantify the impact of the waves on the tidal kinetic energy resource of the Fromveur Strait (western Brittany) - a region that has been identified with strong potential for tidal array development. Numerical results are compared with in situ observations of wave parameters (significant wave height, peak period and mean wave direction) and current amplitude and direction 10 m above the seabed (the assumed technology hub height for this region). The introduction of waves is found to improve predictions of tidal stream power at 10 m above the seabed at the measurement site in the Strait, reducing kinetic energy by up to 9% during storm conditions. Synoptic effects of wave radiation stresses and enhanced bottom friction are more specifically identified at the scale of the Strait. Waves contribute to a slight increase in the spatial gradient of

Power Generation for River and Tidal Generators

Energy Technology Data Exchange (ETDEWEB)

Muljadi, Eduard [National Renewable Energy Lab. (NREL), Golden, CO (United States); Wright, Alan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Gevorgian, Vahan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Donegan, James [Ocean Renewable Power Company (ORPC), Portland, ME (United States); Marnagh, Cian [Ocean Renewable Power Company (ORPC), Portland, ME (United States); McEntee, Jarlath [Ocean Renewable Power Company (ORPC), Portland, ME (United States)

2016-06-01

Renewable energy sources are the second largest contributor to global electricity production, after fossil fuels. The integration of renewable energy continued to grow in 2014 against a backdrop of increasing global energy consumption and a dramatic decline in oil prices during the second half of the year. As renewable generation has become less expensive during recent decades, and it becomes more accepted by the global population, the focus on renewable generation has expanded from primarily wind and solar to include new types with promising future applications, such as hydropower generation, including river and tidal generation. Today, hydropower is considered one of the most important renewable energy sources. In river and tidal generation, the input resource flow is slower but also steadier than it is in wind or solar generation, yet the level of water turbulent flow may vary from one place to another. This report focuses on hydrokinetic power conversion.

The commercial prospects for tidal stream power

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-07-01

The prospects for obtaining energy from tidal currents were examined in 1993 when it was concluded that, although the UK resource is large, the unit cost of energy would be relatively high. Interest has continued, however, and in December 2000 the Energy Technology Support Unit (ETSU), on behalf of the Department of Trade and Industry (DTI), commissioned Binnie Black and Veatch (BBV) to re-examine these prospects from a commercial point of view. (author)

Tidal energy UK Government R and D programme. Final report

International Nuclear Information System (INIS)

Craig, J.W.; Davies, L.M.; Allington, M.A.

1996-05-01

The United Kingdom Government's research programme into the feasibility of exploiting tidal power for electricity generation in Britain's estuaries is described in this document. The history of the research is included from the Severn Barrage Committee in 1978 to the conclusion of the tidal energy barrages programme in 1994. The programme sought to reduce uncertainty on costs, technical performance and environmental and regional effects, in order to firm up on decisions on whether to construct certain specific barrages. It was concluded that, while technically feasible, tidal power from barrages, was and will continue to be uneconomic compared with other energy sources. Other renewable technologies would receive further research. (UK)

Assessment of tidal range energy resources based on flux conservation in Jiantiao Bay, China

Science.gov (United States)

Du, Min; Wu, He; Yu, Huaming; Lv, Ting; Li, Jiangyu; Yu, Yujun

2017-12-01

La Rance Tidal Range Power Station in France and Jiangxia Tidal Range Power Station in China have been both long-term successful commercialized operations as kind of role models for public at large for more than 40 years. The Sihwa Lake Tidal Range Power Station in South Korea has also developed to be the largest marine renewable power station with its installed capacity 254 MW since 2010. These practical applications prove that the tidal range energy as one kind of marine renewable energy exploitation and utilization technology is becoming more and more mature and it is used more and more widely. However, the assessment of the tidal range energy resources is not well developed nowadays. This paper summarizes the main problems in tidal range power resource assessment, gives a brief introduction to tidal potential energy theory, and then we present an analyzed and estimated method based on the tide numerical modeling. The technical characteristics and applicability of these two approaches are compared with each other. Furthermore, based on the theory of tidal range energy generation combined with flux conservation, this paper proposes a new assessment method that include a series of evaluation parameters and it can be easily operated to calculate the tidal range energy of the sea. Finally, this method is applied on assessment of the tidal range power energy of the Jiantiao Harbor in Zhejiang Province, China for demonstration and examination.

Characterising the spatial variability of the tidal stream energy resource from floating turbines

Science.gov (United States)

Ward, Sophie; Neill, Simon; Robins, Peter

2017-04-01

The shelf seas, in particular the northwest European shelf seas surrounding the UK, contain significant tidal power potential. Tidal stream energy is both predictable and reliable providing that sites are well-selected based upon the hydrodynamic regime and the device specifics. In this high resolution three-dimensional tidal modelling study, we investigate how the tidal stream resource around the Welsh coast (UK) varies with water depth and location, with particular focus on the Pembrokeshire region. The potential extractable energy for a floating tidal stream energy converter is compared with that for a bottom-fixed device, highlighting the need to vary the resource characterisation criteria based on device specifics. We demonstrate how small variations in the tidal current speeds - with hub depth or due to tidal asymmetry - can lead to substantial variations in potential power output. Further, the results indicate that power generation from floating tidal energy converters will be more significantly influenced by tidal elevations in regions characterised by a lower tidal range (more progressive waves) than regions that experience a high tidal range (standing waves). As numerical modelling capacity improves and tidal stream energy converter technologies develop, ongoing improved quantification of the tidal resource is needed, as well as consideration of the possible feedbacks of the devices and energy extraction on the hydrodynamic regime and the surrounding area.

The internal flow pattern analysis of a tidal power turbine operating on bidirectional generation-pumping

International Nuclear Information System (INIS)

Luo, Y Y; Xiao, Y X; Wang, Z W

2013-01-01

Using tidal energy can reduce environment pollution, save conventional energy and improve energy structure, hence it presents great advantage and is developing potential. Influenced by flood tide and low tide, a fully functional tidal power station needs to experience six operating modes, including bidirectional generation, pumping and sluice; the internal unsteady flow pattern and dynamic characters are very complicated. Based on a bidirectional tidal generator unit, three-dimensional unsteady flows in the flow path were calculated for four typical operating conditions with the pressure pulsation characteristics analyzed. According to the numerical results, the internal flow characteristics in the flow path were discussed. The influence of gravity to the hydraulic performance and flow characteristics were analysed. The results provide a theoretical analysis method of the hydraulic optimization design of the same type unit as well as a direction for stable operation and optimal scheduling of existing tidal power unit

Operational planning of an independent microgrid containing tidal power generators, SOFCs, and photovoltaics

International Nuclear Information System (INIS)

Obara, Shin’ya; Kawai, Masahito; Kawae, Osamu; Morizane, Yuta

2013-01-01

Highlights: ► The characteristics of a microgrid composed of SOFCs and tidal power generators were investigated. ► The CO 2 emissions of this microgrid were calculated based on an oceanographic investigation. ► The frequency and wave form quality of the electric power system were investigated. ► The voltage regulation and reactive power control of the electric power system need to be improved. -- Abstract: The development of local energy systems is important to curtailing global warming and improving public safety. Therefore, in this work, the basic performance of an independent microgrid consisting of tidal power generators, photovoltaics, fuel cells, and heat pumps to locally produce energy for local consumption was analyzed. Fast tidal currents near inlets that join lakes to the sea were converted into electrical energy via a three-phase synchronized generator connected to Darius water turbines. On the basis of the results of an oceanographic survey, the production of electricity and the CO 2 emissions of each generator were calculated using balanced equations for electricity and heat. The calculations indicated that 33% of the CO 2 emissions were associated with the energy supplied through conventional methods during the summer season. Although the frequency and waveform of the electricity of the microgrid were high quality, improvement in the voltage regulation was still required.

Tidal power: will it bring 40 years of virtually free power, or is it still no more than a dream

Energy Technology Data Exchange (ETDEWEB)

Wood, C

1978-04-01

First proposed in Canada in 1919, the use of tidal power to generate electricity remains a well-studied but unproved option. The Cumberland Basin has been recommended for research and engineering studies as a possible site. A single-effect system is preferred over a double-effect system for the Bay of Fundy area because of construction costs. Although major problems arise because the lunar cycle and solar cycles do not coincide, tidal power could provide utility base loads. No significant dampening of the tidal effect was seen to be caused by a dam across open water, but other complications remain to be solved. System stability, the effect of dredging and sedimentation, social and ecological impacts will be examined in the next phase of assessment. A coalition of conservationists will monitor the environmental study. (DCK)

Counter rotating type hydroelectric unit suitable for tidal power station

International Nuclear Information System (INIS)

Kanemoto, T; Suzuki, T

2010-01-01

The counter rotating type hydroelectric unit, which is composed of the axial flow type tandem runners and the peculiar generator with double rotational armatures,was proposed to utilize effectively the tidal power. In the unit, the front and the rear runners counter drive the inner and the outer armatures of the generator, respectively. Besides, the flow direction at the rear runner outlet must coincide with the flow direction at the front runner inlet, because the angular momentum through the rear runner must coincides with that through the front runner. That is, the flow runs in the axial direction at the rear runner outlet while the axial inflow at the front runner inlet. Such operations are suitable for working at the seashore with rising and falling tidal flows, and the unit may be able to take place of the traditional bulb type turbines. The tandem runners were operated at the on-cam conditions, in keeping the induced frequency constant. The output and the hydraulic efficiency are affected by the adjustment of the front and the blade setting angles. The both optimum angles giving the maximum output and/or efficiency were presented at the various discharges/heads. To promote more the tidal power generation by this type unit, the runners were also modified so as to be suitable for both rising and falling flows. The hydraulic performances are acceptable while the output is determined mainly by the trailing edge profiles of the runner blades.

Tidal power plant energy estimation; Cuantificacion de energia de una planta mareomotriz

Energy Technology Data Exchange (ETDEWEB)

Lopez Gonzalez, J.; Hiriart Le Bert, G.; Silva Casarin, R. [Instituto de Ingenieria, Universidad Nacional Autonoma de Mexico (mexico)]. E-mail: JlopezGo@iingen.unam.mx; gerardo367@yahoo.com.mx; RSilvaC@iingen.unam.mx

2010-04-15

In this paper a methodology is presented which allows a quick and simple means of estimating the potential energy that can be obtained from a tidal power plant. The evaluation is made using a normalised nomograph, which is a function of the area of the tidal basin against the electricity installed capacity to thus obtain the potential energy for any location. The results describe two means of operation, one of flow tide and the other flow-ebb tides, with two tidal basin systems operating: single and double reservoir systems. To obtain the normalised nomograph the numerical results for simulations of several tidal power plants under differing operational conditions over a period of one year. These conditions were established by varying the electricity installed capacity, the hydraulic conditions in flow tide, ebb tides or both and with single or double reservoir systems and using sea level information taken every 15 minutes. To validate the model information from the tidal power plant at Rance, France, was used, which includes data concerning production, electricity installed capacity, turbine characteristics and tidal ranges. A very good correlation was found between the results of the numerical model and those reported in various technical reports. [Spanish] Se presenta una metodologia que permite estimar de manera rapida y sencilla el potencial de energia que puede ser extraido a traves de una planta mareomotriz. La evaluacion se realiza utilizando un nomograma normalizado que es funcion del area del embalse versus la capacidad electrica instalada, para asi obtener el potencial energetico en una zona en particular. Los resultados contemplan dos formas de operacion, una llamada en flujo y otra en flujo-reflujo, dos esquemas de embalse (sencillo y doble embalse). Para la elaboracion del nomograma normalizado se utilizaron resultados numericos de la simulacion de multiples plantas mareomotrices bajo diferentes escenarios durante un ano de operacion. Los escenarios

Assessment of tidal and wave energy conversion technologies in Canada

International Nuclear Information System (INIS)

2009-01-01

This paper presented an attractive option to help meet Canada's future energy needs, notably the vast and energetic Atlantic, Pacific and Arctic coastal waters which make ocean renewable energy, particularly tidal in-stream energy conversion (TISEC) and wave energy conversion (WEC). There is much uncertainty regarding the possible environmental impacts associated with their deployment and operation. In support of commercial development of the industry, a review of scientific knowledge was needed for the development of policy and regulations consistent with Canada's conservation and sustainability priorities. In April 2009, Fisheries and Oceans Canada (DFO) hosted a two-day national science advisory process meeting in order to determine the current state of knowledge on the environmental impacts of tidal and wave energy conversion technologies and their application in the Canadian context based on published reports. Potential mitigation measures were identified and the feasibility of developing a relevant Canadian statement of practice was determined. This report presented an assessment and analysis of wave power, including the impacts on physical processes; impacts on habitat characteristics; impacts on water quality; impacts of noise and vibrations; impacts of electromagnetic fields; impacts of physical encounters; cumulative impacts; and mitigation measures. It was concluded that there is a recognized need to develop and maintain national and regional georeferenced, interoperable, standards-based databases that enable access by governments, developers, academics, non-governmental organizations and the general public. 1 ref., 1 fig.

An Experimental Study on the Darrieus-Savonius Turbine for the Tidal Current Power Generation

Science.gov (United States)

Kyozuka, Yusaku

The Darrieus turbine is popular for tidal current power generation in Japan. It is simple in structure with straight wings rotating around a vertical axis, so that it has no directionality against the motion of tidal flow which changes its direction twice a day. However, there is one defect in the Darrieus turbine; its small starting torque. Once it stops, a Darrieus turbine is hard to re-start until a fairly fast current is exerted on it. To improve the starting torque of the Darrieus turbine used for tidal power generation, a hybrid turbine, composed of a Darrieus turbine and a Savonius rotor is proposed. Hydrodynamic characteristics of a semi-circular section used for the Savonius bucket were measured in a wind tunnel. The torque of a two bucket Savonius rotor was measured in a circulating water channel, where four different configurations of the bucket were compared. A combined Darrieus and Savonius turbine was tested in the circulating water channel, where the effect of the attaching angle between Darrieus wing and Savonius rotor was studied. Finally, power generation experiments using a 48 pole electric generator were conducted in a towing tank and the power coefficients were compared with the results of experiments obtained in the circulating water channel.

Acoustic Monitoring of Beluga Whale Interactions with Cook Inlet Tidal Energy Project

Energy Technology Data Exchange (ETDEWEB)

Worthington, Monty [ORPC Alaska, LLC, Anchorage, AK (United States)

2014-02-05

FERC pilot project process. The Project compared results obtained from this method to results obtained from other passive hydrophone technologies and to visual observation techniques performed simultaneously. This Final Report makes recommendations on the best practice for future data collection, for ORPC’s work in Cook Inlet specifically, and for tidal power projects in general. This Project developed a marine mammal study design and compared technologies for hydroacoustic and visual data collection with potential for broad application to future tidal and hydrokinetic projects in other geographic areas. The data collected for this Project will support the environmental assessment of future Cook Inlet tidal energy projects, including ORPC’s East Foreland Tidal Energy Project and any tidal energy developments at Fire Island. The Project’s rigorous assessment of technology and methodologies will be invaluable to the hydrokinetic industry for developing projects in an environmentally sound and sustainable way for areas with high marine mammal activity or endangered populations. By combining several different sampling methods this Project will also contribute to the future preparation of a comprehensive biological assessment of ORPC’s projects in Cook Inlet.

The Tidal Power Station on the Rance | Gabre - Amlak | Zede Journal

African Journals Online (AJOL)

The Tidal Power Station on the Rance. A Gabre - Amlak. Abstract. No Abstract. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and Conditions of Use · Contact AJOL · News. OTHER RESOURCES... for Researchers · for ...

Tidal energy, a renewable energy within hand reach

International Nuclear Information System (INIS)

Danielo, O.

2011-01-01

Tide energy and oceanic current energy represent a strong potentiality for a few countries in the world including France. In the domain of tidal energy there are 2 strategies. The first one is based on the search for the lowest power production cost in order to contribute efficiently to the country's energy mix. Generally this strategy leads to the construction of tidal dams. The second strategy is based on the search for the lowest environmental impact. This strategy is economically competitive only in places where electrical power is expensive like isolated islands. This strategy is illustrated by the tidal power station of the Alderney island. In fact the amount of energy delivered by a tidal power station depends on the rise of the tide and on the surface of the dam. It appears that tidal dams require less surface that hydroelectric power plants. The energy of oceanic currents like Gulf Stream or the thermal energy of oceans or wave power are very little exploited now but represent a potentiality higher by several orders of magnitude than tidal energy. (A.C.)

Bay of Fundy tidal energy : a response to the strategic environmental assessment

International Nuclear Information System (INIS)

2008-06-01

Tidal in-stream energy conversion is an emerging technology to harness sea power. These energy conversion devices are similar to underwater windmills. The government of Nova Scotia is interested in understanding the potential effects of these devices on the Bay of Fundy. As a result, it commissioned a strategic environmental assessment (SEA) that was completed in the spring of 2008. This document presented a response to the SEA. It discussed Nova Scotia's specific approach to tidal energy as well as the province's broader approach to marine renewable energy in the Bay of Fundy, with specific responses to each recommendation in the SEA. The energy context was presented, with particular reference to energy strategy; emissions; legal requirements; production costs; and carbon costs. The report also discussed tidal lagoon technology as well as a demonstration facility called the Fundy Tidal Energy Centre. The objectives of the SEA were also described and recommendations were presented. Recommendations were grouped under several key themes such as sustainability principles; allowing the demonstration of tidal in-stream energy conversion (TISEC) technologies; marine renewable energy legislation; research program; Mi'kmaq ecological knowledge study; provincial standard for ecological data; Bay of Fundy socioeconomic background study; marine renewable energy demonstration program; siting demonstration projects; and environmental assessment of the demonstration facility. figs

Assessment of tidal circulation and tidal current asymmetry in the Iroise sea with specific emphasis on characterization of tidal energy resources around the Ushant Island.

Science.gov (United States)

Thiébaut, Maxime; Sentchev, Alexei

2015-04-01

We use the current velocity time series recorded by High Frequency Radars (HFR) to study circulation in highly energetic tidal basin - the Iroise sea. We focus on the analysis of tidal current pattern around the Ushant Island which is a promising site of tidal energy. The analysis reveals surface current speeds reaching 4 m/s in the North of Ushant Island and in the Fromveur Strait. In these regions 1 m/s is exceeded 60% of time and up to 70% of time in center of Fromveur. This velocity value is particularly interesting because it represents the cut-in-speed of the most of marine turbine devices. Tidal current asymmetry is not always considered in tidal energy site selection. However, this quantity plays an important role in the quantification of hydrokinetic resources. Current velocity times series recorded by HFR highlights the existence of a pronounced asymmetry in current magnitude between the flood and ebb tide ranging from -0.5 to more 2.5. Power output of free-stream devices depends to velocity cubed. Thus a small current asymmetry can generate a significant power output asymmetry. Spatial distribution of asymmetry coefficient shows persistent pattern and fine scale structure which were quantified with high degree of accuracy. The particular asymmetry evolution on both side of Fromveur strait is related to the spatial distribution of the phase lag of the principal semi-diurnal tidal constituent M2 and its higher order harmonics. In Fromveur, the asymmetry is reinforced due to the high velocity magnitude of the sixth-diurnal tidal harmonics. HF radar provides surface velocity speed, however the quantification of hydrokinetic resources has to take into account the decreasing of velocity with depth. In order to highlight this phenomenon, we plot several velocity profiles given by an ADCP which was installed in the HFR study area during the same period. The mean velocity in the water column calculated by using the ADCP data show that it is about 80% of the

Levelised costs of Wave and Tidal energy in the UK: Cost competitiveness and the importance of 'banded' Renewables Obligation Certificates

International Nuclear Information System (INIS)

Allan, Grant; Gilmartin, Michelle; McGregor, Peter; Swales, Kim

2011-01-01

In this paper, publicly available cost data are used to calculate the private levelised costs of two marine energy technologies for UK electricity generation: Wave and Tidal Stream power. These estimates are compared to those for ten other electricity generation technologies whose costs were identified by the UK Government (). Under plausible assumptions for costs and performance, point estimates of the levelised costs of Wave and Tidal Stream generation are Pounds 190 and Pounds 81/MWh, respectively. Sensitivity analysis shows how these relative private levelised costs calculations are affected by variation in key parameters, specifically the assumed capital costs, fuel costs and the discount rate. We also consider the impact of the introduction of technology-differentiated financial support for renewable energy on the cost competitiveness of Wave and Tidal Stream power. Further, we compare the impact of the current UK government support level to the more generous degree of assistance for marine technologies that is proposed by the Scottish government. - Research highlights: → Levelised costs of electricity generation from wave and tidal stream in UK calculated. → Comparison to ten renewable and non-renewable technologies demonstrated. → Sensitivity of levelised costs to key assumptions is demonstrated. → Technology-specific financial support revealed to be insufficient at current costs.

Tidal Venuses: triggering a climate catastrophe via tidal heating.

Science.gov (United States)

Barnes, Rory; Mullins, Kristina; Goldblatt, Colin; Meadows, Victoria S; Kasting, James F; Heller, René

2013-03-01

Traditionally, stellar radiation has been the only heat source considered capable of determining global climate on long timescales. Here, we show that terrestrial exoplanets orbiting low-mass stars may be tidally heated at high-enough levels to induce a runaway greenhouse for a long-enough duration for all the hydrogen to escape. Without hydrogen, the planet no longer has water and cannot support life. We call these planets "Tidal Venuses" and the phenomenon a "tidal greenhouse." Tidal effects also circularize the orbit, which decreases tidal heating. Hence, some planets may form with large eccentricity, with its accompanying large tidal heating, and lose their water, but eventually settle into nearly circular orbits (i.e., with negligible tidal heating) in the habitable zone (HZ). However, these planets are not habitable, as past tidal heating desiccated them, and hence should not be ranked highly for detailed follow-up observations aimed at detecting biosignatures. We simulated the evolution of hypothetical planetary systems in a quasi-continuous parameter distribution and found that we could constrain the history of the system by statistical arguments. Planets orbiting stars with massesplanet orbiting a 0.3 MSun star at 0.12 AU. We found that it probably did not lose its water via tidal heating, as orbital stability is unlikely for the high eccentricities required for the tidal greenhouse. As the inner edge of the HZ is defined by the onset of a runaway or moist greenhouse powered by radiation, our results represent a fundamental revision to the HZ for noncircular orbits. In the appendices we review (a) the moist and runaway greenhouses, (b) hydrogen escape, (c) stellar mass-radius and mass-luminosity relations, (d) terrestrial planet mass-radius relations, and (e) linear tidal theories.

A modeling study of tidal energy extraction and the associated impact on tidal circulation in a multi-inlet bay system of Puget Sound

Energy Technology Data Exchange (ETDEWEB)

Wang, Taiping; Yang, Zhaoqing

2017-12-01

Previous tidal energy projects in Puget Sound have focused on major deep channels such as Admiralty Inlet that have a larger power potential but pose greater technical challenges than minor tidal channels connecting to small sub-basins. This paper focuses on the possibility of extracting energy from minor tidal channels by using a hydrodynamic model to quantify the power potential and the associated impact on tidal circulation. The study site is a multi-inlet bay system connected by two narrow inlets, Agate Pass and Rich Passage, to the Main Basin of Puget Sound. A three-dimensional hydrodynamic model was applied to the study site and calibrated for tidal elevations and currents. We examined three energy extraction scenarios in which turbines were deployed in each of the two passages and concurrently in both. Extracted power rates and associated changes in tidal elevation, current, tidal flux, and residence time were examined. Maximum instantaneous power rates reached 250 kW, 1550 kW, and 1800 kW, respectively, for the three energy extraction scenarios. The model suggests that with the proposed level of energy extraction, the impact on tidal circulation is very small. It is worth investigating the feasibility of harnessing tidal energy from minor tidal channels of Puget Sound.

Development of a model counter-rotating type horizontal-axis tidal turbine

Science.gov (United States)

Huang, B.; Yoshida, K.; Kanemoto, T.

2016-05-01

In the past decade, the tidal energies have caused worldwide concern as it can provide regular and predictable renewable energy resource for power generation. The majority of technologies for exploiting the tidal stream energy are based on the concept of the horizontal axis tidal turbine (HATT). A unique counter-rotating type HATT was proposed in the present work. The original blade profiles were designed according to the developed blade element momentum theory (BEMT). CFD simulations and experimental tests were adopted to the performance of the model counter-rotating type HATT. The experimental data provides an evidence of validation of the CFD model. Further optimization of the blade profiles was also carried out based on the CFD results.

Multi-Layer Artificial Neural Networks Based MPPT-Pitch Angle Control of a Tidal Stream Generator

Directory of Open Access Journals (Sweden)

Khaoula Ghefiri

2018-04-01

Full Text Available Artificial intelligence technologies are widely investigated as a promising technique for tackling complex and ill-defined problems. In this context, artificial neural networks methodology has been considered as an effective tool to handle renewable energy systems. Thereby, the use of Tidal Stream Generator (TSG systems aim to provide clean and reliable electrical power. However, the power captured from tidal currents is highly disturbed due to the swell effect and the periodicity of the tidal current phenomenon. In order to improve the quality of the generated power, this paper focuses on the power smoothing control. For this purpose, a novel Artificial Neural Network (ANN is investigated and implemented to provide the proper rotational speed reference and the blade pitch angle. The ANN supervisor adequately switches the system in variable speed and power limitation modes. In order to recover the maximum power from the tides, a rotational speed control is applied to the rotor side converter following the Maximum Power Point Tracking (MPPT generated from the ANN block. In case of strong tidal currents, a pitch angle control is set based on the ANN approach to keep the system operating within safe limits. Two study cases were performed to test the performance of the output power. Simulation results demonstrate that the implemented control strategies achieve a smoothed generated power in the case of swell disturbances.

Strategies for the Use of Tidal Stream Currents for Power Generation

Science.gov (United States)

Orhan, Kadir; Mayerle, Roberto

2015-04-01

Indonesia is one of the priority countries in Southeast Asia for the development of ocean renewable energy facilities and The National Energy Council intends to increase the role of ocean energy significantly in the energy mix for 2010-2050. To this end, the joint German-Indonesian project "Ocean Renewable Energy ORE-12" aims at the identification of marine environments in the Indonesian Archipelago, which are suitable for the efficient generation of electric power by converter facilities. This study, within the ORE-12 project, is focused on the tidal stream currents on the straits between the Indian Ocean and Flores Sea to estimate the energy potentials and to develop strategies for producing renewable energy. FLOW module of Delft3D has been used to run hydrodynamic models for site assessment and design development. In site assessment phase, 2D models have been operated for a-month long periods and with a resolution of 500 m. Later on, in design development phase, detailed 3D models have been developed and operated for three-month long periods and with a resolution of 50 m. Bathymetric data for models have been obtained from the GEBCO_08 Grid and wind data from the Global Forecast System of NOAA's National Climatic Data Center. To set the boundary conditions of models, tidal forcing with 11 harmonic constituents was supplied from TPXO Indian Ocean Atlas (1/12° regional model) and data from HYCOM+NCODA Global 1/12° Analysis have been used to determine salinity and temperature on open boundaries. After the field survey is complete, water level time-series supplied from a tidal gauge located in the domain of interest (8° 20΄ 9.7" S, 122° 54΄ 51.9" E) have been used to verify the models and then energy potentials of the straits have been estimated. As a next step, correspondence between model outputs and measurements taken by the radar system of TerraSAR-X satellite (DLR) will be analysed. Also for the assessment of environmental impacts caused by tidal stream

Utilization of tidal power in Russia in overcoming the global energy and ecological crisis

International Nuclear Information System (INIS)

Bernshtein, L.B.; Usachev, I.N.

1997-01-01

The 30 years of the exploitation of the TPP Rance in France and Kyslogubskaya TPP in Russia had proved the energy expedience economical and ecological effectiveness and a high performance of the tidal energy. The possibility of such utilizing could be proved thanks to the application of the theoretical cycles of Gibrat, of the bulb units and the russian model of the tidal utilizing and application of the floating methods of creating the TPP. The investigations at TPP Kislaya Guba helped to solve the row of problems of marine power building with the high exploitation performance and ecological safety. Thus the TPP of Mezen with a capacity of 17 million kW can transfer to the united power system of Europe 50 TWh/year and the Tugur TPP with a capacity 8 million kW can produce 20 TWh/year of energy for the power system of seaside of Russian and Japan. Penzinskaya TPP with the capacity of 87 million kW can be promoted in 21. century in connection to the advanced in USA proposition of construction of the combining transport-power tunnel across the Bering Strait. (authors)

Tidal sails : an alternative to turbines for harvesting tidal current energy

Energy Technology Data Exchange (ETDEWEB)

Hanssen, J.E. [Tidal Sails, Haugesund (Norway)

2008-07-01

Tidal sail technology harnesses the energy of tidal streams in order to produce electricity. Tidal currents move the sails that are attached to wires that rotate generator wheels to produce electricity. The technology has a low impact on the surrounding environment and is simple to install. This presentation discussed the methods used to determine the influence of relative sail velocity and measure estimated energy output levels. The sails were recently tested at an on-grid tidal stream pilot in the Norwegian Arctic. A 300 kW turbine installed at the site demonstrated that the site was suitable for a full-scale development of 20 tripod-mounted 600 kW turbines placed at 50 m depth. It was estimated that the 10 strings of 1000 m length provided between 200 and 250 GWh per year. The sails have also been used at a high speed site in Washington state in the United States. The 25 m pilot plant was installed to verify site suitability and examine sail behaviour in real, high-flow currents. It is expected that the technology will be fully commercialized by 2011. Other pilot tests are being conducted to examine flow behaviour; mooring and flotation functionality; and launch and lift capabilities. Engineering work is ongoing to examine plant designs, variable sail spacing, and collaborations with key component suppliers. tabs., figs.

Tidal Venuses: Triggering a Climate Catastrophe via Tidal Heating

Science.gov (United States)

Mullins, Kristina; Goldblatt, Colin; Meadows, Victoria S.; Kasting, James F.; Heller, René

2013-01-01

Abstract Traditionally, stellar radiation has been the only heat source considered capable of determining global climate on long timescales. Here, we show that terrestrial exoplanets orbiting low-mass stars may be tidally heated at high-enough levels to induce a runaway greenhouse for a long-enough duration for all the hydrogen to escape. Without hydrogen, the planet no longer has water and cannot support life. We call these planets “Tidal Venuses” and the phenomenon a “tidal greenhouse.” Tidal effects also circularize the orbit, which decreases tidal heating. Hence, some planets may form with large eccentricity, with its accompanying large tidal heating, and lose their water, but eventually settle into nearly circular orbits (i.e., with negligible tidal heating) in the habitable zone (HZ). However, these planets are not habitable, as past tidal heating desiccated them, and hence should not be ranked highly for detailed follow-up observations aimed at detecting biosignatures. We simulated the evolution of hypothetical planetary systems in a quasi-continuous parameter distribution and found that we could constrain the history of the system by statistical arguments. Planets orbiting stars with massestidal heating. We have applied these concepts to Gl 667C c, a ∼4.5 MEarth planet orbiting a 0.3 MSun star at 0.12 AU. We found that it probably did not lose its water via tidal heating, as orbital stability is unlikely for the high eccentricities required for the tidal greenhouse. As the inner edge of the HZ is defined by the onset of a runaway or moist greenhouse powered by radiation, our results represent a fundamental revision to the HZ for noncircular orbits. In the appendices we review (a) the moist and runaway greenhouses, (b) hydrogen escape, (c) stellar mass-radius and mass-luminosity relations, (d) terrestrial planet mass-radius relations, and (e) linear tidal theories. Key Words: Extrasolar terrestrial planets—Habitability—Habitable zone�

An optimal tuning strategy for tidal turbines

Science.gov (United States)

2016-01-01

Tuning wind and tidal turbines is critical to maximizing their power output. Adopting a wind turbine tuning strategy of maximizing the output at any given time is shown to be an extremely poor strategy for large arrays of tidal turbines in channels. This ‘impatient-tuning strategy’ results in far lower power output, much higher structural loads and greater environmental impacts due to flow reduction than an existing ‘patient-tuning strategy’ which maximizes the power output averaged over the tidal cycle. This paper presents a ‘smart patient tuning strategy’, which can increase array output by up to 35% over the existing strategy. This smart strategy forgoes some power generation early in the half tidal cycle in order to allow stronger flows to develop later in the cycle. It extracts enough power from these stronger flows to produce more power from the cycle as a whole than the existing strategy. Surprisingly, the smart strategy can often extract more power without increasing maximum structural loads on the turbines, while also maintaining stronger flows along the channel. This paper also shows that, counterintuitively, for some tuning strategies imposing a cap on turbine power output to limit loads can increase a turbine’s average power output. PMID:27956870

An optimal tuning strategy for tidal turbines.

Science.gov (United States)

Vennell, Ross

2016-11-01

Tuning wind and tidal turbines is critical to maximizing their power output. Adopting a wind turbine tuning strategy of maximizing the output at any given time is shown to be an extremely poor strategy for large arrays of tidal turbines in channels. This 'impatient-tuning strategy' results in far lower power output, much higher structural loads and greater environmental impacts due to flow reduction than an existing 'patient-tuning strategy' which maximizes the power output averaged over the tidal cycle. This paper presents a 'smart patient tuning strategy', which can increase array output by up to 35% over the existing strategy. This smart strategy forgoes some power generation early in the half tidal cycle in order to allow stronger flows to develop later in the cycle. It extracts enough power from these stronger flows to produce more power from the cycle as a whole than the existing strategy. Surprisingly, the smart strategy can often extract more power without increasing maximum structural loads on the turbines, while also maintaining stronger flows along the channel. This paper also shows that, counterintuitively, for some tuning strategies imposing a cap on turbine power output to limit loads can increase a turbine's average power output.

Large tidal plants may supply 1,000 TWh / year

International Nuclear Information System (INIS)

Lemperiere, F.

2006-10-01

Many studies of tidal plants have been made fifty years ago: they were usually devoted to sites with average tidal head over 6 m and reduced works at sea: estuaries such as La Rance (France) or Severn (U.K.) were favoured: preferred corresponding operation was using flow from a high basin to low sea level, supplying power 4 hours from 12. Such solutions had 2 drawbacks: power supply poorly adapted to needs and modified shore tidal ecosystems. Beyond that the power cost was usually higher than from thermal plants and very few plants were built, the main one being the Rance plant in France supplying 0,5 TWh/year with 240 MW. The world theoretical tidal potential is in the same range as the traditional hydropower potential. A new approach of tidal plants based upon solutions existing now and using new operating methods substantiates the possibility of over 1,000 TWh/year of cost efficient tidal energy with limited environmental impact and power supply well adapted to requirements. Over 15 countries may be involved. Tidal plants with heads as low as 4 m may be cost efficient. (author)

Cost Assessment Methodology and Economic Viability of Tidal Energy Projects

Directory of Open Access Journals (Sweden)

Eva Segura

2017-11-01

Full Text Available The exploitation of technologies with which to harness the energy from ocean currents will have considerable possibilities in the future thanks to their enormous potential for electricity production and their high predictability. In this respect, the development of methodologies for the economic viability of these technologies is fundamental to the attainment of a consistent quantification of their costs and the discovery of their economic viability, while simultaneously attracting investment in these technologies. This paper presents a methodology with which to determine the economic viability of tidal energy projects, which includes a technical study of the life-cycle costs into which the development of a tidal farm can be decomposed: concept and definition, design and development, manufacturing, installation, operation and maintenance and dismantling. These cost structures are additionally subdivided by considering their sub-costs and bearing in mind the main components of the tidal farm: the nacelle, the supporting tidal energy converter structure and the export power system. Furthermore, a technical study is developed in order to obtain an estimation of the annual energy produced (and, consequently, the incomes generated if the electric tariff is known by considering its principal attributes: the characteristics of the current, the ability of the device to capture energy and its ability to convert and export the energy. The methodology has been applied (together with a sensibility analysis to the particular case of a farm composed of first generation tidal energy converters in one of the Channel Island Races, the Alderney Race, in the U.K., and the results have been attained by means of the computation of engineering indexes, such as the net present value, the internal rate of return, the discounted payback period and the levelized cost of energy, which indicate that the proposed project is economically viable for all the case studies.

Impact of the tidal power dam in the Rance estuary: geomorphological changes, hydrosedimentary processes and reconstructions plans

Science.gov (United States)

Susperregui, A.

2010-12-01

The Rance basin (France) offers potential to make a full-scale assessment of the environmental impact of a tidal power station after 50 years of operation. Consequences on biology, hydrodynamics and sedimentology were observed and nowadays, some of these changes are still acting on the natural system. The tidal dynamic was completely artificialised by the dam construction. The two main consequences are the reduction of exundation area and the extension of slack duration. Sedimentary dynamic depending on hydrodynamics conditions, changes in sediment distribution were also observed. Before the tidal power station construction, sands lined the gravel bed channel, recovered the bottom and formed beaches and banks. Coves and the upstream part of the estuary were dominated by a fine sedimentation, forming mudflats in a classical configuration slikke/schorre. Nowadays, mudflats extended to the center of the basin and all coves are occupied. The important inertia induced by the slack extension caused a slowing down on currents velocities, making easier the fine suspension deposit. The siltation is most important upstream, were the turbidity maximum was shifted, generating problems for navigation and banks access. A solution of sediment management was envisaged from 2001, by the digging of a sediments trap of 91 000 m3, near the Châtelier Lock. Sedimentation monitoring in this trap shows an intense filling over the first two years of functioning, then a slowing down leading to a complete filling from 2005. This trap also showed a beneficial interest on the sedimentation rates of the mudflats closed to it, which decreased. To understand how fine sediment is eroded and transported into this maritime area, an optical backscatter sensor was installed 1.5 km upstream of the tidal power station. During spring tides, the tidal power station functions in a “double-acting” cycle. This particular working leads to an important increase of turbidity during the artificial tidal

Half Moon Cove Tidal Project. Feasibility report

Energy Technology Data Exchange (ETDEWEB)

1980-11-01

The proposed Half Moon Cove Tidal Power Project would be located in a small cove in the northern part of Cobscook Bay in the vicinity of Eastport, Maine. The project would be the first tidal electric power generating plant in the United States of America. The basin impounded by the barrier when full will approximate 1.2 square miles. The average tidal range at Eastport is 18.2 feet. The maximum spring tidal range will be 26.2 feet and the neap tidal range 12.8 feet. The project will be of the single pool-type single effect in which generation takes place on the ebb tide only. Utilizing an average mean tidal range of 18.2 feet the mode of operation enables generation for approximately ten and one-half (10-1/2) hours per day or slightly in excess of five (5) hours per tide. The installed capacity will be 12 MW utilizing 2 to 6 MW units. An axial flow, or Bulb type of turbine was selected for this study.

Estimation of energy potential and power generation from tidal basin in coastal area of malaysia

Directory of Open Access Journals (Sweden)

Nazri Nazani

2016-01-01

Full Text Available This paper presents the potential of tidal energy in Malaysia. Malaysia is heavily depending on the fossil fuel to satisfy the energy demand. However, this reserve energy is reported will be depleted. The population growth also caused the demand on energy increase over the year. This situation can lead to the global warming and climate change that be a major concern around the world. As an alternative, renewable energy become a solution in order to reduce the usage of conventional energy such as fossil fuel, coal and gas. One of the renewable energy that can be used is from ocean energy. Since the tidal energy is not study thoroughly in Malaysia and Malaysia has a potential sites that can implement this tidal energy for electricity generation to meet the local demand. This tidal energy can be harnessed in several approach such as by using tidal barrage single basin with single mode generation consist ebb-mode and flood-mode of generation and the other approach of single mode is double-mode of generation. In order to meet the local demand, single-mode generation and double-mode generation was studied by getting the number of population at that area, the electricity demand then from that data the basin area is estimated for power generation. The result shows that double-mode generation is one of the approaches that meet the local demand for electricity.

Atmospheric noise of a breaking tidal bore.

Science.gov (United States)

Chanson, Hubert

2016-01-01

A tidal bore is a surge of waters propagating upstream in an estuary as the tidal flow turns to rising and the flood tide propagates into a funnel-shaped system. Large tidal bores have a marked breaking roller. The sounds generated by breaking tidal bores were herein investigated in the field (Qiantang River) and in laboratory. The sound pressure record showed two dominant periods, with some similarity with an earlier study [Chanson (2009). J. Acoust. Soc. Am. 125(6), 3561-3568]. The two distinct phases were the incoming tidal bore when the sound amplitude increased with the approaching bore, and the passage of the tidal bore in front of the microphone when loud and powerful noises were heard. The dominant frequency ranged from 57 to 131 Hz in the Qiantang River bore. A comparison between laboratory and prototype tidal bores illustrated both common features and differences. The low pitch sound of the breaking bore had a dominant frequency close to the collective oscillations of bubble clouds, which could be modeled with a bubble cloud model using a transverse dimension of the bore roller. The findings suggest that this model might be over simplistic in the case of a powerful breaking bore, like that of the Qiantang River.

A Framework for Optimizing the Placement of Tidal Turbines

Science.gov (United States)

Nelson, K. S.; Roberts, J.; Jones, C.; James, S. C.

2013-12-01

Power generation with marine hydrokinetic (MHK) current energy converters (CECs), often in the form of underwater turbines, is receiving growing global interest. Because of reasonable investment, maintenance, reliability, and environmental friendliness, this technology can contribute to national (and global) energy markets and is worthy of research investment. Furthermore, in remote areas, small-scale MHK energy from river, tidal, or ocean currents can provide a local power supply. However, little is known about the potential environmental effects of CEC operation in coastal embayments, estuaries, or rivers, or of the cumulative impacts of these devices on aquatic ecosystems over years or decades of operation. There is an urgent need for practical, accessible tools and peer-reviewed publications to help industry and regulators evaluate environmental impacts and mitigation measures, while establishing best sitting and design practices. Sandia National Laboratories (SNL) and Sea Engineering, Inc. (SEI) have investigated the potential environmental impacts and performance of individual tidal energy converters (TECs) in Cobscook Bay, ME; TECs are a subset of CECs that are specifically deployed in tidal channels. Cobscook Bay is the first deployment location of Ocean Renewable Power Company's (ORPC) TidGenTM unit. One unit is currently in place with four more to follow. Together, SNL and SEI built a coarse-grid, regional-scale model that included Cobscook Bay and all other landward embayments using the modeling platform SNL-EFDC. Within SNL-EFDC tidal turbines are represented using a unique set of momentum extraction, turbulence generation, and turbulence dissipation equations at TEC locations. The global model was then coupled to a local-scale model that was centered on the proposed TEC deployment locations. An optimization frame work was developed that used the refined model to determine optimal device placement locations that maximized array performance. Within the

Experimental and numerical study of a flapping tidal stream generator

Science.gov (United States)

Kim, Jihoon; Le, Tuyen Quang; Ko, Jin Hwan; Sitorus, Patar Ebenezer; Tambunan, Indra Hartarto; Kang, Taesam

2017-11-01

The tidal stream turbine is one of the systems that extract kinetic energy from tidal stream, and there are several types of the tidal stream turbine depending on its operating motion. In this research, we conduct experimental and consecutive numerical analyses of a flapping tidal stream generator with a dual configuration flappers. An experimental analysis of a small-scale prototype is conducted in a towing tank, and a numerical analysis is conducted using two-dimensional computational fluid dynamics simulations with an in-house code. Through an experimental analysis conducted while varying these factors, a high applied load and a high input arm angle were found to be advantageous. In consecutive numerical investigations with the kinematics selected from the experiments, it was found that a rear-swing flapper contributes to the total amount of power more than a front-swing flapper with a distance of two times the chord length and with a 90-degree phase difference between the two. This research was a part of the project titled `R&D center for underwater construction robotics', funded by the Ministry of Oceans and Fisheries(MOF), Korea Institute of Marine Science & Technology Promotion(KIMST,PJT200539), and Pohang City in Korea.

Assessment of Kinetic Tidal Energy Resources Using SELFE

Directory of Open Access Journals (Sweden)

Manasa Ranjan Behera

2014-09-01

Full Text Available An investigation is carried out to study the theoretical tidal stream energy resource in the Singapore Strait to support the search for renewable energy in the effort to reduce the carbon footprints in the Southeast Asia. The tidal hydrodynamics in the Singapore Strait has been simulated using a Semi-implicit Eulerian-Lagrangian Finite-Element (SELFE model solving the 3D shallow water equations with Boussinesq approximations. Potential sites, with high tidal current (2.5 m/s and suitable for Tidal Energy Converter (TEC array installation to generate sustainable energy, have been identified. Further, various operational factors for installation of Tidal Energy Converters are considered before computing the theoretical power output for a typical TEC array. An approximate estimation of the possible theoretical power extraction from a TEC array shows an energy potential of up to 4.36% of the total energy demand of Singapore in 2011. Thus, the study suggests a detailed investigation of potential sites to quantify the total tidal stream energy potential in the Singapore Strait.

Quadrennial Technology Review 2015: Technology Assessments--Marine and Hydrokinetic Power

Energy Technology Data Exchange (ETDEWEB)

Sam Baldwin, Gilbert Bindewald, Austin Brown, Charles Chen, Kerry Cheung, Corrie Clark, Joe Cresko,

2015-10-07

Marine and hydrokinetic (MHK) technologies convert the energy of waves, tides, and river and ocean currents into electricity. With more than 50% of the U.S. population living within 50 miles of the nation’s coasts, MHK technologies hold significant potential to supply renewable electricity to consumers in coastal load centers, particularly in the near term in areas with high costs of electricity and longer term in high resource areas in close proximity to major coastal load centers. MHK resource assessments identify a total U.S. technical resource potential of approximately 1250–1850 terawatt-hours (TWh) of generation per year from ocean wave, ocean current, ocean tidal, and river current energy. Of this, the U.S. continental technical resource potential is approximately 500–750 TWh/year. For context, roughly 90,000 homes can be powered by 1 TWh of electricity generation each year. A cost-effective MHK industry could provide a substantial amount of electricity for the nation owing in large part to its unique advantages as a source of energy, including its vast resource potential, its close proximity to major coastal load centers, and its long-term predictability and near-term forecastability.

