A flexible control strategy of plug-in electric vehicles operating in seven modes for smoothing load power curves in smart grid

International Nuclear Information System (INIS)

Khemakhem, Siwar; Rekik, Mouna; Krichen, Lotfi

2017-01-01

Plug-in electric vehicles (PEVs) seem to be an interesting new electrical load for improving the reliability of smart grid. The purpose of this work is to investigate a supervision strategy based on regulated charging of PEVs in order to guarantee an optimized power management of the system and consequently a flatter power demand curve. The system mainly includes PEVs powered by a Lithium-ion battery ensuring the charging and discharging operations of these PEVs at home and a daily load power demanded by home appliances. The purpose of the considered strategy is to detect the connection status of each PEV and to establish the priority order between these PEVs with certain flexibility which results in managing the PEVs through seven operating modes. The response of the control algorithm enables to ensure the power flow exchange between the PEVs and the electrical grid, especially at rush hours, and to minimize load power variance aiming to achieve the smoothness for the power demand curve and to reduce the stress of the electrical grid. The simulation results are presented in order to illustrate the efficiency of this power control approach. - Highlights: • A flexible power management algorithm of Plug-in electric vehicle is proposed. • This control can be applied for any home equipped with two PEVs. • The response is to ensure the power flow exchange between PEVs and power grid. • The main contribution is to achieve the smoothness for the daily power demand curve.

Evaluation of the electric vehicle impact in the power demand curve in a smart grid environment

International Nuclear Information System (INIS)

Morais, Hugo; Sousa, Tiago; Vale, Zita; Faria, Pedro

2014-01-01

Highlights: • Multi-objective optimization of operation costs and load factor. • Contribution of electric vehicles to load diagram leveling. • Use of epigraph variables to transform non-convex functions in convex ones. • Evaluation of the obtained results considering different EVs penetration. - Abstract: Smart grids with an intensive penetration of distributed energy resources will play an important role in future power system scenarios. The intermittent nature of renewable energy sources brings new challenges, requiring an efficient management of those sources. Additional storage resources can be beneficially used to address this problem; the massive use of electric vehicles, particularly of vehicle-to-grid (usually referred as gridable vehicles or V2G), becomes a very relevant issue. This paper addresses the impact of Electric Vehicles (EVs) in system operation costs and in power demand curve for a distribution network with large penetration of Distributed Generation (DG) units. An efficient management methodology for EVs charging and discharging is proposed, considering a multi-objective optimization problem. The main goals of the proposed methodology are: to minimize the system operation costs and to minimize the difference between the minimum and maximum system demand (leveling the power demand curve). The proposed methodology perform the day-ahead scheduling of distributed energy resources in a distribution network with high penetration of DG and a large number of electric vehicles. It is used a 32-bus distribution network in the case study section considering different scenarios of EVs penetration to analyze their impact in the network and in the other energy resources management

Demand Side Management: An approach to peak load smoothing

Science.gov (United States)

Gupta, Prachi

A preliminary national-level analysis was conducted to determine whether Demand Side Management (DSM) programs introduced by electric utilities since 1992 have made any progress towards their stated goal of reducing peak load demand. Estimates implied that DSM has a very small effect on peak load reduction and there is substantial regional and end-user variability. A limited scholarly literature on DSM also provides evidence in support of a positive effect of demand response programs. Yet, none of these studies examine the question of how DSM affects peak load at the micro-level by influencing end-users' response to prices. After nearly three decades of experience with DSM, controversy remains over how effective these programs have been. This dissertation considers regional analyses that explore both demand-side solutions and supply-side interventions. On the demand side, models are estimated to provide in-depth evidence of end-user consumption patterns for each North American Electric Reliability Corporation (NERC) region, helping to identify sectors in regions that have made a substantial contribution to peak load reduction. The empirical evidence supports the initial hypothesis that there is substantial regional and end-user variability of reductions in peak demand. These results are quite robust in rapidly-urbanizing regions, where air conditioning and lighting load is substantially higher, and regions where the summer peak is more pronounced than the winter peak. It is also evident from the regional experiences that active government involvement, as shaped by state regulations in the last few years, has been successful in promoting DSM programs, and perhaps for the same reason we witness an uptick in peak load reductions in the years 2008 and 2009. On the supply side, we estimate the effectiveness of DSM programs by analyzing the growth of capacity margin with the introduction of DSM programs. The results indicate that DSM has been successful in offsetting the

Demand side management program evaluation based on industrial and commercial field data

International Nuclear Information System (INIS)

Eissa, M.M.