Tidal Stream Generators, current state and potential opportunities for condition monitoring

DEFF Research Database (Denmark)

Kappatos, Vassilios; Georgoulas, George; Avdelidis, Nicolas

2016-01-01

Tidal power industry has made significant progress towards commercialization over the past decade. Significant investments from sector leaders, strong technical progress and positive media coverage have established the credibility of this specific renewable energy source. However, its progress...... is being retarded by operation and maintenance problems, which results in very low operational availability times, as low as 25 %. This paper presents a literature review of the current state of tidal device operators as well as some commercial tidal turbine condition monitoring solutions. Furthermore......, an overview is given of the global tidal activity status (tidal energy market size and geography), the key industry activity and the regulations-standards related with tidal energy industry. Therefore, the main goal of this paper is to provide a bird’s view of the current status of the tidal power industry...

Turbine Control of a Tidal and River Power Generator: Preprint

Energy Technology Data Exchange (ETDEWEB)

Muljadi, Eduard; Gevorgian, Vahan; Wright, Alan; Donegan, James; Marnagh, Cian; McEntee, Jarlath

2016-08-01

As renewable generation has become less expensive during recent decades, and it becomes more accepted by the global population, the focus on renewable generation has expanded to include new types with promising future applications, such as river and tidal generation. The input variations to these types of resources are slower but also steadier than wind or solar generation. The level of water turbulent flow may vary from one place to another, however, the control algorithm can be adjusted to local environment. This paper describes the hydrokinetic aspects of river and tidal generation based on a river and tidal generator. Although the information given in this paper is not that of an exact generator deployed on site, the data used is representative of a typical river or tidal generator. In this paper, the hydrokinetic and associated electrical controller of the system were not included; however, the focus of this paper is on the hydrodynamic control.

The Power Coefficient in the Theory of Energy Extraction from Tidal Channels

Science.gov (United States)

Cummins, P. F.

2014-12-01

The maximum average power available from a fence of turbines deployed in a tidal channel is given by the simple formula, Ρ=γρgaQmax, where ρga is the amplitude of pressure difference across ends of the channel, Qmax is the maximum volume flux through the channel in the undisturbed state (i.e., before turbines are deployed), and γ is a numerical coefficient. The latter depends only weakly on the underlying dynamical balance of the channel. This is shown to be consequence of quadratic drag and changes to the natural impedance of the channel as deployment of turbines impedes the flow. Additionally, it is shown that the power coefficient γ is relatively insensitive to the form of the turbine drag.

Modeling and control of a hybrid wind-tidal turbine with hydraulic accumulator

International Nuclear Information System (INIS)

Fan, YaJun; Mu, AnLe; Ma, Tao

2016-01-01

This paper presents the modeling and control of a hybrid wind-tidal turbine with hydraulic accumulator. The hybrid turbine captures the offshore wind energy and tidal current energy simultaneously and stores the excess energy in hydraulic accumulator prior to electricity generation. Two hydraulic pumps installed respectively in wind and tidal turbine nacelles are used to transform the captured mechanical energy into hydraulic energy. To extract the maximal power from wind and tidal current, standard torque controls are achieved by regulating the displacements of the hydraulic pumps. To meet the output power demand, a Proportion Integration Differentiation (PID) controller is designed to distribute the hydraulic energy between the accumulator and the Pelton turbine. A simulation case study based on combining a 5 MW offshore wind turbine and a 1 MW tidal current turbine is undertaken. Case study demonstrates that the hybrid generation system not only captures all the available wind and tidal energy and also delivers the desired generator power precisely through the accumulator damping out all the power fluctuations from the wind and tidal speed disturbances. Energy and exergy analyses show that the energy efficiency can exceed 100% as the small input speeds are considered, and the exergy efficiency has the consistent change trends with demand power. Further more parametric sensitivity study on hydraulic accumulator shows that there is an inversely proportional relationship between accumulator and hydraulic equipments including the pump and nozzle in terms of dimensions. - Highlights: • A hybrid wind-tidal turbine is presented. • Hydraulic accumulator stores/releases the surplus energy. • Standard torque controls extract the maximal power from wind and tidal. • Generator outputs meet the electricity demand precisely. • Parametric sensitivity study on accumulator is implemented.

Tidal Turbines’ Layout in a Stream with Asymmetry and Misalignment

Directory of Open Access Journals (Sweden)

Nicolas Guillou

2017-11-01

Full Text Available A refined assessment of tidal currents variability is a prerequisite for successful turbine deployment in the marine environment. However, the numerical evaluation of the tidal kinetic energy resource relies, most of the time, on integrated parameters, such as the averaged or maximum stream powers. Predictions from a high resolution three-dimensional model are exploited here to characterize the asymmetry and misalignment between the flood and ebb tidal currents in the “Raz de Sein”, a strait off western Brittany (France with strong potential for array development. A series of parameters is considered to assess resource variability and refine the cartography of local potential tidal stream energy sites. The strait is characterized by strong tidal flow divergence with currents’ asymmetry liable to vary output power by 60% over a tidal cycle. Pronounced misalignments over 20 ∘ are furthermore identified in a great part of energetic locations, and this may account for a deficit of the monthly averaged extractable energy by more than 12%. As sea space is limited for turbines, it is finally suggested to aggregate flood and ebb-dominant stream powers on both parts of the strait to output energy with reduced asymmetry.

Virtual Seafloor Reduces Internal Wave Generation by Tidal Flow

Science.gov (United States)

Zhang, Likun; Swinney, Harry L.

2014-03-01

Our numerical simulations of tidal flow of a stratified fluid over periodic knife-edge ridges and random topography reveal that the time-averaged tidal energy converted into internal gravity wave radiation arises only from the section of a ridge above a virtual seafloor. The average radiated power is approximated by the power predicted by linear theory if the height of the ridge is measured relative to the virtual floor. The concept of a virtual floor can extend the applicability of linear theory to global predictions of the conversion of tidal energy into internal wave energy in the oceans.

Tidal Current Energy Resource Assessment Around Buton Island, Southeast Sulawesi, Indonesia

OpenAIRE

Ribal, Agustinus; Amir, Amir Kamal; Toaha, Syamsuddin; Kusuma, Jeffry; Khaeruddin

2017-01-01

International Journal bereputasi An early stage of assessing tidal current energy resources is carried out in this present work. Tidal current power is estimated around Buton Island, Southeast Sulawesi province, Indonesia. Two-dimensional, depth-integrated of Advanced Circulation (ADCIRC) model has been used to simulate tidal elevation and barotropic tidal current around the island. Green???s function approach has been used to improve eight tidal constituents on the open boundary condition...

Review of Tidal Lagoon Technology and Opportunities for Integration within the UK Energy System

Directory of Open Access Journals (Sweden)

Grazia Todeschini

2017-07-01

Full Text Available The number of distributed resources for renewable energy installed worldwide has been increasing rapidly in the last decade, and the great majority of these installations consist of solar panels and wind turbines. Other renewable sources of energy are not exploited to the same level: for instance, tidal energy is still a minute portion of the global energy capacity, in spite of the large amount of potential energy stored in tidal waves, and of the successful experience of the few existing plants. The world’s second largest tidal range occurs in the UK but at the moment tidal installations in this country are limited to a few prototypes. More recently, there has been a renewed interest in harnessing tidal energy in the UK, and a few tidal lagoon projects have been evaluated by the UK government. This paper provides an overview of the historical and current developments of tidal plants, a description of operation of tidal lagoons, challenges and opportunities for their integration within the UK energy systems and solutions to improve the dispatchability of tidal energy. The concepts described in the paper are applied to a tidal project proposed for South Wales.

A Political, Economic, Social, Technology, Legal and Environmental (PESTLE Approach for Risk Identification of the Tidal Industry in the United Kingdom

Directory of Open Access Journals (Sweden)

Athanasios Kolios

2013-09-01

Full Text Available This paper presents a comprehensive analysis of renewable and especially tidal energy through a political, economic, social, technology, legal and environmental (PESTLE analysis approach and by reviewing the most up to date relevant literature. The study focuses on the United Kingdom given the favourable environmental resources for such technologies; the number of different design concepts that are currently under development as well as the research funding that has been invested over the last few years. Findings of the analysis identify the risks and multiple stakeholders involved at all stages of the tidal energy projects development from the conceptualization of the design, right through to decommissioning. Many of the stakeholders present benefits to the tidal developers through funding, incentives and knowledge sharing, but at the same time they also present potential risks to the future of projects. This is mostly down to different approaches of the most important aspect of tidal energy that needs to be considered, making it hard for technologists and developers to equally address all requirements. From this research it can be concluded that several of these risks can be mitigated early on providing that particular stakeholders are involved at the correct stage of a project.

The Integration of Environmental Constraints into Tidal Array Optimisation

Science.gov (United States)

du Feu, Roan; de Trafford, Sebastian; Culley, Dave; Hill, Jon; Funke, Simon W.; Kramer, Stephan C.; Piggott, Matthew D.

2015-04-01

It has been estimated by The Carbon Trust that the marine renewable energy sector, of which tidal stream turbines are projected to play a large part, could produce 20% of the UK's present electricity requirements. This has lead to the important question of how this technology can be deployed in an economically and environmentally friendly manner. Work is currently under way to understand how the tidal turbines that constitute an array can be arranged to maximise the total power generated by that array. The work presented here continues this through the inclusion of environmental constraints. The benefits of the renewable energy sector to our environment at large are not in question. However, the question remains as to the effects this burgeoning sector will have on local environments, and how to mitigate these effects if they are detrimental. For example, the presence of tidal arrays can, through altering current velocity, drastically change the sediment transport into and out of an area along with re-suspending existing sediment. This can have the effects of scouring or submerging habitat, mobilising contaminants within the existing sediment, reducing food supply and altering the turbidity of the water. All of which greatly impact upon any fauna in the affected region. This work pays particular attention to the destruction of habitat of benthic fauna, as this is quantifiable as a direct result of change in the current speed; a primary factor in determining sediment accumulation on the sea floor. OpenTidalFarm is an open source tool that maximises the power generated by an array through repositioning the turbines within it. It currently uses a 2D shallow water model with turbines represented as bump functions of increased friction. The functional of interest, power extracted by the array, is evaluated from the flow field which is calculated at each iteration using a finite element method. A gradient-based local optimisation is then used through solving the

Tidal energy conversion. Renewable energy; 3-3 choseki / choryu hatsuden. II. saisei kano energy ni yoru hatsuden

Energy Technology Data Exchange (ETDEWEB)

Makino, T. [Tobishima Corp., Tokyo (Japan)

1998-10-15

There are not much examples applying tidal energy conversion, but tide and tidal current phenomena can be forecasted so correctly regardless of weather that the applying tidal energy is to be expected in the future. The largest tidal power plant is at Reims in France and install 24 Kaplan turbines each of which outlet power is 10,000kW (rotational direction is reversible) on the breakwater (750m is length). Tidal range at this place being 8.5m on an average, during the period of flowing seawater into the reservoir and on the contrary during the period of discharging seawater to the sea generation is both performed. Though there is no actual result of tidal power plant in Japan, in tidal current power system experimental generators have been installed at Kurushima channel and Naruto channel. Nihon University carried out various kinds of experiment using a Darius turbine (1.6m in dia.) at Kurushima channel and got outlet power of 3kW at the maximum (1983-`88). There are few coasts which have sufficient tide range in Japan, but there are so good many applicable coasts in China and Southeast Asia that the tidal power generation is to be expectatively. 12 refs., 5 figs., 1 tab.

Fundamental investigations for a OWC-tidal power plant with a conventional hydraulic turbine; Basisuntersuchungen fuer ein OWC-Wellenenergiekraftwerk mit konventioneller Hydroturbine. Abschlussbericht

Energy Technology Data Exchange (ETDEWEB)

Graw, K.U.; Lengricht, J.; Schimmels, S.

2001-07-01

At the present the OWC-tidal power plant is the most forward-looking way of converting tidal energy into usable electric power. Current research works focus on the dimensions of the structures in terms of occurring loads, the minimisation of hydraulic losses and the development of new turbine-generator types. The development of all air-turbine systems, which have been investigated so far, is considered as problematic and the commercialisation is likely to be a hindrance. Based on international research results an inventory tata of available hydraulic turbines is supposed to be gathered and fundamental investigations are supposed to check, if the application of conventional hydraulic turbines are an energetic progress in the OWC-tidal power plant. In order to considerably increase the efficiency compared to current developments, small-scale investigations at a physical model are supposed to show if and how a hydraulic turbine can be realised in a OWC-tidal power plant and how a concept of flow rectification as well as a flow-optimised form of inflow and outflow chambers can be achieved. (orig.) [German] Das OWC-Wellenenergiekraftwerk ist der zur Zeit zukunftstraechtigste Typ zur Umwandlung von Wellenenergie in nutzbaren Strom. Die laufenden Forschungsarbeiten beschaeftigen sich insbesondere mit der Dimensionierung der Strukturen hinsichtlich auftretender Belastungen, der Minimierung der hydraulischen Verluste und der Entwicklung von neuartigen Turbinen-Generatoren-Typen. Die Entwicklung aller bisher untersuchten Luftturbinensysteme wird jedoch als problematisch und die Kommerzialisierung hindernd angesehen. Aufbauend auf den internationalen Forschungsergebnissen sollen eine Bestandaufnahme der verfuegbaren Hydroturbinen durchgefuehrt und mit Baisuntersuchungen geprueft werden, ob ein Einsatz konventionaller Hydroturbinen im OWC-Wellenenergiekraftwerk eine energetische Weiterentwicklung darstellen kann. Um den Wirkungsgrad gegenueber derzeitigen Entwicklungen

Deployment Effects of Marin Renewable Energy Technologies

Energy Technology Data Exchange (ETDEWEB)

Brian Polagye; Mirko Previsic

2010-06-17

Given proper care in siting, design, deployment, operation and maintenance, marine and hydrokinetic technologies could become one of the more environmentally benign sources of electricity generation. In order to accelerate the adoption of these emerging hydrokinetic and marine energy technologies, navigational and environmental concerns must be identified and addressed. All developing hydrokinetic projects involve a wide variety of stakeholders. One of the key issues that site developers face as they engage with this range of stakeholders is that many of the possible conflicts (e.g., shipping and fishing) and environmental issues are not well-understood, due to a lack of technical certainty. In September 2008, re vision consulting, LLC was selected by the Department of Energy (DoE) to apply a scenario-based approach to the emerging wave and tidal technology sectors in order to evaluate the impact of these technologies on the marine environment and potentially conflicting uses. The project’s scope of work includes the establishment of baseline scenarios for wave and tidal power conversion at potential future deployment sites. The scenarios will capture variations in technical approaches and deployment scales to properly identify and characterize environmental impacts and navigational effects. The goal of the project is to provide all stakeholders with an improved understanding of the potential effects of these emerging technologies and focus all stakeholders onto the critical issues that need to be addressed. This groundwork will also help in streamlining siting and associated permitting processes, which are considered key hurdles for the industry’s development in the U.S. today. Re vision is coordinating its efforts with two other project teams funded by DoE which are focused on regulatory and navigational issues. The results of this study are structured into three reports: 1. Wave power scenario description 2. Tidal power scenario description 3. Framework for

Puget Sound Tidal Energy In-Water Testing and Development Project Final Technical Report

Energy Technology Data Exchange (ETDEWEB)

Collar, Craig W

2012-11-16

Tidal energy represents potential for the generation of renewable, emission free, environmentally benign, and cost effective energy from tidal flows. A successful tidal energy demonstration project in Puget Sound, Washington may enable significant commercial development resulting in important benefits for the northwest region and the nation. This project promoted the United States Department of Energy's Wind and Hydropower Technologies Program's goals of advancing the commercial viability, cost-competitiveness, and market acceptance of marine hydrokinetic systems. The objective of the Puget Sound Tidal Energy Demonstration Project is to conduct in-water testing and evaluation of tidal energy technology as a first step toward potential construction of a commercial-scale tidal energy power plant. The specific goal of the project phase covered by this award was to conduct all activities necessary to complete engineering design and obtain construction approvals for a pilot demonstration plant in the Admiralty Inlet region of the Puget Sound. Public Utility District No. 1 of Snohomish County (The District) accomplished the objectives of this award through four tasks: Detailed Admiralty Inlet Site Studies, Plant Design and Construction Planning, Environmental and Regulatory Activities, and Management and Reporting. Pre-Installation studies completed under this award provided invaluable data used for site selection, environmental evaluation and permitting, plant design, and construction planning. However, these data gathering efforts are not only important to the Admiralty Inlet pilot project. Lessons learned, in particular environmental data gathering methods, can be applied to future tidal energy projects in the United States and other parts of the world. The District collaborated extensively with project stakeholders to complete the tasks for this award. This included Federal, State, and local government agencies, tribal governments, environmental groups, and

Measuring the environmental costs of tidal power plant construction: A choice experiment study

International Nuclear Information System (INIS)

Lee, Joo-Suk; Yoo, Seung-Hoon

2009-01-01

Korea is considering the construction of a tidal power plant (TPP) at Garolim Bay. However, as the construction of the Garolim TPP (GTPP) is expected to entail some environmental damage, it has become an increasingly important topic for public debate. Using a choice experiment (CE) approach, this study attempts to measure the economic cost that results from the environmental damage caused by the construction of GTPP. The CE is used to measure the environmental costs of individual attributes, including the reduction in the area of the tidal flat, the degradation of seawater quality, and the destruction of marine life. The results indicate that the annual willingness to pay (WTP) per household for mitigating the environmental damage that results from the worst-possible situation in relation to the present situation is about 96,042 Korean won (USD 101.1) in the seven biggest cities (off-site regions) and 18,584 Korean won (USD 19.6) in Seosan and Taean (on-site regions). This study is expected to provide policy-makers with quantitative information that will be useful to decide whether or not GTPP should be constructed.

The prediction of the hydrodynamic performance of tidal current turbines

International Nuclear Information System (INIS)

Xiao, B Y; Zhou, L J; Xiao, Y X; Wang, Z W

2013-01-01

Nowadays tidal current energy is considered to be one of the most promising alternative green energy resources and tidal current turbines are used for power generation. Prediction of the open water performance around tidal turbines is important for the reason that it can give some advice on installation and array of tidal current turbines. This paper presents numerical computations of tidal current turbines by using a numerical model which is constructed to simulate an isolated turbine. This paper aims at studying the installation of marine current turbine of which the hydro-environmental impacts influence by means of numerical simulation. Such impacts include free-stream velocity magnitude, seabed and inflow direction of velocity. The results of the open water performance prediction show that the power output and efficiency of marine current turbine varies from different marine environments. The velocity distribution should be clearly and the suitable unit installation depth and direction be clearly chosen, which can ensure the most effective strategy for energy capture before installing the marine current turbine. The findings of this paper are expected to be beneficial in developing tidal current turbines and array in the future

The importance of iteration and deployment in technology development: A study of the impact on wave and tidal stream energy research, development and innovation

International Nuclear Information System (INIS)

MacGillivray, Andrew; Jeffrey, Henry; Wallace, Robin

2015-01-01

The technological trajectory is the pathway through which an innovative technology develops as it matures. In this paper we model the technological trajectory for a number of energy technologies by analysing technological change (characterised by unit-level capacity up-scaling) and diffusion (characterised by growth in cumulative deployed capacity) using sigmoidal 5 Parameter Logistic (5PL) functions, observed and reported as a function of unit deployment. Application of 5PL functions allows inference of technology development milestones, such as initiation of unit-level up-scaling or industry growth, with respect to the number of unit deployments. This paper compares the technological trajectory followed by mature energy technologies to that being attempted by those in the nascent wave and tidal energy sectors, particularly with regards to unit deployment within a formative phase of development. We identify that the wave and tidal energy sectors are attempting to bypass a formative phase of technological development, which is not in line with technological trajectories experienced by historic energy technologies that have successfully diffused into widespread commercial application, suggesting that demand-pull support mechanisms are premature, and a need for technology push focused policy support mechanisms is vital for stimulating economically sustainable development and deployment of wave and tidal stream energy. - Highlights: • Technology up-scaling should take place after a formative phase of development. • Ocean energy technologies are attempting to bypass a formative phase. • Unit up-scaling has taken place prior to successful technology demonstration. • The cost of the formative phase may be insurmountable using MW-scale technology. • A shift in the research, development and innovation environment is necessary.

Preliminary investigation of the potential of harnessing tidal energy for electricity generation in Malaysia

Energy Technology Data Exchange (ETDEWEB)

Lee, K.S.; Seng, L.Y. [Tunku Abdul Rahman Univ. (Malaysia). Dept. of Electrical and Electronic Engineering

2008-07-01

Malaysia relies heavily on fossil fuels to meet its energy demands. However, Malaysia has started to explore the use of other forms of renewable energy such as solar energy, biofuels and tidal power. This paper focused on the potential of harnessing tidal energy in Malaysia for electricity production. There are several sites with great potential for tidal energy conversion, which could supplement the energy needs of Malaysia while reducing greenhouse gas emissions. Illustrations were included to show the amplitude of the main harmonic component of the tidal range around Malaysia. The main harmonic component found in the region has a maximum amplitude of 1.4 m, confirming the potential of tidal energy in Malaysia's Ocean. Since the tidal cycle is highly predictable, it has the potential to be a very reliable renewable energy source. Two main approaches are being researched internationally to harness the energy from tides, notably the barrage approach and the tidal stream approach. For the barrage approach, a physical barrier is created within the sea, and a sluice gate controls the flow of sea water. In the tidal stream approach, horizontal axis turbines are placed in the path of tidal currents to generate electricity, similar to the operation of wind turbines. This paper described the flow velocity, power output, availability of power supply and monthly yield of turbines using both the barrage and tidal stream approaches. The study showed that for the barrage approach, there are 6 sites in Malaysia where 14,970 kWH of energy can be generated monthly with a single turbine with a 5 m long blade. The tidal stream approach showed equally promising results at 2 sites. It was concluded that tidal energy is a promising form of renewable energy because of its cyclic, reliable and predictable nature and the vast energy contained within it. According to United Kingdom Department of Trade and Industry, 10 per cent of the United Kingdom's electricity needs could be

Resource Assessment of Tidal Current Energy in Hangzhou Bay Based on Long Term Measurement

Science.gov (United States)

Zhang, Feng; Dai, Chun-Ni; Xu, Xue-Feng; Wang, Chuan-Kun; Ye, Qin

2017-05-01

Compared with other marine renewable energy, tidal current energy benefits a lot in high energy density and good predictability. Based on the measured tidal current data in Hangzhou Bay from Nov 2012 to Oct 2012, this paper analysed temporal and spatial changes of tidal current energy in the site. It is the first time measured data of such long time been taken in tidal current energy analysis. Occurrence frequency and duration of the current of different speed are given out in the paper. According to the analysis results, monthly average power density changed a lot in different month, and installation orientation of tidal current turbine significantly affected energy acquisition. Finally, the annual average power density of tidal current energy with coefficient Cp in the site was calculated, and final output of a tidal current plant was also estimated.

Tidal energy, a renewable energy within hand reach; Les marees, une energie renouvelable a portee de lune

Energy Technology Data Exchange (ETDEWEB)

Danielo, O.

2011-06-15

Tide energy and oceanic current energy represent a strong potentiality for a few countries in the world including France. In the domain of tidal energy there are 2 strategies. The first one is based on the search for the lowest power production cost in order to contribute efficiently to the country's energy mix. Generally this strategy leads to the construction of tidal dams. The second strategy is based on the search for the lowest environmental impact. This strategy is economically competitive only in places where electrical power is expensive like isolated islands. This strategy is illustrated by the tidal power station of the Alderney island. In fact the amount of energy delivered by a tidal power station depends on the rise of the tide and on the surface of the dam. It appears that tidal dams require less surface that hydroelectric power plants. The energy of oceanic currents like Gulf Stream or the thermal energy of oceans or wave power are very little exploited now but represent a potentiality higher by several orders of magnitude than tidal energy. (A.C.)

Power generation technologies

CERN Document Server

Breeze, Paul

2014-01-01

The new edition of Power Generation Technologies is a concise and readable guide that provides an introduction to the full spectrum of currently available power generation options, from traditional fossil fuels and the better established alternatives such as wind and solar power, to emerging renewables such as biomass and geothermal energy. Technology solutions such as combined heat and power and distributed generation are also explored. However, this book is more than just an account of the technologies - for each method the author explores the economic and environmental costs and risk factor

Power conversion technologies

Energy Technology Data Exchange (ETDEWEB)

Newton, M. A.

1997-02-01

The Power Conversion Technologies thrust area identifies and sponsors development activities that enhance the capabilities of engineering at Lawrence Livermore National Laboratory (LLNL) in the area of solid- state power electronics. Our primary objective is to be a resource to existing and emerging LLNL programs that require advanced solid-state power electronic technologies.. Our focus is on developing and integrating technologies that will significantly impact the capability, size, cost, and reliability of future power electronic systems. During FY-96, we concentrated our research efforts on the areas of (1) Micropower Impulse Radar (MIR); (2) novel solid-state opening switches; (3) advanced modulator technology for accelerators; (4) compact accelerators; and (5) compact pulse generators.

Optimization Study of Shaft Tubular Turbine in a Bidirectional Tidal Power Station

Directory of Open Access Journals (Sweden)

Xinfeng Ge

2013-01-01

Full Text Available The shaft tubular turbine is a form of tidal power station which can provide bidirectional power. Efficiency is an important turbine performance indicator. To study the influence of runner design parameters on efficiency, a complete 3D flow-channel model of a shaft tubular turbine was developed, which contains the turbine runner, guide vanes, and flow passage and was integrated with hybrid grids calculated by steady-state calculation methods. Three aspects of the core component (turbine runner were optimized by numerical simulation. All the results were then verified by experiments. It was shown that curved-edge blades are much better than straight-edge blades; the optimal blade twist angle is 7°, and the optimal distance between the runner and the blades is 0.75–1.25 times the diameter of the runner. Moreover, the numerical simulation results matched the experimental data very well, which also verified the correctness of the optimal results.

Feasibility of Tidal and Ocean Current Energy in False Pass, Aleutian Islands, Alaska final report

Energy Technology Data Exchange (ETDEWEB)

Wright, Bruce Albert [Aleutian Pribilof Islands Association, Inc., Anchorage, AK (United States)

2014-05-07

, the Project Team developed a conceptual tidal energy project design utilizing ORPC’s TidGen® Power System. While the Project Team has not committed to ORPC technology for future development of a False Pass project, this conceptual design was critical to informing the Project’s economic analysis. The results showed that power from a tidal energy project could be provided to the City of False at a rate at or below the cost of diesel generated electricity and sold to commercial customers at rates competitive with current market rates, providing a stable, flat priced, environmentally sound alternative to the diesel generation currently utilized for energy in the community. The Project Team concluded that with additional grants and private investment a tidal energy project at False Pass is well-positioned to be the first tidal energy project to be developed in Alaska, and the first tidal energy project to be interconnected to an isolated micro grid in the world. A viable project will be a model for similar projects in coastal Alaska.

The effects of tidal range on saltmarsh morphology

Science.gov (United States)

Goodwin, Guillaume; Mudd, Simon

2017-04-01

Saltmarshes are highly productive coastal ecosystems that act simultaneously as flood barriers, carbon storage, pollutant filters and nurseries. As halophytic plants trap suspended sediment and decay in the settled strata, innervated platforms emerge from the neighbouring tidal flats, forming sub-vertical scarps on their eroding borders and sub-horizontal pioneer zones in areas of seasonal expansion. These evolutions are subject to two contrasting influences: stochastically generated waves erode scarps and scour tidal flats, whereas tidally-generated currents transport sediment to and from the marsh through the channel network. Hence, the relative power of waves and tidal currents strongly influences saltmarsh evolution, and regional variations in tidal range yield marshes of differing morphologies. We analyse several sheltered saltmarshes to determine how their morphology reflects variations in tidal forcing. Using tidal, topographic and spectral data, we implement an algorithm based on the open-source software LSDTopoTools to automatically identify features such as marsh platforms, tidal flats, erosion scarps, pioneer zones and tidal channels on local Digital Elevation Models. Normalised geometric properties are then computed and compared throughout the spectrum of tidal range, highlighting a notable effect on channel networks, platform geometry and wave exposure. We observe that micro-tidal marshes typically display jagged outlines and multiple islands along with wide, shallow channels. As tidal range increases, we note the progressive disappearance of marsh islands and linearization of scarps, both indicative of higher hydrodynamic stress, along with a structuration of channel networks and the increase of levee volume, suggesting higher sediment input on the platform. Future research will lead to observing and modelling the evolution of saltmarshes under various tidal forcing in order to assess their resilience to environmental change.

Tidal conversion by a knife-edge

Science.gov (United States)

Llewellyn Smith, S. G.; Young, W. R.

2003-04-01

We obtain an analytic solution for the generation of internal gravity waves by tidal flow past a vertical barrier of height b in a uniformly stratified ocean of depth h>b and buoyancy frequency N. If b/h is small and N is constant, the radiated power (watts per metre of barrier) is (pi/4) ρ_0 b^2 U^2 N sqrt{1-(f/ω)^2} where ρ_0 is the mean density of seawater, U \\cos (ω t) the incident tidal velocity, and f the Coriolis frequency. The radiated power increases rapidly with b/h; as b/h to 1 the radiated power diverges as ln[(h-b)/b]. By solving an integral equation numerically, we calculate the conversion in a realistically stratified ocean in which the buoyancy frequency increases by a factor of fifty between the abyss and the thermocline. The radiated power is greater by a factor of about three than that of a uniformly stratified ocean with N equal to the vertically averaged buoyancy frequency.

Tidal current energy resource assessment in Ireland: Current status and future update

International Nuclear Information System (INIS)

O'Rourke, Fergal; Boyle, Fergal; Reynolds, Anthony

2010-01-01

Interest in renewable energy in Ireland has increased continually over the past decade. This interest is due primarily to security of supply issues and the effects of climate change. Ireland imports over 90% of its primary energy consumption, mostly in the form of fossil fuels. The exploitation of Ireland's vast indigenous renewable energy resources is required in order to reduce this over-dependence on fossil fuel imports to meet energy demand. Various targets have been set by the Irish government to incorporate renewable energy technologies into Ireland's energy market. As a result of these targets, the development in wind energy has increased substantially over the past decade; however this method of energy extraction is intermittent and unpredictable. Ireland has an excellent tidal current energy resource and the use of this resource will assist in the development of a sustainable energy future. Energy extraction using tidal current energy technologies offers a vast and predictable energy resource. This paper reviews the currently accepted tidal current energy resource assessment for Ireland. This assessment was compiled by Sustainable Energy Ireland in a report in 2004. The assessment employed a 2-dimensional numerical model of the tidal current velocities around Ireland, and from this numerical model the theoretical tidal current energy resource was identified. With the introduction of constraints and limitations, the technical, practical, accessible and viable tidal current energy resources were obtained. The paper discusses why the assessment needs updating including the effect on the assessment of the current stage of development of tidal current turbines and their deployment technology. (author)

Assessment of Energy Production Potential from Tidal Streams in the United States

Energy Technology Data Exchange (ETDEWEB)

Haas, Kevin A. [Georgia Inst. of Technology, Savannah, GA (United States); Fritz, Hermann M. [Georgia Inst. of Technology, Savannah, GA (United States); French, Steven P. [Georgia Inst. of Technology, Atlanta, GA (United States); Smith, Brennan T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Neary, Vincent [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2011-06-29

The project documented in this report created a national database of tidal stream energy potential, as well as a GIS tool usable by industry in order to accelerate the market for tidal energy conversion technology.

Environmental Effects of Sediment Transport Alteration and Impacts on Protected Species: Edgartown Tidal Energy Project

Energy Technology Data Exchange (ETDEWEB)

Barrett, Stephen B; Schlezinger, David, Ph.D; Cowles, Geoff, Ph.D; Hughes, Patricia; Samimy,; Roland, I; and Terray, E, Ph.D.

2012-12-29

The Islands of Martha's Vineyard and Nantucket are separated from the Massachusetts mainland by Vineyard and Nantucket Sounds; water between the two islands flows through Muskeget Channel. The towns of Edgartown (on Martha's Vineyard) and Nantucket recognize that they are vulnerable to power supply interruptions due to their position at the end of the power grid, and due to sea level rise and other consequences of climate change. The tidal energy flowing through Muskeget Channel has been identified by the Electric Power Research Institute as the strongest tidal resource in Massachusetts waters. The Town of Edgartown proposes to develop an initial 5 MW (nameplate) tidal energy project in Muskeget Channel. The project will consist of 14 tidal turbines with 13 providing electricity to Edgartown and one operated by the University of Massachusetts at Dartmouth for research and development. Each turbine will be 90 feet long and 50 feet high. The electricity will be brought to shore by a submarine cable buried 8 feet below the seabed surface which will landfall in Edgartown either on Chappaquiddack or at Katama. Muskeget Channel is located between Martha's Vineyard and Nantucket. Its depth ranges between 40 and 160 feet in the deepest portion. It has strong currents where water is transferred between Nantucket Sound and the Atlantic Ocean continental shelf to the south. This makes it a treacherous passage for navigation. Current users of the channel are commercial and recreational fishing, and cruising boats. The US Coast Guard has indicated that the largest vessel passing through the channel is a commercial scallop dragger with a draft of about 10 feet. The tidal resource in the channel has been measured by the University of Massachusetts-Dartmouth and the peak velocity flow is approximately 5 knots. The technology proposed is the helical Gorlov-type turbine positioned with a horizontal axis that is positively buoyant in the water column and held down by

Tidal dissipation in the subsurface ocean of Enceladus

Science.gov (United States)

Matsuyama, I.; Hay, H.; Nimmo, F.; Kamata, S.

2017-12-01

Icy satellites of the outer solar system have emerged as potential habitable worlds due to the presence of subsurface oceans. As a long-term energy source, tidal heating in these oceans can influence the survivability of subsurface oceans, and the thermal, rotational, and orbital evolution of these satellites. Additionally, the spatial and temporal variation of tidal heating has implications for the interior structure and spacecraft observations. Previous models for dissipation in thin oceans are not generally applicable to icy satellites because either they ignore the presence of an overlying solid shell or use a thin shell membrane approximation. We present a new theoretical treatment for tidal dissipation in thin oceans with overlying shells of arbitrary thickness and apply it to Enceladus. The shell's resistance to ocean tides increases with shell thickness, reducing tidal dissipation as expected. Both the magnitude of energy dissipation and the resonant ocean thicknesses decrease as the overlying shell thickness increases, as previously shown using a membrane approximation. In contrast to previous work based on the traditional definition of the tidal quality factor, Q, our new definition is consistent with higher energy dissipation for smaller Q, and introduces a lower limit on Q. The dissipated power and tides are not in phase with the forcing tidal potential due to the delayed ocean response. The phase lag depends on the Rayleigh friction coefficient and ocean and shell thicknesses, which implies that phase lag observations can be used to constrain these parameters. Eccentricity heating produces higher dissipation near the poles, while obliquity heating produces higher dissipation near the equator, in contrast to the dissipation patterns in the shell. The time-averaged surface distribution of tidal heating can generate lateral shell thickness variations, providing an additional constraint on the Rayleigh friction coefficient. Explaining the endogenic power

Prehospital tidal volume influences hospital tidal volume: A cohort study.

Science.gov (United States)

Stoltze, Andrew J; Wong, Terrence S; Harland, Karisa K; Ahmed, Azeemuddin; Fuller, Brian M; Mohr, Nicholas M

2015-06-01

The purposes of the study are to describe current practice of ventilation in a modern air medical system and to measure the association of ventilation strategy with subsequent ventilator care and acute respiratory distress syndrome (ARDS). Retrospective observational cohort study of intubated adult patients (n = 235) transported by a university-affiliated air medical transport service to a 711-bed tertiary academic center between July 2011 and May 2013. Low tidal volume ventilation was defined as tidal volumes less than or equal to 8 mL/kg predicted body weight. Multivariable regression was used to measure the association between prehospital tidal volume, hospital ventilation strategy, and ARDS. Most patients (57%) were ventilated solely with bag valve ventilation during transport. Mean tidal volume of mechanically ventilated patients was 8.6 mL/kg predicted body weight (SD, 0.2 mL/kg). Low tidal volume ventilation was used in 13% of patients. Patients receiving low tidal volume ventilation during air medical transport were more likely to receive low tidal volume ventilation in the emergency department (P tidal volume (P = .840). Low tidal volume ventilation was rare during air medical transport. Air transport ventilation strategy influenced subsequent ventilation but was not associated with ARDS. Copyright © 2015 Elsevier Inc. All rights reserved.

78 FR 44557 - Turnagain Arm Tidal Energy Corporation; Notice of Preliminary Permit Application Accepted for...

Science.gov (United States)

2013-07-24

... Tidal Energy Corporation; Notice of Preliminary Permit Application Accepted for Filing and Soliciting Comments, Motions To Intervene, and Competing Applications On February 1, 2013, the Turnagain Arm Tidal... Federal Power Act (FPA), proposing to study the feasibility of the Turnagain Arm Tidal Electric Generation...

A holistic method for selecting tidal stream energy hotspots under technical, economic and functional constraints

International Nuclear Information System (INIS)

Vazquez, A.; Iglesias, G.

2016-01-01

Highlights: • A method for selecting the most suitable sites for tidal stream farms was presented. • The selection was based on relevant technical, economic and functional aspects. • As a case study, a model of the Bristol Channel was implemented and validated. - Abstract: Although a number of prospective locations for tidal stream farms have been identified, the development of a unified approach for selecting the optimum site in a region remains a current research topic. The objective of this work is to develop and apply a methodology for determining the most suitable sites for tidal stream farms, i.e. sites whose characteristics maximise power performance, minimise cost and avoid conflicts with competing uses of the marine space. Illustrated through a case study in the Bristol Channel, the method uses a validated hydrodynamics model to identify highly energetic areas and a geospatial Matlab-based program (designed ad hoc) to estimate the energy output that a tidal farm at the site with a given technology would have. This output is then used to obtain the spatial distribution of the levelised cost of energy and, on this basis, to preselect certain areas. Subsequently, potential conflicts with other functions of the marine space (e.g. fishing, shipping) are considered. The result is a selection of areas for tidal stream energy development based on a holistic approach, encompassing the relevant technical, economic and functional aspects. This methodology can lead to a significant improvement in the selection of tidal sites, thereby increasing the possibilities of project acceptance and development.

CFD for wind and tidal offshore turbines

CERN Document Server

Montlaur, Adeline

2015-01-01

The book encompasses novel CFD techniques to compute offshore wind and tidal applications. Computational fluid dynamics (CFD) techniques are regarded as the main design tool to explore the new engineering challenges presented by offshore wind and tidal turbines for energy generation. The difficulty and costs of undertaking experimental tests in offshore environments have increased the interest in the field of CFD which is used to design appropriate turbines and blades, understand fluid flow physical phenomena associated with offshore environments, predict power production or characterise offshore environments, amongst other topics.

Tidal tilts observations in the Gran Sasso underground laboratory

International Nuclear Information System (INIS)

Iafolla, V.; Nozzoli, S.; Milyukov, V.

2001-01-01

A new tilt meter, based on the technology for building a space-borne high-sensitivity accelerometer and manufactured at IFSI/CNR, has a been operating during several years in the INFN Gran Sasso underground laboratory. The results of the analysis of a three-year data set, processed with the program package ETERNA, to estimate earth tidal parameters are reported. For the best series of data (1998) tide measurement accuracies are: 0.5-1% for the M 2 (lunar principal) amplitude and 3-4% for the O 1 (lunar declination) amplitude. The tilt meter installed at a depth of 1400 m shows no clear evidence of meteorological effects. Observed tidal parameters are compared with theoretical tidal parameters predicted for a non-hydrostatic inelastic Earth model and demonstrate good agreement for the M 2 component. Due to the high accuracy of the tidal components prediction (better than 1%) tidal measurements were used to estimate the long-term stability of the instrument response

On the sedimentation problems in water abstraction channels at power plant sites at tidal estuaries

International Nuclear Information System (INIS)

Jensen, J.; Arns, A.; Frank, T.; Meiswinkel, R.; Richei, A.

2010-01-01

The required cooling water supply of a nuclear power plant the required flow deepness in the water abstraction channels has to be provided. Since the abstraction channels are usually in main stream orientation of the river periodic sedimentation occur, that have to be removed by dredging techniques. Especially in tidal estuaries the complex flow situation induces transport mechanisms that have to be studied in order to develop cost saving and effective measures and procedures to reduce the sedimentation and pollutants deposition. The authors recommend experimental determinations of the sold material transport and numerical hydrodynamic transport modeling to identify the transport pathways.

Facies architecture of heterolithic tidal deposits : The Holocene Holland Tidal Basin

NARCIS (Netherlands)

Donselaar, M.E.; Geel, C.R.

2007-01-01

The size, shape and spatial position of lithofacies types (or facies architecture) in a tidal estuarine basin are complex and therefore difficult to model. The tidal currents in the basin concentrate sand-sized sediment in a branching pattern of tidal channels and fringing tidal flats. Away from the

2008 NWFSC Tidal Freshwater Genetics Results

Energy Technology Data Exchange (ETDEWEB)

David Teel

2009-05-01

Genetic Analysis of Juvenile Chinook Salmon for inclusion in 'Ecology of Juvenile Salmon in Shallow Tidal Freshwater Habitats in the Vicinity of the Sandy River Delta, Lower Columbia River, 2008. Annual Report to Bonneville Power Administration, Contract DE-AC05-76RL01830.'

Anomaly Detection Techniques for the Condition Monitoring of Tidal Turbines

Science.gov (United States)

2014-09-29

turbine design includes many horizontal and vertical axis solutions, some with major structural and operational variations (Aly & El-Hawary, 2011...However, a common focus is the horizontal axis design, holding many similarities with a standard wind turbine . Maintenance on tidal turbines ...However, despite similarities between tidal and wind power turbine design, the operating environment is vastly different. Water is over 800 times

ENHANCED OFF-CENTER STELLAR TIDAL DISRUPTIONS BY SUPERMASSIVE BLACK HOLES IN MERGING GALAXIES

International Nuclear Information System (INIS)

Liu, F. K.; Chen, Xian

2013-01-01

Off-center stellar tidal disruption flares have been suggested to be a powerful probe of recoiling supermassive black holes (SMBHs) out of galactic centers due to anisotropic gravitational wave radiations. However, off-center tidal flares can also be produced by SMBHs in merging galaxies. In this paper, we computed the tidal flare rates by dual SMBHs in two merging galaxies before the SMBHs become self-gravitationally bounded. We employ an analytical model to calculate the tidal loss-cone feeding rates for both SMBHs, taking into account two-body relaxation of stars, tidal perturbations by the companion galaxy, and chaotic stellar orbits in triaxial gravitational potential. We show that for typical SMBHs with masses 10 7 M ☉ , the loss-cone feeding rates are enhanced by mergers up to Γ ∼ 10 –2 yr –1 , about two orders of magnitude higher than those by single SMBHs in isolated galaxies and about four orders of magnitude higher than those by recoiling SMBHs. The enhancements are mainly due to tidal perturbations by the companion galaxy. We suggest that off-center tidal flares are overwhelmed by those from merging galaxies, making the identification of recoiling SMBHs challenging. Based on the calculated rates, we estimate the relative contributions of tidal flare events by single, binary, and dual SMBH systems during cosmic time. Our calculations show that the off-center tidal disruption flares by un-bound SMBHs in merging galaxies contribute a fraction comparable to that by single SMBHs in isolated galaxies. We conclude that off-center tidal disruptions are powerful tracers of the merging history of galaxies and SMBHs.

An analytic approach to optimize tidal turbine fields

Science.gov (United States)

Pelz, P.; Metzler, M.

2013-12-01

Motivated by global warming due to CO2-emission various technologies for harvesting of energy from renewable sources are developed. Hydrokinetic turbines get applied to surface watercourse or tidal flow to gain electrical energy. Since the available power for hydrokinetic turbines is proportional to the projected cross section area, fields of turbines are installed to scale shaft power. Each hydrokinetic turbine of a field can be considered as a disk actuator. In [1], the first author derives the optimal operation point for hydropower in an open-channel. The present paper concerns about a 0-dimensional model of a disk-actuator in an open-channel flow with bypass, as a special case of [1]. Based on the energy equation, the continuity equation and the momentum balance an analytical approach is made to calculate the coefficient of performance for hydrokinetic turbines with bypass flow as function of the turbine head and the ratio of turbine width to channel width.

Power Technologies Data Book

Energy Technology Data Exchange (ETDEWEB)

Goldstein, L.

2002-09-01

This report, prepared by NREL's Energy Analysis Office, includes up-to-date information on power technologies, including complete technology profiles. The data book also contains charts on electricity restructuring, power technology forecasts and comparisons, electricity supply, electricity capability, electricity generation, electricity demand, prices, economic indicators, environmental indicators, conversion factors, and selected congressional questions and answers.

An innovative and very promising use of tidal turbines. Tidal turbines can produce twenty per cent of the French electricity. An economic solution can produce 500 GW of tide energy. An innovative use of tidal turbines can produce 10 per cent of the World energy

International Nuclear Information System (INIS)

Lemperiere, F.

2013-01-01

A set of articles outlines and describes the opportunities of energy production associated with the use of tidal turbines. Such a technological principle is very efficient in terms of costs but very few natural sea or river sites present favourable conditions, notably in terms of current speed. A first article addresses the peculiarities of sea tide energy, presents the different concepts and components of a sea tide power plant (tanks or basins, plants), describes the present use of tidal turbines, proposes a new solution (the 'Marelienne'), describes and assesses the integration into the grid and the energy storage, evokes the production gain obtained by pumping and the association with wind turbines, describes the construction mode, discusses the various impacts (visual impact, impacts on the environment, direct and indirect socio-economic impacts), discusses issues related to navigation, presents an example of production, costs and impacts (case of the Bay of Somme), evokes other potential areas in France (about the Chausey island and about the Re island), discusses the world potential, evokes other examples in Europe, in Asia, in America, Africa and Australia), indicates the global cost for the main sites, outlines technical and economic uncertainties. The same aspects and issues can be found in the other articles which outline that tidal turbines can produce twenty per cent of the French electricity, that an economic solution can produce 500 GW of tide energy, and that an innovative use of tidal turbines can produce 10 per cent of the World energy

Tidal Energy Research

Energy Technology Data Exchange (ETDEWEB)

Stelzenmuller, Nickolas [Univ of Washington; Aliseda, Alberto [Univ of Washington; Palodichuk, Michael [Univ of Washington; Polagye, Brian [Univ of Washington; Thomson, James [Univ of Washington; Chime, Arshiya [Univ of Washington; Malte, Philip [Univ of washington

2014-03-31

This technical report contains results on the following topics: 1) Testing and analysis of sub-scale hydro-kinetic turbines in a flume, including the design and fabrication of the instrumented turbines. 2) Field measurements and analysis of the tidal energy resource and at a site in northern Puget Sound, that is being examined for turbine installation. 3) Conceptual design and performance analysis of hydro-kinetic turbines operating at high blockage ratio, for use for power generation and flow control in open channel flows.

75 FR 61479 - Kendall Head Tidal Energy Project; Notice of Preliminary Permit Application Accepted for Filing...

Science.gov (United States)

2010-10-05

... Tidal Energy Project; Notice of Preliminary Permit Application Accepted for Filing and Soliciting... Federal Power Act, proposing to study the feasibility of the Kendall Head Tidal Energy Project, located in.... The proposed project would consist of: (1) 4 OCGen\\TM\\ hydrokinetic tidal devices each consisting of...

A Political, Economic, Social, Technology, Legal and Environmental (PESTLE) Approach for Risk Identification of the Tidal Industry in the United Kingdom

OpenAIRE

Kolios, Athanasios J.; Read, G.

2013-01-01

This paper presents a comprehensive analysis of renewable and especially tidal energy through a political, economic, social, technology, legal and environmental (PESTLE) analysis approach and by reviewing the most up to date relevant literature. The study focuses on the United Kingdom given the favourable environmental resources for such technologies; the number of different design concepts that are currently under development as well as the research funding that has been invested over the la...

Study of tidal power projects in the UK, with the exception of the Severn barrage

International Nuclear Information System (INIS)

Shaw, T.L.

1997-01-01

Several estuaries in the UK could be equipped with barrages and tidal power plants and several projects were proposed and studied from the end of the 1960's and 1989, until the electric power industry was privatized. Five projects revealed to be more promising than others: the Conwy estuary in the north of Wales, for which the feasibility study concluded that there was no serious environmental constraints on the project; Duddon, a little bit more in the north, which appears to be not economically interesting; Loughor, in the south of Wales, a small size project for which no advanced ecological consequences studies were carried out; Mersey, near Liverpool, the most important project (700 MW) which stands a good chance of being realized; the Wyre estuary, between Duddon and Mersey, for which the cost seems to be prohibitive. The economical conditions which started in the 1980's are largely responsible for the stand-by of any of these projects. The tide power kWh production cost continues to be viewed as two times more expensive than it would be with a classical power plant. Of course, this cost takes into account the actions for environmental protection. (J.S.)

Tidal radiation

International Nuclear Information System (INIS)

Mashhoon, B.

1977-01-01

The general theory of tides is developed within the framework of Einstein's theory of gravitation. It is based on the concept of Fermi frame and the associated notion of tidal frame along an open curve in spacetime. Following the previous work of the author an approximate scheme for the evaluation of tidal gravitational radiation is presented which is valid for weak gravitational fields. The emission of gravitational radiation from a body in the field of a black hole is discussed, and for some cases of astrophysical interest estimates are given for the contributions of radiation due to center-of-mass motion, purely tidal deformation, and the interference between the center of mass and tidal motions

Marine Hydrokinetic Energy Site Identification and Ranking Methodology Part II: Tidal Energy

Energy Technology Data Exchange (ETDEWEB)

Kilcher, Levi [National Renewable Energy Lab. (NREL), Golden, CO (United States); Thresher, Robert [National Renewable Energy Lab. (NREL), Golden, CO (United States); Tinnesand, Heidi [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2016-10-01

Marine hydrokinetic energy is a promising and growing piece of the renewable energy sector that offers high predictability and additional energy sources for a diversified energy economy. This report investigates the market opportunities for tidal energy along the U.S. coastlines. It is part one of a two-part investigation into the United States' two largest marine hydrokinetic resources (wave and tidal). Tidal energy technology is still an emerging form of renewable energy for which large-scale grid-connected project costs are currently poorly defined. Ideally, device designers would like to know the resource conditions at economical project sites so they can optimize device designs. On the other hand, project developers need detailed device cost data to identify sites where projects are economical. That is, device design and siting are, to some extent, a coupled problem. This work describes a methodology for identifying likely deployment locations based on a set of criteria that tidal energy experts in industry, academia, and national laboratories agree are likely to be important factors for all technology types. Several factors that will affect tidal project costs and siting have not been considered here -- including permitting constraints, conflicting use, seasonal resource variability, extreme event likelihood, and distance to ports -- because consistent data are unavailable or technology-independent scoring could not be identified. As the industry continues to mature and converge around a subset of device archetypes with well-defined costs, more precise investigations of project siting that include these factors will be possible. For now, these results provide a high-level guide pointing to the regions where markets and resource will one day support commercial tidal energy projects.

Development, installation and testing of a large-scale tidal current turbine

Energy Technology Data Exchange (ETDEWEB)

Thake, J.

2005-10-15

This report summarises the findings of the Seaflow project to investigate the feasibility of building and operating a commercial scale marine current horizontal axis tidal turbine and to evaluate the long-term economics of producing electricity using tidal turbines. Details are given of competitive tidal stream technologies and their commercial status, the selection of the site on the North Devon coast of the UK, and the evaluation of the turbine design, manufacture, testing, installation, commissioning, and maintenance of the turbine. The organisations working on the Seaflow project and cost estimations are discussed.

Tidal Power Potential in the Submerged Channels of Dar es

African Journals Online (AJOL)

on the tidal plateau, shallow water area on the sand banks and in the submerged channels, using self—recording .... in a Cartesian frame where iz is directed towards the vertical, ix points ..... Bongoyo, there is a 15 m deep channel that passes.

Tides and tidal currents

NARCIS (Netherlands)

Roos, A.

1997-01-01

Basic phenomena, origin and generation of tides, analysis and prediction of tides, basic equation and types of long waves in one dimension, tidal propagation in one dimension, tidal propagation in two directions, analytical tidal computation, numerical tidal computation.

High-resolution modeling assessment of tidal stream resource in Western Passage of Maine, USA

Science.gov (United States)

Yang, Zhaoqing; Wang, Taiping; Feng, Xi; Xue, Huijie; Kilcher, Levi

2017-04-01

Although significant efforts have been taken to assess the maximum potential of tidal stream energy at system-wide scale, accurate assessment of tidal stream energy resource at project design scale requires detailed hydrodynamic simulations using high-resolution three-dimensional (3-D) numerical models. Extended model validation against high quality measured data is essential to minimize the uncertainties of the resource assessment. Western Passage in the State of Maine in U.S. has been identified as one of the top ranking sites for tidal stream energy development in U.S. coastal waters, based on a number of criteria including tidal power density, market value and transmission distance. This study presents an on-going modeling effort for simulating the tidal hydrodynamics in Western Passage using the 3-D unstructured-grid Finite Volume Community Ocean Model (FVCOM). The model domain covers a large region including the entire the Bay of Fundy with grid resolution varies from 20 m in the Western Passage to approximately 1000 m along the open boundary near the mouth of Bay of Fundy. Preliminary model validation was conducted using existing NOAA measurements within the model domain. Spatial distributions of tidal power density were calculated and extractable tidal energy was estimated using a tidal turbine module embedded in FVCOM under different tidal farm scenarios. Additional field measurements to characterize resource and support model validation were discussed. This study provides an example of high resolution resource assessment based on the guidance recommended by the International Electrotechnical Commission Technical Specification.

Which future for the tidal sector in France? Towards a new model of territorial development

International Nuclear Information System (INIS)

Aelbrecht, Denis; Deroo, Luc; Le Visage, Christophe; Rabain, Antoine

2017-01-01

This document proposes a brief overview of works by a French national work-group of the SHF (French Hydro-technical Society) on the new tidal sector. It indicates recent and current development in the renewable marine energy sector: offshore wind farms along the French coasts, floating wind energy demonstrators, several tidal stream demonstrators, and other projects. British projects are also evoked. Then various aspects which could be success factors, are briefly discussed: the tidal potential, project configuration types (dams in estuary, coastal lagoons, offshore lagoons), interactions with the environment (sea and coastal ecosystems, sediments), opportunities of technological innovation (belt of the tidal basin, machine technology, exploitation mode), the concept of tidal garden, economic performance and viability (orientations for cost reduction and income increase). The issue of feasibility with respect with the NIMBY syndrome is finally addressed, and orientations and principles are briefly defined to evolve towards a YINBY (Yes in my back yard) syndrome

Foundations of pulsed power technology

CERN Document Server

Lehr, Janet

2018-01-01

Pulsed power technologies could be an answer to many cutting-edge applications. The challenge is in how to develop this high-power/high-energy technology to fit current market demands of low-energy consuming applications. This book provides a comprehensive look at pulsed power technology and shows how it can be improved upon for the world of today and tomorrow. Foundations of Pulsed Power Technology focuses on the design and construction of the building blocks as well as their optimum assembly for synergetic high performance of the overall pulsed power system. Filled with numerous design examples throughout, the book offers chapter coverage on various subjects such as: Marx generators and Marx-like circuits; pulse transformers; pulse-forming lines; closing switches; opening switches; multi-gigawatt to multi-terawatt systems; energy storage in capacitor banks; electrical breakdown in gases; electrical breakdown in solids, liquids and vacuum; pulsed voltage and current measurements; electromagnetic interferen...

Clustering and estimating fish fingerling abundance in a tidal river in close ploximity to a thermal power plant in Southern Thailand

Science.gov (United States)

Chesoh, S.; Lim, A.; Luangthuvapranit, C.

2018-04-01

This study aimed to cluster and to quantify the wild-caught fingerlings nearby thermal power plant. Samples were monthly collected by bongo nets from four upstream sites of the Na Thap tidal river in Thailand from 2008 to 2013. Each caught species was identified, counted and calculated density in term of individuals per 1,000 cubic meters. A total of 45 aquatic animal fingerlings was commonly trapped in the average density of 2,652 individuals per 1,000 cubic meters of water volume (1,235–4,570). The results of factor analysis revealed that factor 1 was represented by the largest group of freshwater fish species, factors 2 represented a medium-sized group of mesohaline species, factor 3 represented several brackish species and factor 4 was a few euryhaline species. All four factor reached maximum levels during May to October. Total average numbers of fish fingerling caught at the outflow showed greater than those of other sampling sites. The impact of heated pollution from power plant effluents did not clearly detected. Overall water quality according the Thailand Surface Water Quality Standards Coastal tidal periodic and seasonal runoff phenomena exhibit influentially factors. Continuous ecological monitoring is strongly recommended.

Homogeneous wave turbulence driven by tidal flows

Science.gov (United States)

Favier, B.; Le Reun, T.; Barker, A.; Le Bars, M.

2017-12-01

When a moon orbits around a planet, the rotation of the induced tidal bulge drives a homogeneous, periodic, large-scale flow. The combination of such an excitation with the rotating motion of the planet has been shown to drive parametric resonance of a pair of inertial waves in a mechanism called the elliptical instability. Geophysical fluid layers can also be stratified: this is the case for instance of the Earth's oceans and, as suggested by several studies, of the upper part of the Earth's liquid Outer Core. We thus investigate the stability of a rotating and stratified layer undergoing tidal distortion in the limit where either rotation or stratification is dominant. We show that the periodic tidal flow drives a parametric subharmonic resonance of inertial (resp. internal) waves in the rotating (resp. stratified) case. The instability saturates into a wave turbulence pervading the whole fluid layer. In such a state, the instability mechanism conveys the tidal energy from the large scale tidal flow to the resonant modes, which then feed a succession of triadic resonances also generating small spatial scales. In the rotating case, we observe a kinetic energy spectrum with a k-2 slope for which the Coriolis force is dominant at all spatial scales. In the stratified case, where the timescale separation is increased between the tidal excitation and the Brunt-Väisälä frequencies, the temporal spectrum decays with a ω-2 power law up to the cut-off frequency beyond which waves do not exist. This result is reminiscent of the Garrett and Munk spectrum measured in the oceans and theoretically described as a manifestation of internal wave turbulence. In addition to revealing an instability driving homogeneous turbulence in geophysical fluid layers, our approach is also an efficient numerical tool to investigate the possibly universal properties of wave turbulence in a geophysical context.

Geothermal Power Technologies

DEFF Research Database (Denmark)

Montagud, Maria E. Mondejar; Chamorro, C.R.

2017-01-01

Although geothermal energy has been widely deployed for direct use in locations with especial geologic manifestations, its potential for power generation has been traditionally underestimated. Recent technology developments in drilling techniques and power conversion technologies from low......-temperature heat resources are bringing geothermal energy to the spotlight as a renewable baseload energy option for a sustainable energy mix. Although the environmental impact and economic viability of geothermal exploitation must be carefully evaluated for each case, the use of deep low-temperature geothermal...... reservoirs could soon become an important contributor to the energy generation around the world....

Renewable Energy Potentials along the Bay of Bengal due to Tidal Water Level Variation

Directory of Open Access Journals (Sweden)

Ahmad Myisha

2018-01-01

Full Text Available The projected increase in energy demand coupled with concerns regarding present reliance on fossil fuel and associated environmental concerns had led to increased interest in exploiting renewable energy sources. Among different renewable energy sources, tidal energy is unique and most suitable because of its predictable nature and capability to ensure supply security. Tide consists of both kinetic and potential energy which can be converted to electricity using well-proven technology. The potential energy of tides - the principal focus of the study, is stored due to rise and fall of the sea level. Head difference created due to tidal variation between basin side and sea side of a barrage stores potential energy which is converted into fast-moving water that rotates turbine and generates electricity. Bangladesh with its long coastline has promising prospects of tidal energy resource development. The study focuses on tidal energy resource exploration and exploitation along several competent locations of the Bengal coastline. Tidal records of flood and ebb tide of these locations are analyzed to calculate the potential energy. Finally, available potential techniques of energy extraction are evaluated for annually generated energy estimation. This study investigates the prospect and utilization of tidal energy concept and reviews the possibilities and opportunities of employment of the technology for sustainable development and climate change mitigation in context of Bangladesh.

From Globular Clusters to Tidal Dwarfs: Structure Formation in Tidal Tails

Science.gov (United States)

Knierman, K.; Hunsberger, S.; Gallagher, S.; Charlton, J.; Whitmore, B.; Hibbard, J.; Kundu, A.; Zaritsky, D.

1999-12-01

Galaxy interactions trigger star formation in tidal debris. How does this star formation depend on the local and global physical conditions? Using WFPC2/HST images, we investigate the range of structure within tidal tails of four classic ``Toomre Sequence'' mergers: NGC 4038/9 (``Antennae''), NGC 7252 (``Atoms for Peace''), NGC 3921, and NGC 3256. These tails contain a variety of stellar associations with sizes from globular clusters up to dwarf Irregulars. We explore whether there is a continuum between the two extremes. Our eight fields sample seven tidal tails at a variety of stages in the evolutionary sequence. Some of these tails are rich in HI while others are HI poor. Large tidal dwarfs are embedded in three of the tails. Using V and I WFPC2 images, we measure luminosities and colors of substructures within the tidal tails. The properties of globular cluster candidates in the tails will be contrasted with those of the hundreds of young clusters in the central regions of these mergers. We address whether globular clusters form and survive in the tidal tails and whether tidal dwarfs are composed of only young stars. By comparing the properties of structures in the tails of the four mergers with different ages, we examine systematic evolution of structure along the evolutionary sequence and as a function of HI content. We acknowledge support from NASA through STScI, and from NSF for an REU supplement for Karen Knierman.

Variability of stratification according to operation of the tidal power plant in Lake Sihwa, South Korea.

Science.gov (United States)

Woo, S. B.; Song, J. I.; Jang, T. H.; Park, C. J.; Kwon, H. K.

2017-12-01

Artificial forcing according to operation of the tidal power plant (TPP) affects the physical environmental changes near the power plant. Strong turbulence by generation is expected to change the stratification structure of the Lake Sihwa inside. In order to examine the stratification changes by the power plant operation, ship bottom mounted observation were performed for 13 hours using an acoustic Doppler current profiler (ADCP) and Conductivity-Temperature-Depth (CTD) in Lake Sihwa at near TPP. The strong stratification in Sihwa Lake is maintained before TPP operation. The absence of external forces and freshwater inflow from the land forms the stratification in the Lake. Strong winds in a stratification statement lead to two-layer circulation. After wind event, multi-layer velocity structure is formed which lasted for approximately 4 h. After TPP operation, the jet flow was observed in entire water column at the beginning of the power generation. Vortex is formed by strong jet flow and maintained throughout during power generation period. Strong turbulence flow is generated by the turbine blades, enhancing vertical mixing. External forces, which dominantly affect Lake Sihwa, have changed from the wind to the turbulent flow. The stratification was extinguished by strong turbulent flow and becomes fully-mixed state. Changes in stratification structure are expected to affect material transport and ecological environment change continuously.

Stingray tidal stream energy device - phase 3

International Nuclear Information System (INIS)

2005-01-01

The 150 kW Stingray demonstrator was designed, built and installed by The Engineering Business (EB) in 2002, becoming the world's first full-scale tidal stream generator. The concept and technology are described in the reports from Phases 1 and 2 of the project. This report provides an overview of Phase 3 - the re-installation of Stingray in Yell Sound in the Shetland Isles between July and September 2003 for further testing at slack water and on the flood tide to confirm basic machine characteristics, develop the control strategy and to demonstrate performance and power collection through periods of continuous operation. The overall aim was to demonstrate that electricity could be generated at a potentially commercially viable unit energy cost; cost modelling indicated a future unit energy cost of 6.7 pence/kWh when 100 MW capacity had been installed. The report describes: project objectives, targets and activities; design and production; marine operations including installation and demobilisation; environmental monitoring and impact, including pre-installation and post-decommissioning surveys; stakeholder involvement; test results on machine characteristics, sensor performance, power cycle analysis, power collection, transmission performance and efficiency, current data analysis; validation of the mathematical model; the background to the economic model; cost modelling; and compliance with targets set by the Department of Trade and Industry (DTI)

Stingray tidal stream energy device - phase 3

Energy Technology Data Exchange (ETDEWEB)

NONE

2005-07-01

The 150 kW Stingray demonstrator was designed, built and installed by The Engineering Business (EB) in 2002, becoming the world's first full-scale tidal stream generator. The concept and technology are described in the reports from Phases 1 and 2 of the project. This report provides an overview of Phase 3 - the re-installation of Stingray in Yell Sound in the Shetland Isles between July and September 2003 for further testing at slack water and on the flood tide to confirm basic machine characteristics, develop the control strategy and to demonstrate performance and power collection through periods of continuous operation. The overall aim was to demonstrate that electricity could be generated at a potentially commercially viable unit energy cost; cost modelling indicated a future unit energy cost of 6.7 pence/kWh when 100 MW capacity had been installed. The report describes: project objectives, targets and activities; design and production; marine operations including installation and demobilisation; environmental monitoring and impact, including pre-installation and post-decommissioning surveys; stakeholder involvement; test results on machine characteristics, sensor performance, power cycle analysis, power collection, transmission performance and efficiency, current data analysis; validation of the mathematical model; the background to the economic model; cost modelling; and compliance with targets set by the Department of Trade and Industry (DTI).

A large-eddy simulation study of wake propagation and power production in an array of tidal-current turbines.

Science.gov (United States)

Churchfield, Matthew J; Li, Ye; Moriarty, Patrick J

2013-02-28

This paper presents our initial work in performing large-eddy simulations of tidal turbine array flows. First, a horizontally periodic precursor simulation is performed to create turbulent flow data. Then those data are used as inflow into a tidal turbine array two rows deep and infinitely wide. The turbines are modelled using rotating actuator lines, and the finite-volume method is used to solve the governing equations. In studying the wakes created by the turbines, we observed that the vertical shear of the inflow combined with wake rotation causes lateral wake asymmetry. Also, various turbine configurations are simulated, and the total power production relative to isolated turbines is examined. We found that staggering consecutive rows of turbines in the simulated configurations allows the greatest efficiency using the least downstream row spacing. Counter-rotating consecutive downstream turbines in a non-staggered array shows a small benefit. This work has identified areas for improvement. For example, using a larger precursor domain would better capture elongated turbulent structures, and including salinity and temperature equations would account for density stratification and its effect on turbulence. Additionally, the wall shear stress modelling could be improved, and more array configurations could be examined.

Development and the environmental impact analysis of tidal current energy turbines in China

Science.gov (United States)

Liu, Yuxin; Ma, Changlei; Jiang, Bo

2018-02-01

Chinese government pays more attentions to renewable energies (RE) in the context of increasing energy demand and climate change problems. As a promising RE, the utilization of marine renewable energy (MRE) is engaging in the world, including the wave energy and tidal current energy mainly. At the same time, the tidal current energy resources in China are abundant. Thus, the utilization of tidal current energy becomes an inevitable choice for China to meet the challenge of global climate change. The Renewable Energy Law (amendment) and “Twelfth Five-Year” Plan of Renewable Energy Development (2011-2015) were released in recent years in China, the tidal current energy are successfully implemented in China, including the R&D and pilot projects. After the summary of the status of tidal current energy converters in recent years in China, especially the devices being in the open sea test. The environmental impact study in China is also introduced in order to offer reference for the environmental impact assessment of tidal current power generation.

Turbine Siting Metrics for Simulated Tidal Flow in a Double-Silled Channel

Science.gov (United States)

Thyng, K. M.; Kawase, M.; Riley, J. J.; Northwest National Marine Renewable Energy Center

2010-12-01

An important component of site and resource characterization for marine renewable energy projects is to identify areas with large potential resource but also with easy extractability of the available resource for commercial develop- ment. Metrics that characterize potential resource include mean kinetic power density and speed over a tidal cycle, while important metrics for extractability include measures of the bidirectionality of the tidal flow (asymmetry, directional deviation, and power bias of ebb versus flood tide) as well as percentage of time spent by the device producing power at the particular site. This study examines the character of a tidal flow over an idealized two- dimensional (x-z) double sill in a rectangular channel in terms of these resource characterization metrics. This domain is meant to capture the bulk features of Admiralty Inlet, the main entrance to the Puget Sound, a fjord-like estuary in western Washington State. Admiralty Inlet is an area of interest for build- ing a commercial-scale tidal turbine array, and is currently the location of two potential pilot-scale tidal hydrokinetic projects. Initial results point to the speed up of the incoming flow due to the shallowest sill as an area of strong resource. The presence of the deeper sill affects the character of this strong resource in a way that the metrics can help quantify in terms of extractability of the resource and vertical structure. Together, these metrics will give a clear understanding of the tidal turbine siting characteristics of the domain. In the case of the idealized double sill simulation, the mean speed is increased by a factor of more than 2 over the mean incoming speed at the entrance of the channel due to the shallower, more prominent sill, while the deeper sill sees a multiplication factor of close to 1.5. This is a modest increase in mean speed, but translates to a multiplication factor of over 8 from the nominal far field value near the shallow sill in the mean

Policy for tidal energy

Energy Technology Data Exchange (ETDEWEB)

Shaw, T L

1977-01-01

The potential of tidal energy for the United Kingdom should be reassessed, it is argued, and some of its advantages are cited. The technology for its development is available and proven; experience suggests that the capital works will have an indefinite life, with only the turbine blades needing to be replaced occasionally. It is a source of water power, and can be regulated to generate when required, on a flexible basis and only by day if so desired; this compares favorably with the relatively unpredictable nature of the other sources. It can be made to complement directly, and so to improve the performance of the coal and nuclear sources at a scale readily possible from a proportionately small installed capacity. The fuel is free. Present indications unquestionably suggest that it will be timely to reassess this source as part of the present energy review, so that its potential may be realized when needed after 1990. It is especially significant that the environmental effects of the necessary works appear to be comparatively small whereas the industrial and social rewards, so far not financially quantified, could be appreciable. The disadvantages that have been expressed are cited, but the author counters the attack on them. (MCW)

Image formation in weak gravitational lensing by tidal charged black holes

International Nuclear Information System (INIS)

Horvath, Zsolt; Gergely, Laszlo Arpad; Hobill, David

2010-01-01

We derive a generic weak lensing equation and apply it for the study of images produced by tidal charged brane black holes. We discuss the similarities and point out the differences with respect to the Schwarzschild black hole weak lensing, to both first- and second-order accuracy, when either the mass or the tidal charge dominates. In the case of mass-dominated weak lensing, we analyze the position of the images, the magnification factors and the flux ratio, as compared to the Schwarzschild lensing. The most striking modification appears in the flux ratio. When the tidal charge represents the dominating lensing effect, the number and orientation of the images with respect to the optical axis resembles the lensing properties of a Schwarzschild geometry, where the sign associated with the mass is opposite to that for the tidal charge. Finally it is found that the ratio of the brightness of the images as a function of image separation in the case of tidal charged black holes obeys a power-law relation significantly different from that of Schwarzschild black holes. This might provide a means for determining the underlying spacetime structure.

Investigating the Trade-Off Between Power Generation and Environmental Impact of Tidal-Turbine Arrays Using Array Layout Optimisation and Habitat Sustainability Modelling.

Science.gov (United States)

du Feu, R. J.; Funke, S. W.; Kramer, S. C.; Hill, J.; Piggott, M. D.

2016-12-01

The installation of tidal turbines into the ocean will inevitably affect the environment around them. However, due to the relative infancy of this sector the extent and severity of such effects is unknown. The layout of an array of turbines is an important factor in determining not only the array's final yield but also how it will influence regional hydrodynamics. This in turn could affect, for example, sediment transportation or habitat suitability. The two potentially competing objectives of extracting energy from the tidal current, and of limiting any environmental impact consequent to influencing that current, are investigated here. This relationship is posed as a multi-objective optimisation problem. OpenTidalFarm, an array layout optimisation tool, and MaxEnt, habitat sustainability modelling software, are used to evaluate scenarios off the coast of the UK. MaxEnt is used to estimate the likelihood of finding a species in a given location based upon environmental input data and presence data of the species. Environmental features which are known to impact habitat, specifically those affected by the presence of an array, such as bed shear stress, are chosen as inputs. MaxEnt then uses a maximum-entropy modelling approach to estimate population distribution across the modelled area. OpenTidalFarm is used to maximise the power generated by an array, or multiple arrays, through adjusting the position and number of turbines within them. It uses a 2D shallow water model with turbine arrays represented as adjustable friction fields. It has the capability to also optimise for user created functionals that can be expressed mathematically. This work uses two functionals; power extracted by the array, and the suitability of habitat as predicted by MaxEnt. A gradient-based local optimisation is used to adjust the array layout at each iteration. This work presents arrays that are optimised for both yield and the viability of habitat for chosen species. In each scenario

High technology supporting nuclear power industry in CRIEPI

International Nuclear Information System (INIS)

Ueda, Nobuyuki

2009-01-01

As a central research institute of electric power industry, Central Research Institute of Electric Power Industry (CRIEPI) has carried out R and D on broad range of topics such as power generation, power transmission, power distribution, power application and energy economics and society, aiming to develop prospective and advanced technologies, fundamental reinforce technologies and next-generation core technologies. To realize low-carbon society to cope with enhancement of global environmental issues, nuclear power is highly recommended as large-scale power with low-carbon emission. At the new start of serial explanation on advanced technologies, R and D on electric power industry was outlined. (T. Tanaka)

Empirical Tidal Dissipation in Exoplanet Hosts From Tidal Spin-up

Science.gov (United States)

Penev, Kaloyan; Bouma, L. G.; Winn, Joshua N.; Hartman, Joel D.

2018-04-01

Stars with hot Jupiters (HJs) tend to rotate faster than other stars of the same age and mass. This trend has been attributed to tidal interactions between the star and planet. A constraint on the dissipation parameter {Q}\\star {\\prime } follows from the assumption that tides have managed to spin up the star to the observed rate within the age of the system. This technique was applied previously to HATS-18 and WASP-19. Here, we analyze the sample of all 188 known HJs with an orbital period tidal dissipation parameter ({Q}\\star {\\prime }) increases sharply with forcing frequency, from 105 at 0.5 day‑1 to 107 at 2 day‑1. This helps to resolve a number of apparent discrepancies between studies of tidal dissipation in binary stars, HJs, and warm Jupiters. It may also allow for a HJ to damp the obliquity of its host star prior to being destroyed by tidal decay.

Staged Introduction of Non-power and Power Nuclear Technologies to Newcomer Countries

International Nuclear Information System (INIS)

Uesaka, M.

2016-01-01

Full text: Staged introduction of non-power and power nuclear technologies to new comer countries and related knowledge management are presented. Contribution and benefit of radiation technology to medicine and society are very important before nuclear power plants are introduced. Recently, not only new nuclear power technologies but also compact and high performance accelerators for medicine and industrial/social infrastructure maintenance have been developed and used. Such staged introduction with respect to technology, education and economy contributes to enhancement of PA (Public Acceptance). Organized education, knowledge management and network should be associated. (author

Dynamic Braking System of a Tidal Generator: Preprint

Energy Technology Data Exchange (ETDEWEB)

Muljadi, Eduard; Wright, Alan; Gevorgian, Vahan; Donegan, James; Marnagh, Cian; McEntee, Jarlath

2016-08-01

Renewable energy generation has experienced significant cost reductions during the past decades, and it has become more accepted by the global population. In the beginning, wind generation dominated the development and deployment of renewable energy; however, during recent decades, photovoltaic (PV) generation has grown at a very significant pace due to the tremendous decrease in the cost of PV modules. The focus on renewable energy generation has now expanded to include new types with promising future applications, such as river and tidal generation. The input water flow to these types of resources is more predictable than wind or solar generation. The data used in this paper is representative of a typical river or tidal generator. The analysis is based on a generator with a power rating of 40 kW. The tidal generator under consideration is driven by two sets of helical turbines connected to each side of the generator located in between the turbines. The generator is operated in variable speed, and it is controlled to maximize the energy harvested as well as the operation of the turbine generator. The electrical system consists of a three-phase permanent magnet generator connected to a three-phase passive rectifier. The output of the rectifier is connected to a DC-DC converter to match the rectifier output to the DC bus voltage of the DC-AC inverter. The three-phase inverter is connected to the grid, and it is controlled to provide a good interface with the grid. One important aspect of river and tidal generation is the braking mechanism. In a tidal generator, the braking mechanism is important to avoid a runaway condition in case the connection to the grid is lost when there is a fault in the lines. A runaway condition may lead to an overspeed condition and cause extreme stresses on the turbine blade structure and eventual disintegration of the mechanical structure. In this paper, the concept of the dynamic braking system is developed and investigated for normal

Power plant chemical technology

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-12-01

17 contributions covering topies of fossil fuel combustion, flue gas cleaning, power plant materials, corrosion, water/steam cycle chemistry, monitoring and control were presented at the annual meeting devoted to Power Plant Chemical Technology 1996 at Kolding (Denmark) 4-6 September 1996. (EG)

Fission Surface Power Technology Development Update

Science.gov (United States)

Palac, Donald T.; Mason, Lee S.; Houts, Michael G.; Harlow, Scott

2011-01-01

Power is a critical consideration in planning exploration of the surfaces of the Moon, Mars, and places beyond. Nuclear power is an important option, especially for locations in the solar system where sunlight is limited or environmental conditions are challenging (e.g., extreme cold, dust storms). NASA and the Department of Energy are maintaining the option for fission surface power for the Moon and Mars by developing and demonstrating technology for a fission surface power system. The Fission Surface Power Systems project has focused on subscale component and subsystem demonstrations to address the feasibility of a low-risk, low-cost approach to space nuclear power for surface missions. Laboratory demonstrations of the liquid metal pump, reactor control drum drive, power conversion, heat rejection, and power management and distribution technologies have validated that the fundamental characteristics and performance of these components and subsystems are consistent with a Fission Surface Power preliminary reference concept. In addition, subscale versions of a non-nuclear reactor simulator, using electric resistance heating in place of the reactor fuel, have been built and operated with liquid metal sodium-potassium and helium/xenon gas heat transfer loops, demonstrating the viability of establishing system-level performance and characteristics of fission surface power technologies without requiring a nuclear reactor. While some component and subsystem testing will continue through 2011 and beyond, the results to date provide sufficient confidence to proceed with system level technology readiness demonstration. To demonstrate the system level readiness of fission surface power in an operationally relevant environment (the primary goal of the Fission Surface Power Systems project), a full scale, 1/4 power Technology Demonstration Unit (TDU) is under development. The TDU will consist of a non-nuclear reactor simulator, a sodium-potassium heat transfer loop, a power

Increased Tidal Dissipation Using Advanced Rheological Models: Implications for Io and Tidally Active Exoplanets

Science.gov (United States)

Renaud, Joe P.; Henning, Wade G.

2018-04-01

The advanced rheological models of Andrade and Sundberg & Cooper are compared to the traditional Maxwell model to understand how each affects the tidal dissipation of heat within rocky bodies. We find both Andrade and Sundberg–Cooper rheologies can produce at least 10× the tidal heating compared to a traditional Maxwell model for a warm (1400–1600 K) Io-like satellite. Sundberg–Cooper can cause even larger dissipation around a critical temperature and frequency. These models allow cooler planets to stay tidally active in the face of orbital perturbations—a condition we term “tidal resilience.” This has implications for the time evolution of tidally active worlds and the long-term equilibria they fall into. For instance, if Io’s interior is better modeled by the Andrade or Sundberg–Cooper rheologies, the number of possible resonance-forming scenarios that still produce a hot, modern Io is expanded, and these scenarios do not require an early formation of the Laplace resonance. The two primary empirical parameters that define the Andrade anelasticity are examined in several phase spaces to provide guidance on how their uncertainties impact tidal outcomes, as laboratory studies continue to constrain their real values. We provide detailed reference tables on the fully general equations required for others to insert the models of Andrade and Sundberg–Cooper into standard tidal formulae. Lastly, we show that advanced rheologies can greatly impact the heating of short-period exoplanets and exomoons, while the properties of tidal resilience could mean a greater number of tidally active worlds among all extrasolar systems.

Korean experiences on nuclear power technology

International Nuclear Information System (INIS)

Kim, H.; Yang, H.

1994-01-01

This paper describes the outstanding performance of the indigenous development program of nuclear power technology such as the design and fabrication of both CANDU and PWR fuel and in the design and construction of nuclear steam supply system in Korea. The success has been accomplished through the successful technology transfer from foreign suppliers and efficient utilization of R and D manpower in the design and engineering of nuclear power projects. In order to implement the technology transfer successfully, the joint design concept has been introduced along with effective on-the-job training and the transfer of design documents and computer codes. Korea's successful development of nuclear power program has resulted in rapid expansion of nuclear power generation capacity in a short time, and the nuclear power has contributed to the national economy through lowering electricity price by about 50 % as well as stabilizing electricity supply in 1980s. The nuclear power is expected to play a key role in the future electricity supply in Korea. Now Korea is under way of taking a step toward advanced nuclear technology. The national electricity system expansion plan includes 18 more units of NPPs to be constructed by the year 2006. In this circumstance, the country has fixed the national long-term nuclear R and D program (lgg2-2001) to enhance the national capability of nuclear technology. This paper also briefly describes future prospects of nuclear technology development program in Korea

Advanced Radioisotope Power Conversion Technology Research and Development

Science.gov (United States)

Wong, Wayne A.

2004-01-01

NASA's Radioisotope Power Conversion Technology program is developing next generation power conversion technologies that will enable future missions that have requirements that cannot be met by either the ubiquitous photovoltaic systems or by current Radioisotope Power System (RPS) technology. Performance goals of advanced radioisotope power systems include improvement over the state-of-practice General Purpose Heat Source/Radioisotope Thermoelectric Generator by providing significantly higher efficiency to reduce the number of radioisotope fuel modules, and increase specific power (watts/kilogram). Other Advanced RPS goals include safety, long-life, reliability, scalability, multi-mission capability, resistance to radiation, and minimal interference with the scientific payload. NASA has awarded ten contracts in the technology areas of Brayton, Stirling, Thermoelectric, and Thermophotovoltaic power conversion including five development contracts that deal with more mature technologies and five research contracts. The Advanced RPS Systems Assessment Team includes members from NASA GRC, JPL, DOE and Orbital Sciences whose function is to review the technologies being developed under the ten Radioisotope Power Conversion Technology contracts and assess their relevance to NASA's future missions. Presented is an overview of the ten radioisotope power conversion technology contracts and NASA's Advanced RPS Systems Assessment Team.

Power Technologies Data Book 2003 Edition

Energy Technology Data Exchange (ETDEWEB)

Aabakken, J.

2004-06-01

The 2003 edition of this report, prepared by NREL's Energy Analysis Office, includes up-to-date information on power technologies, including complete technology profiles. The data book also contains charts on electricity restructuring, power technology forecasts and comparisons, electricity supply, electricity capability, electricity generation, electricity demand, prices, economic indicators, environmental indicators, conversion factors, and selected congressional questions and answers.

The Effects of Surface Waves and Submergence on the Performance and Loading of a Tidal Turbine

OpenAIRE

Guo, Xiaoxian; Gao, Zhen; Yang, Jianmin; Moan, Torgeir; Lu, Haining; Li, Xin; Lu, Wenyue

2017-01-01

Tidal energy has the advantages of high predictability, high energy density, and limited environmental impacts. As tidal turbines are expected to be used in the most energetic waters where there might be significant waves, the assessment of unsteady hydrodynamic load due to surface waves is of great concern. The objective of this paper is to assess the effects of surface waves and submergence of the turbine on the power performance and loads of a tidal turbine by experimental approach. The ex...

Tidal Energy Conversion Installation at an Estuarine Bridge Site: Resource Evaluation and Energy Production Estimate

Science.gov (United States)

Wosnik, M.; Gagnon, I.; Baldwin, K.; Bell, E.

2015-12-01

The "Living Bridge" project aims to create a self-diagnosing, self-reporting "smart bridge" powered by a local renewable energy source, tidal energy - transforming Memorial Bridge, a vertical lift bridge over the tidal Piscataqua River connecting Portsmouth, NH and Kittery, ME, into a living laboratory for researchers, engineers, scientists, and the community. The Living Bridge project includes the installation of a tidal turbine at the Memorial Bridge. The energy converted by the turbine will power structural health monitoring, environmental and underwater instrumentation. Utilizing locally available tidal energy can make bridge operation more sustainable, can "harden" transportation infrastructure against prolonged grid outages and can demonstrate a prototype of an "estuarine bridge of the future". A spatio-temporal tidal energy resource assessment was performed using long term bottom-deployed Acoustic Doppler Current Profilers (ADCP) at two locations: near the planned deployment location in 2013-14 for 123 days and mid-channel in 2007 for 35 days. Data were evaluated to determine the amount of available kinetic energy that can be converted into usable electrical energy on the bridge. Changes in available kinetic energy with ebb/flood and spring/neap tidal cycles and electrical energy demand were analyzed. The target deployment site exhibited significantly more energetic ebb tides than flood tides, which can be explained by the local bathymetry of the tidal estuary. A system model is used to calculate the net energy savings using various tidal generator and battery bank configurations. Different resource evaluation methodologies were also analyzed, e.g., using a representative ADCP "bin" vs. a more refined, turbine-geometry-specific methodology, and using static bin height vs. bin height that move w.r.t. the free surface throughout a tidal cycle (representative of a bottom-fixed or floating turbine deployment, respectively). ADCP operating frequencies and bin

Plant distributions along salinity and tidal gradients in Oregon tidal marshes

Science.gov (United States)

Accurately modeling climate change effects on tidal marshes in the Pacific Northwest requires understanding how plant assemblages and species are presently distributed along gradients of salinity and tidal inundation. We outline on-going field efforts by the EPA and USGS to dete...

EPRI nuclear power plant decommissioning technology program

International Nuclear Information System (INIS)

Kim, Karen S.; Bushart, Sean P.; Naughton, Michael; McGrath, Richard

2011-01-01

The Electric Power Research Institute (EPRI) is a non-profit research organization that supports the energy industry. The Nuclear Power Plant Decommissioning Technology Program conducts research and develops technology for the safe and efficient decommissioning of nuclear power plants. (author)

On luminescence bleaching of tidal channel sediments

DEFF Research Database (Denmark)

Fruergaard, Mikkel; Pejrup, Morten; Murray, Andrew S.

2015-01-01

We investigate the processes responsible for bleaching of the quartz OSL signal from tidal channel sediment. Tidal dynamics are expected to play an important role for complete bleaching of tidal sediments. However, no studies have examined the amount of reworking occurring in tidal channels...... and on tidal flats due to the mixing caused by currents and waves. We apply bed level data to evaluate the amount of vertical sediment reworking in modern tidal channels and at a tidal flat. Cycles of deposition and erosion are measured with a bed level sensor, and the results show that gross sedimentation...... was several times higher than net sedimentation. We propose that tidal channel sediment is bleached either on the tidal flat before it is transported to the tidal channels and incorporated in channel-fill successions or, alternatively, on the shallow intertidal part of the channel banks. Based...

The environmental interactions of tidal and wave energy generation devices

International Nuclear Information System (INIS)

Frid, Chris; Andonegi, Eider; Depestele, Jochen; Judd, Adrian; Rihan, Dominic; Rogers, Stuart I.; Kenchington, Ellen

2012-01-01

Global energy demand continues to grow and tidal and wave energy generation devices can provide a significant source of renewable energy. Technological developments in offshore engineering and the rising cost of traditional energy means that offshore energy resources will be economic in the next few years. While there is now a growing body of data on the ecological impacts of offshore wind farms, the scientific basis on which to make informed decisions about the environmental effects of other offshore energy developments is lacking. Tidal barrages have the potential to cause significant ecological impacts particularly on bird feeding areas when they are constructed at coastal estuaries or bays. Offshore tidal stream energy and wave energy collectors offer the scope for developments at varying scales. They also have the potential to alter habitats. A diversity of designs exist, including floating, mid-water column and seabed mounted devices, with a variety of moving-part configurations resulting in a unique complex of potential environmental effects for each device type, which are discussed to the extent possible. - Highlights: ► We review the environmental impacts of tidal barrages and fences, tidal stream farms and wave energy capture devices. ► Impacts on habitats, species and the water column, and effects of noise and electromagnetic fields are considered. ► Tidal barrages can cause significant impacts on bird feeding areas when constructed at coastal estuaries or bays. ► Wave energy collectors can alter water column and sea bed habitats locally and over large distances.

The environmental interactions of tidal and wave energy generation devices

Energy Technology Data Exchange (ETDEWEB)

Frid, Chris, E-mail: c.l.j.frid@liv.ac.uk [School of Environmental Sciences, University of Liverpool, Crown Street, Liverpool, L69 7ZB (United Kingdom); Andonegi, Eider, E-mail: eandonegi@azti.es [AZTI-Tecnalia, Txatxarramendi ugartea, z/g E-48395 Sukarrieta (Bizkaia) (Spain); Depestele, Jochen, E-mail: jochen.depestele@ilvo.vlaanderen.be [Institute for Agricultural and Fisheries Research, Ankerstraat 1, B-8400 Oostende (Belgium); Judd, Adrian, E-mail: Adrian.Judd@cefas.co.uk [Centre for Environment, Fisheries and Aquaculture Science , Lowestoft Laboratory, Pakefield Road, Lowestoft NR33 0HT United Kingdom (United Kingdom); Rihan, Dominic, E-mail: Dominic.RIHAN@ec.europa.eu [Irish Sea Fisheries Board, P.O. Box 12 Dun Laoghaire, Co. Dublin (Ireland); Rogers, Stuart I., E-mail: stuart.rogers@cefas.co.uk [Centre for Environment, Fisheries and Aquaculture Science , Lowestoft Laboratory, Pakefield Road, Lowestoft NR33 0HT United Kingdom (United Kingdom); Kenchington, Ellen, E-mail: Ellen.Kenchington@dfo-mpo.gc.ca [Fisheries and Oceans Canada, Bedford Institute of Oceanography, P.O. Box 1006, Dartmouth Canada, NS B2Y 4A2 (Canada)

2012-01-15

Global energy demand continues to grow and tidal and wave energy generation devices can provide a significant source of renewable energy. Technological developments in offshore engineering and the rising cost of traditional energy means that offshore energy resources will be economic in the next few years. While there is now a growing body of data on the ecological impacts of offshore wind farms, the scientific basis on which to make informed decisions about the environmental effects of other offshore energy developments is lacking. Tidal barrages have the potential to cause significant ecological impacts particularly on bird feeding areas when they are constructed at coastal estuaries or bays. Offshore tidal stream energy and wave energy collectors offer the scope for developments at varying scales. They also have the potential to alter habitats. A diversity of designs exist, including floating, mid-water column and seabed mounted devices, with a variety of moving-part configurations resulting in a unique complex of potential environmental effects for each device type, which are discussed to the extent possible. - Highlights: Black-Right-Pointing-Pointer We review the environmental impacts of tidal barrages and fences, tidal stream farms and wave energy capture devices. Black-Right-Pointing-Pointer Impacts on habitats, species and the water column, and effects of noise and electromagnetic fields are considered. Black-Right-Pointing-Pointer Tidal barrages can cause significant impacts on bird feeding areas when constructed at coastal estuaries or bays. Black-Right-Pointing-Pointer Wave energy collectors can alter water column and sea bed habitats locally and over large distances.