2011-01-01

Demand Response is increasingly viewed as an important tool for use by the electric utility industry in meeting the growing demand for electricity. There are two basic categories of demand response options: time varying retail tariffs and incentive Demand Response Programs. is applying the time varying retail tariffs program, which is not suitable according to the studied load curves captured from the industrial and commercial sectors. Different statistical studies on daily load curves for consumers connected to 22 kV lines are classified. The load curve criteria used for classification is based on peak ratio and night ratio. The data considered here is a set of 120 annual load curves corresponding to the electric power consumption (the western area in the King Saudi Arabia (KSA)) of many clients in winter and some months in the summer (peak period). The study is based on real data from several Saudi customer sectors in many geographical areas with larger commercial and industrial customers. The study proved that the suitable Demand Response for the ESC is the incentive program. - Highlights: → Study helps in selecting the proper demand side program. → A credit will be given for the customers during summer months. → Reduction in the electric bill. → Monthly bill credit is decreased based on customers' peak load reduction. → Guide for applying the proper demand side program suitable for the utility and customers.

The maximum contraceptive prevalence 'demand curve': guiding discussions on programmatic investments.

Science.gov (United States)

Weinberger, Michelle; Sonneveldt, Emily; Stover, John

2017-12-22

Most frameworks for family planning include both access and demand interventions. Understanding how these two are linked and when each should be prioritized is difficult. The maximum contraceptive prevalence 'demand curve' was created based on a relationship between the modern contraceptive prevalence rate (mCPR) and mean ideal number of children to allow for a quantitative assessment of the balance between access and demand interventions. The curve represents the maximum mCPR that is likely to be seen given fertility intentions and related norms and constructs that influence contraceptive use. The gap between a country's mCPR and this maximum is referred to as the 'potential use gap.' This concept can be used by countries to prioritize access investments where the gap is large, and discuss implications for future contraceptive use where the gap is small. It is also used within the FP Goals model to ensure mCPR growth from access interventions does not exceed available demand.

Assessment of Industrial Load for Demand Response across Western Interconnect

Energy Technology Data Exchange (ETDEWEB)

Alkadi, Nasr E [ORNL; Starke, Michael R [ORNL; Ma, Ookie [United States Department of Energy (DOE), Office of Efficiency and Renewable Energy (EERE)

2013-11-01

Demand response (DR) has the ability to both increase power grid reliability and potentially reduce operating system costs. Understanding the role of demand response in grid modeling has been difficult due to complex nature of the load characteristics compared to the modeled generation and the variation in load types. This is particularly true of industrial loads, where hundreds of different industries exist with varying availability for demand response. We present a framework considering industrial loads for the development of availability profiles that can provide more regional understanding and can be inserted into analysis software for further study. The developed framework utilizes a number of different informational resources, algorithms, and real-world measurements to perform a bottom-up approach in the development of a new database with representation of the potential demand response resource in the industrial sector across the U.S. This tool houses statistical values of energy and demand response (DR) potential by industrial plant and geospatially locates the information for aggregation for different territories without proprietary information. This report will discuss this framework and the analyzed quantities of demand response for Western Interconnect (WI) in support of evaluation of the cost production modeling with power grid modeling efforts of demand response.

Influential Factors for Accurate Load Prediction in a Demand Response Context

DEFF Research Database (Denmark)

Wollsen, Morten Gill; Kjærgaard, Mikkel Baun; Jørgensen, Bo Nørregaard

2016-01-01

Accurate prediction of a buildings electricity load is crucial to respond to Demand Response events with an assessable load change. However, previous work on load prediction lacks to consider a wider set of possible data sources. In this paper we study different data scenarios to map the influence....... Next, the time of day that is being predicted greatly influence the prediction which is related to the weather pattern. By presenting these results we hope to improve the modeling of building loads and algorithms for Demand Response planning.......Accurate prediction of a buildings electricity load is crucial to respond to Demand Response events with an assessable load change. However, previous work on load prediction lacks to consider a wider set of possible data sources. In this paper we study different data scenarios to map the influence...

Effect of reverse cyclic loading on the fracture resistance curve of nuclear piping material

International Nuclear Information System (INIS)

Weon, Jong Il; Seok, Chang Sung

1999-01-01

Fracture resistance (J-R) curves, which are used for the elastic-plastic fracture mechanics analyses, are known to be dependent on the cyclic loading history. The objective of this paper is to study the effect of reverse cyclic loading on J-R curves in CT specimens. The effect of two parameters was observed on the J-R curves during the reverse cyclic loading. One was the minimum-to-maximum load ratio (R) and the other was the incremental plastic displacement (δ cycle /δ i ), which is related to the amount of crack growth that occurs in a cycle. Fracture resistance test on CT specimens with varying load ratio and incremental plastic displacement were performed. For the SA 516 Gr. 70 steel, the results showed that the J-R curves were decreased with decreasing the load ratio and the incremental plastic displacement. When the load ratio was set to -1, the results of the J-R curves and the J i value were about 40-50 percent of those for the monotonic loading condition. Also on condition that the incremental plastic displacement reached 1/40, the J-R curves and the J i value were about 50-60 percent of those for the incremental plastic displacement of 1/10

Load curves of industrial consumers: aggregation with other loads; Curvas de carga de consumidores industriais - agregacao com outras cargas

Energy Technology Data Exchange (ETDEWEB)

Casolari, Ronaldo Pedro; Jardini, Jose Antonio

1996-07-01

This work presents a methodology for load curves of industrial consumers, considering voltages up to 13.8 kV and inclusive. Initially, load curves representing the most significant activities were obtained, by performing a research of the industrial consumers from a survey of consumers and the respective month basis electric power consumption. The analysis similarity among the curves of various activities was conducted without using of any appropriated software, in accordance with the results obtained from the study of the commercial area. A computer program was developed for the determination of the expected loading in primary transformers and feeders, from representative curves and the month basis consumption of the consumers connected to those systems, considering the residential, commercial and industrial sectors. The test of the proposed methodology, for evaluation of loading of transformers and feeders, was performed by comparing the obtained curves with the measurements conducted by the electric power utilities in a transformer and a feeder.

Non-ideal assembly of the driving unit affecting shape of load-displacement curves

International Nuclear Information System (INIS)

Huang, Hu; Zhao, Hongwei

2015-01-01

The results of nanoindentation testing strongly rely on load-displacement curves, but an abnormal load-displacement curve with obvious inflection in the unloading portion was commonly observed in previously published papers and the reason is not clear. In this paper, possible reasons involved in a custom-made indentation instrument, such as sensors, control and assembly issues, are analyzed and discussed step by step. Experimental results indicate that non-ideal assembly of the precision driving unit strongly affects the shape of the load-displacement curve and its affecting mechanism is studied by theoretical analysis and finite element simulations. This paper reveals the reason leading to the abnormal load-displacement curve, which is helpful for debugging of indentation instruments and can enhance comparability of indentation results. (paper)

Load Reduction, Demand Response and Energy Efficient Technologies and Strategies

Energy Technology Data Exchange (ETDEWEB)

Boyd, Paul A.; Parker, Graham B.; Hatley, Darrel D.