TidGen Power System Commercialization Project

Energy Technology Data Exchange (ETDEWEB)

Sauer, Christopher R. [President & CEO; McEntee, Jarlath [VP Engineering & CTO

2013-12-30

ORPC Maine, LLC, a wholly-owned subsidiary of Ocean Renewable Power Company, LLC (collectively ORPC), submits this Final Technical Report for the TidGen® Power System Commercialization Project (Project), partially funded by the U.S. Department of Energy (DE-EE0003647). The Project was built and operated in compliance with the Federal Energy Regulatory Commission (FERC) pilot project license (P-12711) and other permits and approvals needed for the Project. This report documents the methodologies, activities and results of the various phases of the Project, including design, engineering, procurement, assembly, installation, operation, licensing, environmental monitoring, retrieval, maintenance and repair. The Project represents a significant achievement for the renewable energy portfolio of the U.S. in general, and for the U.S. marine hydrokinetic (MHK) industry in particular. The stated Project goal was to advance, demonstrate and accelerate deployment and commercialization of ORPC’s tidal-current based hydrokinetic power generation system, including the energy extraction and conversion technology, associated power electronics, and interconnection equipment capable of reliably delivering electricity to the domestic power grid. ORPC achieved this goal by designing, building and operating the TidGen® Power System in 2012 and becoming the first federally licensed hydrokinetic tidal energy project to deliver electricity to a power grid under a power purchase agreement in North America. Located in Cobscook Bay between Eastport and Lubec, Maine, the TidGen® Power System was connected to the Bangor Hydro Electric utility grid at an on-shore station in North Lubec on September 13, 2012. ORPC obtained a FERC pilot project license for the Project on February 12, 2012 and the first Maine Department of Environmental Protection General Permit issued for a tidal energy project on January 31, 2012. In addition, ORPC entered into a 20-year agreement with Bangor Hydro Electric

The influence of neap-spring tidal variation and wave energy on sediment flux in salt marsh tidal creeks

Science.gov (United States)

Lacy, Jessica; Ferner, Matthew C.; Callaway, John C.

2018-01-01

Sediment flux in marsh tidal creeks is commonly used to gage sediment supply to marshes. We conducted a field investigation of temporal variability in sediment flux in tidal creeks in the accreting tidal marsh at China Camp State Park adjacent to northern San Francisco Bay. Suspended-sediment concentration (SSC), velocity, and depth were measured near the mouths of two tidal creeks during three six-to-ten-week deployments: two in winter and one in summer. Currents, wave properties and SSC were measured in the adjacent shallows. All deployments spanned the largest spring tides of the season. Results show that tidally-averaged suspended-sediment flux (SSF) in the tidal creeks decreased with increasing tidal energy, and SSF was negative (bayward) for tidal cycles with maximum water surface elevation above the marsh plain. Export during the largest spring tides dominated the cumulative SSF measured during the deployments. During ebb tides following the highest tides, velocities exceeded 1 m/s in the narrow tidal creeks, resulting in negative tidally-averaged water flux, and mobilizing sediment from the creek banks or bed. Storm surge also produced negative SSF. Tidally-averaged SSF was positive in wavey conditions with moderate tides. Spring-tide sediment export was about 50% less at a station 130 m further up the tidal creek than at the creek mouth. The negative tidally-averaged water flux near the creek mouth during spring tides indicates that in the lower marsh, some of the water flooding directly across the bay--marsh interface drains through the tidal creeks, and suggests that this interface may be a pathway for sediment supply to the lower marsh as well.

Coastal inlets and tidal basins

NARCIS (Netherlands)

De Vriend, H.J.; Dronkers, J.; Stive, M.J.F.; Van Dongeren, A.; Wang, J.H.

2002-01-01

lecture note: Tidal inlets and their associated basins (lagoons) are a common feature of lowland coasts all around the world. A significant part ofthe world's coastlines is formed by barrier island coasts, and most other tidal coasts are interrupted by estuaries and lagoon inlets. These tidal

Gas-fired electric power generating technologies

International Nuclear Information System (INIS)

1994-09-01

The workshop that was held in Madrid 25-27 May 1994 included participation by experts from 16 countries. They represented such diverse fields and disciplines as technology, governmental regulation, economics, and environment. Thus, the participants provided an excellent cross section of key areas and a diversity of viewpoints. At the workshop, a broad range of topics regarding gas-fired electric power generation was discussed. These included political, regulatory and financial issues as well as more specific technical questions regarding the environment, energy efficiency, advanced generation technologies and the status of competitive developments. Important technological advances in gas-based power and CHP technologies have already been achieved including higher energy efficiency and lower emissions, with further improvements expected in the near future. Advanced technology trends include: (a) The use of gas technology to reduce emissions from existing coal-fired power plants. (b) The wide-spread application of combined-cycle gas turbines in new power plants and the growing use of aero-derivative gas turbines in CHP applications. (c) Phosphoric acid fuel cells that are being introduced commercially. Their market penetration will grow over the next 10 years. The next generation of fuel cells (solid oxide and molten carbonate) is expected to enter the market around the year 2000. (EG)

Topics in LIGO-related physics: Interferometric speed meters and tidal work

Science.gov (United States)

Purdue, Patricia Marie

In the quest to develop viable designs for third-generation interferometric gravitational-wave detectors (such as the Laser Interferometer Gravitational-Wave Observatory, LIGO), one strategy is monitoring the relative momentum or speed of the test-mass mirrors, rather than monitoring their relative position. The most straightforward design for a speed-meter interferometer that accomplishes this is analyzed in Chapter 2. It is shown that in principle this design can beat the standard quantum limit (SQL) by an arbitrarily large amount, over an arbitrarily wide range of frequencies. However, in practice, this specific speed meter requires exorbitantly high input light power. Chapter 3 proposes a more sophisticated version of a speed meter. This new design requires modest input power and appears to be a fully practical candidate for third-generation detectors. It can beat the SQL over a broad range of frequencies (˜10 to 100 Hz in practice) by a factor h/hSQL ˜ WSQLcirc/Wc irc . Here Wcirc is the light power circulating in the interferometer arms and WSQL ≃ 800 kW is the circulating power required to beat the SQL at 100 Hz. If squeezed vacuum (with a power-squeeze factor e-2 R) is injected into the interferometer's output port, the SQL can be beat with less laser power: h/h SQL ˜ WSQLcirc/Wc irce2R . For realistic parameters (e2 R ≃ 10 and Wcirc ≃ 800 kW), the SQL can be beat by a factor ˜3 from 10 to 100 Hz. By performing frequency-dependent homodyne detection on the output (using two kilometer-scale filter cavities), one can markedly improve the interferometer's sensitivity at frequencies above 100 Hz. Chapter 4 is a contribution to the foundations for analyzing sources of gravitational waves. Specifically, it presents an analysis of the tidal work done on a self-gravitating body in an external tidal field. By examining the change in the mass-energy of the body as a result of the tidal field, it is shown that the work done is gauge invariant, while the body-tidal

Tidal Friction in the Earth and Ocean

Science.gov (United States)

Ray, R. D.

2006-12-01

"Tidal Friction" is a classic subject in geophysics, with ties to some of the great scientists of the Victorian era. The subject has been reinvigorated over the past decade by space geodesy, and particularly by the Topex/Poseidon satellite altimeter mission. In fact, the topic has now taken on some significance in oceanography, with potential implications for problems of mixing, thermocline maintenance, and the thermohaline circulation. Likewise, tidal measurements have become sufficiently precise to reveal new information about the solid earth. In this respect, the tidal force is an invaluable "probe" of the earth, at frequencies well outside the seismic band. This talk will "follow the energy" of tides while noting some important geophysical implications at each stage. In the present earth-moon-sun configuration, energy for tides is extracted from the earth's rotation. Ancient eclipses bear witness to this, and the discrepancy between Babylonian (and other) observations and tidal predictions yields unique information about the mantle and the overlying fluid envelope. Complementary information comes from tidal anelasticity estimates, which are now available at frequencies ranging from semidiurnal to fortnightly, monthly, and 18.6 years. These data, when combined with various kinds of gravity measurements, are relevant to the present-day sea-level problem. Solid-earth tidal dissipation represents less than 5% of the system total. As has long been realized, the largest energy sink is the ocean. About 70% of the oceanic dissipation occurs in shallow seas (the traditional sink) and 30% in the deep ocean, generally near rugged bottom topography. The latter represents a substantial amount of power, roughly 1 gigawatt, available for generation of internal tides and other baroclinic motions. Experiments like HOME are helping unravel the links between barotropic tides, internal tides, turbulence, and mixing. The latter opens possible linkages to climate, and recent work

Biomass combustion technologies for power generation

Energy Technology Data Exchange (ETDEWEB)

Wiltsee, G.A. Jr. [Appel Consultants, Inc., Stevenson Ranch, CA (United States); McGowin, C.R.; Hughes, E.E. [Electric Power Research Institute, Palo Alto, CA (United States)

1993-12-31

Technology in power production from biomass has been advancing rapidly. Industry has responded to government incentives such as the PURPA legislation in the US and has recognized that there are environmental advantages to using waste biomass as fuel. During the 1980s many new biomass power plants were built. The relatively mature stoker boiler technology was improved by the introduction of water-cooled grates, staged combustion air, larger boiler sizes up to 60 MW, higher steam conditions, and advanced sootblowing systems. Circulating fluidized-bed (CFB) technology achieved full commercial status, and now is the leading process for most utility-scale power applications, with more complete combustion, lower emissions, and better fuel flexibility than stoker technology. Bubbling fluidized-bed (BFB) technology has an important market niche as the best process for difficult fuels such as agricultural wastes, typically in smaller plants. Other biomass power generation technologies are being developed for possible commercial introduction in the 1990s. Key components of Whole Tree Energy{trademark} technology have been tested, conceptual design studies have been completed with favorable results, and plans are being made for the first integrated process demonstration. Fluidized-bed gasification processes have advanced from pilot to demonstration status, and the world`s first integrated wood gasification/combined cycle utility power plant is starting operation in Sweden in early 1993. Several European vendors offer biomass gasification processes commercially. US electric utilities are evaluating the cofiring of biomass with fossil fuels in both existing and new plants. Retrofitting existing coal-fired plants gives better overall cost and performance results than any biomass technologies;but retrofit cofiring is {open_quotes}fuel-switching{close_quotes} that provides no new capacity and is attractive only with economic incentives.

An integrated model for estimating energy cost of a tidal current turbine farm

International Nuclear Information System (INIS)

Li, Ye; Lence, Barbara J.; Calisal, Sander M.

2011-01-01

A tidal current turbine is a device for harnessing energy from tidal currents and functions in a manner similar to a wind turbine. A tidal current turbine farm consists of a group of tidal current turbines distributed in a site where high-speed current is available. The accurate prediction of energy cost of a tidal current turbine farm is important to the justification of planning and constructing such a farm. However, the existing approaches used to predict energy cost of tidal current turbine farms oversimplify the hydrodynamic interactions between turbines in energy prediction and oversimplify the operation and maintenance strategies involved in cost estimation as well as related fees. In this paper, we develop a model, which integrates a marine hydrodynamic model with high accuracy for predicting energy output and a comprehensive cost-effective operation and maintenance model for estimating the cost that may be incurred in producing the energy, to predict energy cost from a tidal current turbine farm. This model is expected to be able to simulate more complicated cases and generate more accurate results than existing models. As there is no real tidal current turbine farm, we validate this model with offshore wind studies. Finally, case studies about Vancouver are conducted with a scenario-based analysis. We minimize the energy cost by minimizing the total cost and maximizing the total power output under constraints related to the local conditions (e.g., geological and labor information) and the turbine specifications. The results suggest that tidal current energy is about ready to penetrate the electricity market in some major cities in North America if learning curve for the operational and maintenance is minimum. (author)

Tidal locking of habitable exoplanets

Science.gov (United States)

Barnes, Rory

2017-12-01

Potentially habitable planets can orbit close enough to their host star that the differential gravity across their diameters can produce an elongated shape. Frictional forces inside the planet prevent the bulges from aligning perfectly with the host star and result in torques that alter the planet's rotational angular momentum. Eventually the tidal torques fix the rotation rate at a specific frequency, a process called tidal locking. Tidally locked planets on circular orbits will rotate synchronously, but those on eccentric orbits will either librate or rotate super-synchronously. Although these features of tidal theory are well known, a systematic survey of the rotational evolution of potentially habitable exoplanets using classic equilibrium tide theories has not been undertaken. I calculate how habitable planets evolve under two commonly used models and find, for example, that one model predicts that the Earth's rotation rate would have synchronized after 4.5 Gyr if its initial rotation period was 3 days, it had no satellites, and it always maintained the modern Earth's tidal properties. Lower mass stellar hosts will induce stronger tidal effects on potentially habitable planets, and tidal locking is possible for most planets in the habitable zones of GKM dwarf stars. For fast-rotating planets, both models predict eccentricity growth and that circularization can only occur once the rotational frequency is similar to the orbital frequency. The orbits of potentially habitable planets of very late M dwarfs ([InlineEquation not available: see fulltext.]) are very likely to be circularized within 1 Gyr, and hence, those planets will be synchronous rotators. Proxima b is almost assuredly tidally locked, but its orbit may not have circularized yet, so the planet could be rotating super-synchronously today. The evolution of the isolated and potentially habitable Kepler planet candidates is computed and about half could be tidally locked. Finally, projected TESS planets

Morphological effect of a scallop shell on a flapping-type tidal stream generator

International Nuclear Information System (INIS)

Le, Tuyen Quang; Ko, Jin Hwan; Byun, Doyoung

2013-01-01

Inspired by nature, flapping-type tidal stream generators have been introduced in recent years. The improvement in their power generation ability is known to be a critical factor in the success of these generators. So far, corrugation and camber observed in flying insects and swimming animals are known to enhance the performance of a flapping-type propulsive system. In this study, we explore the effect of corrugation and camber in a system that mimics a scallop shell in terms of its ability to extract flow energy through a two-dimensional Navier–Stokes simulation. The simulations show that the size and the activity of the leading edge vortex are strongly affected by the morphological factors of the mimicked foils, the effects of which are then advantageous in terms of the power efficiency of the flapping-type tidal stream generator. Eventually, an optimal mimicked foil, as suggested based on the morphological effects, would be a good alternative type of foil with a typical section with regard to the hydrodynamic performance and structural properties of tidal stream generators. (paper)

Space power subsystem automation technology

Science.gov (United States)

Graves, J. R. (Compiler)

1982-01-01

The technology issues involved in power subsystem automation and the reasonable objectives to be sought in such a program were discussed. The complexities, uncertainties, and alternatives of power subsystem automation, along with the advantages from both an economic and a technological perspective were considered. Whereas most spacecraft power subsystems now use certain automated functions, the idea of complete autonomy for long periods of time is almost inconceivable. Thus, it seems prudent that the technology program for power subsystem automation be based upon a growth scenario which should provide a structured framework of deliberate steps to enable the evolution of space power subsystems from the current practice of limited autonomy to a greater use of automation with each step being justified on a cost/benefit basis. Each accomplishment should move toward the objectives of decreased requirement for ground control, increased system reliability through onboard management, and ultimately lower energy cost through longer life systems that require fewer resources to operate and maintain. This approach seems well-suited to the evolution of more sophisticated algorithms and eventually perhaps even the use of some sort of artificial intelligence. Multi-hundred kilowatt systems of the future will probably require an advanced level of autonomy if they are to be affordable and manageable.

Advance Power Technology Demonstration on Starshine 3

Science.gov (United States)

Jenkins, Phillip; Scheiman, David; Wilt, David; Raffaelle, Ryne; Button, Robert; Smith, Mark; Kerslake, Thomas; Miller, Thomas

2002-01-01

The Starshine 3 satellite will carry several power technology demonstrations. Since Starshine 3 is primarily a passive experiment and does not need electrical power to successfully complete its mission, the requirement for a highly reliable power system is greatly reduced. This creates an excellent opportunity to test new power technologies. Several government and commercial interests have teamed up to provide Starshine 3 with a small power system using state-of-the-art components. Starshine 3 will also fly novel integrated microelectronic power supplies (IMPS) for evaluation.

Research on process management of nuclear power technological innovation

International Nuclear Information System (INIS)

Yang Hua; Zhou Yu

2005-01-01

Different from the other technological innovation processes, the technological innovation process of nuclear power engineering project is influenced deeply by the extensive environmental factors, the technological innovation of nuclear power engineering project needs to make an effort to reduce environmental uncertainty. This paper had described the mechanism of connection technological innovation process of nuclear power engineering project with environmental factors, and issued a feasible method based on model of bargaining to incorporate technological innovation process management of nuclear power engineering project with environmental factors. This method has realistic meanings to guide the technological innovation of nuclear power engineering project. (authors)

Power Technologies Energy Data Book - Fourth Edition

Energy Technology Data Exchange (ETDEWEB)

Aabakken, J.

2006-08-01

This report, prepared by NREL's Strategic Energy Analysis Center, includes up-to-date information on power technologies, including complete technology profiles. The data book also contains charts on electricity restructuring, power technology forecasts, electricity supply, electricity capability, electricity generation, electricity demand, prices, economic indicators, environmental indicators, and conversion factors.

Power Technologies Energy Data Book - Third Edition

Energy Technology Data Exchange (ETDEWEB)

Aabakken, J.

2005-04-01

This report, prepared by NREL's Energy Analysis Office, includes up-to-date information on power technologies, including complete technology profiles. The data book also contains charts on electricity restructuring, power technology forecasts, electricity supply, electricity capability, electricity generation, electricity demand, prices, economic indicators, environmental indicators, and conversion factors.

Localization of nuclear power plant technology

International Nuclear Information System (INIS)

Stiteler, F.Z.; Rudek, T.G.

1998-01-01

Asia, and particularly China, has an enormous need for power and must deal with the practicalities of building large base load units. In China, as in other countries, there are limitations on the use of large quantities of fossil fuel. This raises the possibility of turning to nuclear power to satisfy their energy needs. Other issues tend to point to the nuclear option for these growing economies, including economic considerations, environmental concerns, energy independence and raising the technological capabilities of the country. When a country embarks on a nuclear power program with the intention of localizing the technology, a long-term commitment is necessary to achieve this objective. Localization of nuclear technology is not a new phenomenon. The nature of the industry from the early beginnings has always involved transfer of technology when a new country initiated a nuclear power construction program. In fact, most previous experiences with this localization process involved heavy governmental, political and financial support to drive the success of the program. Because of this strong governmental support, only the receiving nation's companies were generally allowed to participate in the local business operations of the technology recipient. What is new and different today is the retreat from heavy financial support by the receiving country's government. This change has created a strong emphasis on cost-effectiveness in the technology transfer process and opportunities for foreign companies to participate in local business activities. ABB is a world-wide company with two parent companies that have been very active over many years in establishing cost-justified local operations throughout the world. Today, ABB has become the largest electrical engineering company in the world with respected local operations in nearly every country. Lessons learned by ABB in their world-wide localization initiatives are being applied to the challenge of cost

Tidal energy

International Nuclear Information System (INIS)

Lochte, H.G.

1995-01-01

Together with wave energy, ocean thermal energy, and the often overlooked energy from ocean curents tidal energy belongs to those renewable energy sources that can be subsumed under the generic term of ocean energy. All that these energy sources have in common, however, is that they are found in the ocean. The present article discusses tidal energy with respect to the four principal factors determining the scope of a renewable energy source, namely global, technical, and economic availability and ecological acceptability. (orig.) [de

Tidally Heated Terrestrial Exoplanets

Science.gov (United States)

Henning, Wade Garrett

This work models the surface and internal temperatures for hypothetical terrestrial planets in situations involving extreme tidal heating. The feasibility of such planets is evaluated in terms of the orbital perturbations that may give rise to them, their required proximity to a hoststar, and the potential for the input tidal heating to cause significant partial melting of the mantle. Trapping terrestrial planets into 2:1 resonances with migrating Hot Jupiters is considered as a reasonable way for Earth-like worlds to both maintain high eccentricities and to move to short enough orbital periods (1-20 days) for extreme tidal heating to occur. Secular resonance and secular orbital perturbations may support moderate tidal heating at a low equilibrium eccentricity. At orbital periods below 10-30 days, with eccentricities from 0.01 to 0.1, tidal heat may greatly exceed radiogenic heat production. It is unlikely to exceed insolation, except when orbiting very low luminosity hosts, and thus will have limited surface temperature expression. Observations of such bodies many not be able to detect tidal surface enhancements given a few percent uncertainty in albedo, except on the nightside of spin synchronous airless objects. Otherwise detection may occur via spectral detection of hotspots or high volcanic gas concentrations including sulfur dioxide and hydrogen sulfide. The most extreme cases may be able to produce magma oceans, or magma slush mantles with up to 40-60% melt fractions. Tides may alter the habitable zones for smaller red dwarf stars, but are generally detrimental. Multiple viscoelastic models, including the Maxwell, Voigt-Kelvin, Standard Anelastic Solid, and Burgers rheologies are explored and applied to objects such as Io and the super-Earth planet GJ 876d. The complex valued Love number for the Burgers rheology is derived and found to be a useful improvement when modeling the low temperature behavior of tidal bodies, particularly during low eccentricity

Ireland’s tidal energy resource; An assessment of a site in the Bulls Mouth and the Shannon Estuary using measured data

International Nuclear Information System (INIS)

O’Rourke, Fergal; Boyle, Fergal; Reynolds, Anthony

2014-01-01

Highlights: • This study is concentrated on tidal current energy assessment at two sites in Ireland. • Tidal–current-speed and direction data was measured at a range of depths using ADCPs. • A best-fit power law exponent is proposed based on the measured data from both sites. • Mean power densities, annual energy output and capacity factors at both sites were calculated. - Abstract: The issues associated with Ireland’s over reliance on fossil fuels to meet energy demands have sparked an interest in renewable energy. Renewable energy resources typically are intermittent and vary significantly in energy intensity. Tidal energy however has the advantage of predictability over large time scales and high power densities. A study of Ireland’s tidal–current-energy resource has identified several viable sites. As part of this resource assessment, Acoustic Doppler Current Profilers were installed at two locations along Ireland’s west coast, at a site in the Bulls Mouth and the Shannon Estuary. The Acoustic Doppler Current Profilers measured tidal current speed and direction at 30 min intervals over a 30 day period at a range of depths through the water column. This is the first time the measured data appears in the literature as it has only recently been made public. This paper presents tidal current speed and direction, frequency of occurrence of speed, tidal roses at several depths through the water column, and a comparison of theoretical tidal–current-speed profiles with measured data for a site in the Bulls Mouth and in the Shannon Estuary. The paper compares power density at both sites over a lunar month and also proposes a best fit power law exponent with the measured data through the water column. Finally, the paper presents an energetic performance comparison for a tidal current turbine operating at both sites. The data presented in this paper can be used in the design process to estimate the hydrodynamic and structural performance of a tidal

Commercialization of terrestrial applications of aerospace power technology

International Nuclear Information System (INIS)

Landsberg, D.R.

1992-01-01

The potential for commercialization of terrestrial energy systems based upon aerospace power technology's explored. Threats to the aerospace power technology industry, caused by the end of the cold war and weak world economy are described. There are also new opportunities caused by increasing terrestrial energy needs and world-wide concern for the environment. In this paper, the strengths and weaknesses of the aerospace power industry in commercializing terrestrial energy technologies are reviewed. Finally, actions which will enable the aerospace power technology industry to commercialize products into terrestrial energy markets are described

Phase lag control of tidally reversing mega-ripple geometry and bed stress in tidal inlets

Science.gov (United States)

Traykovski, P.

2016-02-01

Recent observations in the Columbia River Mouth, New River Inlet, and Wasque Shoals have shown that tidally reversing mega-ripples are an ubiquitous bedform morphology in energetic tidal inlets. As the name implies, these bedforms reverse asymmetry and migration direction in each half tidal cycle. With wavelengths of 2 to 5 m and heights of 0.2 to 0.5 m, these bedforms are larger than current formed ripples, but smaller than dunes. Unlike dunes which have a depth dependent geometry, observations indicate the tidally reversing mega-ripples geometry is related to the time dependent tidal flow and independent of depth. Previous empirical relations for predicting the geometry of ripples or dunes do not successfully predict the geometry of these features. A time dependent geometric model was developed that accounts for the reversal of migration and asymmetry to successfully predict bedform geometry. The model requires sufficient sediment transport in each half tidal cycle to reverse the asymmetry before the bedforms begin to grow. Both the observations and model indicate that the complete reversal of asymmetry and development of a steep lee face occurs near or after maximum flow in each half tidal cycle. This phase lag in bedform response to tidal forcing also has important implications for bed stress in tidal inlets. Observations of frictional drag in the Columbia River mouth based on a tidal momentum balance of surface slope over 10 km regressed against quadratic near bed velocity show drag coefficients that fall off as CD U-1.4. Reynolds stress measurements performed using the dual ADV differencing technique show similar relations. The Reynolds stress measurements also show a dramatic asymmetry between accelerating flows and decelerating flows with a factor of 5 increase during deceleration. Pulse coherent Doppler profiles of near bed turbulence indicate that the turbulence is dominated by energetic fluctuations in separation zones downstream of steep lee faces. The

A scoping study for an environmental impact field programme in tidal current energy

Energy Technology Data Exchange (ETDEWEB)

NONE

2002-07-01

This report summarises the results of a study to identify the environmental impacts of tidal current energy with the aim of prioritising research. The background to the study is traced, and the interaction between tidal current energy technology and the marine environment, the modeling of the consequences of the environmental interactions, the quantification of the environmental impacts of key environmental interactions, and the formulation of a programme of research are discussed. Recommendations are given and research needs are highlighted.

Space Solar Power Technology Demonstration for Lunar Polar Applications: Laser-Photovoltaic Wireless Power Transmission

Science.gov (United States)

Henley, M. W.; Fikes, J. C.; Howell, J.; Mankins, J. C.; Howell, Joe T. (Technical Monitor)

2002-01-01

Space Solar Power technology offers unique benefits for near-term NASA space science missions, which can mature this technology for other future applications. "Laser-Photo-Voltaic Wireless Power Transmission" (Laser-PV WPT) is a technology that uses a laser to beam power to a photovoltaic receiver, which converts the laser's light into electricity. Future Laser-PV WPT systems may beam power from Earth to satellites or large Space Solar Power satellites may beam power to Earth, perhaps supplementing terrestrial solar photo-voltaic receivers. In a near-term scientific mission to the moon, Laser-PV WPT can enable robotic operations in permanently shadowed lunar polar craters, which may contain ice. Ground-based technology demonstrations are proceeding, to mature the technology for this initial application, in the moon's polar regions.

Tidal alignment of galaxies

Energy Technology Data Exchange (ETDEWEB)

Blazek, Jonathan; Vlah, Zvonimir; Seljak, Uroš

2015-08-01

We develop an analytic model for galaxy intrinsic alignments (IA) based on the theory of tidal alignment. We calculate all relevant nonlinear corrections at one-loop order, including effects from nonlinear density evolution, galaxy biasing, and source density weighting. Contributions from density weighting are found to be particularly important and lead to bias dependence of the IA amplitude, even on large scales. This effect may be responsible for much of the luminosity dependence in IA observations. The increase in IA amplitude for more highly biased galaxies reflects their locations in regions with large tidal fields. We also consider the impact of smoothing the tidal field on halo scales. We compare the performance of this consistent nonlinear model in describing the observed alignment of luminous red galaxies with the linear model as well as the frequently used "nonlinear alignment model," finding a significant improvement on small and intermediate scales. We also show that the cross-correlation between density and IA (the "GI" term) can be effectively separated into source alignment and source clustering, and we accurately model the observed alignment down to the one-halo regime using the tidal field from the fully nonlinear halo-matter cross correlation. Inside the one-halo regime, the average alignment of galaxies with density tracers no longer follows the tidal alignment prediction, likely reflecting nonlinear processes that must be considered when modeling IA on these scales. Finally, we discuss tidal alignment in the context of cosmic shear measurements.

An assessment of tidal energy potential. The Lima estuary

Energy Technology Data Exchange (ETDEWEB)

Trigo-Teixeira, A. [Department of Civil Engineering and Architecture, Instituto Superior Tecnico, Lisbon Technical University, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Rebordao, I. [WW Consulting Engineers, Laveiras, Caxias 2760-032 (Portugal)

2009-07-01

A hydrodynamic model was set up for the Lima estuary (Portugal) and a preliminary assessment of the strength of tidal currents to produce tidal energy was made. To calibrate the model results were compared with measured data, and the model tuned to reproduce water levels and currents in several locations within the estuary. The data was acquired with ADCPs, during a field campaign that was planed to cover a spring-neap tide cycle, in October 2006. The Advanced Circulation Model - ADCIRC was forced with the most important harmonic constituents present in the ocean tide signal. Upstream, in the river boundary, the discharge was taken from hydrographs. The wetting and drying tool was also applied and a detailed bathymetry was considered, since there are areas in the domain where salt marshes occur, drying out at low tide. The tidal currents potential were assessed for a scenario of tidal forcing only, without any river discharge. The lower estuary is occupied by the port infrastructure and navigation channels which conflicts with any kind of equipment installation. Values of the currents and water depths given by the model indicate that some places in the main channel of the middle estuary, might be interesting to install micro turbines in the future, depending on the evolution of the requirements of this technology.

Free-piston Stirling technology for space power

Science.gov (United States)

Slaby, Jack G.

1989-01-01

An overview is presented of the NASA Lewis Research Center free-piston Stirling engine activities directed toward space power. This work is being carried out under NASA's new Civil Space Technology Initiative (CSTI). The overall goal of CSTI's High Capacity Power element is to develop the technology base needed to meet the long duration, high capacity power requirements for future NASA space missions. The Stirling cycle offers an attractive power conversion concept for space power needs. Discussed here is the completion of the Space Power Demonstrator Engine (SPDE) testing-culminating in the generation of 25 kW of engine power from a dynamically-balanced opposed-piston Stirling engine at a temperature ratio of 2.0. Engine efficiency was approximately 22 percent. The SPDE recently has been divided into two separate single-cylinder engines, called Space Power Research Engine (SPRE), that now serve as test beds for the evaluation of key technology disciplines. These disciplines include hydrodynamic gas bearings, high-efficiency linear alternators, space qualified heat pipe heat exchangers, oscillating flow code validation, and engine loss understanding.

TIDAL FRICTION AND TIDAL LAGGING. APPLICABILITY LIMITATIONS OF A POPULAR FORMULA FOR THE TIDAL TORQUE

International Nuclear Information System (INIS)

Efroimsky, Michael; Makarov, Valeri V.

2013-01-01

Tidal torques play a key role in rotational dynamics of celestial bodies. They govern these bodies' tidal despinning and also participate in the subtle process of entrapment of these bodies into spin-orbit resonances. This makes tidal torques directly relevant to the studies of habitability of planets and their moons. Our work begins with an explanation of how friction and lagging should be built into the theory of bodily tides. Although much of this material can be found in various publications, a short but self-consistent summary on the topic has been lacking in the hitherto literature, and we are filling the gap. After these preparations, we address a popular concise formula for the tidal torque, which is often used in the literature, for planets or stars. We explain why the derivation of this expression, offered in the paper by Goldreich and in the books by Kaula (Equation (4.5.29)) and Murray and Dermott (Equation (4.159)), implicitly sets the time lag to be frequency independent. Accordingly, the ensuing expression for the torque can be applied only to bodies having a very special (and very hypothetical) rheology which makes the time lag frequency independent, i.e., the same for all Fourier modes in the spectrum of tide. This expression for the torque should not be used for bodies of other rheologies. Specifically, the expression cannot be combined with an extra assertion of the geometric lag being constant, because at finite eccentricities the said assumption is incompatible with the constant-time-lag condition.

TIDAL FRICTION AND TIDAL LAGGING. APPLICABILITY LIMITATIONS OF A POPULAR FORMULA FOR THE TIDAL TORQUE

Energy Technology Data Exchange (ETDEWEB)

Efroimsky, Michael; Makarov, Valeri V., E-mail: michael.efroimsky@usno.navy.mil, E-mail: vvm@usno.navy.mil [US Naval Observatory, Washington, DC 20392 (United States)

2013-02-10

Tidal torques play a key role in rotational dynamics of celestial bodies. They govern these bodies' tidal despinning and also participate in the subtle process of entrapment of these bodies into spin-orbit resonances. This makes tidal torques directly relevant to the studies of habitability of planets and their moons. Our work begins with an explanation of how friction and lagging should be built into the theory of bodily tides. Although much of this material can be found in various publications, a short but self-consistent summary on the topic has been lacking in the hitherto literature, and we are filling the gap. After these preparations, we address a popular concise formula for the tidal torque, which is often used in the literature, for planets or stars. We explain why the derivation of this expression, offered in the paper by Goldreich and in the books by Kaula (Equation (4.5.29)) and Murray and Dermott (Equation (4.159)), implicitly sets the time lag to be frequency independent. Accordingly, the ensuing expression for the torque can be applied only to bodies having a very special (and very hypothetical) rheology which makes the time lag frequency independent, i.e., the same for all Fourier modes in the spectrum of tide. This expression for the torque should not be used for bodies of other rheologies. Specifically, the expression cannot be combined with an extra assertion of the geometric lag being constant, because at finite eccentricities the said assumption is incompatible with the constant-time-lag condition.

Effective Methods of Nuclear Power Technology Transfer

International Nuclear Information System (INIS)

Shave, D. F.; Kent, G. F.; Giambusso, A.

1987-01-01

An effective technology transfer program is a necessary and significant step towards independence in nuclear power technology. Attaining success in the conduct of such a program is a result of a) the donor and recipient jointly understanding the fundamental concepts of the learning process, b) sharing a mutual philosophy involving a partnership relationship, c) joint and careful planning, d) rigorous adherence to proven project management techniques, and e) presence of adequate feedback to assure continuing success as the program proceeds. Several years ago, KEPCO President Park, Jung-KI presented a paper on technology in which he stated, 'Nuclear technology is an integration of many unit disciplines, and thus requires extensive investment and training in order to establish the base for efficient absorption of transferred technology.' This paper addresses President Park's observations by discussing the philosophy, approach, and mechanisms that are necessary to support an efficient and effective process of nuclear power technology transfer. All technical content and presentation methods discussed are based on a technology transfer program developed by Stone and Webster, as an Engineer/Constructor for nuclear power plants, and are designed and implemented to promote the primary program goal - the ability of the trainees and the organization to perform specific nuclear power related multi-discipline function independently and competitively

Evaluation of tidal stream energy and its impacts on surrounding dynamics in the Eastern Region of Pingtan Island, China

Science.gov (United States)

Wu, He; Wang, Xin; Wang, Bingzhen; Bai, Yang; Wang, Peitao

2017-11-01

Using an improved FVCOM numerical model, combined with the momentum-sinking scheme based on the structural characteristics of specific turbines, this study analyzed the temporal and spatial distributions of tidal energy resources before and after the deployment of tidal turbines near Pingtan Island, China. Considering factors such as the distribution of tidal stream energy, bathymetry, topography, and the design parameters of the turbines, an appropriate location for a demonstration tidal turbine was selected and the corresponding energy resource was evaluated. Several sites with strong tidal streams were considered: south of the northern cape, east of the southern cape, and the southern end of Haitan Bay. The former was thought most suitable for the deployment of a tidal energy turbine, with projected power generation for approximately 470 h per month. The average power of this demonstration was about 2.4 kW, and the annual electricity output was approximately 17.47 MWh. The intervention of the turbine device had little influence on the near-field tidal stream or water level. The tidal stream was reduced slightly in the area south of the northern cape, although the effect weakened further from the turbine. Conversely, the velocity increased slightly on both sides of the demonstration site. The difference in current speed with and without the turbine was greater at slack tide than still tide. The influence of turbine operation on water level was minor. The method adopted in this study can be considered a reference for the selection of sites for the demonstration of tidal stream energy. However, the method is unable describe the dynamic characteristics of the turbulent flow surrounding the deployed turbines, which has an important role regarding the optimal designs of the turbine blade and pile foundations. Therefore, we will continue to work to improve this model in future research.

Technological implications of fusion power: requirements and status

International Nuclear Information System (INIS)

Steiner, D.

1978-01-01

The major technological requirements for fusion power, as implied by current conceptual designs of fusion power plants, are identified and assessed relative to the goals of existing technology programs. The focus of the discussion is on the tokamak magnetic confinement concept; however, key technological requirements of mirror magnetic confinement systems and of inertial confinement concepts will also be addressed. The required technology is examined on the basis of three general areas of concern: (a) the power balance, that is, the unique power handling requirements associated with the production of electrical power by fusion; (b) reactor design, focusing primarily on the requirements imposed by a tritium-based fuel cycle, thermal hydraulic considerations, and magnet systems; and (c) materials considerations, including radiation damage effects, neutron-induced activation, and resource limitations

History of electric power technological innovation in 2017

International Nuclear Information System (INIS)

Yamaguchi, Hiroshi; Okabe, Kazuhiko; Ichimura, Yasunori

2017-01-01

This is an overview of the electric power technology innovation of 12 electric power companies in 2016. Among them, this paper outlines the technological contents related to nuclear power of three major companies. TEPCO group applied a sealant from the outside to the back-up seal of reactor containment vessel that had deteriorated. It developed a good sealing system by combining with an improved sealant, and confirmed the effect at an experimental level. Regarding environmental restoration in Fukushima, TEPCO developed a personal dosimetry technology, environmental monitoring technology, and a technology to simulate radiation reduction amount after decontamination. Chubu Electric Power Company conducted researches on the applicability of the start-up range neutron monitor count rate prediction method related to fuel loading after a long-term shut-down of nuclear power generation, basic examination for practical use of laser decontamination, and possibility of tsunami prediction using satellite positioning information. With regard to the decommissioning measures of nuclear power plants, Japan Nuclear Power Electric Generation Co., Ltd. conducted studies on the decommissioning work of the Tokai Power Station, the safe dismantling method of the Tsuruga Power Station Unit 1 as decommissioning measures and fuel management, and the disposal method of radioactive contaminants. In the development of future reactor, this company conducted research on the development of fast breeder reactor system, etc. (A.O.)

ON THE DIRECT IMAGING OF TIDALLY HEATED EXOMOONS

Energy Technology Data Exchange (ETDEWEB)

Peters, Mary Anne; Turner, Edwin L., E-mail: mapeters@princeton.edu [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)

2013-06-01

We demonstrate the ability of existing and planned telescopes, on the ground and in space, to directly image tidally heated exomoons orbiting gas-giant exoplanets. Tidally heated exomoons can plausibly be far more luminous than their host exoplanet and as much as 0.1% as bright as the system's stellar primary if it is a low mass star. Because emission from exomoons can be powered by tidal forces, they can shine brightly at arbitrarily large separations from the system's stellar primary with temperatures of several hundreds degrees Kelvin or even higher in extreme cases. Furthermore, these high temperatures can occur in systems that are billions of years old. Tidally heated exomoons may thus be far easier targets for direct imaging studies than giant exoplanets which must be both young and at a large projected separation (typically at least tens of AU) from their primary to be accessible to current generation direct imaging studies. For example, the (warm) Spitzer Space Telescope and the next generation of ground based instruments could detect an exomoon roughly the size of the Earth at a temperature Almost-Equal-To 600 K and a distance Almost-Equal-To 5 pc in the K, L, and M bands at the 5{sigma} confidence level with a one hour exposure; in more favorable but still plausible cases, detection at distances of tens of parsecs is feasible. Future mid-infrared space telescopes, such as James Webb Space Telescope and SPICA, will be capable of directly imaging tidally heated exomoons around the nearest two dozen stars with a brightness temperature {>=}300 K and R {>=} 1 R{sub Circled-Plus} orbiting at {>=}12 AU from the primary star at a 5{sigma} confidence level in a 10{sup 4} s integration. In addition it is possible that some of the exoplanets which have already been directly imaged are actually tidally heated exomoons or blends of such objects with hot young planets. If such exomoons exist and are sufficiently common (i.e., nearby), it may well be far

Ecology of Juvenile Salmonids in Shallow Tidal Freshwater Habitats in the Vicinity of the Sandy River Delta, Lower Columbia River, 2007 Annual Report.

Energy Technology Data Exchange (ETDEWEB)

Sobocinski, Kathryn; Johnson, Gary; Sather, Nichole [Pacific Northwest National Laboratory

2008-03-17

) Determine fish community characteristics, including species composition, abundance, and temporal and spatial distributions. (1c) Estimate the stock of origin for the yearling and subyearling Chinook salmon captured at the sampling sites using genetic analysis. (1d) Statistically assess the relationship between salmonid abundance and habitat parameters, including ancillary variables such as temperature and river stage. (2) Acoustic Telemetry Monitoring-Assess feasibility of applying Juvenile Salmon Acoustic Telemetry System (JSATS) technology to determine migration characteristics from upriver of Bonneville Dam through the study area (vicinity of the Sandy River delta/Washougal River confluence). (2a) Determine species composition, release locations, and distributions of JSATS-tagged fish. (2b) Estimate run timing, residence times, and migration pathways for these fish. Additionally, both objectives serve the purpose of baseline research for a potential tidal rechannelization project on the Sandy River. The U.S. Forest Service, in partnership with the Bonneville Power Administration and the U.S. Army Corps of Engineers, is currently pursuing reconnection of the east (relict) Sandy River channel with the current channel to improve fish and wildlife habitat in the Sandy River delta. Our study design and the location of sampling sites in this reach provide baseline data to evaluate the potential restoration.

Formation of double galaxies by tidal capture

International Nuclear Information System (INIS)

Alladin, S.M.; Potdar, A.; Sastry, K.S.

1975-01-01

The conditions under which double galaxies may be formed by tidal capture are considered. Estimates for the increase in the internal energy of colliding galaxies due to tidal effects are used to determine the magnitudes Vsub(cap) and Vsub(dis) of the maximum relative velocities at infinite separation required for tidal capture and tidal disruption respectively. A double galaxy will be formed by tidal capture without tidal disruption of a component if Vsub(cap)>Vsub(i) and Vsub(cap)>Vsub(dis) where Vsub(i) is the initial relative speed of the two galaxies at infinite separation. If the two galaxies are of the same dimension, formulation of double galaxies by tidal capture is possible in a close collision either if the two galaxies do not differ much in mass and density distribution or if the more massive galaxy is less centrally concentrated than the other. If it is assumed as statistics suggest, that the mass of a galaxy is proportional to the square of its radius, it follows that the probability of the formation of double galaxies by tidal capture increases with the increase in mass of the galaxies and tidal distribution does not occur in a single collision for any distance of closest approach of the two galaxies. (Auth.)

Tidal controls on earthquake size-frequency statistics

Science.gov (United States)

Ide, S.; Yabe, S.; Tanaka, Y.

2016-12-01

The possibility that tidal stresses can trigger earthquakes is a long-standing issue in seismology. Except in some special cases, a causal relationship between seismicity and the phase of tidal stress has been rejected on the basis of studies using many small events. However, recently discovered deep tectonic tremors are highly sensitive to tidal stress levels, with the relationship being governed by a nonlinear law according to which the tremor rate increases exponentially with increasing stress; thus, slow deformation (and the probability of earthquakes) may be enhanced during periods of large tidal stress. Here, we show the influence of tidal stress on seismicity by calculating histories of tidal shear stress during the 2-week period before earthquakes. Very large earthquakes tend to occur near the time of maximum tidal stress, but this tendency is not obvious for small earthquakes. Rather, we found that tidal stress controls the earthquake size-frequency statistics; i.e., the fraction of large events increases (i.e. the b-value of the Gutenberg-Richter relation decreases) as the tidal shear stress increases. This correlation is apparent in data from the global catalog and in relatively homogeneous regional catalogues of earthquakes in Japan. The relationship is also reasonable, considering the well-known relationship between stress and the b-value. Our findings indicate that the probability of a tiny rock failure expanding to a gigantic rupture increases with increasing tidal stress levels. This finding has clear implications for probabilistic earthquake forecasting.