2008-11-19

The Department of Energy’s (DOE’s) Pacific Northwest National Laboratory (PNNL) was tasked by the DOE Office of Electricity (OE) to recommend load reduction and grid integration strategies, and identify additional demand response (energy efficiency/conservation opportunities) and strategies at the Forest City Housing (FCH) redevelopment at Pearl Harbor and the Marine Corps Base Hawaii (MCBH) at Kaneohe Bay. The goal was to provide FCH staff a path forward to manage their electricity load and thus reduce costs at these FCH family housing developments. The initial focus of the work was at the MCBH given the MCBH has a demand-ratchet tariff, relatively high demand (~18 MW) and a commensurate high blended electricity rate (26 cents/kWh). The peak demand for MCBH occurs in July-August. And, on average, family housing at MCBH contributes ~36% to the MCBH total energy consumption. Thus, a significant load reduction in family housing can have a considerable impact on the overall site load. Based on a site visit to the MCBH and meetings with MCBH installation, FCH, and Hawaiian Electric Company (HECO) staff, recommended actions (including a "smart grid" recommendation) that can be undertaken by FCH to manage and reduce peak-demand in family housing are made. Recommendations are also made to reduce overall energy consumption, and thus reduce demand in FCH family housing.

Curved bones: An adaptation to habitual loading.

Science.gov (United States)

Milne, Nick

2016-10-21

Why are long bones curved? It has long been considered a paradox that many long bones supporting mammalian bodies are curved, since this curvature results in the bone undergoing greater bending, with higher strains and so greater fracture risk under load. This study develops a theoretical model wherein the curvature is a response to bending strains imposed by the requirements of locomotion. In particular the radioulna of obligate quadrupeds is a lever operated by the triceps muscle, and the bending strains induced by the triceps muscle counter the bending resulting from longitudinal loads acting on the curved bone. Indeed the theoretical model reverses this logic and suggests that the curvature is itself a response to the predictable bending strains induced by the triceps muscle. This, in turn, results in anatomical arrangements of bone, muscle and tendon that create a simple physiological mechanism whereby the bone can resist the bending due to the action of triceps in supporting and moving the body. The model is illustrated by contrasting the behaviour of a finite element model of a llama radioulna to that of a straightened version of the same bone. The results show that longitudinal and flexor muscle forces produce bending strains that effectively counter strains due to the pull of the triceps muscle in the curved but not in the straightened model. It is concluded that the curvature of these and other curved bones adds resilience to the skeleton by acting as pre-stressed beams or strainable pre-buckled struts. It is also proposed that the cranial bending strains that result from triceps, acting on the lever that is the radioulna, can explain the development of the curvature of such bones. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

Start point to savings - Better load demand analysis in commercial buildings

Energy Technology Data Exchange (ETDEWEB)

Abaravicius, Juozas; Pyrko, Jurek [Lund Univ., Dept of Energy Sciences (Sweden)

2007-07-01

Existing installations and energy systems in most commercial buildings could be used in a more efficient way to provide savings - both in terms of energy and load demand. The key for effective operation is a thorough and detailed analysis of energy use patterns that creates essential baseline for energy savings and the development of demand response (DR) strategies. The knowledge of energy demand variations is still very limited and the use of methods to analyse the load demand is rare. Many utilities have recently installed interval (hourly) metering even for smaller commercial users and households. This is a big step forward; however, experience shows that the data is being used only to a limited extent, mostly for billing purposes only. This paper reports about a study conducted with the objective of developing a detailed load demand analysis for commercial buildings. The study results should provide essential information for the formation and evaluation of future DR and energy efficiency strategies. This study was performed in collaboration with IKEA and E.ON and contributes to an ongoing IKEA energy efficiency programme. Two sample department stores in Sweden were selected and analysed within this project. The demand data analysis covers almost 3 years period, 2004-2006.This study contributes to new knowledge of energy use patterns (load demand) in commercial buildings. It proposes solutions of load-related problems, evaluates energy and load savings potential, identifies and analyses the needs, motives and barriers for participation in DR programmes. The study provides recommendations for ongoing and future efficiency and DR strategies and discusses the potential economic benefits from the DR measures.

Impact of onsite solar generation on system load demand forecast

International Nuclear Information System (INIS)

Kaur, Amanpreet; Pedro, Hugo T.C.; Coimbra, Carlos F.M.

2013-01-01

Highlights: • We showed the impact onsite solar generation on system demand load forecast. • Forecast performance degrades by 9% and 3% for 1 h and 15 min forecast horizons. • Error distribution for onsite case is best characterized as t-distribution. • Relation between error, solar penetration and solar variability is characterized. - Abstract: Net energy metering tariffs have encouraged the growth of solar PV in the distribution grid. The additional variability associated with weather-dependent renewable energy creates new challenges for power system operators that must maintain and operate ancillary services to balance the grid. To deal with these issues power operators mostly rely on demand load forecasts. Electric load forecast has been used in power industry for a long time and there are several well established load forecasting models. But the performance of these models for future scenario of high renewable energy penetration is unclear. In this work, the impact of onsite solar power generation on the demand load forecast is analyzed for a community that meets between 10% and 15% of its annual power demand and 3–54% of its daily power demand from a solar power plant. Short-Term Load Forecasts (STLF) using persistence, machine learning and regression-based forecasting models are presented for two cases: (1) high solar penetration and (2) no penetration. Results show that for 1-h and 15-min forecasts the accuracy of the models drops by 9% and 3% with high solar penetration. Statistical analysis of the forecast errors demonstrate that the error distribution is best characterized as a t-distribution for the high penetration scenario. Analysis of the error distribution as a function of daily solar penetration for different levels of variability revealed that the solar power variability drives the forecast error magnitude whereas increasing penetration level has a much smaller contribution. This work concludes that the demand forecast error distribution

Income inequality and price elasticity of market demand: the case of crossing Lorenz curves

OpenAIRE

Ibragimov, M; Ibragimov, R; Kattuman, Paul Antony; Ma, J

2017-01-01

This paper extends Ibragimov and Ibragimov (Econ Theory 32:579–587, 2007) in which the effect of changes income inequality on the price elasticity of market demand is characterized for the class of income distribution changes occurring through non-intersecting Lorenz curve shifts. We derive sufficient conditions for increase/decrease in price elasticity of market demand, under general changes in income distribution, allowing Lorenz curves to intersect as they shift. We conclude by drawing out...

Calculation approaches for grid usage fees to influence the load curve in the distribution grid level; Berechnungsansaetze fuer Netznutzungsentgelte zur Beeinflussung des Lastverlaufs in der Verteilernetzebene

Energy Technology Data Exchange (ETDEWEB)

Illing, Bjoern

2014-09-08

Dominated by the energy policy the decentralized German energy market is changing. One mature target of the government is to increase the contribution of renewable generation to the gross electricity consumption. In order to achieve this target disadvantages like an increased need for capacity management occurs. Load reduction and variable grid fees offer the grid operator solutions to realize capacity management by influencing the load profile. The evolution of the current grid fees towards more causality is required to adapt these approaches. Two calculation approaches are developed in this assignment. On the one hand multivariable grid fees keeping the current components demand and energy charge. Additional to the grid costs grid load dependent parameters like the amount of decentralized feed-ins, time and local circumstances as well as grid capacities are considered. On the other hand the grid fee flat-rate which represents a demand based model on a monthly level. Both approaches are designed to meet the criteria for future grid fees. By means of a case study the effects of the grid fees on the load profile at the low voltage grid is simulated. Thereby the consumption is represented by different behaviour models and the results are scaled at the benchmark grid area. The resulting load curve is analyzed concerning the effects of peak load reduction as well as the integration of renewable energy sources. Additionally the combined effect of grid fees and electricity tariffs is evaluated. Finally the work discusses the launching of grid fees in the tense atmosphere of politics, legislation and grid operation. Results of this work are two calculation approaches designed for grid operators to define the grid fees. Multivariable grid fees are based on the current calculation scheme. Hereby demand and energy charges are weighted by time, locational and load related dependencies. The grid fee flat-rate defines a limitation in demand extraction. Different demand levels

Effect of reverse cyclic loading on the fracture resistance curve in C(T) specimen

International Nuclear Information System (INIS)

Sung Seok, C.; Jin Kim, Y.; Il Weon, J.