Comprehensive Characterization a Tidal Energy Site (Invited)

Science.gov (United States)

Polagye, B. L.; Thomson, J. M.; Bassett, C. S.; Epler, J.; Northwest National Marine Renewable Energy Center

2010-12-01

Northern Admiralty Inlet, Puget Sound, Washington is the proposed location of a pilot tidal energy project. Site-specific characterization of the physical and biological environment is required for device engineering and environmental analysis. However, the deep water and strong currents which make the site attractive for tidal energy development also pose unique challenges to collecting comprehensive information. This talk focuses on efforts to optimally site hydrokinetic turbines and estimate their acoustic impact, based on 18 months of field data collected to date. Additional characterization efforts being undertaken by the University of Washington branch of the Northwest National Marine Renewable Energy Center and its partners include marine mammal presence and behavior, water quality, seabed geology, and biofouling potential. Because kinetic power density varies with the cube of horizontal current velocity, an accurate map of spatial current variations is required to optimally site hydrokinetic turbines. Acoustic Doppler profilers deployed on the seabed show operationally meaningful variations in flow characteristics (e.g., power density, directionality, vertical shear) and tidal harmonic constituents over length scales of less than 100m. This is, in part, attributed to the proximity of this site to a headland. Because of these variations, interpolation between stationary measurement locations introduces potentially high uncertainty. The use of shipboard acoustic Doppler profilers is shown to be an effective tool for mapping peak currents and, combined with information from seabed profilers, may be able to resolve power density variations in the project area. Because noise levels from operating turbines are expected to exceed regulatory thresholds for incidental harassment of marine mammals known to be present in the project area, an estimate of the acoustic footprint is required to permit the pilot project. This requires site-specific descriptions of pre

IEA Energy Technology Essentials: Nuclear Power

Energy Technology Data Exchange (ETDEWEB)

NONE

2007-03-15

The IEA Energy Technology Essentials series offers concise four-page updates on the different technologies for producing, transporting and using energy. Nuclear power is the topic covered in this edition.

Field migration rates of tidal meanders recapitulate fluvial morphodynamics

Science.gov (United States)

Finotello, Alvise; Lanzoni, Stefano; Ghinassi, Massimiliano; Marani, Marco; Rinaldo, Andrea; D'Alpaos, Andrea

2018-02-01

The majority of tidal channels display marked meandering features. Despite their importance in oil-reservoir formation and tidal landscape morphology, questions remain on whether tidal-meander dynamics could be understood in terms of fluvial processes and theory. Key differences suggest otherwise, like the periodic reversal of landscape-forming tidal flows and the widely accepted empirical notion that tidal meanders are stable landscape features, in stark contrast with their migrating fluvial counterparts. On the contrary, here we show that, once properly normalized, observed migration rates of tidal and fluvial meanders are remarkably similar. Key to normalization is the role of tidal channel width that responds to the strong spatial gradients of landscape-forming flow rates and tidal prisms. We find that migration dynamics of tidal meanders agree with nonlinear theories for river meander evolution. Our results challenge the conventional view of tidal channels as stable landscape features and suggest that meandering tidal channels recapitulate many fluvial counterparts owing to large gradients of tidal prisms across meander wavelengths.

Media analysis of the representations of fusion and other future energy technologies

Energy Technology Data Exchange (ETDEWEB)

Delicado, Ana; Schmidt, Luisa; Pereira, Sergio [Institute of Social Sciences of the University of Lisbon, Av. Prof. Anibal de Bettencourt, 9 1600-189 Lisbon (Portugal); Oltra, Christian; Prades, Ana [CISOT-CIEMAT. Gran Via de les Corts Catalanes 604, 4, 2, 08007 Barcelona (Spain)

2015-07-01

Media representations of energy have a relevant impact on public opinion and public support for investment in new energy sources. Fusion energy is one among several emerging energy technologies that requires a strong public investment on its research and development. This paper aims to characterise and compare the media representations of fusion and other emerging energy technologies in Portugal and in Spain. The emerging energy technologies selected for analysis are wave and tidal power, hydrogen, deep sea offshore wind power, energy applications of nanotechnology, bio-fuels from microalgae and IV generation nuclear fission. This work covered the news published in a selection of newspapers in Portugal and Spain between January 2007 and June 2013. (authors)

Media analysis of the representations of fusion and other future energy technologies

International Nuclear Information System (INIS)

Delicado, Ana; Schmidt, Luisa; Pereira, Sergio; Oltra, Christian; Prades, Ana

2015-01-01

Media representations of energy have a relevant impact on public opinion and public support for investment in new energy sources. Fusion energy is one among several emerging energy technologies that requires a strong public investment on its research and development. This paper aims to characterise and compare the media representations of fusion and other emerging energy technologies in Portugal and in Spain. The emerging energy technologies selected for analysis are wave and tidal power, hydrogen, deep sea offshore wind power, energy applications of nanotechnology, bio-fuels from microalgae and IV generation nuclear fission. This work covered the news published in a selection of newspapers in Portugal and Spain between January 2007 and June 2013. (authors)

Seasonal variability of tidal and non-tidal currents off Beypore, SW coast of India

Digital Repository Service at National Institute of Oceanography (India)

DineshKumar, P.K.; Srinivas, K.; AnilKumar, N.

and summer monsoon seasons of year 2000. Information on tidal signals contained in the currents were extracted using harmonic analysis - Least Squares Method and non-tidal component were analyzed using the Chi sub(o) filter. The study established...

Remnants of strong tidal interactions

International Nuclear Information System (INIS)

Mcglynn, T.A.

1990-01-01

This paper examines the properties of stellar systems that have recently undergone a strong tidal shock, i.e., a shock which removes a significant fraction of the particles in the system, and where the shocked system has a much smaller mass than the producer of the tidal field. N-body calculations of King models shocked in a variety of ways are performed, and the consequences of the shocks are investigated. The results confirm the prediction of Jaffe for shocked systems. Several models are also run where the tidal forces on the system are constant, simulating a circular orbit around a primary, and the development of tidal radii under these static conditions appears to be a mild process which does not dramatically affect material that is not stripped. The tidal radii are about twice as large as classical formulas would predict. Remnant density profiles are compared with a sample of elliptical galaxies, and the implications of the results for the development of stellar populations and galaxies are considered. 38 refs

Dynamics of tidal and non-tidal currents along the southwest continental shelf of India

Digital Repository Service at National Institute of Oceanography (India)

Aruna, C.; Ravichandran, C.; Srinivas, K.; Rasheed, P.A.A.; Lekshmi, S.

are predominantly mixed, semidiurnal in nature. Motion over any continental shelf is governed by the tide-driven oscillatory flow. In this paper, tidal and non-tidal characteristics of the waters of Southwest continental shelf of India are assessed using...

Nuclear power strategy: requirements for technology

International Nuclear Information System (INIS)

Orlov, V.V.; Rachkov, V.I.

2001-01-01

The possible role of nuclear power in sustainable development demands answers to at least three questions: Is large-scale nuclear power essential to future development? - Is it feasible to have modern nuclear power transformed for large-scale deployment? - When will large-scale nuclear power be practically needed? The questions are analysed with the requirements to be fulfilled concerning present-day technologies

Progress of technological innovation on electric power in FY2014

International Nuclear Information System (INIS)

Nishikawa, Yoshikazu; Fujii, Yutaka; Sasagawa, Toshiro

2015-01-01

This paper overviews the technological development in FY2014 at Tokyo Electric Power Company, Chubu Electric Power Company, Hokuriku Electric Power Company, Shikoku Electric Power Company, and Electric Power Development Company. In this overview, further breakdown was made for the following departments of each company: nuclear power generation, thermal power generation, hydraulic power generation, power transmission, power distribution, transformation, research and development and technological development, and information and communication. In addition, this paper outlines the achievement of technological development at Japan Atomic Power Company, such as the technological development related to the existing power station, development of new technology, and the development of future reactor. Fukushima Daiichi Nuclear Power Station has developed an investigative system using a high altitude survey robot and a movable monitoring system. Hamaoka Nuclear Power Station examined the feasibility of state diagnostic technique based on multi-point analysis, and studied stress corrosion cracking at the newly established Nuclear Safety Research Laboratory. Shika Nuclear Power Station (Unit 1) applied a pipe stress improvement process by means of high frequency induction heating as a stress corrosion cracking countermeasure. Ikata Nuclear Power Station newly adopted high degree cross-linking cation resin, and high cracking strength anion resin as the primary resins. Oma Nuclear Power Station worked on the all reactor core utilization technology of MOX fuel. (A.O.)

Thermal Management of Power Semiconductor Packages - Matching Cooling Technologies with Packaging Technologies (Presentation)

Energy Technology Data Exchange (ETDEWEB)

Bennion, K.; Moreno, G.

2010-04-27

Heat removal for power semiconductor devices is critical for robust operation. Because there are different packaging options, different thermal management technologies, and a range of applications, there is a need for a methodology to match cooling technologies and package configurations to target applications. To meet this need, a methodology was developed to compare the sensitivity of cooling technologies on the overall package thermal performance over a range of power semiconductor packaging configurations. The results provide insight into the trade-offs associated with cooling technologies and package configurations. The approach provides a method for comparing new developments in power semiconductor packages and identifying potential thermal control technologies for the package. The results can help users select the appropriate combination of packaging configuration and cooling technology for the desired application.

Economy and technology roles played by nuclear power

International Nuclear Information System (INIS)

Yamada, Eiji

1985-01-01

On the basis of the survey analysis made by Atomic Energy Commission on the roles in economy and technology played in the nuclear energy development and utilization, the following are described: economic roles in nuclear energy development and utilization (the present state of nuclear power industry in Japan and the economy effects); technological roles in the same (the present state of nuclear power technology in Japan and the technology effects). The economy effects in other areas are on higher level than in other industries etc. Then, in the technology effects, system technology and quality control in the nuclear power possess significant effects in other areas. While the nuclear energy development and utilization is important in Japan's energy security, it is contributing largely to the economy and society in Japan. (Mori, K.)

Linear perturbation theory for tidal streams and the small-scale CDM power spectrum

Science.gov (United States)

Bovy, Jo; Erkal, Denis; Sanders, Jason L.

2017-04-01

Tidal streams in the Milky Way are sensitive probes of the population of low-mass dark matter subhaloes predicted in cold dark matter (CDM) simulations. We present a new calculus for computing the effect of subhalo fly-bys on cold streams based on the action-angle representation of streams. The heart of this calculus is a line-of-parallel-angle approach that calculates the perturbed distribution function of a stream segment by undoing the effect of all relevant impacts. This approach allows one to compute the perturbed stream density and track in any coordinate system in minutes for realizations of the subhalo distribution down to 105 M⊙, accounting for the stream's internal dispersion and overlapping impacts. We study the statistical properties of density and track fluctuations with large suites of simulations of the effect of subhalo fly-bys. The one-dimensional density and track power spectra along the stream trace the subhalo mass function, with higher mass subhaloes producing power only on large scales, while lower mass subhaloes cause structure on smaller scales. We also find significant density and track bispectra that are observationally accessible. We further demonstrate that different projections of the track all reflect the same pattern of perturbations, facilitating their observational measurement. We apply this formalism to data for the Pal 5 stream and make a first rigorous determination of 10^{+11}_{-6} dark matter subhaloes with masses between 106.5 and 109 M⊙ within 20 kpc from the Galactic centre [corresponding to 1.4^{+1.6}_{-0.9} times the number predicted by CDM-only simulations or to fsub(r matter is clumpy on the smallest scales relevant for galaxy formation.

Field migration rates of tidal meanders recapitulate fluvial morphodynamics.

Science.gov (United States)

Finotello, Alvise; Lanzoni, Stefano; Ghinassi, Massimiliano; Marani, Marco; Rinaldo, Andrea; D'Alpaos, Andrea

2018-02-13

The majority of tidal channels display marked meandering features. Despite their importance in oil-reservoir formation and tidal landscape morphology, questions remain on whether tidal-meander dynamics could be understood in terms of fluvial processes and theory. Key differences suggest otherwise, like the periodic reversal of landscape-forming tidal flows and the widely accepted empirical notion that tidal meanders are stable landscape features, in stark contrast with their migrating fluvial counterparts. On the contrary, here we show that, once properly normalized, observed migration rates of tidal and fluvial meanders are remarkably similar. Key to normalization is the role of tidal channel width that responds to the strong spatial gradients of landscape-forming flow rates and tidal prisms. We find that migration dynamics of tidal meanders agree with nonlinear theories for river meander evolution. Our results challenge the conventional view of tidal channels as stable landscape features and suggest that meandering tidal channels recapitulate many fluvial counterparts owing to large gradients of tidal prisms across meander wavelengths. Copyright © 2018 the Author(s). Published by PNAS.

Canadian Experience in Nuclear Power Technology Transfer

International Nuclear Information System (INIS)

Boulton, J.

1987-01-01

Technology transfer has and will continue to play a major role in the development of nuclear power programs. From the early beginnings of the development of the peaceful uses of nuclear power by just a few nations in the mid-1940s there has been a considerable transfer of technology and today 34 countries have nuclear programs in various stages of development. Indeed, some of the major nuclear vendors achieves their present position through a process of technology transfer and subsequent development. Canada, one of the early leaders in the development of nuclear power, has experience with a wide range of programs bout within its own borders and with other countries. This paper briefly describes this experience and the lessons learned from Canada's involvement in the transfer of nuclear power technology. Nuclear technology is complex and diverse and yet it can be assimilated by a nation given a fire commitment of both suppliers and recipients of technology to achieve success. Canada has reaped large benefits from its nuclear program and we believe this has been instrumentally linked to the sharing of goals and opportunity for participation over extended periods of time by many interests within the Canadian infrastructure. While Canada has accumulated considerable expertise in nuclear technology transfer, we believe there is still much for US to learn. Achieving proficiency in any of the many kinds of nuclear related technologies will place a heavy burden on the financial and human resources of a nation. Care must be taken to plan carefully the total criteria which will assure national benefits in industrial and economic development. Above all, effective transfer of nuclear technology requires a long term commitment by both parties

Revolution of Nuclear Power Plant Design Through Digital Technology

International Nuclear Information System (INIS)

Zhang, L.; Shi, J.; Chen, W.

2015-01-01

In the digital times, digital technology has penetrated into every industry. As the highest safety requirement standard, nuclear power industry needs digital technology more to breed high quality and efficiency. Digital power plant is derived from digital design and the digitisation of power plant transfer is an inevitable trend. This paper introduces the technical solutions and features of digital nuclear power plant construction by Shanghai Nuclear Engineering Research & Design Institute, points out the key points and technical difficulties that exist in the process of construction and can serve as references for further promoting construction of digital nuclear power plant. Digital technology is still flourishing. Although many problems will be encountered in construction, it is believed that digital technology will make nuclear power industry more safe, cost-effective and efficient. (author)

Monitoring Tidal Currents with a Towed ADCP System

Science.gov (United States)

2015-12-22

dynamical properties of the upper ocean. Geophys Res Abstr 16. EGU2014- 13078, EGU General Assembly Barth A, Alvera-Azcárate A, Beckers J-M, Weisberg...energy conversion in a future energy generation mix is under evaluation in different countries (e.g., Weisberg et al. 2012; Quirapas et al. 2015). In...vehicle. It is well established now that, at pilot sites, the power generating potential of the tidal stream is characterized by significant

Global wind power potential: Physical and technological limits

International Nuclear Information System (INIS)

Castro, Carlos de; Mediavilla, Margarita; Miguel, Luis Javier; Frechoso, Fernando

2011-01-01

This paper is focused on a new methodology for the global assessment of wind power potential. Most of the previous works on the global assessment of the technological potential of wind power have used bottom-up methodologies (e.g. ). Economic, ecological and other assessments have been developed, based on these technological capacities. However, this paper tries to show that the reported regional and global technological potential are flawed because they do not conserve the energetic balance on Earth, violating the first principle of energy conservation (). We propose a top-down approach, such as that in , to evaluate the physical-geographical potential and, for the first time, to evaluate the global technological wind power potential, while acknowledging energy conservation. The results give roughly 1 TW for the top limit of the future electrical potential of wind energy. This value is much lower than previous estimates and even lower than economic and realizable potentials published for the mid-century (e.g. ). - Highlights: → Reported wind power potentials are flawed because they violate energy conservation. → For the first time, it is evaluated the technological wind power potential with a top-down approach. → Our results show 1 TWe for the limit of wind power energy, which is much lower than previous estimates.

Space power technology for the twenty-first century (SPT21)

International Nuclear Information System (INIS)

Borger, W.U.; Massie, L.D.

1988-01-01

During the spring and summer months of 1987, the Aero Propulsion Laboratory of the Air Force Wright Aeronautical Laboratories, Wright-Patterson AFB, Ohio in cooperation with the Air Force Space Technology Center at Kirtland AFB, New Mexico, undertook an initiative to develop a Strategic Plan for Space Power Technology Development. The initiative was called SPT21, Space Power Technology for the Twenty-First Century. The planning process involved the participation of other Government organizations (U.S. Army, Navy, DOE and NASA) along with major aerospace companies and universities. Following an SPT21 kickoff meeting on 28 May 1987, detailed strategic planning was accomplished through seven (7) Space Power Technology Discipline Workshops commencing in June 1987 and concluding in August 1987. Technology Discipline Workshops were conducted in the following areas: (1) Solar Thermal Dynamic Power Systems (2) Solar Photovoltaic Cells and Arrays (3) Thermal Management Technology (4) Energy Storage Technology (5) Nuclear Power Systems Technology (6) Power Conditioning, Distribution and Control and (7) Systems Technology/Advanced Concepts. This technical paper summarizes the planning process and describes the salient findings and conclusions of the workshops

Sustainability assessment of renewable power and heat generation technologies

International Nuclear Information System (INIS)

Dombi, Mihály; Kuti, István; Balogh, Péter

2014-01-01

Rationalisation of consumption, more efficient energy usage and a new energy structure are needed to be achieved in order to shift the structure of energy system towards sustainability. The required energy system is among others characterised by intensive utilisation of renewable energy sources (RES). RES technologies have their own advantages and disadvantages. Nevertheless, for the strategic planning there is a great demand for the comparison of RES technologies. Furthermore, there are additional functions of RES utilisation expected beyond climate change mitigation, e.g. increment of employment, economic growth and rural development. The aim of the study was to reveal the most beneficial RES technologies with special respect to sustainability. Ten technologies of power generation and seven technologies of heat supply were examined in a multi-criteria sustainability assessment frame of seven attributes which were evaluated based on a choice experiment (CE) survey. According to experts the most important characteristics of RES utilisation technologies are land demand and social impacts i.e. increase in employment and local income generation. Concentrated solar power (CSP), hydropower and geothermal power plants are favourable technologies for power generation, while geothermal district heating, pellet-based non-grid heating and solar thermal heating can offer significant advantages in case of heat supply. - highlights: • We used choice experiment to estimate the weights of criteria for the sustainability assessment of RES technologies. • The most important attributes of RES technologies according to experts are land demand and social impacts. • Concentrated solar power (CSP), hydropower and geothermal power plants are advantageous technologies for power generation. • Geothermal district heating, pellet-based non-grid heating and solar thermal heating are favourable in case of heat supply

Advanced power plant materials, design and technology

Energy Technology Data Exchange (ETDEWEB)

Roddy, D. (ed.) [Newcastle University (United Kingdom). Sir Joseph Swan Institute

2010-07-01

The book is a comprehensive reference on the state of the art of gas-fired and coal-fired power plants, their major components and performance improvement options. Selected chapters are: Integrated gasification combined cycle (IGCC) power plant design and technology by Y. Zhu, and H. C. Frey; Improving thermal cycle efficiency in advanced power plants: water and steam chemistry and materials performance by B. Dooley; Advanced carbon dioxide (CO{sub 2}) gas separation membrane development for power plants by A. Basile, F. Gallucci, and P. Morrone; Advanced flue gas cleaning systems for sulphur oxides (SOx), nitrogen oxides (NOx) and mercury emissions control in power plants by S. Miller and B.G. Miller; Advanced flue gas dedusting systems and filters for ash and particulate emissions control in power plants by B.G. Miller; Advanced sensors for combustion monitoring in power plants: towards smart high-density sensor networks by M. Yu and A.K. Gupta; Advanced monitoring and process control technology for coal-fired power plants by Y. Yan; Low-rank coal properties, upgrading and utilisation for improving the fuel flexibility of advanced power plants by T. Dlouhy; Development and integration of underground coal gasification (UCG) for improving the environmental impact of advanced power plants by M. Green; Development and application of carbon dioxide (CO{sub 2}) storage for improving the environmental impact of advanced power plants by B. McPherson; and Advanced technologies for syngas and hydrogen (H{sub 2}) production from fossil-fuel feedstocks in power plants by P. Chiesa.

Measurements of Turbulence at Two Tidal Energy Sites in Puget Sound, WA

Energy Technology Data Exchange (ETDEWEB)

Thomson, Jim; Polagye, Brian; Durgesh, Vibhav; Richmond, Marshall C.

2012-06-05

Field measurements of turbulence are pre- sented from two sites in Puget Sound, WA (USA) that are proposed for electrical power generation using tidal current turbines. Rapidly sampled data from multiple acoustic Doppler instruments are analyzed to obtain statistical mea- sures of fluctuations in both the magnitude and direction of the tidal currents. The resulting turbulence intensities (i.e., the turbulent velocity fluctuations normalized by the harmonic tidal currents) are typically 10% at the hub- heights (i.e., the relevant depth bin) of the proposed turbines. Length and time scales of the turbulence are also analyzed. Large-scale, anisotropic eddies dominate the energy spectra, which may be the result of proximity to headlands at each site. At small scales, an isotropic turbulent cascade is observed and used to estimate the dissipation rate of turbulent kinetic energy. Data quality and sampling parameters are discussed, with an emphasis on the removal of Doppler noise from turbulence statistics.

The economics of tidal energy

International Nuclear Information System (INIS)

Denny, Eleanor

2009-01-01

Concern over global climate change has led policy makers to accept the importance of reducing greenhouse gas emissions. This in turn has led to a large growth in clean renewable generation for electricity production. Much emphasis has been on wind generation as it is among the most advanced forms of renewable generation, however, its variable and relatively unpredictable nature result in increased challenges for electricity system operators. Tidal generation on the other hand is almost perfectly forecastable and as such may be a viable alternative to wind generation. This paper calculates the break-even capital cost for tidal generation on a real electricity system. An electricity market model is used to determine the impact of tidal generation on the operating schedules of the conventional units on the system and on the resulting cycling costs, emissions and fuel savings. It is found that for tidal generation to produce positive net benefits for the case study, the capital costs would have to be less than Euro 510,000 per MW installed which is currently an unrealistically low capital cost. Thus, it is concluded that tidal generation is not a viable option for the case system at the present time.

Tidal volume in acute respiratory distress syndrome: how best to select it.

Science.gov (United States)

Umbrello, Michele; Marino, Antonella; Chiumello, Davide

2017-07-01

Mechanical ventilation is the type of organ support most widely provided in the intensive care unit. However, this form of support does not constitute a cure for acute respiratory distress syndrome (ARDS), as it mainly works by buying time for the lungs to heal while contributing to the maintenance of vital gas exchange. Moreover, it can further damage the lung, leading to the development of a particular form of lung injury named ventilator-induced lung injury (VILI). Experimental evidence accumulated over the last 30 years highlighted the factors associated with an injurious form of mechanical ventilation. The present paper illustrates the physiological effects of delivering a tidal volume to the lungs of patients with ARDS, and suggests an approach to tidal volume selection. The relationship between tidal volume and the development of VILI, the so called volotrauma, will be reviewed. The still actual suggestion of a lung-protective ventilatory strategy based on the use of low tidal volumes scaled to the predicted body weight (PBW) will be presented, together with newer strategies such as the use of airway driving pressure as a surrogate for the amount of ventilatable lung tissue or the concept of strain, i.e., the ratio between the tidal volume delivered relative to the resting condition, that is the functional residual capacity (FRC). An ultra-low tidal volume strategy with the use of extracorporeal carbon dioxide removal (ECCO 2 R) will be presented and discussed. Eventually, the role of other ventilator-related parameters in the generation of VILI will be considered (namely, plateau pressure, airway driving pressure, respiratory rate (RR), inspiratory flow), and the promising unifying framework of mechanical power will be presented.

Homogeneous internal wave turbulence driven by tidal flows

Science.gov (United States)

Le Reun, Thomas; Favier, Benjamin; Le Bars, Michael; Erc Fludyco Team

2017-11-01

We propose a novel investigation of the stability of strongly stratified planetary fluid layers undergoing periodic tidal distortion in the limit where rotational effects are negligible compared to buoyancy. With the help of a local model focusing on a small fluid area compared to the global layer, we find that periodic tidal distortion drives a parametric subharmonic resonance of internal. This instability saturates into an homogeneous internal wave turbulence pervading the whole fluid interior: the energy is injected in the unstable waves which then feed a succession of triadic resonances also generating small spatial scales. As the timescale separation between the forcing and Brunt-Väisälä is increased, the temporal spectrum of this turbulence displays a -2 power law reminiscent of the Garrett and Munk spectrum measured in the oceans (Garett & Munk 1979). Moreover, in this state consisting of a superposition of waves in weak non-linear interaction, the mixing efficiency is increased compared to classical, Kolmogorov-like stratified turbulence. This study is of wide interest in geophysical fluid dynamics ranging from oceanic turbulence and tidal heating in icy satellites to dynamo action in partially stratified planetary cores as it could be the case in the Earth. We acknowledge support from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (Grant Agreement No. 681835-FLUDYCO-ERC-2015-CoG).

Relativistic theory of tidal Love numbers

International Nuclear Information System (INIS)

Binnington, Taylor; Poisson, Eric

2009-01-01

In Newtonian gravitational theory, a tidal Love number relates the mass multipole moment created by tidal forces on a spherical body to the applied tidal field. The Love number is dimensionless, and it encodes information about the body's internal structure. We present a relativistic theory of Love numbers, which applies to compact bodies with strong internal gravities; the theory extends and completes a recent work by Flanagan and Hinderer, which revealed that the tidal Love number of a neutron star can be measured by Earth-based gravitational-wave detectors. We consider a spherical body deformed by an external tidal field, and provide precise and meaningful definitions for electric-type and magnetic-type Love numbers; and these are computed for polytropic equations of state. The theory applies to black holes as well, and we find that the relativistic Love numbers of a nonrotating black hole are all zero.

Automation technology in power plants

International Nuclear Information System (INIS)

Essen, E.R.

1995-01-01

In this article a summery of the current architecture of modern process control systems in power plants and future trends have been explained. The further development of process control systems for power plants is influenced both by the developments in component and software technologies as well as the increased requirements of the power plants. The convenient and low cost configuration facilities of new process control systems have now reached a significance which makes it easy for customers to decide to purchase. (A.B.)

Nuclear power technology requirements for NASA exploration missions

International Nuclear Information System (INIS)

Bloomfield, H.S.

1990-01-01

This paper discusses how future exploration of the Moon and Mars will mandate developments in many areas of technology. In particular, major advances will be required in planet surface power systems and space transportation systems. Critical nuclear technology challenges that can enable strategic self-sufficiency, acceptable operational costs and cost-effective space transportation goals for NASA exploration missions have been identified. Critical technologies for surface power systems include stationary and mobile nuclear reactor and radio-isotope heat sources coupled to static and dynamic power conversion devices. These technologies can provide dramatic reductions in mass leading to operational and transportation cost savings. Critical technologies for space transportation systems include nuclear thermal rocket and nuclear electric propulsion options which present compelling concepts for significantly reducing mass, cost or travel time required for Earth-Mars transport

Status of Wind Power Technologies

DEFF Research Database (Denmark)

Zhao, Haoran; Wu, Qiuwei

2018-01-01

With the development of wind turbine technology, wind power will become more controllable and grid‐friendly. It is desirable to make wind farms operate as conventional power plants. Wind turbine generators (WTGs) were mainly used in rural and remote areas for wind power generation. WTG‐based wind...... energy conversion systems (WECS) can be divided into the four main types (type 1‐4). Due to the inherent variability and uncertainty of the wind, the integration of wind power into the grid has brought challenges in several different areas, including power quality, system reliability, stability......, and planning. The impact of each is largely dependent on the level of wind power penetration in the grid. In many countries, relatively high levels of wind power penetration have been achieved. This chapter shows the estimated wind power penetration in leading wind markets....

Battery Energy Storage Technology for power systems-An overview

DEFF Research Database (Denmark)

Chandrashekhara, Divya K; Østergaard, Jacob

2009-01-01

the present status of battery energy storage technology and methods of assessing their economic viability and impact on power system operation. Further, a discussion on the role of battery storage systems of electric hybrid vehicles in power system storage technologies had been made. Finally, the paper...... suggests a likely future outlook for the battery technologies and the electric hybrid vehicles in the context of power system applications....

The origin of neap-spring tidal cycles

Science.gov (United States)

Kvale, E.P.

2006-01-01

The origin of oceanic tides is a basic concept taught in most introductory college-level sedimentology/geology, oceanography, and astronomy courses. Tides are typically explained in the context of the equilibrium tidal theory model. Yet this model does not take into account real tides in many parts of the world. Not only does the equilibrium tidal model fail to explicate amphidromic circulation, it also does not explain diurnal tides in low latitude positions. It likewise fails to explain the existence of tide-dominated areas where neap-spring cycles are synchronized with the 27.32-day orbital cycle of the Moon (tropical month), rather than with the more familiar 29.52-day cycle of lunar phases (synodic month). Both types of neap-spring cycles can be recognized in the rock record. A complete explanation of the origin of tides should include a discussion of dynamic tidal theory. In the dynamic tidal model, tides resulting from the motions of the Moon in its orbit around the Earth and the Earth in its orbit around the Sun are modeled as products of the combined effects of a series of phantom satellites. The movement of each of these satellites, relative to the Earth's equator, creates its own tidal wave that moves around an amphidromic point. Each of these waves is referred to as a tidal constituent. The geometries of the ocean basins determine which of these constituents are amplified. Thus, the tide-raising potential for any locality on Earth can be conceptualized as the result of a series of tidal constituents specific to that region. A better understanding of tidal cycles opens up remarkable opportunities for research on tidal deposits with implications for, among other things, a more complete understanding of the tidal dynamics responsible for sediment transport and deposition, changes in Earth-Moon distance through time, and the possible influences tidal cycles may exert on organisms. ?? 2006 Elsevier B.V. All rights reserved.

Emission Control Technologies for Thermal Power Plants

Science.gov (United States)

Nihalani, S. A.; Mishra, Y.; Juremalani, J.

2018-03-01

Coal thermal power plants are one of the primary sources of artificial air emissions, particularly in a country like India. Ministry of Environment and Forests has proposed draft regulation for emission standards in coal-fired power plants. This includes significant reduction in sulphur-dioxide, oxides of nitrogen, particulate matter and mercury emissions. The first step is to evaluate the technologies which represent the best selection for each power plant based on its configuration, fuel properties, performance requirements, and other site-specific factors. This paper will describe various technology options including: Flue Gas Desulfurization System, Spray Dryer Absorber (SDA), Circulating Dry Scrubber (CDS), Limestone-based Wet FGD, Low NOX burners, Selective Non Catalytic Reduction, Electrostatic Precipitator, Bag House Dust Collector, all of which have been evaluated and installed extensively to reduce SO2, NOx, PM and other emissions. Each control technology has its advantages and disadvantages. For each of the technologies considered, major features, potential operating and maintenance cost impacts, as well as key factors that contribute to the selection of one technology over another are discussed here.

Technology Efficiency Study on Nuclear Power and Coal Power in Guangdong Province Based on DEA

International Nuclear Information System (INIS)

Yinong Li; Dong Wang

2006-01-01

Guangdong Province has taken the lead in embarking on nuclear power development to resolve its dire lack of primary resources. With the deepening of the on-going structural reform in the electric power sector in China, the market competition scheme is putting electricity generation enterprises under severe strain. Consequently, it is incumbent upon the nuclear power producers to steadily upgrade management, enhance technical capabilities, reduce cost and improve efficiency. At present, gradual application of such efficiency evaluation methodology has already commenced in some sectors in China including the electric power industry. The purpose of this paper is to use the Data Envelopment Analysis (DEA), which is a cutting-edge approach in the efficiency evaluation field - to study the technological efficiency between nuclear power and coal power in Guangdong Province. The DEA results demonstrate that, as far as Guangdong Province is concerned, the technological efficiency of nuclear power is higher than that of coal power in terms of Technological Efficiency (TE), Pure Technology Efficiency (PTE) and Scale Efficiency (SE). The reason is that nuclear power technology is advanced with a much higher equipment availability factor. Under the same scale, the generation output of nuclear power is far higher than that of equivalent coal power generation. With the environmental protection and sustainable development requirements taken into full account, nuclear power constitutes a clean, safe and highly-efficient energy form which should be extensively harnessed in Guangdong Province to fuel its future continuing economic growth. (authors)

Technology in the policy process - controlling nuclear power

International Nuclear Information System (INIS)

Collingridge, D.

1983-01-01

The discussion in this book is built around nuclear power. The technology of nuclear power is shown to have features which make it inflexible in the sense that, once built, it is difficult and expensive to control. If inflexible technology is to be avoided, it is crucially important to be able to identify this failing at an early stage in the technology's development, before it has acquired an immunity to political control. Again, this problem is approached through the example of nuclear power, in particular the breeder reactor. The breeder is shown to be even less flexible than today's nuclear technology, because it will have higher capital costs, be of greater capital intensity, longer lead time, larger unit size, and will require more infrastructure for its operation. If this is developed, the breeder will be even less open to political control than the nuclear plant of the present. To put it another way, its planning will be even more open to errors and whatever errors are made will be even more costly than for existing nuclear technology. It is therefore even less of a socially and economically acceptable technology than today's nuclear power. (author)

Development of tidal watersheds in the Wadden Sea

NARCIS (Netherlands)

Wang, Z.B.; Vroom, J.; van Prooijen, B.C.; Labeur, R.J.; Stive, M.J.F.; Hansen, M.H.P.

2011-01-01

The Wadden Sea consists of a series of tidal lagoons which are connected to the North Sea by tidal inlets. Boundaries to each lagoon are the mainland coast, the barrier islands on both sides of the tidal inlet, and the tidal watersheds behind the two barrier islands. Behind each Wadden Island there

TIDALLY HEATED TERRESTRIAL EXOPLANETS: VISCOELASTIC RESPONSE MODELS

International Nuclear Information System (INIS)

Henning, Wade G.; O'Connell, Richard J.; Sasselov, Dimitar D.

2009-01-01

Tidal friction in exoplanet systems, driven by orbits that allow for durable nonzero eccentricities at short heliocentric periods, can generate internal heating far in excess of the conditions observed in our own solar system. Secular perturbations or a notional 2:1 resonance between a hot Earth and hot Jupiter can be used as a baseline to consider the thermal evolution of convecting bodies subject to strong viscoelastic tidal heating. We compare results first from simple models using a fixed Quality factor and Love number, and then for three different viscoelastic rheologies: the Maxwell body, the Standard Anelastic Solid (SAS), and the Burgers body. The SAS and Burgers models are shown to alter the potential for extreme tidal heating by introducing the possibility of new equilibria and multiple response peaks. We find that tidal heating tends to exceed radionuclide heating at periods below 10-30 days, and exceed insolation only below 1-2 days. Extreme cases produce enough tidal heat to initiate global-scale partial melting, and an analysis of tidal limiting mechanisms such as advective cooling for earthlike planets is discussed. To explore long-term behaviors, we map equilibria points between convective heat loss and tidal heat input as functions of eccentricity. For the periods and magnitudes discussed, we show that tidal heating, if significant, is generally detrimental to the width of habitable zones.

Prospects for power plant technology

International Nuclear Information System (INIS)

Schilling, H.D.

1993-01-01

Careful conservation of resources in the enlarged context of the rational utilization of energy, the environment and capital will determine future power plant technology. The mainstays will be the further development of power plant concepts based on fossil (predominantly coal) and nuclear fuels; world-wide, also regenerative and CO 2 -free hydro-electric power will play a role. Rapid conversion of the available potential requires clear, long-term stable and reliable political framework conditions for the release of the necessary entrepreneurial forces. (orig.) [de

Current status of Chinese nuclear power industry and technology

International Nuclear Information System (INIS)

Kim, Hyun Min; Kim, Min; Jeong, Hee Jong; Hwang, Jeong Ki; Cho, Chung Hee

1996-10-01

China has been carrying out active international cooperation aiming to be a country where is to be an economical super power and an advanced country in nuclear power technology by the year early 2000, and China also has begun to be recognized as the largest potential market for the construction of nuclear power plants(NPPs) expecting to construct more than thirty nuclear power units by the year 2020. China has advanced technology in the basic nuclear science including liquid metal breeder reactor technology, nuclear material, medium and small size power plants, and isotope production technology, and also China has complete nuclear fuel cycle technology. However, China still has low NPP technology. Therefore, it is expected that China may have complementary cooperative relationship with China, it is expected that Korea may have an access to the advanced Chinese nuclear science technology, and may have a good opportunity to explore the Chinese market actively exporting excellent Korean NPP technology, and further may have a good position to the neighboring Asian countries' NPP markets. From this perspective, general Chinese social status, major nuclear R and D activity status, and correct NPP and technology status have been analyzed in this report, and this report is expected to be a useful resource for cooperating with China in future. 10 tabs., 6 figs., 16 refs. (Author)

Comparative analysis of the application of different Low Power Wide Area Network technologies in power grid

Science.gov (United States)

Wang, Hao; Sui, Hong; Liao, Xing; Li, Junhao

2018-03-01

Low Power Wide Area Network (LPWAN) technologies developed rapidly in recent years, but the application principle of different LPWAN technologies in power grid is still not clear. This paper gives a comparative analysis of two mainstream LPWAN technologies including NB-IoT and LoRa, and gives an application suggestion of these two LPWAN technologies, which can guide the planning and construction of LPWAN in power grid.

Tidal flow separation at protruding beach nourishments

NARCIS (Netherlands)

Radermacher, M.; de Schipper, M.A.; Swinkels, Cilia M.; MacMahan, Jamie; Reniers, A.J.H.M.

2016-01-01

In recent years, the application of large-scale beach nourishments has been discussed, with the Sand Motor in the Netherlands as the first real-world example. Such protruding beach nourishments have an impact on tidal currents, potentially leading to tidal flow separation and the generation of tidal

Innovation on Energy Power Technology (1)

Science.gov (United States)

Nagano, Susumu; Kakishima, Masayoshi

After the last war, the output of single Steam Turbine Generator produced by the own technology in Japan returned to a prewar level. Electric power companies imported the large-capacity high efficiency Steam Turbine Generator from the foreign manufacturers in order to support the sudden increase of electric power demand. On the other hand, they decided to produce those in our own country to improve industrial technology. The domestic production of large-capacity 125MW Steam Turbine Generator overcome much difficulty and did much contribution for the later domestic technical progress.

TIDAL NOVAE IN COMPACT BINARY WHITE DWARFS

International Nuclear Information System (INIS)

Fuller, Jim; Lai Dong

2012-01-01

Compact binary white dwarfs (WDs) undergoing orbital decay due to gravitational radiation can experience significant tidal heating prior to merger. In these WDs, the dominant tidal effect involves the excitation of outgoing gravity waves in the inner stellar envelope and the dissipation of these waves in the outer envelope. As the binary orbit decays, the WDs are synchronized from outside in (with the envelope synchronized first, followed by the core). We examine the deposition of tidal heat in the envelope of a carbon-oxygen WD and study how such tidal heating affects the structure and evolution of the WD. We show that significant tidal heating can occur in the star's degenerate hydrogen layer. This layer heats up faster than it cools, triggering runaway nuclear fusion. Such 'tidal novae' may occur in all WD binaries containing a CO WD, at orbital periods between 5 minutes and 20 minutes, and precede the final merger by 10 5 -10 6 years.

European coal technology applied by the Danish power companies

Energy Technology Data Exchange (ETDEWEB)

Frydenberg, B. [Elsamprojekt A/S, Fredericia (Denmark)

1996-12-31

The development of coal-fired power plants has shown remarkable improvements with regard to efficiency and cleaner technology, and as coal remains the most important fuel for electric power production, it is important to make use of this technological development to reduce CO{sub 2} emissions. Of the three available technologies: Integrated Coal Gasification and Combined Cycle, Fluid Bed Combustion and Pulverised Coal with Ultra Supercritical Steam Data, the technology chosen by I/S ELSAM is the PC-USC with power production efficiencies growing from 45% to 50%. 5 figs., 1 tab.

Nuclear power technologies for application in developing countries

International Nuclear Information System (INIS)

Zrodnikov, A.V.

2000-01-01

The tremendous social and political changes which have occurred during the recent decade in the former USSR made it possible to launch the process of commercialization of defense-related technologies in Russia. The so-called dual-use technologies are meant to be initially developed by the state for defense needs, but having a high commercial potential as well. To date, the process of such technology transfer from the state sector to a private one has been limited primarily by insufficient progress of the national private sector. Essentially, the main economic problem still remains the attraction of private capital for the promotion of dual-use technologies to the point at where they acquire commercially viable. A large number of advanced technologies are waiting to be commercialized. The report presented considers the prospects of civil use of some technologies related to the nuclear power area: space nuclear power systems, nuclear powered submarines and rector-pumped lasers. (author)

Desulfurization technologies for flue gases from power stations, technological and financial characteristics

International Nuclear Information System (INIS)

Naumoski, Koce

1997-01-01

Harms on life environment, caused by aero pollution, for the last decades enforced fast development of technologies for filtration of gases that come from thermal power plants and other objects. SO 2 , that appear as one of outputs of fossil fuels combustion, and also processing of sulphide ore, is a main component of acid rains. Acid rains represent one of the most risky factors, responsible for dryne of woods and changing of flora and fauna on land and in water. Starting from 1931 year when on the thermal power plant BATTERSEA STATION, property of London Power, first scrubbers were monnted for filtration of flue gases of SO 2 , and up till today, many procedures are developed for desulfurization of flue gases. For easier coping with numerous technologies for desulfurization , various classifications were made. By state of aggregation of the absorption agent , the technologies for desulfurization of gases are divided in wet , semidry and dry procedures. Wet procedures are technologies with highness rate of desulfurization of 90-95 % and most flexible of the quality of fuel whose flue gases are filtered. Presently they have high price of 90-220 $/kw installed power. According to American sources, their price at the world market is forecasted that till 2000 year will reach price of 100 $/kw. Dry technologies for desulfurization of flue gases are last technologies. The rate of desulfurization is 50-60 % and its prise is 76 -113 $/kw. Their negative side is high variable costs 250 - 388 $/ ton SO 2 (at wet procedures variable costs 76 - 157 $/ton SO 2 ). Semidry technologies by financial and technological characteristics are wet and dry procedures. (Author)

Preventive maintenance technology for nuclear power stations

International Nuclear Information System (INIS)

Miyazawa, Tatsuo

1992-01-01

With the increase of the number of nuclear power plants in operation and the number of years of operation, the improvement of reliability and the continuation of safe operation have become more important, and the expectation for preventive maintenance technology has also heightened. The maintenance of Japanese nuclear power plants is based on the time schedule maintenance mainly by the regular inspection carried out every year, but the monitoring of the conditions of various machinery and equipment in operation has been performed widely. In this report, the present state of checkup and inspection technologies and the monitoring and diagnostic technologies for operational condition, which are the key technologies of preventive maintenance, are described. As the checkup and inspection technologies, ultrasonic flow detection technology, phased array technology, Amplituden und Laufzeit Orts Kurven method and X-ray CT, and as the monitoring and diagnostic technologies for operational condition, the diagnosis support system for BWR plants 'PLADIS', those for rotary machines, those for turbogenerators, those for solenoid valves, the mechanization of patrol works and the systematizing technology are reported. (K.I.)

Radioisotope Power Systems Technology Development

Data.gov (United States)

National Aeronautics and Space Administration — The goal of the RPS's technology portfolio is to advance performance of radioisotope power systems through new and novel innovations being developed and transitioned...

Tidally influenced alongshore circulation at an inlet-adjacent shoreline

Science.gov (United States)

Hansen, Jeff E.; Elias, Edwin P.L.; List, Jeffrey H.; Erikson, Li H.; Barnard, Patrick L.

2013-01-01

The contribution of tidal forcing to alongshore circulation inside the surfzone is investigated at a 7 km long sandy beach adjacent to a large tidal inlet. Ocean Beach in San Francisco, CA (USA) is onshore of a ∼150 km2 ebb-tidal delta and directly south of the Golden Gate, the sole entrance to San Francisco Bay. Using a coupled flow-wave numerical model, we find that the tides modulate, and in some cases can reverse the direction of, surfzone alongshore flows through two separate mechanisms. First, tidal flow through the inlet results in a barotropic tidal pressure gradient that, when integrated across the surfzone, represents an important contribution to the surfzone alongshore force balance. Even during energetic wave conditions, the tidal pressure gradient can account for more than 30% of the total alongshore pressure gradient (wave and tidal components) and up to 55% during small waves. The wave driven component of the alongshore pressure gradient results from alongshore wave height and corresponding setup gradients induced by refraction over the ebb-tidal delta. Second, wave refraction patterns over the inner shelf are tidally modulated as a result of both tidal water depth changes and strong tidal flows (∼1 m/s), with the effect from currents being larger. These tidally induced changes in wave refraction result in corresponding variability of the alongshore radiation stress and pressure gradients within the surfzone. Our results indicate that tidal contributions to the surfzone force balance can be significant and important in determining the direction and magnitude of alongshore flow.