1999-01-01

Fracture resistance (J-R) curves, which are used for elastic-plastic fracture mechanics analyses, are known to be dependent on the cyclic loading history. The objective of this paper is to investigate the effect of reverse cyclic loading on the J-R curves in C(T) specimens. The effect of two parameters was observed on the J-R curves during the reverse cyclic loading. One was the minimum-to-maximum load ratio (R) and the other was the incremental plastic displacement (δ cycle /δ i ), which is related to the amount of crack growth that occurs in a cycle. Fracture resistance tests on C(T) specimens with varying the load ratio and the incremental plastic displacement were performed, and the test results showed that the J-R curves were decreased with decreasing the load ratio and decreasing the incremental plastic displacement. Direct current potential drop (DCPD) method was used for the detection of crack initiation and crack growth in typical laboratory J-R tests. The values of crack initiation J-integral (J I ) and crack initiation displacement (δ i ) were also obtained by using the DCPD method. (orig.)

Modeling and Analysis of Commercial Building Electrical Loads for Demand Side Management

Science.gov (United States)

Berardino, Jonathan

In recent years there has been a push in the electric power industry for more customer involvement in the electricity markets. Traditionally the end user has played a passive role in the planning and operation of the power grid. However, many energy markets have begun opening up opportunities to consumers who wish to commit a certain amount of their electrical load under various demand side management programs. The potential benefits of more demand participation include reduced operating costs and new revenue opportunities for the consumer, as well as more reliable and secure operations for the utilities. The management of these load resources creates challenges and opportunities to the end user that were not present in previous market structures. This work examines the behavior of commercial-type building electrical loads and their capacity for supporting demand side management actions. This work is motivated by the need for accurate and dynamic tools to aid in the advancement of demand side operations. A dynamic load model is proposed for capturing the response of controllable building loads. Building-specific load forecasting techniques are developed, with particular focus paid to the integration of building management system (BMS) information. These approaches are tested using Drexel University building data. The application of building-specific load forecasts and dynamic load modeling to the optimal scheduling of multi-building systems in the energy market is proposed. Sources of potential load uncertainty are introduced in the proposed energy management problem formulation in order to investigate the impact on the resulting load schedule.

The role of the demand-duration curve in the evaluation of power station installation policies. Remarks on its effects on stations' utilization, generating capacity, load factor history and consumptions

International Nuclear Information System (INIS)

Graziani, G.; Maineri, M.; Zanantoni, C.

1976-12-01

The role of the load-duration curve in determining the installation policy for an electric power system, is examined. The effect of the priority order for the allocation of the power stations in the load-diagram is also discussed: in the model used here (program TOTEM) this priority is given as a function of type and age of the station. The significance of the load factor history for a power station as a function of its age is also discussed. It is suggested that such a curve be deduced as a result of strategy calculations made with TOTEM rather than assumping it as input data

A Closed-Loop Control Strategy for Air Conditioning Loads to Participate in Demand Response

Directory of Open Access Journals (Sweden)

Xiaoqing Hu

2015-08-01

Full Text Available Thermostatically controlled loads (TCLs, such as air conditioners (ACs, are important demand response resources—they have a certain heat storage capacity. A change in the operating status of an air conditioner in a small range will not noticeably affect the users’ comfort level. Load control of TCLs is considered to be equivalent to a power plant of the same capacity in effect, and it can significantly reduce the system pressure to peak load shift. The thermodynamic model of air conditioning can be used to study the aggregate power of a number of ACs that respond to the step signal of a temperature set point. This paper analyzes the influence of the parameters of each AC in the group to the indoor temperature and the total load, and derives a simplified control model based on the two order linear time invariant transfer function. Then, the stability of the model and designs its Proportional-Integral-Differential (PID controller based on the particle swarm optimization (PSO algorithm is also studied. The case study presented in this paper simulates both scenarios of constant ambient temperature and changing ambient temperature to verify the proposed transfer function model and control strategy can closely track the reference peak load shifting curves. The study also demonstrates minimal changes in the indoor temperature and the users’ comfort level.