Tidal influence on subtropical estuarine methane emissions

Science.gov (United States)

Sturm, Katrin; Grinham, Alistair; Werner, Ursula; Yuan, Zhiguo

2014-05-01

The relatively unstudied subtropical estuaries, particularly in the Southern Hemisphere, represent an important gap in our understanding of global greenhouse gas (GHG) emissions. These systems are likely to form an important component of GHG budgets as they occupy a relatively large surface area, over 38 000 km2 in Australia. Here, we present studies conducted in the Brisbane River estuary, a representative system within the subtropical region of Queensland, Australia. This is a highly modified system typical of 80% of Australia's estuaries. Generally, these systems have undergone channel deepening and straightening for safer shipping access and these modifications have resulted in large increases in tidal reach. The Brisbane River estuary's natural tidal reach was 16 km and this is now 85 km and tidal currents influence double the surface area (9 km2 to 18 km2) in this system. Field studies were undertaken to improve understanding of the driving factors behind methane water-air fluxes. Water-air fluxes in estuaries are usually calculated with the gas exchange coefficient (k) for currents and wind as well as the concentration difference across the water-air interface. Tidal studies in the lower and middle reaches of the estuary were performed to monitor the influence of the tidal stage (a proxy for kcurrent) on methane fluxes. Results for both investigated reaches showed significantly higher methane fluxes during the transition time of tides, the time of greatest tidal currents, than during slack tide periods. At these tidal transition times with highest methane chamber fluxes, lowest methane surface water concentrations were monitored. Modelled fluxes using only wind speed (kwind) were at least one order of magnitude lower than observed from floating chambers, demonstrating that current speed was likely the driving factor of water-air fluxes. An additional study was then conducted sampling the lower, middle and upper reaches during a tidal transition period

Counter-rotating type tidal stream power unit boarded on pillar (performances and flow conditions of tandem propellers)

Science.gov (United States)

Usui, Yuta; Kanemoto, Toshiaki; Hiraki, Koju

2013-12-01

The authors have invented the unique counter-rotating type tidal stream power unit composed of the tandem propellers and the double rotational armature type peculiar generator without the traditional stator. The front and the rear propellers counter-drive the inner and the outer armatures of the peculiar generator, respectively. The unit has the fruitful advantages that not only the output is sufficiently higher without supplementary equipment such as a gearbox, but also the rotational moment hardly act on the pillar because the rotational torque of both propellers/armatures are counter-balanced in the unit. This paper discusses experimentally the performances of the power unit and the effects of the propeller rotation on the sea surface. The axial force acting on the pillar increases naturally with the increase of not only the stream velocity but also the drag of the tandem propellers. Besides, the force vertical to the stream also acts on the pillar, which is induced from the Karman vortex street and the dominant frequencies appear owing to the front and the rear propeller rotations. The propeller rotating in close to the sea surface brings the abnormal wave and the amplitude increases as the stream velocity is faster and/or the drag is stronger.

Multi-criteria decision-making on assessment of proposed tidal barrage schemes in terms of environmental impacts.

Science.gov (United States)

Wu, Yunna; Xu, Chuanbo; Ke, Yiming; Chen, Kaifeng; Xu, Hu

2017-12-15

For tidal range power plants to be sustainable, the environmental impacts caused by the implement of various tidal barrage schemes must be assessed before construction. However, several problems exist in the current researches: firstly, evaluation criteria of the tidal barrage schemes environmental impact assessment (EIA) are not adequate; secondly, uncertainty of criteria information fails to be processed properly; thirdly, correlation among criteria is unreasonably measured. Hence the contributions of this paper are as follows: firstly, an evaluation criteria system is established from three dimensions of hydrodynamic, biological and morphological aspects. Secondly, cloud model is applied to describe the uncertainty of criteria information. Thirdly, Choquet integral with respect to λ-fuzzy measure is introduced to measure the correlation among criteria. On the above bases, a multi-criteria decision-making decision framework for tidal barrage scheme EIA is established to select the optimal scheme. Finally, a case study demonstrates the effectiveness of the proposed framework. Copyright © 2017 Elsevier Ltd. All rights reserved.

Numerical Simulations of the Effects of a Tidal Turbine Array on Near-Bed Velocity and Local Bed Shear Stress

Directory of Open Access Journals (Sweden)

Philip A. Gillibrand

2016-10-01

Full Text Available We apply a three-dimensional hydrodynamic model to consider the potential effects of energy extraction by an array of tidal turbines on the ambient near-bed velocity field and local bed shear stress in a coastal channel with strong tidal currents. Local bed shear stress plays a key role in local sediment dynamics. The model solves the Reynold-averaged Navier-Stokes (RANS equations on an unstructured mesh using mixed finite element and finite volume techniques. Tidal turbines are represented through an additional form drag in the momentum balance equation, with the thrust imparted and power generated by the turbines being velocity dependent with appropriate cut-in and cut-out velocities. Arrays of 1, 4 and 57 tidal turbines, each of 1.5 MW capacity, were simulated. Effects due to a single turbine and an array of four turbines were negligible. The main effect of the array of 57 turbines was to cause a shift in position of the jet through the tidal channel, as the flow was diverted around the tidal array. The net effect of this shift was to increase near-bed velocities and bed shear stress along the northern perimeter of the array by up to 0.8 m·s−1 and 5 Pa respectively. Within the array and directly downstream, near-bed velocities and bed shear stress were reduced by similar amounts. Changes of this magnitude have the potential to modify the known sand and shell banks in the region. Continued monitoring of the sediment distributions in the region will provide a valuable dataset on the impacts of tidal energy extraction on local sediment dynamics. Finally, the mean power generated per turbine is shown to decrease as the turbine array increased in size.

Tidal disruption of fuzzy dark matter subhalo cores

Science.gov (United States)

Du, Xiaolong; Schwabe, Bodo; Niemeyer, Jens C.; Bürger, David

2018-03-01

We study tidal stripping of fuzzy dark matter (FDM) subhalo cores using simulations of the Schrödinger-Poisson equations and analyze the dynamics of tidal disruption, highlighting the differences with standard cold dark matter. Mass loss outside of the tidal radius forces the core to relax into a less compact configuration, lowering the tidal radius. As the characteristic radius of a solitonic core scales inversely with its mass, tidal stripping results in a runaway effect and rapid tidal disruption of the core once its central density drops below 4.5 times the average density of the host within the orbital radius. Additionally, we find that the core is deformed into a tidally locked ellipsoid with increasing eccentricities until it is completely disrupted. Using the core mass loss rate, we compute the minimum mass of cores that can survive several orbits for different FDM particle masses and compare it with observed masses of satellite galaxies in the Milky Way.

The technological construction of social power.

NARCIS (Netherlands)

Brey, Philip A.E.

2007-01-01

This essay presents a theory of the role of technology in the distribution and exercise of social power. The paper studies how technical artefacts and systems are used to construct, maintain or strengthen power relations between agents, whether individuals or groups, and how their introduction and

Study of LANs access technologies in wind power system

DEFF Research Database (Denmark)

Wei, Mu; Chen, Zhe

2010-01-01

Due to the energy challenges in the world, new types of generation technologies, such as renewable energy based generators, attract great attention and are being quickly developed, which results in the dramatic developments and changes in modern power systems, the communication technologies play...... a increasingly important role in guaranteeing the power system’s stability, reliability, and security. In this paper the necessity of communication technologies employed in wind power system are introduced. According the International Standards Organization (ISO) reference 7-layered model, the communication...... power environment are explained and discussed. Furthermore the simulation of application of Ethernet in an offshore wind farm communication network by a software, OPNET, is elaborated. With the investigation of the communication technologies in this paper, the offshore wind farm SCADA system can...

Technology on the storage of laser power

International Nuclear Information System (INIS)

Urakawa, Junji

2001-01-01

I report the technology on the storage of laser power using Fabry-Perot Optical Cavity. This technology is applicable for the generation of high brightness X-ray with the combination of compact electron linac or small storage ring in which about 100 MeV electron beam with normalized emittance of 10 -5 m is controlled. The distance of two concave mirrors with high reflectivity is controlled within sub-nm is essential to keep the resonance condition for the storage of laser power. I also report the possibility on several kind of applications and the status of this technology. (author)

Advance in technologies of electric power in 2008

International Nuclear Information System (INIS)

Hamada, Kenichi; Maekawa, Fumiaki; Nakamura, Akio

2008-01-01

Ten electric power companies and two related companies reported their advance in technologies. The technologies of nuclear power plants were stated by ten companies, which consisted of introduction of new main control board to Tomari-3 in Hokkaido Electric Power Co., Inc., reduction methods of exposure dose of Higashidori-1 in Tohoku Electric Power, hot water based two-phase flow testing device for pipe thinning test by Tokyo Electric Power Company, Guideline for prevention of piping damage caused by combustion of mixture gases in BWR (the second edition) published by Thermal and Nuclear Power Engineering Society, setting up distributor in the low-pressure turbine of Shika-2 in Hokuriku Electric Power Company, development of rapid estimation method of release radioactivity and application of high density neutron source to nuclear transmutation of nuclear fuel cycle and introduction of new core monitor system by The Kansai Electric Power Co., Inc., upgrade of investigation of the effects of hot waste water and development of detector for dropout parts of cooling system in reactor by Shikoku Electric Power Co., Inc., change of transformer in Sendai-1 by Kyushu Electric Power Co., Inc., and reactor core design for Oma ABWR by J-Power. The Japan Atomic Power Company reported four articles such as development of technologies for established nuclear power plants, promotion of Tsuruga-3 and Tsuruga-4, application of clearance system in Japan and development of future reactors. (S.Y.)

Tidal exchange between a freshwater tidal marsh and an impacted estuary: the Scheldt estuary, Belgium

NARCIS (Netherlands)

van Damme, S.; Dehairs, F.; Tackx, M.; Beauchard, O.; Struyf, E.; Gribsholt, B.; van Cleemput, O.; Meire, P.

2009-01-01

Tidal marsh exchange studies are relatively simple tools to investigate the interaction between tidal marshes and estuaries. They have mostly been confined to only a few elements and to saltwater or brackish systems. This study presents mass-balance results of an integrated one year campaign in a

Advance Power Technology Experiment for the Starshine 3 Satellite

Science.gov (United States)

Jenkins, Phillip; Scheiman, David; Wilt, David; Raffaelle, Ryne; Button, Robert; Smith, Mark; Kerslake, Thomas; Miller, Thomas; Bailey, Sheila (Technical Monitor); Hepp, A. (Technical Monitor)

2001-01-01

The Starshine 3 satellite will carry several power technology demonstrations. Since Starshine 3 is primarily a passive experiment and does not need electrical power to successfully complete its mission, the requirement for a highly reliable power system is greatly reduced. This creates an excellent opportunity to test new power technologies. Several government and commercial interests have teamed up to provide Starshine 3 with a small power system using state-of-the-art components. Starshine 3 will also fly novel integrated microelectronic power supplies (IWS) for evaluation.

Flow paths of water and sediment in a tidal marsh: relations with marsh developmental stage and tidal inundation height

NARCIS (Netherlands)

Temmerman, S.; Bouma, T.J.; Govers, G.; Lauwaet, D.

2005-01-01

This study provides new insights in the relative role of tidal creeks and the marsh edge in supplying water and sediments to and from tidal marshes for a wide range of tidal inundation cycles with different high water levels and for marsh zones of different developmental stage. Net import or export

Widespread infilling of tidal channels and navigable waterways in human-modified tidal deltaplain of southwest Bangladesh

Directory of Open Access Journals (Sweden)

Carol Wilson

2017-12-01

Full Text Available Since the 1960s, ~5000 km2 of tidal deltaplain in southwest Bangladesh has been embanked and converted to densely inhabited, agricultural islands (i.e., polders. This landscape is juxtaposed to the adjacent Sundarbans, a pristine mangrove forest, both well connected by a dense network of tidal channels that effectively convey water and sediment throughout the region. The extensive embanking in poldered areas, however, has greatly reduced the tidal prism (i.e., volume of water transported through local channels. We reveal that >600 km of these major waterways have infilled in recent decades, converting to land through enhanced sedimentation and the direct blocking of waterways by embankments and sluice gates. Nearly all of the observed closures (~98% have occurred along the embanked polder systems, with no comparable changes occurring in channels of the Sundarbans (<2% change. We attribute most of the channel infilling to the local reduction of tidal prism in poldered areas and the associated decline in current velocities. The infilled channels account for ~90 km2 of new land in the last 40–50 years, the rate of which, ~2 km2/yr, offsets the 4 km2/yr that is eroded at the coast, and is equivalent to ~20% of the new land produced naturally at the Ganges-Brahmaputra tidal rivermouth. Most of this new land, called ‘khas’ in Bengali, has been reclaimed for agriculture or aquaculture, contributing to the local economy. However, benefits are tempered by the loss of navigable waterways for commerce, transportation, and fishing, as well as the forced rerouting of tidal waters and sediments necessary to sustain this low-lying landscape against rising sea level. A more sustainable delta will require detailed knowledge of the consequences of these hydrodynamic changes to support more scientifically-grounded management of water, sediment, and tidal energy distribution.

Cogeneration (hydrogen and electrical power) using the Texaco Gasification Power Systems (TGPS) technology

International Nuclear Information System (INIS)

Gardner, J.

1994-01-01

The information herein presents preliminary technical and cost data for an actual case study using Texaco Gasification Power Systems (TGPS) technology, incorporated as part of an overall refinery upgrade project. This study is based on gasification of asphalt and vacuum residue (see Table 1, feedstock properties) to produce hydrogen plus carbon monoxide (synthesis gas) for the ultimate production of high purity hydrogen and power at a major refinery in Eastern Europe. A hydrogen production of 101,000 Nm 3 /hr (9.1 tons/hr) at 99.9 (wt.%) purity plus 50 MW (net) power slated to be used by the refinery was considered for this study. Figure I shows a block diagram depicting the general refinery configuration upgrade as envisioned by the owner operator; included in the configuration as shown in the shaded area is the TGPS plant. Figure II shows a block flow diagram depicting the TGPS unit and its battery limits as defined for this project. The technology best suited to meet the demand for clean and efficient electric power generation and hydrogen production is the Texaco Gasification Power Systems (TGPS) process. This technology is based upon Texaco's proprietary gasification technology which is well proven with over 40 years of gasification experience. There are currently 37 operating units in the world today which have licensed the Texaco gasification process technology, with another 12 in design/construction. Total synthesis gas (hydrogen + carbon monoxide) production capacity is over 2,8 billion standard cubic feet per day. The TGPS, which is basically the Integrated Gasification Combined Cycle (IGCC) based upon the Texaco gasification technology, was developed by combining and integrating gasification with power generation facilities. (author). 3 figs., 9 tabs., 4 refs

TIDAL LIMITS TO PLANETARY HABITABILITY

International Nuclear Information System (INIS)

Barnes, Rory; Jackson, Brian; Greenberg, Richard; Raymond, Sean N.

2009-01-01

The habitable zones (HZs) of main-sequence stars have traditionally been defined as the range of orbits that intercept the appropriate amount of stellar flux to permit surface water on a planet. Terrestrial exoplanets discovered to orbit M stars in these zones, which are close-in due to decreased stellar luminosity, may also undergo significant tidal heating. Tidal heating may span a wide range for terrestrial exoplanets and may significantly affect conditions near the surface. For example, if heating rates on an exoplanet are near or greater than that on Io (where tides drive volcanism that resurfaces the planet at least every 1 Myr) and produce similar surface conditions, then the development of life seems unlikely. On the other hand, if the tidal heating rate is less than the minimum to initiate plate tectonics, then CO 2 may not be recycled through subduction, leading to a runaway greenhouse that sterilizes the planet. These two cases represent potential boundaries to habitability and are presented along with the range of the traditional HZ for main-sequence, low-mass stars. We propose a revised HZ that incorporates both stellar insolation and tidal heating. We apply these criteria to GJ 581 d and find that it is in the traditional HZ, but its tidal heating alone may be insufficient for plate tectonics.

Wireless electricity (Power) transmission using solar based power satellite technology

International Nuclear Information System (INIS)

Maqsood, M; Nasir, M Nauman

2013-01-01

In the near future due to extensive use of energy, limited supply of resources and the pollution in environment from present resources e.g. (wood, coal, fossil fuel) etc, alternative sources of energy and new ways to generate energy which are efficient, cost effective and produce minimum losses are of great concern. Wireless electricity (Power) transmission (WET) has become a focal point as research point of view and nowadays lies at top 10 future hot burning technologies that are under research these days. In this paper, we present the concept of transmitting power wirelessly to reduce transmission and distribution losses. The wired distribution losses are 70 – 75% efficient. We cannot imagine the world without electric power which is efficient, cost effective and produce minimum losses is of great concern. This paper tells us the benefits of using WET technology specially by using Solar based Power satellites (SBPS) and also focuses that how we make electric system cost effective, optimized and well organized. Moreover, attempts are made to highlight future issues so as to index some emerging solutions.

Power system technologies for the manned Mars mission

International Nuclear Information System (INIS)

Bents, D.; Patterson, M.J.; Berkopec, F.; Myers, I.; Presler, A.

1986-01-01

The high impulse of electric propulsion makes it an attractive option for manned interplanetary missions such as a manned mission to Mars. This option is, however, dependent on the availability of high energy sources for propulsive power in addition to that required for the manned interplanetary transit vehicle. Two power system technologies are presented: nuclear and solar. The ion thruster technology for the interplanetary transit vehicle is described for a typical mission. The power management and distribution system components required for such a mission must be further developed beyond today's technology status. High voltage-high current technology advancements must be achieved. These advancements are described. In addition, large amounts of waste heat must be rejected to the space environment by the thermal management system. Advanced concepts such as the liquid droplet radiator are discussed as possible candidates for the manned Mars mission. These thermal management technologies have great potential for significant weight reductions over the more conventional systems

The Pastoral Power of Technology. Rethinking Alienation in Digital Culture

Directory of Open Access Journals (Sweden)

Katarina Giritli Nygren

2012-05-01

Full Text Available The purpose of this paper is to bring Foucault’s elaboration on ‘the pastoral modalities of power’ into play in order to rethink alienation in digital culture. Pastoral power is not displacing other conceptions of power, but provides another level of analysis involved in the forging of reasonable responsible subjects willing and able to sustain other conceptions of power. We will draw particularly on the early writings of Marx and the more recent poststructuralist developments concerning hegemony and superstructure in relation to technology. Technology as such is analysed in terms of repercussions of ‘design of the machine’ in industrial technological contexts and ‘design of digital culture’ in digital technological contexts. Pastoral power not only directs our focus to the making of technologies, but also to the making of individuals capable of taking on the responsibilities of technologies. This means that it is necessary to take on the notion of effective power of ideologies and their material reality.

Electrical power technology for robotic planetary rovers

Science.gov (United States)

Bankston, C. P.; Shirbacheh, M.; Bents, D. J.; Bozek, J. M.

1993-01-01

Power technologies which will enable a range of robotic rover vehicle missions by the end of the 1990s and beyond are discussed. The electrical power system is the most critical system for reliability and life, since all other on board functions (mobility, navigation, command and data, communications, and the scientific payload instruments) require electrical power. The following are discussed: power generation, energy storage, power management and distribution, and thermal management.

Sedimentary structures of tidal flats

Indian Academy of Sciences (India)

Sedimentary structures of some coastal tropical tidal flats of the east coast of India, and inner estuarine tidal point bars located at 30 to 50 kilometers inland from the coast, have been extensively studied under varying seasonal conditions. The results reveal that physical features such as flaser bedding, herringbone ...

Analysis of Tidal Data for Dagang Tidal Gauge and Study of the Changes for the National Height Datum

Directory of Open Access Journals (Sweden)

WU Fumei

2015-07-01

Full Text Available The main tides affecting Dagang sea level are analyzed and the national height datum is studied by analyzing 1980—2011 hourly tidal data and 1952—2007 monthly mean tidal data. Firstly, the frequencies and amplitudes of main tides including 180 short-period tides and 6 long-period tides are gained by the Fouirer transform. Then the actual amplitudes and their variations of main tides are obtained by the harmonic analysis of the 1980—2011 hourly tidal data, and the changes with about 19 year period can easily be found in the amplitudes of Q1、O1、M2、K1、K2. And then the changes of the mean sea level at Dagang tidal gauge defining national height datum during the period of 1952—2011 are studied by the harmonic analysis and the shifting average of 18.61 year tidal heights. The results of these methods show that the mean sea level at Dagang tidal gauge descended with the speed of 1.07 mm/a and 0.76 mm/a respectively during 1952—1980, and that it ascended with the speed of 1.59 mm/a and 1.62 mm/a respectively during 1980—2011. And finally the difference of 0.14 cm is achieved by the shifting average of 18.61 year tidal heights for 1985 National Height Datum.

From Globular Clusters to Tidal Dwarfs: Structure Formation in the Tidal Tails of Merging Galaxies

Science.gov (United States)

Knierman, Karen A.; Gallagher, Sarah C.; Charlton, Jane C.; Hunsberger, Sally D.; Whitmore, Bradley; Kundu, Arunav; Hibbard, J. E.; Zaritsky, Dennis

2003-09-01

Using V and I images obtained with the Wide Field Planetary Camera 2 (WFPC2) of the Hubble Space Telescope, we investigate compact stellar structures within tidal tails. Six regions of tidal debris in the four classic ``Toomre sequence'' mergers: NGC 4038/39 (``Antennae''), NGC 3256, NGC 3921, and NGC 7252 (``Atoms for Peace'') have been studied in order to explore how the star formation depends on the local and global physical conditions. These mergers sample a range of stages in the evolutionary sequence and tails with and without embedded tidal dwarf galaxies. The six tails are found to contain a variety of stellar structures, with sizes ranging from those of globular clusters up to those of dwarf galaxies. From V and I WFPC2 images, we measure the luminosities and colors of the star clusters. NGC 3256 is found to have a large population of blue clusters (0.2<~V-I<~0.9), particularly in its western tail, similar to those found in the inner region of the merger. In contrast, NGC 4038/39 has no clusters in the observed region of the tail, only less luminous point sources likely to be individual stars. NGC 3921 and NGC 7252 have small populations of clusters along their tails. A significant cluster population is clearly associated with the prominent tidal dwarf candidates in the eastern and western tails of NGC 7252. The cluster-rich western tail of NGC 3256 is not distinguished from the others by its dynamical age or by its total H I mass. However, the mergers that have few clusters in the tail all have tidal dwarf galaxies, while NGC 3256 does not have prominent tidal dwarfs. We speculate that star formation in tidal tails may manifest itself either in small structures like clusters along the tail or in large structures such as dwarf galaxies, but not in both. Also, NGC 3256 has the highest star formation rate of the four mergers studied, which may contribute to the high number of star clusters in its tidal tails. Based in part on observations obtained with the

Fuel cycle comparison of distributed power generation technologies

International Nuclear Information System (INIS)

Elgowainy, A.; Wang, M.Q.

2008-01-01

The fuel-cycle energy use and greenhouse gas (GHG) emissions associated with the application of fuel cells to distributed power generation were evaluated and compared with the combustion technologies of microturbines and internal combustion engines, as well as the various technologies associated with grid-electricity generation in the United States and California. The results were primarily impacted by the net electrical efficiency of the power generation technologies and the type of employed fuels. The energy use and GHG emissions associated with the electric power generation represented the majority of the total energy use of the fuel cycle and emissions for all generation pathways. Fuel cell technologies exhibited lower GHG emissions than those associated with the U.S. grid electricity and other combustion technologies. The higher-efficiency fuel cells, such as the solid oxide fuel cell (SOFC) and molten carbonate fuel cell (MCFC), exhibited lower energy requirements than those for combustion generators. The dependence of all natural-gas-based technologies on petroleum oil was lower than that of internal combustion engines using petroleum fuels. Most fuel cell technologies approaching or exceeding the DOE target efficiency of 40% offered significant reduction in energy use and GHG emissions

Preliminary nuclear power reactor technology qualitative assessment for Malaysia

International Nuclear Information System (INIS)

Shamsul Amri Sulaiman

2011-01-01

Since the worlds first nuclear reactor major breakthrough in December 02, 1942, the nuclear power industry has undergone tremendous development and evolution for more than half a century. After surpassing moratorium of nuclear power plant construction caused by catastrophic accidents at Three-mile island (1979) and Chernobyl (1986), today, nuclear energy is back on the policy agendas of many countries, both developed and developing, signaling nuclear revival or nuclear renaissance. Selection of suitable nuclear power technology has thus been subjected to primary attention. This short paper attempts to draw preliminary technology assessment for the first nuclear power reactor technology for Malaysia. Methodology employed is qualitative analysis collating recent finding of tnb-kepco preliminary feasibility study for nuclear power program in peninsular malaysia and other published presentations and/or papers by multiple experts. The results suggested that pressurized water reactor (PWR) is the prevailing technology in terms of numbers and plant performances, and while the commercialization of generation IV reactors is remote (e.g. Not until 2030), generation III/ III+ NPP models are commercially available on the market today. Five (5) major steps involved in reactor technology selection were introduced with a focus on introducing important aspects of selection criteria. Three (3) categories for the of reactor technology selection were used for the cursory evaluation. The outcome of these analyses shall lead to deeper and full analyses of the recommended reactor technologies for a comprehensive feasibility study in the near future. Recommendations for reactor technology option were also provided for both strategic and technical recommendations. The paper shall also implore the best way to select systematically the first civilian nuclear power reactor. (Author)

Challenges in the modeling of tidal disruption events lightcurves

Directory of Open Access Journals (Sweden)

Lodato G.

2012-12-01

Full Text Available In this contribution, I review the recent developments on the modeling of the lightcurve of tidal disruption events. Our understanding has evolved significantly from the earlier seminal results that imply a simple power-law decay of the bolometric light curve as t−5/3. We now know that the details of the rise to the peak of the lightcurve is determined mainly by the internal structure of the disrupted star. We also have improved models for the disc thermal emission, showing that in this case the decline of the luminosity with time should be much flatter than the standard t−5/3 law, especially in optical and UV wavelengths, while the X-ray lightcurve is generally best suited to track the bolometric one. Finally, we are just starting to explore the interesting general relativistic effects that might arise for such events, for which the tidal radius lies very close to the black hole event horizon.

Downstream hydraulic geometry of a tidally influenced river delta

NARCIS (Netherlands)

Sassi, M.G.; Hoitink, A.J.F.; Brye, de B.; Deleersnijder, E.

2012-01-01

Channel geometry in tidally influenced river deltas can show a mixed scaling behavior between that of river and tidal channel networks, as the channel forming discharge is both of river and tidal origin. We present a method of analysis to quantify the tidal signature on delta morphology, by

Conditions for tidal bore formation in convergent alluvial estuaries

Science.gov (United States)

Bonneton, Philippe; Filippini, Andrea Gilberto; Arpaia, Luca; Bonneton, Natalie; Ricchiuto, Mario

2016-04-01

Over the last decade there has been an increasing interest in tidal bore dynamics. However most studies have been focused on small-scale bore processes. The present paper describes the first quantitative study, at the estuary scale, of the conditions for tidal bore formation in convergent alluvial estuaries. When freshwater discharge and large-scale spatial variations of the estuary water depth can be neglected, tide propagation in such estuaries is controlled by three main dimensionless parameters: the nonlinearity parameter ε0 , the convergence ratio δ0 and the friction parameter ϕ0. In this paper we explore this dimensionless parameter space, in terms of tidal bore occurrence, from a database of 21 estuaries (8 tidal-bore estuaries and 13 non tidal-bore estuaries). The field data point out that tidal bores occur for convergence ratios close to the critical convergence δc. A new proposed definition of the friction parameter highlights a clear separation on the parameter plane (ϕ0,ε0) between tidal-bore estuaries and non tidal-bore estuaries. More specifically, we have established that tidal bores occur in convergent estuaries when the nonlinearity parameter is greater than a critical value, εc , which is an increasing function of the friction parameter ϕ0. This result has been confirmed by numerical simulations of the two-dimensional Saint Venant equations. The real-estuary observations and the numerical simulations also show that, contrary to what is generally assumed, tide amplification is not a necessary condition for tidal bore formation. The effect of freshwater discharge on tidal bore occurrence has been analyzed from the database acquired during three long-term campaigns carried out on the Gironde/Garonne estuary. We have shown that in the upper estuary the tidal bore intensity is mainly governed by the local dimensionless tide amplitude ε. The bore intensity is an increasing function of ε and this relationship does not depend on freshwater

Tidal energy site - Tidal energy site mammal/bird survey

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — A vessel-based line visual transect survey was conducted for birds and marine mammals near the proposed Snohomish County PUD Admiralty Inlet tidal energy site...

Tidal and sub-tidal sea level variability at the northern shelf of the Brazilian Northeast Region.

Science.gov (United States)

Frota, Felipe F; Truccolo, Eliane C; Schettini, Carlos A F

2016-09-01

A characterization of the sea level variability at tidal and sub-tidal frequencies at the northern shore of the Brazilian Northeast shelf for the period 2009-2011 is presented. The sea level data used was obtained from the Permanent Geodetic Tide Network from the Brazilian Institute of Geography and Statistics for the Fortaleza gauge station. Local wind data was also used to assess its effects on the low-frequency sea level variability. The variability of the sea level was investigated by classical harmonic analysis and by morphology assessment over the tidal signal. The low frequencies were obtained by low-pass filtering. The tidal range oscillated with the highest value of 3.3 m during the equinox and the lowest value of 0.7 m during the solstice. Differences between the spring and neap tides were as high as 1 m. A total of 59 tidal constituents were obtained from harmonic analysis, and the regional tide was classified as semi-diurnal pure with a form number of 0.11. An assessment of the monthly variability of the main tidal constituents (M2, S2, N2, O1, and K1) indicated that the main semi-diurnal solar S2 presented the highest variability, ranging from 0.21 to 0.41 m; it was the main element altering the form number through the years. The low frequency sea-level variability is negligible, although there is a persistent signal with an energy peak in the 10-15 day period, and it cannot be explained by the effects of local winds.

Progress and plans for the EnCurrent power generation system

Energy Technology Data Exchange (ETDEWEB)

Bear, C. [New Energy Corp. Inc., Calgary, AB (Canada)

2008-07-01

This presentation discussed a new vertical axis hydro turbine designed by New Energy Corporation. The EnCurrent turbine design was based on the Darrieus wind turbine, and suited for use in rivers, irrigation canals, industrial outflows, and tidal current applications. The turbine has a flexible deployment configuration with a variable aspect ratio. Designs for the turbine were initiated in fresh water applications, and the size of the equipment was increased to include tidal applications and large river arrays after the technology was proven. A study has demonstrated that use of the turbines in Canada's canal systems would result in significant annual power generation revenues. The use of smaller turbine systems can provide indirect sales to owners through local resellers, while larger systems can provide power or additional revenues for utilities, large cooperatives, and project developers. Case studies of small turbine installations were provided, as well as case studies of turbines used by larger commercial plants. The presentation also discussed several large projects recently undertaken by the company, including the $6.5 million Canoe pass installation. tabs., figs.

Industrial Arts Test Development, Book III. Resource Items for Graphics Technology, Power Technology, Production Technology.

Science.gov (United States)

New York State Education Dept., Albany.

This booklet is designed to assist teachers in developing examinations for classroom use. It is a collection of 955 objective test questions, mostly multiple choice, for industrial arts students in the three areas of graphics technology, power technology, and production technology. Scoring keys are provided. There are no copyright restrictions,…

VISCOELASTIC MODELS OF TIDALLY HEATED EXOMOONS

International Nuclear Information System (INIS)

Dobos, Vera; Turner, Edwin L.

2015-01-01

Tidal heating of exomoons may play a key role in their habitability, since the elevated temperature can melt the ice on the body even without significant solar radiation. The possibility of life has been intensely studied on solar system moons such as Europa or Enceladus where the surface ice layer covers a tidally heated water ocean. Tidal forces may be even stronger in extrasolar systems, depending on the properties of the moon and its orbit. To study the tidally heated surface temperature of exomoons, we used a viscoelastic model for the first time. This model is more realistic than the widely used, so-called fixed Q models because it takes into account the temperature dependence of the tidal heat flux and the melting of the inner material. Using this model, we introduced the circumplanetary Tidal Temperate Zone (TTZ), which strongly depends on the orbital period of the moon and less on its radius. We compared the results with the fixed Q model and investigated the statistical volume of the TTZ using both models. We have found that the viscoelastic model predicts 2.8 times more exomoons in the TTZ with orbital periods between 0.1 and 3.5 days than the fixed Q model for plausible distributions of physical and orbital parameters. The viscoelastic model provides more promising results in terms of habitability because the inner melting of the body moderates the surface temperature, acting like a thermostat

VISCOELASTIC MODELS OF TIDALLY HEATED EXOMOONS

Energy Technology Data Exchange (ETDEWEB)

Dobos, Vera [Konkoly Thege Miklos Astronomical Institute, Research Centre of Astronomy and Earth Sciences, Hungarian Academy of Sciences, H-1121 Konkoly Thege Miklós út 15-17, Budapest (Hungary); Turner, Edwin L., E-mail: dobos@konkoly.hu [Department of Astrophysical Sciences, Princeton University, 08544, 4 Ivy Lane, Peyton Hall, Princeton, NJ (United States)

2015-05-01

Tidal heating of exomoons may play a key role in their habitability, since the elevated temperature can melt the ice on the body even without significant solar radiation. The possibility of life has been intensely studied on solar system moons such as Europa or Enceladus where the surface ice layer covers a tidally heated water ocean. Tidal forces may be even stronger in extrasolar systems, depending on the properties of the moon and its orbit. To study the tidally heated surface temperature of exomoons, we used a viscoelastic model for the first time. This model is more realistic than the widely used, so-called fixed Q models because it takes into account the temperature dependence of the tidal heat flux and the melting of the inner material. Using this model, we introduced the circumplanetary Tidal Temperate Zone (TTZ), which strongly depends on the orbital period of the moon and less on its radius. We compared the results with the fixed Q model and investigated the statistical volume of the TTZ using both models. We have found that the viscoelastic model predicts 2.8 times more exomoons in the TTZ with orbital periods between 0.1 and 3.5 days than the fixed Q model for plausible distributions of physical and orbital parameters. The viscoelastic model provides more promising results in terms of habitability because the inner melting of the body moderates the surface temperature, acting like a thermostat.

Maturing Technologies for Stirling Space Power Generation

Science.gov (United States)

Wilson, Scott D.; Nowlin, Brentley C.; Dobbs, Michael W.; Schmitz, Paul C.; Huth, James

2016-01-01

Stirling Radioisotope Power Systems (RPS) are being developed as an option to provide power on future space science missions where robotic spacecraft will orbit, flyby, land or rove. A Stirling Radioisotope Generator (SRG) could offer space missions a more efficient power system that uses one fourth of the nuclear fuel and decreases the thermal footprint of the current state of the art. The RPS Program Office, working in collaboration with the U.S. Department of Energy (DOE), manages projects to develop thermoelectric and dynamic power systems, including Stirling Radioisotope Generators (SRGs). The Stirling Cycle Technology Development (SCTD) Project, located at Glenn Research Center (GRC), is developing Stirling-based subsystems, including convertors and controllers. The SCTD Project also performs research that focuses on a wide variety of objectives, including increasing convertor temperature capability to enable new environments, improving system reliability or fault tolerance, reducing mass or size, and developing advanced concepts that are mission enabling. Research activity includes maturing subsystems, assemblies, and components to prepare them for infusion into future convertor and generator designs. The status of several technology development efforts are described here. As part of the maturation process, technologies are assessed for readiness in higher-level subsystems. To assess the readiness level of the Dual Convertor Controller (DCC), a Technology Readiness Assessment (TRA) was performed and the process and results are shown. Stirling technology research is being performed by the SCTD Project for NASA's RPS Program Office, where tasks focus on maturation of Stirling-based systems and subsystems for future space science missions.

CO{sub 2} control technologies: ALSTOM Power approach

Energy Technology Data Exchange (ETDEWEB)

Stamatelopoulos, G.N.; Marion, J.L.; Nsakala, N.; Griffin, T.; Bill, A. [ALSTOM Power Boiler GmbH, Stuttgart (Germany)

2002-07-01

ALSTOM Power is one of the largest providers of power generation equipment, turnkey power plants and services in the world. The Company is aware of the present scientific concerns regarding greenhouse gas emissions and the role of fossil fuels used in power generation. ALSTOM Power R&D laboratories run various programs aiming to find options that reduce greenhouse gas emissions through: Increasing the efficiency of power generation equipment by implementing the most modern technologies. Application of technologies to remove and sequester carbon dioxide created in power plants in an environmentally and economically favorable manner. In this paper an overview of ALSTOM's on-going CO{sub 2} mitigation development activities will be presented. First, energy efficiency improvements for both new and existing fossil fuel power plants are reviewed for both coal and natural gas fuels. Second, the development of novel power generation processes, including those involving combustion in O{sub 2}/CO{sub 2} atmospheres using pure or enriched oxygen for the purpose of CO{sub 2} capture is discussed. And finally, novel chemical-looping CO{sub 2} capture process technologies are introduced. The major challenge in CO{sub 2} capture techniques is the efficient separation and capture of CO{sub 2}. Conclusions are drawn herein regarding the technical feasibility, the resultant efficiency penalties, and the CO{sub 2} mitigation costs for the various options under study and development within ALSTOM Power. 7 refs., 8 figs.

Competitiveness through cooperation between electricity and information technology. TESLA - Information technology and electric power systems technology programme 1998-2002

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-11-01

The electricity markets are being opened up to competition all round the world. To succeed in competition electricity sellers want new information technology tools to use in managing the sale of electricity. The network companies are aiming to step up utilization of their distribution capacity and to optimize power quality and the reliability of supply. Consumers need solutions with which they can manage their own power consumption and tendering sellers. The Nordic countries have been the first to deregulate their electricity markets. This head start in time is being made use of to generate a head start in technology. Tekes has initiated a technology programme for the years 1998 to 2002, named TESLA - Information Technology and Electric Power Systems, to promote the competitiveness of the Finnish electricity industry in changing conditions. The objective of the programme is to adapt information technology extensively to power distribution and thus develop the potential for Finland`s electricity industry to succeed on world markets. At the moment power distribution technology forms about one third of Finland`s energy technology exports. The programme is also aimed at developing new data transfer and data processing applications for companies in information technology clusters. For Finnish parties in the electricity markets the programme will produce ways and means of (1) improving management and use of distribution networks, (2) implementing competition in electricity sales, and (3) increasing the efficiency of electricity use

Concentrating Solar Power. Technology Roadmap

Energy Technology Data Exchange (ETDEWEB)

NONE

2010-10-15

Concentrating solar power can contribute significantly to the world's energy supply. As shown in this roadmap, this decade is a critical window of opportunity during which CSP could become a competitive source of electrical power to meet peak and intermediate loads in the sunniest parts of the world. This roadmap identifies technology, economy and policy goals and milestones needed to support the development and deployment of CSP, as well as ongoing advanced research in CSF. It also sets out the need for governments to implement strong, balanced policies that favour rapid technological progress, cost reductions and expanded industrial manufacturing of CSP equipment to enable mass deployment. Importantly, this roadmap also establishes a foundation for greater international collaboration. The overall aim of this roadmap is to identify actions required - on the part of all stakeholders - to accelerate CSP deployment globally. Many countries, particularly in emerging regions, are only just beginning to develop CSP. Accordingly, milestone dates should be considered as indicative of urgency, rather than as absolutes. This roadmap is a work in progress. As global CSP efforts advance and an increasing number of CSP applications are developed, new data will provide the basis for updated analysis. The IEA will continue to track the evolution of CSP technology and its impacts on markets, the power sector and regulatory environments, and will update its analysis and set additional tasks and milestones as new learning comes to light.

Advance of technological innovations of electric power in 2012

International Nuclear Information System (INIS)

Mayumi, Akihiko; Tanaka, Masanori; Takebe, Toshiro

2013-01-01

Twelve companies in Japan reported on the technological innovations in 2012. The Japan Atomic Power Company mainly studied five projects; (1) control of wall thinning of the secondary system in PWR by injection of molybdic acid, (2) application of pipe test method using electromagnetic acoustic resonance to existing equipment, (3) developed high performance Co-60 crud removal resin for Tsuruga Power Station Unit 2, (4) improvement of technology for safety of core in FBR, and (5) improvement of technology for coolant of FBR by dispersing nano-particles in liquid sodium metal. Tokyo Electric Power Company developed mainly three projects; (1) the support for the mental health care activities by industry protection staff at the Fukushima Daiichi and Daini Nuclear Power Plant, (2) laboratory test method using non-radioactive cesium for performance of decontamination reagent, and (3) decontamination effects estimation code (DeConEP). Hokuriku Electric Power Company reported the operations management measures in accordance with the safety enhancement measures to Shika nuclear power station. Other nine reports are published by Hokkaido Electric Power Co., Inc. Tohoku Electric Power Co., Inc. Chubu Electric Power Co., Inc., The Kansai Electric Power Co., Inc., The Chugoku Electric Power Co., Inc., Shikoku Electric Power Co., Inc., Kyushu Electric Power Co., Inc., Okinawa Electric Power Company Inc. and J-Power. (S.Y.)

Tidal interactions with Kerr black holes

International Nuclear Information System (INIS)

Hiscock, W.A.

1977-01-01

The tidal deformation of an extended test body falling with zero angular momentum into a Kerr black hole is calculated. Numerical results for infall along the symmetry axis and in the equatorial plane of the black hole are presented for a range of values of a, the specific angular momentum of the black hole. Estimates of the tidal contribution to the gravitational radiation are also given. The tidal contribution in equatorial infall into a maximally rotating Kerr black hole may be of the same order as the center-of-mass contribution to the gravitational radiation

The technology transfer and the Laguna Verde power plants

International Nuclear Information System (INIS)

Garza, R.F. de La

1991-01-01

The process of technology transfer to the construction of Laguna Verde Nuclear Power Plants, Mexico, is described. The options and the efforts for absorbing the technology of Nuclear Power Plant design and construction by the mexican engineers are emphasized. (author)

Free-piston Stirling technology for space power

International Nuclear Information System (INIS)

Slaby, J.G.

1994-01-01

An overview is presented of the NASA Lewis Research Center free-piston Stirling engine activities directed toward space power. This work is being carried out under NASA's new Civil Space Technology Initiative (CSTI). The overall goal of CSTI's High Capacity Power element is to develop the technology base needed to meet the long duration, high capacity power requirements for future NASA space missions. The Stirling cycle offers an attractive power conversion concept for space power needs. Discussed in this paper is the completion of the Space Power Demonstrator Engine (SPDE) testing - culminating in the generation of 25 kW of engine power from a dynamically-balanced opposed-piston Stirling engine at a temperature ratio of 2.0. Engine efficiency was approximately 22 percent. The SPDE recently has been divided into two separate single-cylinder engines, called Space Power Research Engines (SPRE), that now serve as test beds for the evaluation of key technology disciplines. These disciplines include hydrodynamic gas bearings, high-efficiency linear alternators, space qualified heat pipe heat exchangers, oscillating flow code validation, and engine loss understanding. The success of the SPDE at 650 K has resulted in a more ambitious Stirling endeavor - the design, fabrication, test and evaluation of a designed-for-space 25 kW per cylinder Stirling Space Engine (SSE). The SSE will operate at a hot metal temperature of 1050 K using superalloy materials. This design is a low temperature confirmation of the 1300 K design. It is the 1300 K free-piston Stirling power conversion system that is the ultimate goal; to be used in conjunction with the SP-100 reactor. The approach to this goal is in three temperature steps. However, this paper concentrates on the first two phases of this program - the 650 K SPDE and the 1050 K SSE

Information Technology for Nuclear Power Plant Configuration Management

International Nuclear Information System (INIS)

2010-07-01

Configuration management (CM) is an essential component of nuclear power plant design, construction and operation. The application of information technology (IT) offers a method to automate and ensure the timely and effective capture, processing and distribution of key nuclear power plant information to support CM principles and practical processes and procedures for implementation of CM at nuclear power plants. This publication reviews some of the principles established in IAEA-TECDOC-1335, 'Configuration Management in Nuclear Power Plants.' It also recaps tenets laid out in IAEA- TECDOC-1284, 'Information Technology Impact on Nuclear Power Plant Documentation' that supports CM programmes. This publication has been developed in conjunction with and designed to support these other two publications. These three publications combined provide a comprehensive discussion on configuration management, information technology and the relationship between them. An extensive discussion is also provided in this publication on the role of the design basis of the facility and its control through the CM process throughout the facility's lifetime. While this report was developed specifically for nuclear power plants, the principles discussed can be usefully applied to any high hazard nuclear facility

Archimedes in Cephalonia and in Euripus Strait: Modern Horizontal Archimedean Screw Turbines for Recovering Marine Power

Directory of Open Access Journals (Sweden)

A. Stergiopoulou

2013-01-01

Full Text Available The possibility of exploiting sea and tidal currents for power generation has given little attention in Mediterranean countries despite the fact that these currents representing a large renewable energy resource could be exploited by “modern old technologies” to provide important levels of electric power. It is also well known that one of the oldest machines still in use is the Archimedes screw, a device for lifting water for irrigation and drainage, invention credited to Archimedes. The main aim of this paper is to present a new small hydro philosophy of recovering the unexploited coastal and tidal hydraulic potential by following an efficient “Archimedean philosophy” and by using modern horizontal-axis unconventional cochlear turbines. Our work proposes “the presence of Archimedes in Cephalonia and in Euripus Strait” and the optimal “Archimedean” exploitation of the Euripus tidal current and of the Cephalonia coastal paradox cross flowing continuously from Livadi Gulf to the Gulf of Sami. The present paper intends to prove the useful modern rediscovering of some old Archimedean ideas concerning spiral water wheel technologies under the form of new and efficient horizontal-axis Archimedean hydropower turbines.

Relevance of tidal heating on large TNOs

Science.gov (United States)

Saxena, Prabal; Renaud, Joe P.; Henning, Wade G.; Jutzi, Martin; Hurford, Terry

2018-03-01

We examine the relevance of tidal heating for large Trans-Neptunian Objects, with a focus on its potential to melt and maintain layers of subsurface liquid water. Depending on their past orbital evolution, tidal heating may be an important part of the heat budget for a number of discovered and hypothetical TNO systems and may enable formation of, and increased access to, subsurface liquid water. Tidal heating induced by the process of despinning is found to be particularly able to compete with heating due to radionuclide decay in a number of different scenarios. In cases where radiogenic heating alone may establish subsurface conditions for liquid water, we focus on the extent by which tidal activity lifts the depth of such conditions closer to the surface. While it is common for strong tidal heating and long lived tides to be mutually exclusive, we find this is not always the case, and highlight when these two traits occur together. We find cases where TNO systems experience tidal heating that is a significant proportion of, or greater than radiogenic heating for periods ranging from100‧s of millions to a billion years. For subsurface oceans that contain a small antifreeze component, tidal heating due to very high initial spin states may enable liquid water to be preserved right up to the present day. Of particular interest is the Eris-Dysnomia system, which in those cases may exhibit extant cryovolcanism.

No Snowball on Habitable Tidally Locked Planets

Science.gov (United States)

Checlair, Jade; Menou, Kristen; Abbot, Dorian S.

2017-08-01

The TRAPPIST-1, Proxima Centauri, and LHS 1140 systems are the most exciting prospects for future follow-up observations of potentially inhabited planets. All of the planets orbit nearby M-stars and are likely tidally locked in 1:1 spin–orbit states, which motivates the consideration of the effects that tidal locking might have on planetary habitability. On Earth, periods of global glaciation (snowballs) may have been essential for habitability and remote signs of life (biosignatures) because they are correlated with increases in the complexity of life and in the atmospheric oxygen concentration. In this paper, we investigate the snowball bifurcation (sudden onset of global glaciation) on tidally locked planets using both an energy balance model and an intermediate-complexity global climate model. We show that tidally locked planets are unlikely to exhibit a snowball bifurcation as a direct result of the spatial pattern of insolation they receive. Instead, they will smoothly transition from partial to complete ice coverage and back. A major implication of this work is that tidally locked planets with an active carbon cycle should not be found in a snowball state. Moreover, this work implies that tidally locked planets near the outer edge of the habitable zone with low CO2 outgassing fluxes will equilibrate with a small unglaciated substellar region rather than cycling between warm and snowball states. More work is needed to determine how the lack of a snowball bifurcation might affect the development of life on a tidally locked planet.

No Snowball on Habitable Tidally Locked Planets

International Nuclear Information System (INIS)

Checlair, Jade; Abbot, Dorian S.; Menou, Kristen

2017-01-01

The TRAPPIST-1, Proxima Centauri, and LHS 1140 systems are the most exciting prospects for future follow-up observations of potentially inhabited planets. All of the planets orbit nearby M-stars and are likely tidally locked in 1:1 spin–orbit states, which motivates the consideration of the effects that tidal locking might have on planetary habitability. On Earth, periods of global glaciation (snowballs) may have been essential for habitability and remote signs of life (biosignatures) because they are correlated with increases in the complexity of life and in the atmospheric oxygen concentration. In this paper, we investigate the snowball bifurcation (sudden onset of global glaciation) on tidally locked planets using both an energy balance model and an intermediate-complexity global climate model. We show that tidally locked planets are unlikely to exhibit a snowball bifurcation as a direct result of the spatial pattern of insolation they receive. Instead, they will smoothly transition from partial to complete ice coverage and back. A major implication of this work is that tidally locked planets with an active carbon cycle should not be found in a snowball state. Moreover, this work implies that tidally locked planets near the outer edge of the habitable zone with low CO 2 outgassing fluxes will equilibrate with a small unglaciated substellar region rather than cycling between warm and snowball states. More work is needed to determine how the lack of a snowball bifurcation might affect the development of life on a tidally locked planet.

Tidal mixing in Dahej creek waters

Digital Repository Service at National Institute of Oceanography (India)

Swamy, G.N.; Sarma, R.V.

Mixing characteristics of a tidal inlet near Dahej at the mouth of Narmada River, Gujarat, India are examined in terms of tides, currents and bathymetry. The dilution potential of the Dahej Creek waters during a tidal march for a given rate...

Microturbine Power Conversion Technology Review

Energy Technology Data Exchange (ETDEWEB)

Staunton, R.H.

2003-07-21

In this study, the Oak Ridge National Laboratory (ORNL) is performing a technology review to assess the market for commercially available power electronic converters that can be used to connect microturbines to either the electric grid or local loads. The intent of the review is to facilitate an assessment of the present status of marketed power conversion technology to determine how versatile the designs are for potentially providing different services to the grid based on changes in market direction, new industry standards, and the critical needs of the local service provider. The project includes data gathering efforts and documentation of the state-of-the-art design approaches that are being used by microturbine manufacturers in their power conversion electronics development and refinement. This project task entails a review of power converters used in microturbines sized between 20 kW and 1 MW. The power converters permit microturbine generators, with their non-synchronous, high frequency output, to interface with the grid or local loads. The power converters produce 50- to 60-Hz power that can be used for local loads or, using interface electronics, synchronized for connection to the local feeder and/or microgrid. The power electronics enable operation in a stand-alone mode as a voltage source or in grid-connect mode as a current source. Some microturbines are designed to automatically switch between the two modes. The information obtained in this data gathering effort will provide a basis for determining how close the microturbine industry is to providing services such as voltage regulation, combined control of both voltage and current, fast/seamless mode transfers, enhanced reliability, reduced cost converters, reactive power supply, power quality, and other ancillary services. Some power quality improvements will require the addition of storage devices; therefore, the task should also determine what must be done to enable the power conversion circuits to

A 100 kW-Class Technology Demonstrator for Space Solar Power

Science.gov (United States)

Howell, J.; Carrington, C.; Day, G.

2004-12-01

A first step in the development of solar power from space is the flight demonstration of critical technologies. These fundamental technologies include efficient solar power collection and generation, power management and distribution, and thermal management. In addition, the integration and utilization of these technologies into a viable satellite bus could provide an energy-rich platform for a portfolio of payload experiments such as wireless power transmission (WPT). This paper presents the preliminary design of a concept for a 100 kW-class free-flying platform suitable for flight demonstration of Space Solar Power (SSP) technology experiments.

New technologies deployment for advanced power plants

International Nuclear Information System (INIS)

Kiyoshi, Yamauchi

2007-01-01

Mitsubishi Heavy Industries, Ltd. (MHI) has been the total engineering and manufacturing company of pressurized water reactors (PWRs) in Japan since the commencement of commercial operations of Mihama Unit 1 of the Kansai Electric Power Company in 1970. Over these decades, MHI has endeavored to develop a broad spread of nuclear technology, from design, manufacturing, and construction, to plant maintenance services. More recently, with the ever rising need for nuclear power generation around the world to prevent global warming and to cope with surging oil prices, MHI is striving to expand its nuclear power business in the world market, such as US-APWR (Advanced Pressurized Water Reactor) in the U.S., as well as to develop technology for advanced reactors and nuclear fuel cycles to ensure energy security in the future. This paper introduces these approaches, especially focused on new technologies deployment for the global needs, and clarifies the current status and future prospects of MHI as the world's leading nuclear company. (author)

An assessment of fish mortality at the Rance tidal power barrage, Brittany, France

International Nuclear Information System (INIS)

Lockwood, S.J.; Baynes, S.M.

1992-01-01

This report describes the results of three weeks field work carried out on the Rance Estuary in August 1991. The objectives were to make a preliminary assessment of the relative frequency with which dead fish accumulate in the Rance barrage lock pit; to assess the likely cause of mortality; and to assess the success with which marine fish migrate across a tidal barrage by tagging a variety of species within the barrage basin. (author)

A 100 kW-Class Technology Demonstrator for Space Solar Power

Science.gov (United States)

Carrington, Connie; Howell, Joe; Day, Greg

2004-01-01

A first step in the development of solar power from space is the flight demonstration of critical technologies. These fundamental technologies include efficient solar power collection and generation, power management and distribution, and thermal management. In addition, the integration and utilization of these technologies into a viable satellite bus could provide an energy-rich platform for a portfolio of payload experiments such as wireless power transmission (WPT). This paper presents the preliminary design of a concept for a 100 kW-class fiee-flying platform suitable for flight demonstration of technology experiments. Recent space solar power (SSP) studies by NASA have taken a stepping stones approach that lead to the gigawatt systems necessary to cost-effectively deliver power from space. These steps start with a 100 kW-class satellite, leading to a 500 kW and then a 1 MW-class platform. Later steps develop a 100 M W bus that could eventually lead to a 1-2 GW pilot plant for SSP. Our studies have shown that a modular approach is cost effective. Modular designs include individual laser-power-beaming satellites that fly in constellations or that are autonomously assembled into larger structures at geosynchronous orbit (GEO). Microwave power-beamed approaches are also modularized into large numbers of identical units of solar arrays, power converters, or supporting structures for arrays and microwave transmitting antennas. A cost-effective approach to launching these modular units is to use existing Earth-to-orbit (ETO) launch systems, in which the modules are dropped into low Earth orbit (LEO) and then the modules perform their own orbit transfer to GEO using expendable solar arrays to power solar electric thrusters. At GEO, the modules either rendezvous and are assembled robotically into larger platforms, or are deployed into constellations of identical laser power-beaming satellites. Since solar electric propulsion by the modules is cost-effective for both

Geometry of tidal inlet systems : A key factor for the net sediment transport in tidal inlets

NARCIS (Netherlands)

Ridderinkhof, W.; de Swart, H. E.; van der Vegt, M.; Alebregtse, N. C.; Hoekstra, P.

2014-01-01

The net transport of sediment between the back-barrier basin and the sea is an important process for determining the stability of tidal inlet systems. Earlier studies showed that in a short basin, tidal flats favor peak ebb-currents stronger than peak flood currents, implying export of coarse

Tidal variations of earth rotation

Science.gov (United States)

Yoder, C. F.; Williams, J. G.; Parke, M. E.

1981-01-01

The periodic variations of the earths' rotation resulting from the tidal deformation of the earth by the sun and moon were rederived including terms with amplitudes of 0.002 millisec and greater. The series applies to the mantle, crust, and oceans which rotate together for characteristic tidal periods; the scaling parameter is the ratio of the fraction of the Love number producing tidal variations in the moment of inertia of the coupled mantle and oceans (k) to the dimensionless polar moment of inertia of the coupled moments (C). The lunar laser ranging data shows that k/C at monthly and fortnightly frequencies equals 0.99 + or - 0.15 and 0.99 + or - 0.20 as compared to the theoretical value of 0.94 + or - 0.04.

Pulse-power technology and its applications at LBT, Nagaoka

Energy Technology Data Exchange (ETDEWEB)

Yatsui, K; Masuda, W; Grigoriu, C; Masugata, K; Jiang, W; Imada, G; Imanari, K; Sonegawa, T; Chishiro, E [Laboratory of Beam Technology, Nagaoka University of Technology (Japan)

1997-12-31

Research activities on pulsed power technology and its applications at Laboratory of Beam Technology, Nagaoka University of Technology are reviewed. These activities include 1) development of a high power induction type linear accelerator (8 MV, 5 kA, 50 ns), 2) development of intense ion beam source, and 3) applications of pulsed ion beam in thin film and nanosize powder production. (author). 20 figs., 9 refs.

Digital Process Management Technology for Nuclear Power Plants

International Nuclear Information System (INIS)

You, Young M.; Suh, Kune Y.

2009-01-01

PHILOSOPHIA, Inc. and Seoul National University have utilized the cutting edge Digital Process Management (DPM) technology for the good of Nuclear Power Plant in recent days. This work represent the overall benefits and the use of this new flow of technology which come into the spotlight. Before realizing the three dimensional (3D) technologies and applying it to real mechanical manufactures and constructions, majority of planning and designing works need huge time and cost even if the process is before the real work. Especially, for a massive construction such as power plant and harbor, without computer-aided technology currently we cannot imagine the whole process can be established easily. Computer-aided Design (CAD) is now main and common technology for manufacturing or construction. This technology lead the other virtual reality 3D technologies into the job site. As a member of these new technologies, DPM is utilized in high-tech and huge scale manufacturing and construction for the benefits of time and cost

A Curriculum Guide for Power Technology, Grades 9-12.

Science.gov (United States)

Callahan, J. Thomas

Designed to help the high school industrial arts instructor in teaching power technology, this curriculum guide concentrates on seven subject areas: exploratory power technology, electricity, electronics, small gas engines, automotive repair, transportation, and alternate energy sources. The general course objectives are identified as enabling the…

TIDAL INTERACTIONS IN MERGING WHITE DWARF BINARIES

International Nuclear Information System (INIS)

Piro, Anthony L.

2011-01-01

The recently discovered system J0651 is the tightest known detached white dwarf (WD) binary. Since it has not yet initiated Roche-lobe overflow, it provides a relatively clean environment for testing our understanding of tidal interactions. I investigate the tidal heating of each WD, parameterized in terms of its tidal Q parameter. Assuming that the heating can be radiated efficiently, the current luminosities are consistent with Q 1 ∼ 7 x 10 10 and Q 2 ∼ 2 x 10 7 , for the He and C/O WDs, respectively. Conversely, if the observed luminosities are merely from the cooling of the WDs, these estimated values of Q represent the upper limits. A large Q 1 for the He WD means its spin velocity will be slower than that expected if it was tidally locked, which, since the binary is eclipsing, may be measurable via the Rossiter-McLaughlin effect. After one year, gravitational wave emission shifts the time of eclipses by 5.5 s, but tidal interactions cause the orbit to shrink more rapidly, changing the time by up to an additional 0.3 s after a year. Future eclipse timing measurements may therefore infer the degree of tidal locking.

Military space power systems technology trends and issues

International Nuclear Information System (INIS)

Barthelemy, R.R.; Massie, L.D.

1985-01-01

This paper assesses baseload and above-baseload (alert, active, pulsed and burst mode) power system options, places them in logical perspective relative to power level and operating time, discusses power systems technology state-of-the-art and trends and finally attempts to project future (post 2000) space power system capabilities

No Snowball on Habitable Tidally Locked Planets

Energy Technology Data Exchange (ETDEWEB)

Checlair, Jade; Abbot, Dorian S. [Department of the Geophysical Sciences, University of Chicago, 5734 South Ellis Avenue, Chicago, IL 60637 (United States); Menou, Kristen, E-mail: jadecheclair@uchicago.edu [Centre for Planetary Sciences, Department of Physical and Environmental Sciences, University of Toronto at Scarborough, Toronto, ON M1C 1A4 (Canada)

2017-08-20

The TRAPPIST-1, Proxima Centauri, and LHS 1140 systems are the most exciting prospects for future follow-up observations of potentially inhabited planets. All of the planets orbit nearby M-stars and are likely tidally locked in 1:1 spin–orbit states, which motivates the consideration of the effects that tidal locking might have on planetary habitability. On Earth, periods of global glaciation (snowballs) may have been essential for habitability and remote signs of life (biosignatures) because they are correlated with increases in the complexity of life and in the atmospheric oxygen concentration. In this paper, we investigate the snowball bifurcation (sudden onset of global glaciation) on tidally locked planets using both an energy balance model and an intermediate-complexity global climate model. We show that tidally locked planets are unlikely to exhibit a snowball bifurcation as a direct result of the spatial pattern of insolation they receive. Instead, they will smoothly transition from partial to complete ice coverage and back. A major implication of this work is that tidally locked planets with an active carbon cycle should not be found in a snowball state. Moreover, this work implies that tidally locked planets near the outer edge of the habitable zone with low CO{sub 2} outgassing fluxes will equilibrate with a small unglaciated substellar region rather than cycling between warm and snowball states. More work is needed to determine how the lack of a snowball bifurcation might affect the development of life on a tidally locked planet.

Overview on the high power excimer laser technology

Science.gov (United States)

Liu, Jingru

2013-05-01

High power excimer laser has essential applications in the fields of high energy density physics, inertial fusion energy and industry owing to its advantages such as short wavelength, high gain, wide bandwidth, energy scalable and repetition operating ability. This overview is aimed at an introduction and evaluation of enormous endeavor of the international high power excimer laser community in the last 30 years. The main technologies of high power excimer laser are reviewed, which include the pumping source technology, angular multiplexing and pulse compressing, beam-smoothing and homogenous irradiation, high efficiency and repetitive operation et al. A high power XeCl laser system developed in NINT of China is described in detail.

Possibilities for retrofitting of the existing thermal electric power plants using solar power technologies

International Nuclear Information System (INIS)

Matjanov, Erkinjon K.; Abduganieva, Farogat A.; Aminov, Zarif Z.

2012-01-01

Full text: Total installed electric power output of the existing thermal electric power plants in Uzbekistan is reaches 12 GW. Thermal electric power plants, working on organic fuel, produce around 88 % of the electricity in the country. The emission coefficient of CO 2 gases is 620 gram/kwph. Average electric efficiency of the thermal electric power plants is 32.1 %. The mentioned above data certifies, that the existing thermal electric power plants of Uzbekistan are physically and morally aged and they need to be retrofitted. Retrofitting of the existing thermal electric power plants can be done by several ways such as via including gas turbine toppings, by using solar technologies, etc. Solar thermal power is a relatively new technology which has already shown its enormous promise. With few environmental impacts and a massive resource, it offers a comparable opportunity to the sunniest Uzbekistan. Solar thermal power uses direct sunlight, so it must be sited in regions with high direct solar radiation. In many regions, one square km of land is enough to generate as much as 100-120 GWh of electricity per year using the solar thermal technology. This is equivalent to the annual production of a 50 MW conventional coal or gas-fired mid-load power plant. Solar thermal power plants can be designed for solar-only or for hybrid operation. Producing electricity from the energy in the sun's rays is a straightforward process: direct solar radiation can be concentrated and collected by a range of Concentrating Solar Power technologies to provide medium- to high temperature heat. This heat is then used to operate a conventional power cycle, for example through a steam turbine or a Stirling engine. Solar heat collected during the day can also be stored in liquid or solid media such as molten salts, ceramics, concrete or, in the future, phase-changing salt mixtures. At night, it can be extracted from the storage medium thereby continuing turbine operation. Currently, the

Assessment of a satellite power system and six alternative technologies

Energy Technology Data Exchange (ETDEWEB)

Wolsko, T.; Whitfield, R.; Samsa, M.; Habegger, L.S.; Levine, E.; Tanzman, E.

1981-04-01

The satellite power system is assessed in comparison to six alternative technologies. The alternatives are: central-station terrestrial photovoltaic systems, conventional coal-fired power plants, coal-gasification/combined-cycle power plants, light water reactor power plants, liquid-metal fast-breeder reactors, and fusion. The comparison is made regarding issues of cost and performance, health and safety, environmental effects, resources, socio-economic factors, and insitutional issues. The criteria for selecting the issues and the alternative technologies are given, and the methodology of the comparison is discussed. Brief descriptions of each of the technologies considered are included. (LEW)

Technological and social change and the future of nuclear power

International Nuclear Information System (INIS)

Douglas, H.

1988-01-01

Over the past decade and a half, the nuclear power industry has experienced growing public opposition. Underlying the nuclear industry's problems is a very fundamental anti-technology outlook by the public - visibly apparent in the environmental movement - that not only affects nuclear power but business in general. Is this anti-technology attitude of the public and media writers a passing phase, or will it wane and yield to a positive attitude toward technology? This paper discusses historical, sociological and technological change in the Western industrial world, and how changing attitudes might affect nuclear power in the future. (author)

TIDAL EVOLUTION OF CLOSE-IN PLANETS

International Nuclear Information System (INIS)

Matsumura, Soko; Rasio, Frederic A.; Peale, Stanton J.

2010-01-01

Recent discoveries of several transiting planets with clearly non-zero eccentricities and some large obliquities started changing the simple picture of close-in planets having circular and well-aligned orbits. The two major scenarios that form such close-in planets are planet migration in a disk and planet-planet interactions combined with tidal dissipation. The former scenario can naturally produce a circular and low-obliquity orbit, while the latter implicitly assumes an initially highly eccentric and possibly high-obliquity orbit, which are then circularized and aligned via tidal dissipation. Most of these close-in planets experience orbital decay all the way to the Roche limit as previous studies showed. We investigate the tidal evolution of transiting planets on eccentric orbits, and find that there are two characteristic evolution paths for them, depending on the relative efficiency of tidal dissipation inside the star and the planet. Our study shows that each of these paths may correspond to migration and scattering scenarios. We further point out that the current observations may be consistent with the scattering scenario, where the circularization of an initially eccentric orbit occurs before the orbital decay primarily due to tidal dissipation in the planet, while the alignment of the stellar spin and orbit normal occurs on a similar timescale to the orbital decay largely due to dissipation in the star. We also find that even when the stellar spin-orbit misalignment is observed to be small at present, some systems could have had a highly misaligned orbit in the past, if their evolution is dominated by tidal dissipation in the star. Finally, we also re-examine the recent claim by Levrard et al. that all orbital and spin parameters, including eccentricity and stellar obliquity, evolve on a similar timescale to orbital decay. This counterintuitive result turns out to have been caused by a typo in their numerical code. Solving the correct set of tidal

Relativistic tidal properties of neutron stars

International Nuclear Information System (INIS)

Damour, Thibault; Nagar, Alessandro

2009-01-01

We study the various linear responses of neutron stars to external relativistic tidal fields. We focus on three different tidal responses, associated to three different tidal coefficients: (i) a gravito-electric-type coefficient Gμ l =[length] 2l+1 measuring the lth-order mass multipolar moment GM a 1 ...a l induced in a star by an external lth-order gravito-electric tidal field G a 1 ...a l ; (ii) a gravito-magnetic-type coefficient Gσ l =[length] 2l+1 measuring the lth spin multipole moment GS a 1 ...a l induced in a star by an external lth-order gravito-magnetic tidal field H a 1 ...a l ; and (iii) a dimensionless 'shape' Love number h l measuring the distortion of the shape of the surface of a star by an external lth-order gravito-electric tidal field. All the dimensionless tidal coefficients Gμ l /R 2l+1 , Gσ l /R 2l+1 , and h l (where R is the radius of the star) are found to have a strong sensitivity to the value of the star's 'compactness'c≡GM/(c 0 2 R) (where we indicate by c 0 the speed of light). In particular, Gμ l /R 2l+1 ∼k l is found to strongly decrease, as c increases, down to a zero value as c is formally extended to the 'black hole (BH) limit'c BH =1/2. The shape Love number h l is also found to significantly decrease as c increases, though it does not vanish in the formal limit c→c BH , but is rather found to agree with the recently determined shape Love numbers of black holes. The formal vanishing of μ l and σ l as c→c BH is a consequence of the no-hair properties of black holes. This vanishing suggests, but in no way proves, that the effective action describing the gravitational interactions of black holes may not need to be augmented by nonminimal worldline couplings.

Ecology of Juvenile Salmonids in Shallow Tidal Freshwater Habitats in the Vicinity of the Sandy River Delta, Lower Columbia River, 2007

Energy Technology Data Exchange (ETDEWEB)

Sobocinski, Kathryn L.; Johnson, Gary E.; Sather, Nichole K.; Storch, Adam; Jones, Tucker A.; Mallette, Christine; Dawley, Earl M.; Skalski, John R.; Teel, David; Moran, Paul

2008-03-18

This document is the first annual report for the study titled “Ecology of Juvenile Salmonids in Shallow Tidal Freshwater Habitats in the Vicinity of the Sandy River Delta in the Lower Columbia River.” Hereafter, we refer to this research as the Tidal Freshwater Monitoring (TFM) Study. The study is part of the research, monitoring, and evaluation effort developed by the Action Agencies (Bonneville Power Administration, U.S. Army Corps of Engineers, U.S. Bureau of Reclamation) in response to obligations arising from the Endangered Species Act as a result of operation of the Federal Columbia River Power System (FCRPS). The project is performed under the auspices of the Northwest Power and Conservation Council’s Columbia Basin Fish and Wildlife Program.

Parametric instability and wave turbulence driven by tidal excitation of internal waves

Science.gov (United States)

Le Reun, Thomas; Favier, Benjamin; Le Bars, Michael

2018-04-01

We investigate the stability of stratified fluid layers undergoing homogeneous and periodic tidal deformation. We first introduce a local model which allows to study velocity and buoyancy fluctuations in a Lagrangian domain periodically stretched and sheared by the tidal base flow. While keeping the key physical ingredients only, such a model is efficient to simulate planetary regimes where tidal amplitudes and dissipation are small. With this model, we prove that tidal flows are able to drive parametric subharmonic resonances of internal waves, in a way reminiscent of the elliptical instability in rotating fluids. The growth rates computed via Direct Numerical Simulations (DNS) are in very good agreement with WKB analysis and Floquet theory. We also investigate the turbulence driven by this instability mechanism. With spatio-temporal analysis, we show that it is a weak internal wave turbulence occurring at small Froude and buoyancy Reynolds numbers. When the gap between the excitation and the Brunt-V\\"ais\\"al\\"a frequencies is increased, the frequency spectrum of this wave turbulence displays a -2 power law reminiscent of the high-frequency branch of the Garett and Munk spectrum (Garrett & Munk 1979) which has been measured in the oceans. In addition, we find that the mixing efficiency is altered compared to what is computed in the context of DNS of stratified turbulence excited at small Froude and large buoyancy Reynolds numbers and is consistent with a superposition of waves.

China general nuclear power corporation--The recent research and application of the modular technology in nuclear power engineering

International Nuclear Information System (INIS)

Lu Qinwu

2014-01-01

Modular design and construction is one of the distinctive features of the 3"r"d generation nuclear power technology. In order to promote the technological innovations in nuclear power engineering design and construction and develop the self-owned modular technology, China General Nuclear Power Corporation (CGN) has carried out the R and D and application of the modular technology based on the CPR1000-type nuclear power plants, and has made the national-level achievements in the establishment of modular design technology system, development of 3D modular design system and application of modular construction of containment steel liner in the demonstration projects. (author)

Introduction of Capacitive Power Transfer Technology

OpenAIRE

Hattori, Reiji

2017-01-01

Wireless power transfer (WPT) technology is expected for eliminating troublesomeness of connecting an electronic cable. The development of WPT technology has a long history since Nikola Tesla built up Wardenclyffe Tower located in Long Island, New York for developing a WPT system in the early 1980’s. But it cannot be said that WPT technology is widely spread in a current human life space enough. The reason is that it cannot find the specific application which only WPT can achieve yet. There a...

Geometro-thermodynamics of tidal charged black holes

International Nuclear Information System (INIS)

Gergely, Laszlo Arpad; Pidokrajt, Narit; Winitzki, Sergei

2011-01-01

Tidal charged spherically symmetric vacuum brane black holes are characterized by their mass m and tidal charge q, an imprint of the five-dimensional Weyl curvature. For q>0 they are formally identical to the Reissner-Nordstroem black hole of general relativity. We study the thermodynamics and thermodynamic geometries of tidal charged black holes and discuss similarities and differences as compared to the Reissner-Nordstroe m black hole. As a similarity, we show that (for q>0) the heat capacity of the tidal charged black hole diverges on a set of measure zero of the parameter space, nevertheless both the regularity of the Ruppeiner metric and a Poincare stability analysis show no phase transition at those points. The thermodynamic state spaces being different indicates that the underlying statistical models could be different. We find that the q<0 parameter range, which enhances the localization of gravity on the brane, is thermodynamically preferred. Finally we constrain for the first time the possible range of the tidal charge from the thermodynamic limit on gravitational radiation efficiency at black hole mergers. (orig.)

Impact of Storage Technologies upon Power System Losses

Directory of Open Access Journals (Sweden)

DULAU Lucian Ioan

2015-05-01

Full Text Available The paper describes the main characteristics of storage technologies. The most important storage technologies are the batteries, hydrogen, pumped hydro, flywheels, compressed air, super-capacitors and superconducting magnetic devices. The storage technologies can be classified based on the function principle into electrochemical, mechanical and electromagnetic devices. The storage systems can also be classified based on their capacity to store power into short and long term devices. A power flow analysis is performed for the situation with and without a storage unit. The storage unit is inserted into the IEEE 14 bus test system.

Tidal Marshes: The Boundary between Land and Ocean.

Science.gov (United States)

Gosselink, James

An overview of the ecology of the tidal marshes along the gulf coast of the United States is presented. The following topics are included: (1) the human impact on tidal marshes; (2) the geologic origins of tidal marshes; (3) a description of the physical characteristics and ecosystem of the marshlands; (4) a description of the marshland food chain…

Satellite Tidal Magnetic Signals Constrain Oceanic Lithosphere-Asthenosphere Boundary Earth Tomography with Tidal Magnetic Signals

Science.gov (United States)

Grayver, Alexander V.; Schnepf, Neesha R.; Kuvshinov, Alexey V.; Sabaka, Terence J.; Chandrasekharan, Manoj; Olsen, Niles

2016-01-01

The tidal flow of electrically conductive oceans through the geomagnetic field results in the generation of secondary magnetic signals, which provide information on the subsurface structure. Data from the new generation of satellites were shown to contain magnetic signals due to tidal flow; however, there are no reports that these signals have been used to infer subsurface structure. Here we use satellite-detected tidal magnetic fields to image the global electrical structure of the oceanic lithosphere and upper mantle down to a depth of about 250 km. The model derived from more than 12 years of satellite data reveals an Approximately 72 km thick upper resistive layer followed by a sharp increase in electrical conductivity likely associated with the lithosphere-asthenosphere boundary, which separates colder rigid oceanic plates from the ductile and hotter asthenosphere.

Ecological state of the Rance marine basin after 30 years of functioning of the tidal power plant

International Nuclear Information System (INIS)

Retiere, Ch.; Desroy, N.; Bonnot-Courtois, C.; Le Mao, P.

1997-01-01

The Rance basin on the Brittany coast (France) is the unique site in the world where the long term ecological impacts of the functioning of a tidal power plant can be evaluated. Two aspects are distinguished: the consequences due to the building the plant and those due to the functioning of the plant. During the building of the barrage which lasted 3 years, the estuary was isolated from the sea and led to an increase of sedimentation and organic matter and to important variations of the water salinity. Thus the whole marine flora and fauna disappeared. Today, the operation of the plant has changed the rhythm and amplitude of the tide inside the basin. Ten to fifteen years were necessary for the marine fauna and flora to recover a new equilibrium inside the basin after the plant was built. The functioning of the new ecosystem is governed by the relationship between species independently of the initial perturbation and its equilibrium is based on the regular functioning of the plant. (J.S.)

Soft-Fault Detection Technologies Developed for Electrical Power Systems

Science.gov (United States)

Button, Robert M.

2004-01-01

The NASA Glenn Research Center, partner universities, and defense contractors are working to develop intelligent power management and distribution (PMAD) technologies for future spacecraft and launch vehicles. The goals are to provide higher performance (efficiency, transient response, and stability), higher fault tolerance, and higher reliability through the application of digital control and communication technologies. It is also expected that these technologies will eventually reduce the design, development, manufacturing, and integration costs for large, electrical power systems for space vehicles. The main focus of this research has been to incorporate digital control, communications, and intelligent algorithms into power electronic devices such as direct-current to direct-current (dc-dc) converters and protective switchgear. These technologies, in turn, will enable revolutionary changes in the way electrical power systems are designed, developed, configured, and integrated in aerospace vehicles and satellites. Initial successes in integrating modern, digital controllers have proven that transient response performance can be improved using advanced nonlinear control algorithms. One technology being developed includes the detection of "soft faults," those not typically covered by current systems in use today. Soft faults include arcing faults, corona discharge faults, and undetected leakage currents. Using digital control and advanced signal analysis algorithms, we have shown that it is possible to reliably detect arcing faults in high-voltage dc power distribution systems (see the preceding photograph). Another research effort has shown that low-level leakage faults and cable degradation can be detected by analyzing power system parameters over time. This additional fault detection capability will result in higher reliability for long-lived power systems such as reusable launch vehicles and space exploration missions.

Nuclear power technologies. Abstracts of reports

International Nuclear Information System (INIS)

Koltysheva, G.I.; Mukusheva, M.K.; Perepelkin, I.G.

2000-01-01

In May 14-17, 2000, and on the initiative of the Ministry of Science and High Education of the Republic of Kazakstan with cooperation of Department of Energy US, International Seminar on Nuclear Power Technologies was held in Astana, Kazakhstan. More than 70 reports of scientists from different countries (USA, Russia, Japan and Kazakhstan) were presented during the Seminar. Representatives from different international organizations (European Commission Delegation, IAEA), from organizations of Kazakstan, Russia, USA, Japan took part in the Seminar. In all at the Seminar there were more then 100 participants. The Seminar included Plenary Session, two sections: 1) Nuclear Safety and Nuclear Technologies; 2) Material Investigations for Nuclear and Thermonuclear Power; Workshop: Nuclear Facilities Decommissioning and Decontamination; and Posters

Tidal regimes and salt marshes - the River Hamble analogue

International Nuclear Information System (INIS)

Gray, A.J.; Moy, I.L.; Warman, E.A.; Dawson, F.H.; Henville, P.

1993-01-01

Construction of estuarine tidal-energy barrages has a potentially major effect on the tidal regime of the estuary, particularly upstream of a barrage. Because tidal regime largely controls the distribution and species composition of intertidal plant and animal communities, it is important to understand how barrages may affect such communities. The main objectives of the research described in this report were to relate recent changes in tidal regime within an embanked area of salt marsh and mudflat to changes in the distribution of plant species. This was to test predictions about tidal control of species' range and to assess the site's suitability as an analogue of post-barrage conditions. (author)

WIYN Open Cluster Study: Tidal Interactions in Solar type Binaries

OpenAIRE

Meibom, S.; Mathieu, R. D.

2003-01-01

We present an ongoing study on tidal interactions in late-type close binary stars. New results on tidal circularization are combined with existing data to test and constrain theoretical predictions of tidal circularization in the pre-main-sequence (PMS) phase and throughout the main-sequence phase of stellar evolution. Current data suggest that tidal circularization during the PMS phase sets the tidal cutoff period for binary populations younger than ~1 Gyr. Binary populations older than ~1 G...

Smart Power: New power integrated circuit technologies and their applications

Science.gov (United States)

Kuivalainen, Pekka; Pohjonen, Helena; Yli-Pietilae, Timo; Lenkkeri, Jaakko

1992-05-01

Power Integrated Circuits (PIC) is one of the most rapidly growing branches of the semiconductor technology. The PIC markets has been forecast to grow from 660 million dollars in 1990 to 1658 million dollars in 1994. It has even been forecast that at the end of the 1990's the PIC markets would correspond to the value of the whole semiconductor production in 1990. Automotive electronics will play the leading role in the development of the standard PIC's. Integrated motor drivers (36 V/4 A), smart integrated switches (60 V/30 A), solenoid drivers, integrated switch-mode power supplies and regulators are the latest standard devices of the PIC manufactures. ASIC (Application Specific Integrated Circuits) PIC solutions are needed for the same reasons as other ASIC devices: there are no proper standard devices, a company has a lot of application knowhow, which should be kept inside the company, the size of the product must be reduced, and assembly costs are wished to be reduced by decreasing the number of discrete devices. During the next few years the most probable ASIC PIC applications in Finland will be integrated solenoid and motor drivers, an integrated electronic lamp ballast circuit and various sensor interface circuits. Application of the PIC technologies to machines and actuators will strongly be increased all over the world. This means that various PIC's, either standard PIC's or full custom ASIC circuits, will appear in many products which compete with the corresponding Finnish products. Therefore the development of the PIC technologies must be followed carefully in order to immediately be able to apply the latest development in the smart power technologies and their design methods.

Tidal propagation off the central west coast of India

Digital Repository Service at National Institute of Oceanography (India)

Unnikrishnan, A.S.

. [Keywords: Tidal propagation, Mumbai high, Global tidal model, Shelf model, Central west coast of India] Introduction In coastal regions, tides play an important role in determining circulation and hydrography. Barotropic tides coming from the open... with increase in the width of the shelf. Materials and Methods Global tidal models Schwiderski5 used a hydrodynamic interpolation technique to determine the amplitude and phase of tidal constituents of global ocean. Since the availability of satellite...

Workshop on power conditioning for alternative energy technologies. Executive summary

Energy Technology Data Exchange (ETDEWEB)

Smith, D. R.

1979-01-01

As various alternative energy technologies such as photovoltaics, wind, fuel cells, and batteries are emerging as potential sources of energy for the future, the need arises for development of suitable power-conditioning systems to interface these sources to their respective loads. Since most of these sources produce dc electricity and most electrical loads require ac, an important component of the required power-conditioning units is a dc-to-ac inverter. The discussions deal with the development of power conditioners for each alternative energy technology. Discussion topics include assessments of current technology, identification of operational requirements with a comparison of requirements for each source technology, the identification of future technology trends, the determination of mass production and marketing requirements, and recommendations for program direction. Specifically, one working group dealt with source technology: photovoltaics, fuel cells and batteries, and wind followed by sessions discussing system size and application: large grid-connected systems, small grid-connected systems, and stand alone and dc applications. A combined group session provided an opportunity to discuss problems common to power conditioning development.

Facing technological challenges of Solar Updraft Power Plants

Science.gov (United States)

Lupi, F.; Borri, C.; Harte, R.; Krätzig, W. B.; Niemann, H.-J.

2015-01-01

The Solar Updraft Power Plant technology addresses a very challenging idea of combining two kinds of renewable energy: wind and solar. The working principle is simple: a Solar Updraft Power Plant (SUPP) consists of a collector area to heat the air due to the wide-banded ultra-violet solar radiation, the high-rise solar tower to updraft the heated air to the atmosphere, and in between the power conversion unit, where a system of coupled turbines and generators transforms the stream of heated air into electric power. A good efficiency of the power plant can only be reached with extra-large dimensions of the tower and/or the collector area. The paper presents an up-to-date review of the SUPP technology, focusing on the multi-physics modeling of the power plant, on the structural behavior of the tower and, last but not least, on the modeling of the stochastic wind loading process.

Dissipation of Tidal Energy

Science.gov (United States)

2002-01-01

The moon's gravity imparts tremendous energy to the Earth, raising tides throughout the global oceans. What happens to all this energy? This question has been pondered by scientists for over 200 years, and has consequences ranging from the history of the moon to the mixing of the oceans. Richard Ray at NASA's Goddard Space Flight Center, Greenbelt, Md. and Gary Egbert of the College of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, Ore. studied six years of altimeter data from the TOPEX/Poseidon satellite to address this question. According to their report in the June 15 issue of Nature, about 1 terawatt, or 25 to 30 percent of the total tidal energy dissipation, occurs in the deep ocean. The remainder occurs in shallow seas, such as on the Patagonian Shelf. 'By measuring sea level with the TOPEX/Poseidon satellite altimeter, our knowledge of the tides in the global ocean has been remarkably improved,' said Richard Ray, a geophysicist at Goddard. The accuracies are now so high that this data can be used to map empirically the tidal energy dissipation. (Red areas, above) The deep-water tidal dissipation occurs generally near rugged bottom topography (seamounts and mid-ocean ridges). 'The observed pattern of deep-ocean dissipation is consistent with topographic scattering of tidal energy into internal motions within the water column, resulting in localized turbulence and mixing', said Gary Egbert an associate professor at OSU. One important implication of this finding concerns the possible energy sources needed to maintain the ocean's large-scale 'conveyor-belt' circulation and to mix upper ocean heat into the abyssal depths. It is thought that 2 terawatts are required for this process. The winds supply about 1 terawatt, and there has been speculation that the tides, by pumping energy into vertical water motions, supply the remainder. However, all current general circulation models of the oceans ignore the tides. 'It is possible that properly

Carbon sequestration by Australian tidal marshes

KAUST Repository

Macreadie, Peter I.

2017-03-10

Australia\\'s tidal marshes have suffered significant losses but their recently recognised importance in CO2 sequestration is creating opportunities for their protection and restoration. We compiled all available data on soil organic carbon (OC) storage in Australia\\'s tidal marshes (323 cores). OC stocks in the surface 1 m averaged 165.41 (SE 6.96) Mg OC ha-1 (range 14-963 Mg OC ha-1). The mean OC accumulation rate was 0.55 ± 0.02 Mg OC ha-1 yr-1. Geomorphology was the most important predictor of OC stocks, with fluvial sites having twice the stock of OC as seaward sites. Australia\\'s 1.4 million hectares of tidal marshes contain an estimated 212 million tonnes of OC in the surface 1 m, with a potential CO2-equivalent value of $USD7.19 billion. Annual sequestration is 0.75 Tg OC yr-1, with a CO2-equivalent value of $USD28.02 million per annum. This study provides the most comprehensive estimates of tidal marsh blue carbon in Australia, and illustrates their importance in climate change mitigation and adaptation, acting as CO2 sinks and buffering the impacts of rising sea level. We outline potential further development of carbon offset schemes to restore the sequestration capacity and other ecosystem services provided by Australia tidal marshes.

The 'CETO' wave power generation devices

Energy Technology Data Exchange (ETDEWEB)

Profitt, Michael

2007-07-01

Renewable Energy Holdings plc (REH) is an international company established to be an operator of, and undertake active investments in both proven and innovative renewable energy technologies. The CETO devices have been developed in Western Australia by Seapower Pacific PTY Ltd (SPPL), a subsidiary of Renewable Energy Holdings Plc (REH). This paper reports on the technology and also includes the findings from an independent technical appraisal undertaken by PB Power. The CETO device consists primarily of a novel pump anchored to the seabed and driven by a spherical buoyant actuator that collects wave energy and transmits it to the pump. High pressure seawater is delivered ashore where it can be used to drive a turbine to generate electricity or passed through a reverse osmosis desalination unit to produce fresh water. The competitive edge of CETO against other current wave and tidal generation devices: Electricity generated onshore (using well-proven hydro-power technology); Low cost mass produced device; Simplified infrastructure from pumping pressurised sea water ashore rather than electricity; Allows shore-based desalination; Modular design and self deployment; and, Transport in standard containers.

Technology Development Prospects for the Indian Power Sector

Energy Technology Data Exchange (ETDEWEB)

NONE

2011-07-01

The Indian power sector will face numerous challenges over the next four decades. More than one third of India's population currently do not have access to electricity. Urgent action is needed to overcome this problem of energy poverty. At the same time rapid economic growth is projected to increase electricity demand by fivefold to sixfold between now and 2050. Massive investments will be needed to meet this increased demand, but this will also create unique opportunities to transform the power sector towards a low-carbon future. This Information Paper presents in more detail the analysis for India published in Energy Technology Perspectives 2010. The paper investigates the best way of achieving deep CO2 emission cuts in the Indian power system while allowing the Indian economy to continue growing and meeting the challenge of alleviating energy poverty. It does so from a techno-economic perspective - building on detailed resource and technology data for India - and identifies the key power sector technologies needed for India to realise such a transition.

Water treatment for fossil fuel power generation - technology status report

International Nuclear Information System (INIS)

2006-01-01

This technology status report focuses on the use of water treatment technology in fossil fuel power plants. The use of polymeric ion exchange resins for deionization of water, the currently preferred use of ion exchange for economically treating water containing low dissolved salts, the use of low pressure high-flux membranes, membrane microfiltration, and reverse osmosis are discussed. Details are given of the benefits of the technologies, water use at power plants, the current status of water treatment technologies, and the potential for future developments, along with power plant market trends and potentials, worldwide developments, and UK capabilities in water treatment plant design and manufacturing

Nuclear power economics and technology: an overview

International Nuclear Information System (INIS)

1992-01-01

Intended for the non-specialist reader interested in energy and environmental policy matters, this report presents an overview of the current expert consensus on the status of nuclear power technology and its economic position. It covers the potential demand for nuclear energy, its economic competitivity, and the relevant aspects of reactor performance and future technological developments. The report provides an objective contribution to the ongoing scientific and political debate about what nuclear power can offer, now and in the future, in meeting the world's growing demand for energy and in achieving sustainable economic development. 24 refs., 18 figs;, 12 tabs., 5 photos

Study on modular technology based on the reference nuclear power plant

International Nuclear Information System (INIS)

Lu Qinwu; Zhao Shuyu; Li Yi; Han Xiaoping; Chai Weidong; Zhang Shuxia

2014-01-01

As an important technology for shortening the construction period and reducing the cost of nuclear power project, modular technology has become one of the development orientations of the third generation nuclear power plant. Taking CPR1000 nuclear power reactor as reference plant and drawing on advanced foreign technology of modularization, the overall concept design has been completed with the help of the self-developed 3D modular design system. On this basis, a typical detailed design work has been carried out so as to verify the feasibility of technology. Besides, an analysis on implementation of modular technology has been made from two aspects (procurement and construction), and the feasibility of research results in actual project has been evaluated. It provides references for the promotion of self-reliant modular technology in nuclear power project in China. (authors)

Generator technology for HTGR power plants

International Nuclear Information System (INIS)

Lomba, D.; Thiot, D.

1997-01-01

Approximately 15% of the worlds installed capacity in electric energy production is from generators developed and manufactured by GEC Alsthom. GEC Alsthom is now working on the application of generators for HTGR power conversion systems. The main generator characteristics induced by the different HTGR power conversion technology include helium immersion, high helium pressure, brushless excitation system, magnetic bearings, vertical lineshaft, high reliability and long periods between maintenance. (author)

Powered by technology or powering technology?---Belief-based decision-making in nuclear power and synthetic fuel

Science.gov (United States)

Yang, Chi-Jen

The overarching question in this study is how and why technical-fixes in energy policy failed. In the post-WWII era, civilian nuclear power and synthetic fuel had both been top priorities on the U.S. national policy agenda during certain periods of time. Nuclear power was promoted and pursued persistently with great urgency for over two decades. In contrast, synthetic fuel policy suffered from boom-and-bust cycles. The juxtaposition of policy histories of nuclear power and synthetic fuel highlights many peculiarities in policymaking. The U.S. government forcefully and consistently endorsed the development of civilian nuclear power for two decades. It adopted policies to establish the competitiveness of civilian nuclear power far beyond what would have occurred under free-market conditions. Even though synthetic fuel was characterized by a similar level of economic potential and technical feasibility, the policy approach toward synthetic fuel was almost the opposite of nuclear power. Political support usually stopped when the development of synthetic fuel technology encountered economic difficulties. The contrast between the unfaltering faith in nuclear power and the indeterminate attitude toward synthetic fuel raises many important questions. I argue that these diverging paths of development can be explained by exploring the dominant government ideology of the time or "ideology of the state" as the sociology literature describes it. The price-determining approach was a result of government preoccupied with fighting the Cold War. The U.S. intentionally idealized and deified nuclear power to serve its Cold War psychological strategy. These psychological maneuverings attached important symbolic meaning to nuclear power. The society-wide enthusiasm and resulting bandwagon market are better understood by taking the role of symbolism in the political arena into account. On the other hand, a "welfare state" ideology that stood behind synthetic fuel was confused

Marine Hydrokinetic (MHK) Systems: A Systems Engineering Approach to Select Locations for the Practical Harvest of Electricity from Shallow Water Tidal Currents

Science.gov (United States)

Domenech, John

Due to increasing atmospheric CO2 concentration and its effect on global climates, the United States Environmental Protection Agency (EPA) proposes a Clean Power Plan (CPP) mandating CO2 reductions which will likely force the early retirement of inefficient, aging power plants. Consequentially, removing these plants equates to a shortfall of approximately 66 GW of electricity. These factors add to the looming resource problems of choosing whether to build large replacement power plants or consider alternative energy sources as a means to help close the gap between electricity supply and demand in a given region. One energy source, shallow water tidal currents, represents opportunities to convert kinetic energy to mechanical forms and provide electricity to homes and businesses. Nearly 2,000 National Oceanic Atmospheric Administration (NOAA) tidal current data points from Maine to Texas are considered. This paper, based on systems engineering thinking, provides key attributes (e.g. turbine efficiency, array size, transmission losses) for consideration as decision makers seek to identify where to site Marine Hydrokinetic (MHK) systems and the number of homes powered by the practical harvest of electricity from tidal currents at those locations with given attributes. A systems engineering process model is proposed for consideration as is a regression based equation to estimate MHK machine parameters needed for power a given number of homes.

Modeling In-stream Tidal Energy Extraction and Its Potential Environmental Impacts

Energy Technology Data Exchange (ETDEWEB)

Yang, Zhaoqing; Wang, Taiping; Copping, Andrea; Geerlofs, Simon H.

2014-09-30

In recent years, there has been growing interest in harnessing in-stream tidal energy in response to concerns of increasing energy demand and to mitigate climate change impacts. While many studies have been conducted to assess and map tidal energy resources, efforts for quantifying the associated potential environmental impacts have been limited. This paper presents the development of a tidal turbine module within a three-dimensional unstructured-grid coastal ocean model and its application for assessing the potential environmental impacts associated with tidal energy extraction. The model is used to investigate in-stream tidal energy extraction and associated impacts on estuarine hydrodynamic and biological processes in a tidally dominant estuary. A series of numerical experiments with varying numbers and configurations of turbines installed in an idealized estuary were carried out to assess the changes in the hydrodynamics and biological processes due to tidal energy extraction. Model results indicated that a large number of turbines are required to extract the maximum tidal energy and cause significant reduction of the volume flux. Preliminary model results also indicate that extraction of tidal energy increases vertical mixing and decreases flushing rate in a stratified estuary. The tidal turbine model was applied to simulate tidal energy extraction in Puget Sound, a large fjord-like estuary in the Pacific Northwest coast.

Tidal effects in twin-degenerate binaries

International Nuclear Information System (INIS)

Campbell, C.G.

1984-01-01

The tidal velocity field is calculated for an initially non-rotating low mass white dwarf secondary in a twin-degenerate binary. These motions are used to find the tidal torque on the secondary, to first order in the orbital frequency, and an expression is derived for the synchronization time. For a lobe-filling secondary the synchronization time has a weak dependence on the mass and luminosity of the star, and for the binary G61-29 is found to be of the same order as the estimated lifetime of the system. It is emphasized, however, that tidal excitation of non-radial oscillatory modes in the secondary may significantly shorten the synchronization time. (author)

Spin-orbital Tidal Dynamics and Tidal Heating in the TRAPPIST-1 Multiplanet System

Science.gov (United States)

Makarov, Valeri V.; Berghea, Ciprian T.; Efroimsky, Michael

2018-04-01

We perform numerical simulations of the TRAPPIST-1 system of seven exoplanets orbiting a nearby M dwarf, starting with a previously suggested stable configuration. The long-term stability of this configuration is confirmed, but the motion of planets is found to be chaotic. The eccentricity values are found to vary within finite ranges. The rates of tidal dissipation and tidal evolution of orbits are estimated, assuming an Earth-like rheology for the planets. We find that under this assumption, the planets b, d, and e were captured in the 3:2 or higher spin–orbit resonances during the initial spin-down, but slipped further down into the 1:1 resonance. Depending on its rheology, the innermost planet b may be captured in a stable pseudosynchronous rotation. Nonsynchronous rotation ensures higher levels of tidal dissipation and internal heating. The positive feedback between the viscosity and the dissipation rate—and the ensuing runaway heating—are terminated by a few self-regulation processes. When the temperature is high and the viscosity is low enough, the planet spontaneously leaves the 3:2 resonance. Further heating is stopped either by passing the peak dissipation or by the emergence of partial melt in the mantle. In the post-solidus state, the tidal dissipation is limited to the levels supported by the heat transfer efficiency. The tides on the host star are unlikely to have had a significant dynamical impact. The tides on the synchronized inner planets tend to reduce these planets’ orbital eccentricity, possibly contributing thereby to the system’s stability.

Understanding the Influence of Retention Basin on Tidal Dynamics in Tidal Estuaries

Science.gov (United States)

Kumar, Mohit; Schuttelaars, Henk; Roos, Pieter

2014-05-01

Both the tidal motion and suspended sediment concentration (SSC) in tidal embayments and estuaries are influenced by anthropogenic (e.g. deepening ) and natural changes. An example of such an estuary is the Ems estuary, situated on the border of the Netherlands and Germany. The mean tidal range towards the end of the Ems estuary has increased from 1.5m in the 1950s to more than 3m in the 1990s while the suspended concentration has increased by a factor 10. To possibly reduce these negative effects, the construction of retention basin(s) (RB) is considered. In this contribution, the influence of location and geometry of RBs on tidal dynamics and SSC is investigated. For this purpose, a three-dimensional semi-analytic idealized model is developed. This model is an extension of the model proposed by Winant (2007) to arbitrary domain and realistic bathymetry with partial slip boundary condition at the bottom. The sea surface elevation (SSE) is calculated numerically using a finite element method. Next, the three-dimensional velocities are calculated by combining the analytically calculated vertical profiles and the gradients of the SSE which are obtained numerically. Firstly, the influence of a RB on the tidal dynamics in an infinitely long, rectangular, frictionless estuary is considered. The SSE decreases when the RB is located between a node and a landward antinode, consistent with the work of Alebregtse et al. (2013). Secondly, an estuary of finite length is connected to a sea. By varying the width of the sea, not only the effect of the distance of the RB to the landward end plays a role, but also the distance to the open sea becomes important. Finally, we discuss the influence of a RB on the tidal motion and initial sediment transport, considering the Ems estuary with realistic bathymetry. Results show that the SSE at the landward end of the Ems estuary decreases for all locations of the RBs. This decrease is most pronounced for the RB which is closest to the end

Can nuclear power be enough for future technology?

International Nuclear Information System (INIS)

Serizawa, Akimi

2017-01-01

This paper focused on the report 'Can nuclear power be future technology?' published on September 28, 2008 by the Leading R and D Committee of Japan Society for the Promotion of Science. It took up part of the discussions at the general discussion session, and those of two working groups mainly by young committee members, and summarized and compiled them. Regarding 'maturity of nuclear technology as future technology,' this paper summarized and discussed from the technical viewpoint the current situation and problems of nuclear power in consideration of the future. Major topics include (1) nuclear safety and disaster prevention, (2) decommissioning of rectors (normal reactors, and accident reactors), (3) back end, (4) effects of low-level radiation, (5) technology trends, (6) economic efficiency, and (7) human resource development. Regarding 'social acceptability of nuclear energy,' the following were discussed: (1) basic human rights such as 'moral rights' and nuclear technologies, (2) risk communication and its problems, and (3) measures to improve the reliability of stakeholders involved in nuclear power. Regarding 'nuclear accident responding team,' this paper covered the nuclear accident responding unit founded in France after the nuclear accident in Japan, and nuclear accident responding unit founded in Japan. (A.O.)

Space power needs and forecasted technologies for the 1990s and beyond

International Nuclear Information System (INIS)

Buden, D.; Albert, T.

1987-01-01

A new generation of reactors for electric power will be available for space missions to satisfy military and civilian needs in the 1990s and beyond. To ensure a useful product, nuclear power plant development must be cognizant of other space power technologies. Major advances in solar and chemical technologies need to be considered in establishing the goals of future nuclear power plants. In addition, the mission needs are evolving into new regimes. Civilian and military power needs are forecasted to exceed anything used in space to date. Technology trend forecasts have been mapped as a function of time for solar, nuclear, chemical, and storage systems to illustrate areas where each technology provides minimum mass. Other system characteristics may dominate the usefulness of a technology on a given mission. This paper will discuss some of these factors, as well as forecast future military and civilian power needs and the status of technologies for the 1990s and 2000s. 6 references

The environmental interactions of tidal and wave energy generation devices

OpenAIRE

Frid, C.; Andonegi, E.; Depestele, J.; Judd, A.; Rihan, D.; Rogers, S.I.; Kenchington, E.

2012-01-01

Global energy demand continues to grow and tidal and wave energy generation devices can provide a significant source of renewable energy. Technological developments in offshore engineering and the rising cost of traditional energy means that offshore energy resources will be economic in the next few years. While there is now a growing body of data on the ecological impacts of offshore wind farms, the scientific basis on which to make informed decisions about the environmental effects of other...

Simple Tidal Prism Models Revisited

Science.gov (United States)

Luketina, D.

1998-01-01

Simple tidal prism models for well-mixed estuaries have been in use for some time and are discussed in most text books on estuaries. The appeal of this model is its simplicity. However, there are several flaws in the logic behind the model. These flaws are pointed out and a more theoretically correct simple tidal prism model is derived. In doing so, it is made clear which effects can, in theory, be neglected and which can not.

High Thrust-to-Power Annular Engine Technology

Science.gov (United States)

Patterson, Michael J.; Thomas, Robert E.; Crofton, Mark W.; Young, Jason A.; Foster, John E.

2015-01-01

Gridded ion engines have the highest efficiency and total impulse of any mature electric propulsion technology, and have been successfully implemented for primary propulsion in both geocentric and heliocentric environments with excellent ground/in-space correlation of performance. However, they have not been optimized to maximize thrust-to-power, an important parameter for Earth orbit transfer applications. This publication discusses technology development work intended to maximize this parameter. These activities include investigating the capabilities of a non-conventional design approach, the annular engine, which has the potential of exceeding the thrust-to-power of other EP technologies. This publication discusses the status of this work, including the fabrication and initial tests of a large-area annular engine. This work is being conducted in collaboration among NASA Glenn Research Center, The Aerospace Corporation, and the University of Michigan.

Admiralty Inlet Pilot Tidal Project Final Technical Report

Energy Technology Data Exchange (ETDEWEB)

Collar, Craig [Public Utility District No. 1 of Snohomish County, Everett, WA (United States)

2015-09-14

This document represents the final report for the Admiralty Inlet Pilot Tidal Project, located in Puget Sound, Washington, United States. The Project purpose was to license, permit, and install a grid-connected deep-water tidal turbine array (two turbines) to be used as a platform to gather operational and environmental data on tidal energy generation. The data could then be used to better inform the viability of commercial tidal energy generation from technical, economic, social, and environmental standpoints. This data would serve as a critical step towards the responsible advancement of commercial scale tidal energy in the United States and around the world. In late 2014, Project activities were discontinued due to escalating costs, and the DOE award was terminated in early 2015. Permitting, licensing, and engineering design activities were completed under this award. Final design, deployment, operation, and monitoring were not completed. This report discusses the results and accomplishments achieved under the subject award.

Generating power at high efficiency combined cycle technology for sustainable energy production

CERN Document Server

Jeffs, E

2008-01-01

Combined cycle technology is used to generate power at one of the highest levels of efficiency of conventional power plants. It does this through primary generation from a gas turbine coupled with secondary generation from a steam turbine powered by primary exhaust heat. Generating power at high efficiency thoroughly charts the development and implementation of this technology in power plants and looks to the future of the technology, noting the advantages of the most important technical features - including gas turbines, steam generator, combined heat and power and integrated gasification com

Tidal Forces in Dyonic Reissner-Nördstrom Black Hole

Science.gov (United States)

Sharif, M.; Kousar, Lubna

2018-03-01

This paper investigates the tidal as well as magnetic charge effects produced in dyonic Reissner-Nordström black hole. We evaluate Newtonian radial acceleration using radial geodesics for freely falling test particles. We establish system of equations governing radial and angular tidal forces using geodesic deviation equation and discuss their solutions for bodies falling freely towards this black hole. The radial tidal force turns out to be compressing outside the event horizon whereas the angular tidal force changes sign between event and Cauchy horizons unlike Schwarzschild black hole. The radial geodesic component starts decreasing in dyonic Reissner-Nordström black hole unlike Schwarzschild case. We conclude that magnetic charge strongly affects the radial as well as angular components of tidal force.

Short-term effects of tidal flooding on soil nitrogen mineralization in a Chinese tidal salt marsh

Science.gov (United States)

Gao, Haifeng; Bai, Junhong; Deng, Xiaoya; Lu, Qiongqiong; Ye, Xiaofei

2018-02-01

Tidal flooding is an important control of nitrogen biogeochemistry in wetland ecosystems of Yellow River Delta, China. Variations in hydrology could change soil redox dynamics and conditions for microorganisms living. A tidal simulation experiment was designed to extract tidal flooding effect on nitrogen mineralization of salt marsh soil. Inorganic nitrogen and relevant enzyme were measured during the 20-day incubation period. Considering the variation of both inorganic N and enzymes, nitrogen mineralization process in tidal salt marsh could be divided into 2 phases of short term response and longtime adaption by around 12th incubation day as the inflection point. Soil ammonium nitrogen (NH4+-N) and volatilized ammonia (NH3) occupied the mineralization process since nitrate nitrogen (NO3--N) was not detected over whole incubation period. NH4+-N varied fluctuant and increased significantly after 12 day's incubation. Released NH3 reached to peak value of 14.24 mg m-2 d-1 at the inflection point and declined thereafter. Inorganic nitrogen released according to net nitrogen mineralization rate (RM) under the tidal flooding condition without plant uptake except first 2 days. However, during the transitional period of 6-12 days, RM decreased notably to almost 0 and increased again after inflection point with the value of 0.182 mg kg-1 d-1. It might be due to the change of microbial composition and function when soil shifted from oxic to anoxic, which were reflected by arylamidase, urease and fluorescein diacetate. Fluorescein diacetate hydrolysis and arylamidase had the similar variation of U style with decreasing activities before 12 days' incubation. All the enzymes measured in this experiment increased after inflection point. Whereas, urease activity kept constant from 2 to 12 days. Alternant oxidation reduction condition would increase N loss through denitrification and ammonia volatilization during the transitional period, while more inorganic nitrogen would be

Groundwater Waves in a Coastal Fractured Aquifer of the Third Phase Qinshan Nuclear Power Engineering Field

Institute of Scientific and Technical Information of China (English)

ZHOU Nian-qing; TANG Yi-qun; TANG He-ping

2005-01-01

Tidal fluctuations of Hangzhou Bay produce progressive pressure waves in adjacent field fractured aquifers, as the pressure waves propagate, groundwater levels and hydraulic gradients continuously fluctuate. The effect of tidal fluctuations on groundwater flow can be determined using the mean hydraulic gradient that can be calculated by comparing mean ground and surface water elevations. Tidal fluctuation is shown to affect the piezometer readings taken in a nearshore fractured aquifer around the nuclear power engineering field. Continuous monitoring of a network of seven piezometers provided relations between the tidal cycle and the piezometer readings. The relations can be expressed in times of a time and amplitude scaling factor. The time lag and the tidal effi ciency factor and wavelength are calculated using these parameters. It provides significant scientific basis to prevent tide and groundwater for the nuclear power engineering construction and safety run of nuclear power station in the future.

Physics and application of plasmas based on pulsed power technology

International Nuclear Information System (INIS)

Hotta, Eiki; Ozaki, Tetsuo

2012-04-01

The papers presented at the symposium on 'Physics and Application of Plasmas Based on Pulsed Power Technology' held on December 21-22, 2010 at National Institute of Fusion Science are collected. The papers in this proceeding reflect the current status and progress in the experimental and theoretical researches on high power particle beams and high energy density plasmas produced by pulsed power technology. (author)

Morphodynamics of the Manyema Tidal Delta at Kunduchi, Tanzania

African Journals Online (AJOL)

Keywords: Morphodynamics, Kunduchi, Manyema, shoreline change, tidal creek, tidal delta. Abstract—The prevailing northward longshore drift of beach sand on the northern part of Msasani Bay, north of Dar es Salaam, is interrupted at Kunduchi by the tidal flushing of ... Western Indian Ocean J. Mar. Sci. Vol. 11, No. 2, pp.

Integration of Pneumatic Technology in Powered Mobility Devices.

Science.gov (United States)

Daveler, Brandon; Wang, Hongwu; Gebrosky, Benjamin; Grindle, Garrett G; Schneider, Urs; Cooper, Rory A

2017-01-01

Advances in electric motors, electronics, and control systems have enhanced the capability and drivability of electric power mobility devices over the last 60 years. Yet, battery technologies used in powered mobility devices (PMDs) have not kept pace. Recent advances in pneumatic technology, primarily the high torque, low speed design of rotary piston air motors, directly align with the needs of PMD. Pneumatic technology has advantages over battery-powered technology, including lighter weight, lower operating costs, decreased environmental impact, better reliability, and increased safety. Two prototypes were created that incorporated rotary piston air motors, high-pressure air tanks, and air-pressure regulators. Prototype 1 was created by modifying an existing electric PMD. Range tests were performed to determine the feasibility of pneumatic technology and the optimal combination of components to allow the longest range possible at acceptable speeds over ideal conditions. Using a 1.44 L air tank for feasibility testing, prototype 1 was capable of traveling 800 m, which confirmed the feasibility of pneumatic technology usage in PMDs. Prototype 2 was designed based on the testing results from prototype 1. After further optimization of prototype 2, the average maximum range was 3,150 m. Prototype 2 is up to 28.3% lighter than an equivalent size electric PMD and can be fully recharged in approximately 2 minutes. It decreases the cost of PMDs by approximately $1,500, because batteries do not need to be replaced over the lifetime of the device. The results provide justification for the use of pneumatic technology in PMDs.

Guidelines for wireless technology in nuclear power plants

International Nuclear Information System (INIS)

Shankar, Ramesh

2003-01-01

As a result of technological breakthroughs, increased demand for the use of wireless technology is common in all industries today, and the electric power industry is no exception. Already, wireless technology has many applications in our industry, including - but not limited to - cellular phone systems, paging systems, two-way radio communication systems, dose management and tracking systems, and operator logs. EPRI has prepared a comprehensive guidelines document to support evaluation of wireless technologies in power plants for integrated (voice/data/video) communication, remote equipment and system monitoring, and to complement an electronic procedures support system (EPSS). The guidelines effort focuses on the development of a rules structure to support the deployment of wireless devices in a plant without compromising continuous, safe, and reliable operation. The guidelines document consists of two volumes. The first volume is introductory in nature and lays out the business case for applying wireless technologies. The intended audience is senior plant management personnel and utility industry executives. This volume contains background information, templates, worksheets, processes, and presentations that will allow internal sponsors to create business cases for piloting wireless projects. The second volume includes guidance on implementation and regulatory issues relevant to plant implementation. It covers the following application areas: implementation of integrated communication capability, equipment monitoring, work quality control, time and knowledge management, and business process automation. It details regulatory issues relevant to the adoption of wireless technology within nuclear power plants and offers guidance on preparing for and executing pilot and implementations of wireless technologies. The paper will cover important aspects on the guidelines. (author)

Tidal extension and sea-level rise: recommendations for a research agenda

Science.gov (United States)

Ensign, Scott H.; Noe, Gregory

2018-01-01

Sea-level rise is pushing freshwater tides upstream into formerly non-tidal rivers. This tidal extension may increase the area of tidal freshwater ecosystems and offset loss of ecosystem functions due to salinization downstream. Without considering how gains in ecosystem functions could offset losses, landscape-scale assessments of ecosystem functions may be biased toward worst-case scenarios of loss. To stimulate research on this concept, we address three fundamental questions about tidal extension: Where will tidal extension be most evident, and can we measure it? What ecosystem functions are influenced by tidal extension, and how can we measure them? How do watershed processes, climate change, and tidal extension interact to affect ecosystem functions? Our preliminary answers lead to recommendations that will advance tidal extension research, enable better predictions of the impacts of sea-level rise, and help balance the landscape-scale benefits of ecosystem function with costs of response.

Adélie penguin foraging location predicted by tidal regime switching.

Science.gov (United States)

Oliver, Matthew J; Irwin, Andrew; Moline, Mark A; Fraser, William; Patterson, Donna; Schofield, Oscar; Kohut, Josh

2013-01-01

Penguin foraging and breeding success depend on broad-scale environmental and local-scale hydrographic features of their habitat. We investigated the effect of local tidal currents on a population of Adélie penguins on Humble Is., Antarctica. We used satellite-tagged penguins, an autonomous underwater vehicle, and historical tidal records to model of penguin foraging locations over ten seasons. The bearing of tidal currents did not oscillate daily, but rather between diurnal and semidiurnal tidal regimes. Adélie penguins foraging locations changed in response to tidal regime switching, and not to daily tidal patterns. The hydrography and foraging patterns of Adélie penguins during these switching tidal regimes suggest that they are responding to changing prey availability, as they are concentrated and dispersed in nearby Palmer Deep by variable tidal forcing on weekly timescales, providing a link between local currents and the ecology of this predator.

Techno-Human Mesh: The Growing Power of Information Technologies.

Science.gov (United States)

West, Cynthia K.

This book examines the intersection of information technologies, power, people, and bodies. It explores how information technologies are on a path of creating efficiency, productivity, profitability, surveillance, and control, and looks at the ways in which human-machine interface technologies, such as wearable computers, biometric technologies,…

[Evaluation of tidal volume delivered by ventilators during volume-controlled ventilation].

Science.gov (United States)

Zhou, Juan; Yan, Yong; Cao, Desen

2014-12-01

To study the ways which ensure the delivery of enough tidal volume to patients under various conditions close to the demand of the physician. The volume control ventilation model was chosen, and the simulation lung type was active servo lung ASL 5000 or Michigan lung 1601. The air resistance, air compliance and lung type in simulation lungs were set. The tidal volume was obtained from flow analyzer PF 300. At the same tidal volume, the displaying values of tidal volume of E5, Servo i, Evital 4, and Evital XL ventilators with different lung types of patient, compliance of gas piping, leakage, gas types, etc. were evaluated. With the same setting tidal volume of a same ventilator, the tidal volume delivered to patients was different with different lung types of patient, compliance of gas piping, leakage, gas types, etc. Reducing compliance and increasing resistance of the patient lungs caused high peak airway pressure, the tidal volume was lost in gas piping, and the tidal volume be delivered to the patient lungs was decreased. If the ventilator did not compensate to leakage, the tidal volume delivered to the patient lungs was decreased. When the setting gas type of ventilator did not coincide with that applying to the patient, the tidal volume be delivered to the patient lungs might be different with the setting tidal volume of ventilator. To ensure the delivery of enough tidal volume to patients close to the demand of the physician, containable factors such as the compliance of gas piping, leakage, and gas types should be controlled.

Pollution control technologies applied to coal-fired power plant operation

Directory of Open Access Journals (Sweden)

Maciej Rozpondek

2009-09-01

Full Text Available Burning of fossil fuels is the major source of energy in today's global economy with over one-third of the world's powergeneration derived from coal combustion. Although coal has been a reliable, abundant, and relatively inexpensive fuel source for mostof the 20th century, its future in electric power generation is under increasing pressure as environmental regulations become morestringent worldwide. Current pollution control technologies for combustion exhaust gas generally treat the release of regulatedpollutants: sulfur dioxide, nitrogen oxides and particulate matter as three separate problems instead of as parts of one problem. Newand improved technologies have greatly reduced the emissions produced per ton of burning coal. The term “Clean Coal CombustionTechnology” applies generically to a range of technologies designed to greatly reduce the emissions from coal-fired power plants.The wet methods of desulfurization at present are the widest applied technology in professional energetics. This method is economicand gives good final results but a future for clean technologies is the biomass. Power from biomass is a proven commercial optionof the electricity generation in the World. An increasing number of power marketers are starting to offer environmentally friendlyelectricity, including biomass power, in response to the consumer demand and regulatory requirements.

Observed tidal braking in the earth/moon/sun system

Science.gov (United States)

Christodoulidis, D. C.; Smith, D. E.; Williamson, R. G.; Klosko, S. M.

1987-01-01

The low degree and order terms in the spherical harmonic model of the tidal potential were observed through the perturbations which are induced on near-earth satellite orbital motions. Evaluations of tracking observations from 17 satellites and a GEM-T1 geopotential model were used in the tidal recovery which was made in the presence of over 600 long-wavelength coefficients from 32 major and minor tides. Wahr's earth tidal model was used as a basis for the recovery of the ocean tidal terms. Using this tidal model, the secular change in the moon's mean motion due to tidal dissipation was found to be -25.27 + or - 0.61 arcsec/century squared. The estimation of lunar acceleration agreed with that observed from lunar laser ranging techniques (-24.9 + or - 1.0 arcsec/century squared), with the corresponding tidal braking of earth's rotation being -5.98 + or - 0.22 x 10 to the minus 22 rad/second squared. If the nontidal braking of the earth due to the observed secular change in the earth's second zonal harmonic is considered, satellite techniques yield a total value of the secular change of the earth's rotation rate of -4.69 + or - 0.36 x 10 to the minus 22 rad/second squared.

Tidal exchange of larvae of Sesarma catenata (Decapoda, Brachyura)

African Journals Online (AJOL)

The tidal exchange of larvae of the salt-marsh grapsid crab Sesarma catenata was studied in the Swartkops estuary, a tidally driven, shallow estuary in Algoa Bay, South Africa. Plankton samples were collected bimonlhly during spring and neap tides from October to March at the tidal inlet. Samples were collected hourly for ...

Progress update of NASA's free-piston Stirling space power converter technology project

Science.gov (United States)

Dudenhoefer, James E.; Winter, Jerry M.; Alger, Donald

1992-01-01

A progress update is presented of the NASA LeRC Free-Piston Stirling Space Power Converter Technology Project. This work is being conducted under NASA's Civil Space Technology Initiative (CSTI). The goal of the CSTI High Capacity Power Element is to develop the technology base needed to meet the long duration, high capacity power requirements for future NASA space initiatives. Efforts are focused upon increasing system power output and system thermal and electric energy conversion efficiency at least five fold over current SP-100 technology, and on achieving systems that are compatible with space nuclear reactors. This paper will discuss progress toward 1050 K Stirling Space Power Converters. Fabrication is nearly completed for the 1050 K Component Test Power Converter (CTPC); results of motoring tests of the cold end (525 K), are presented. The success of these and future designs is dependent upon supporting research and technology efforts including heat pipes, bearings, superalloy joining technologies, high efficiency alternators, life and reliability testing, and predictive methodologies. This paper will compare progress in significant areas of component development from the start of the program with the Space Power Development Engine (SPDE) to the present work on CTPC.

Utilizing Solar Power Technologies for On-Orbit Propellant Production

Science.gov (United States)

Fikes, John C.; Howell, Joe T.; Henley, Mark W.

2006-01-01

The cost of access to space beyond low Earth orbit may be reduced if vehicles can refuel in orbit. The cost of access to low Earth orbit may also be reduced by launching oxygen and hydrogen propellants in the form of water. To achieve this reduction in costs of access to low Earth orbit and beyond, a propellant depot is considered that electrolyzes water in orbit, then condenses and stores cryogenic oxygen and hydrogen. Power requirements for such a depot require Solar Power Satellite technologies. A propellant depot utilizing solar power technologies is discussed in this paper. The depot will be deployed in a 400 km circular equatorial orbit. It receives tanks of water launched into a lower orbit from Earth, converts the water to liquid hydrogen and oxygen, and stores up to 500 metric tons of cryogenic propellants. This requires a power system that is comparable to a large Solar Power Satellite capable of several 100 kW of energy. Power is supplied by a pair of solar arrays mounted perpendicular to the orbital plane, which rotates once per orbit to track the Sun. The majority of the power is used to run the electrolysis system. Thermal control is maintained by body-mounted radiators; these also provide some shielding against orbital debris. The propellant stored in the depot can support transportation from low Earth orbit to geostationary Earth orbit, the Moon, LaGrange points, Mars, etc. Emphasis is placed on the Water-Ice to Cryogen propellant production facility. A very high power system is required for cracking (electrolyzing) the water and condensing and refrigerating the resulting oxygen and hydrogen. For a propellant production rate of 500 metric tons (1,100,000 pounds) per year, an average electrical power supply of 100 s of kW is required. To make the most efficient use of space solar power, electrolysis is performed only during the portion of the orbit that the Depot is in sunlight, so roughly twice this power level is needed for operations in sunlight

The physical characteristics of the French MRE zones. Focus on the tidal turbine sites. PP presentations

International Nuclear Information System (INIS)

Jambu, Emilie; Laporte, Patrice; Garlan, Thierry; Le Boulluec, Marc; Germain, Gregory; Michel, Sylvain; Belan, Pierre-Yves

2014-04-01

This document gathers Power Point presentations which were contributions to a workshop on French sites of marine renewable energies (MRE). A first one presents the production potential of tidal energy sites in Basse-Normandie, and how favourable areas are defined. The second one reports works performed by the SHOM to characterize the physical marine environment of French MRE sites (SHOM missions, objectives, knowledge on tidal currents, 3D current models, location of current meters offshore Cotentin and the Iroise Sea). The next contribution discusses the relationship between MREs and sedimentology in the case of different offshore wind farms and tidal energy sites. A contribution addresses modelling based on the HOMERE database (Hydrodynamics Ocean-Meteorology and Marine Renewable Energies). The next one presents programmes undertaken by the French Agency of Protected Marine Areas for a better knowledge of the natural patrimony of MRE sites. The last contribution presents the CEREMA, the development of a geographical information system to plan MRE sites, and information activities

Salmon habitat use, tidal-fluvial estuary - Columbia River Estuary Tidal Habitats

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The goal of the tidal-fluvial estuary study is to determine the estuary's contribution to the spatial structure and life history diversity of Columbia River salmon...

Earthquake potential revealed by tidal influence on earthquake size-frequency statistics

Science.gov (United States)

Ide, Satoshi; Yabe, Suguru; Tanaka, Yoshiyuki

2016-11-01

The possibility that tidal stress can trigger earthquakes is long debated. In particular, a clear causal relationship between small earthquakes and the phase of tidal stress is elusive. However, tectonic tremors deep within subduction zones are highly sensitive to tidal stress levels, with tremor rate increasing at an exponential rate with rising tidal stress. Thus, slow deformation and the possibility of earthquakes at subduction plate boundaries may be enhanced during periods of large tidal stress. Here we calculate the tidal stress history, and specifically the amplitude of tidal stress, on a fault plane in the two weeks before large earthquakes globally, based on data from the global, Japanese, and Californian earthquake catalogues. We find that very large earthquakes, including the 2004 Sumatran, 2010 Maule earthquake in Chile and the 2011 Tohoku-Oki earthquake in Japan, tend to occur near the time of maximum tidal stress amplitude. This tendency is not obvious for small earthquakes. However, we also find that the fraction of large earthquakes increases (the b-value of the Gutenberg-Richter relation decreases) as the amplitude of tidal shear stress increases. The relationship is also reasonable, considering the well-known relationship between stress and the b-value. This suggests that the probability of a tiny rock failure expanding to a gigantic rupture increases with increasing tidal stress levels. We conclude that large earthquakes are more probable during periods of high tidal stress.

Tidal pumping facilitates dissimilatory nitrate reduction in intertidal marshes

Science.gov (United States)

Zheng, Yanling; Hou, Lijun; Liu, Min; Liu, Zhanfei; Li, Xiaofei; Lin, Xianbiao; Yin, Guoyu; Gao, Juan; Yu, Chendi; Wang, Rong; Jiang, Xiaofen

2016-01-01

Intertidal marshes are alternately exposed and submerged due to periodic ebb and flood tides. The tidal cycle is important in controlling the biogeochemical processes of these ecosystems. Intertidal sediments are important hotspots of dissimilatory nitrate reduction and interacting nitrogen cycling microorganisms, but the effect of tides on dissimilatory nitrate reduction, including denitrification, anaerobic ammonium oxidation and dissimilatory nitrate reduction to ammonium, remains unexplored in these habitats. Here, we use isotope-tracing and molecular approaches simultaneously to show that both nitrate-reduction activities and associated functional bacterial abundances are enhanced at the sediment-tidal water interface and at the tide-induced groundwater fluctuating layer. This pattern suggests that tidal pumping may sustain dissimilatory nitrate reduction in intertidal zones. The tidal effect is supported further by nutrient profiles, fluctuations in nitrogen components over flood-ebb tidal cycles, and tidal simulation experiments. This study demonstrates the importance of tides in regulating the dynamics of dissimilatory nitrate-reducing pathways and thus provides new insights into the biogeochemical cycles of nitrogen and other elements in intertidal marshes. PMID:26883983

Power Amplifiers in CMOS Technology: A contribution to power amplifier theory and techniques

NARCIS (Netherlands)

Acar, M.

2011-01-01

In order to meet the demands from the market on cheaper, miniaturized mobile communications devices realization of RF power amplifiers in the mainstream CMOS technology is essential. In general, CMOS Power Amplifiers (PAs) require high voltage to decrease the matching network losses and for high

On tidal radius determination for a globular cluster

International Nuclear Information System (INIS)

Ninkovic, S.

1985-01-01

A tidal radius determination for a globular cluster based on its density minimum, which is caused by the galactic tidal forces and derivable from a model of the Galaxy, is proposed. Results obtained on the basis of the Schmidt model for two clusters are in a satisfactory agreement with those obtained earlier by means of other methods. A mass determination for the clusters through the tidal radius, when the latter one is identified with the cluster perigalactic distance, yields unusually large mass values. Probably, the tidal radius should be identified with the instantaneous galactocentric distance. Use of models more recent than the Schmidt one indicates that a globular cluster may contain a significant portion of an invisible interstellar matter. (author)

Sensitivity of growth characteristics of tidal sand ridges and long bed waves to formulations of bed shear stress, sand transport and tidal forcing : A numerical model study

NARCIS (Netherlands)

Yuan, Bing; de Swart, Huib E.; Panadès, Carles

2016-01-01

Tidal sand ridges and long bed waves are large-scale bedforms that are observed on continental shelves. They differ in their wavelength and in their orientation with respect to the principal direction of tidal currents. Previous studies indicate that tidal sand ridges appear in areas where tidal

Solar Power System Options for the Radiation and Technology Demonstration Spacecraft

Science.gov (United States)

Kerslake, Thomas W.; Haraburda, Francis M.; Riehl, John P.

2000-01-01

The Radiation and Technology Demonstration (RTD) Mission has the primary objective of demonstrating high-power (10 kilowatts) electric thruster technologies in Earth orbit. This paper discusses the conceptual design of the RTD spacecraft photovoltaic (PV) power system and mission performance analyses. These power system studies assessed multiple options for PV arrays, battery technologies and bus voltage levels. To quantify performance attributes of these power system options, a dedicated Fortran code was developed to predict power system performance and estimate system mass. The low-thrust mission trajectory was analyzed and important Earth orbital environments were modeled. Baseline power system design options are recommended on the basis of performance, mass and risk/complexity. Important findings from parametric studies are discussed and the resulting impacts to the spacecraft design and cost.

Control technology for nuclear power system of next generation

International Nuclear Information System (INIS)

1995-01-01

This report is the summary of the results obtained by the investigation activities for two years carried out by the expert committee on investigation of control technology for nuclear power system of next generation. The course of investigation is outlined, and as the results, as advanced control technologies, adaptive control. H sub (infinite) control, fuzzy control and the application of autonomous distributed system and genetic algorithm to control; as operation support technology, the operation and monitoring system for nuclear power plants and safety support system; as interface technology which is the basic technology of them, virtual reality, multimedia and so on; further, various problems due to human factors, computer technology, artificial intelligence and others were taken up, and the grasp of the present status and the future subjects was carried out, including the information in international conferences. The items of the investigation are roughly divided into measurement and control technologies, interface technology and operation support, human factors, computer technology and artificial intelligence, and the trend in foreign countries, and the results of investigation for respective items are reported. (K.I.)

Gas-fired power. IEA ETSAP technology brief E02

Energy Technology Data Exchange (ETDEWEB)

Seebregts, A.J. [Energy research Centre of the Netherlands (Netherlands)], E-mail: seebregts@ecn.nl

2010-04-15

This technology brief on gas-fired power is part of a series produced by the IEA called the energy technology data source (E-Tech-DS). The E-Tech-DS series consists of a number of 5-10 page technology briefs similar to the IEA Energy Technology Essentials. Based on the data collected for the models that the Energy Technology Systems Analysis Programme (ETSAP) is known for, ETSAP also prepares technology briefs, called E-TechDS. The E-TechDS briefs are standardized presentations of basic information (process, status, performance, costs, potential, and barriers) for key energy technology clusters. Each brief includes an overview of the technology, charts and graphs, and a summary data table, and usually ending with some key references and further information. The E TechDS briefs are intended to offer essential, reliable and quantitative information to energy analysts, experts, policymakers, investors and media from both developed and developing countries. This specific brief focuses on the state of combined-cycle gas turbines (CCGT). CCGT's have become the technology of choice for new gas-fired power plants since the 1990's.

Life cycle analysis of advanced nuclear power generation technologies

International Nuclear Information System (INIS)

Uchiyama, Yoji; Yokoyama, Hayaichi

1996-01-01

In this research, as for light water reactors and fast breeder reactors, for the object of all the processes from the mining, transport and refining of fuel, electric power generation to the treatment and disposal of waste, the amount of energy input and the quantity of CO 2 emission over the life cycle were analyzed, and regarding the influence that the technical progress of nuclear power generation exerted to environment, the effect of improvement was elucidated. Attention has been paid to nuclear power generation as its CO 2 emission is least, and the effect of global warming is smallest. In order to reduce the quantity of radioactive waste generation in LWRs and the cost of fuel cycle, and to extend the operation cycle, the technical development for heightening fuel burnup is in progress. The process of investigation of the new technologies of nuclear power generation taken up in this research is described. The analysis of the energy balance of various power generation methods is discussed. In the case of pluthermal process, the improvement of energy balance ratio is dependent on uranium enrichment technology. Nuclear power generation requires much materials and energy for the construction, and emits CO 2 indirectly. The CO 2 unit emission based on the analysis of energy balance was determined for the new technologies of nuclear power generation, and the results are shown. (K.I.)

Impact of Different Tidal Volume Levels at Low Mechanical Power on Ventilator-Induced Lung Injury in Rats

Directory of Open Access Journals (Sweden)

Lillian Moraes

2018-04-01

Full Text Available Tidal volume (VT has been considered the main determinant of ventilator-induced lung injury (VILI. Recently, experimental studies have suggested that mechanical power transferred from the ventilator to the lungs is the promoter of VILI. We hypothesized that, as long as mechanical power is kept below a safe threshold, high VT should not be injurious. The present study aimed to investigate the impact of different VT levels and respiratory rates (RR on lung function, diffuse alveolar damage (DAD, alveolar ultrastructure, and expression of genes related to inflammation [interleukin (IL-6], alveolar stretch (amphiregulin, epithelial [club cell secretory protein (CC16] and endothelial [intercellular adhesion molecule (ICAM-1] cell injury, and extracellular matrix damage [syndecan-1, decorin, and metalloproteinase (MMP-9] in experimental acute respiratory distress syndrome (ARDS under low-power mechanical ventilation. Twenty-eight Wistar rats received Escherichia coli lipopolysaccharide intratracheally. After 24 h, 21 animals were randomly assigned to ventilation (2 h with low mechanical power at three different VT levels (n = 7/group: (1 VT = 6 mL/kg and RR adjusted to normocapnia; (2 VT = 13 mL/kg; and 3 VT = 22 mL/kg. In the second and third groups, RR was adjusted to yield low mechanical power comparable to that of the first group. Mechanical power was calculated as [(ΔP,L2/Est,L/2]× RR (ΔP,L = transpulmonary driving pressure, Est,L = static lung elastance. Seven rats were not mechanically ventilated (NV and were used for molecular biology analysis. Mechanical power was comparable among groups, while VT gradually increased. ΔP,L and mechanical energy were higher in VT = 22 mL/kg than VT = 6 mL/kg and VT = 13 mL/kg (p < 0.001 for both. Accordingly, DAD score increased in VT = 22 mL/kg compared to VT = 6 mL/kg and VT = 13 mL/kg [23(18.5–24.75 vs. 16(12–17.75 and 16(13.25–18, p < 0.05, respectively]. VT = 22 mL/kg was associated with higher

Assessment of Kinetic Tidal Energy Resources Using SELFE

OpenAIRE

Manasa Ranjan Behera; Pavel Tkalich

2014-01-01

An investigation is carried out to study the theoretical tidal stream energy resource in the Singapore Strait to support the search for renewable energy in the effort to reduce the carbon footprints in the Southeast Asia. The tidal hydrodynamics in the Singapore Strait has been simulated using a Semi-implicit Eulerian-Lagrangian Finite-Element (SELFE) model solving the 3D shallow water equations with Boussinesq approximations. Potential sites, with high tidal current (2.5 m/s) and suitable fo...

Vertical Distribution of Tidal Flow Reynolds Stress in Shallow Sea

Institute of Scientific and Technical Information of China (English)

SONG Zhi-yao; NI Zhi-hui; LU Guo-nian

2009-01-01

Based on the results of the tidal flow Reynolds stresses of the field observations,indoor experiments,and numerical models,the parabolic distribution of the tidal flow Reynolds stress is proposed and its coefficients are determined theoretically in this paper.Having been well verified with the field data and experimental data,the proposed distribution of Reynolds stress is also compared with numerical model results,and a good agreement is obtained,showing that this distribution can well reflect the basic features of Reynolds stress deviating from the linear distribution that is downward when the tidal flow is of acceleration,upward when the tidal flow is of deceleration.Its dynamics cause is also discussed preliminarily and the influence of the water depth is pointed out from the definition of Reynolds stress,turbulent generation,transmission,and so on.The established expression for the vertical distribution of the tidal flow Reynolds stress is not only simple and explicit,but can also well reflect the features of the tidal flow acceleration and deceleration for further study on the velocity profile of tidal flow.

Space Solar Power Technology Demonstration for Lunar Polar Applications

Science.gov (United States)

Henley, M. W.; Fikes, J. C.; Howell, J.; Mankins, J. C.; Howell, J.

2002-01-01

A solar power generation station on a mountaintop near the moon's North or South pole can receive sunlight 708 hours per lunar day, for continuous power generation. Power can be beamed from this station over long distances using a laser-based wireless power transmission system and a photo-voltaic receiver. This beamed energy can provide warmth, electricity, and illumination for a robotic rover to perform scientific experiments in cold, dark craters where no other power source is practical. Radio-frequency power transmission may also be demonstrated in lunar polar applications to locate and recover sub-surface deposits of volatile material, such as water ice. High circular polarization ratios observed in data from Clementine spacecraft and Arecibo radar reflections from the moon's South pole suggest that water ice is indeed present in certain lunar polar craters. Data from the Lunar Prospector spacecraft's epi-thermal neutron spectrometer also indicate that hydrogen is present at the moon's poles. Space Solar Power technology enables investigation of these craters, which may contain a billion-year-old stratigraphic record of tremendous scientific value. Layers of ice, preserved at the moon's poles, could help us determine the sequence and composition of comet impacts on the moon. Such ice deposits may even include distinct strata deposited by secondary ejecta following significant Earth (ocean) impacts, linked to major extinctions of life on Earth. Ice resources at the moon's poles could provide water and air for human exploration and development of space as well as rocket propellant for future space transportation. Technologies demonstrated and matured via lunar polar applications can also be used in other NASA science missions (Valles Marineris. Phobos, Deimos, Mercury's poles, asteroids, etc.) and in future large-scale SSP systems to beam energy from space to Earth. Ground-based technology demonstrations are proceeding to mature the technology for such a near

Infrared emission and tidal interactions of spiral galaxies

International Nuclear Information System (INIS)

Byrd, G.G.

1987-01-01

Computer simulations of tidal interactions of spiral galaxies are used to attempt to understand recent discoveries about infrared (IR) emitting galaxies. It is found that the stronger tidal perturbation by a companion the more disk gas clouds are thrown into nucleus crossing orbits and the greater the velocity jumps crossing spiral arms. Both these tidally created characteristics would create more IR emission by high speed cloud collisions and more IR via effects of recently formed stars. This expectation at greater tidal perturbation matches the observation of greater IR emission for spiral galaxies with closer and/or more massive companions. The greater collision velocities found at stronger perturbations on the models will also result in higher dust temperature in the colliding clouds. In the IR pairs examined, most have only one member, the larger, detected and when both are detected, the larger is always the more luminous. In simulations and in a simple analytic description of the strong distance dependence of the tidal force, it is found that the big galaxy of a pair is more strongly affected than the small

On the Formation of Ultra-Difuse Galaxies as Tidally-Stripped Systems