Use of loading-unloading compression curves in medical device design

Science.gov (United States)

Ciornei, M. C.; Alaci, S.; Ciornei, F. C.; Romanu, I. C.

2017-08-01

The paper presents a method and experimental results regarding mechanical testing of soft materials. In order to characterize the mechanical behaviour of technological materials used in prosthesis, a large number of material constants are required, as well as the comparison to the original. The present paper proposes as methodology the comparison between compression loading-unloading curves corresponding to a soft biological tissue and to a synthetic material. To this purpose, a device was designed based on the principle of the dynamic harness test. A moving load is considered and the force upon the indenter is controlled for loading-unloading phases. The load and specimen deformation are simultaneously recorded. A significant contribution of this paper is the interpolation of experimental data by power law functions, a difficult task because of the instability of the system of equations to be optimized. Finding the interpolation function was simplified, from solving a system of transcendental equations to solving a unique equation. The characteristic parameters of the experimentally curves must be compared to the ones corresponding to actual tissue. The tests were performed for two cases: first, using a spherical punch, and second, for a flat-ended cylindrical punch.

Spatial electric load forecasting

CERN Document Server

Willis, H Lee

2002-01-01

Spatial Electric Load Forecasting Consumer Demand for Power and ReliabilityCoincidence and Load BehaviorLoad Curve and End-Use ModelingWeather and Electric LoadWeather Design Criteria and Forecast NormalizationSpatial Load Growth BehaviorSpatial Forecast Accuracy and Error MeasuresTrending MethodsSimulation Method: Basic ConceptsA Detailed Look at the Simulation MethodBasics of Computerized SimulationAnalytical Building Blocks for Spatial SimulationAdvanced Elements of Computerized SimulationHybrid Trending-Simulation MethodsAdvanced

Assessment of Industrial Load for Demand Response across U.S. Regions of the Western Interconnect

Energy Technology Data Exchange (ETDEWEB)

Starke, Michael [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Alkadi, Nasr [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ma, Ookie [USDOE Office of Energy Efficiency and Renewable Energy (EERE), Washington, DC (United States)

2013-09-01

Demand response has the ability to both increase power grid reliability and potentially reduce operating system costs. Understanding the role of demand response in grid modeling has been difficult due to complex nature of the load characteristics compared to the modeled generation and the variation in load types. This is particularly true of industrial loads, where hundreds of different industries exist with varying availability for demand response. We present a framework considering industrial loads for the development of availability profiles for demand response that can provide more regional understanding and can be inserted into analysis software for further study.

Aggregate modeling of fast-acting demand response and control under real-time pricing

International Nuclear Information System (INIS)

Chassin, David P.; Rondeau, Daniel

2016-01-01

Highlights: • Demand elasticity for fast-acting demand response load under real-time pricing. • Validated first-principles logistic demand curve matches random utility model. • Logistic demand curve suitable for diversified aggregate loads market-based transactive control systems. - Abstract: This paper develops and assesses the performance of a short-term demand response (DR) model for utility load control with applications to resource planning and control design. Long term response models tend to underestimate short-term demand response when induced by prices. This has two important consequences. First, planning studies tend to undervalue DR and often overlook its benefits in utility demand management program development. Second, when DR is not overlooked, the open-loop DR control gain estimate may be too low. This can result in overuse of load resources, control instability and excessive price volatility. Our objective is therefore to develop a more accurate and better performing short-term demand response model. We construct the model from first principles about the nature of thermostatic load control and show that the resulting formulation corresponds exactly to the Random Utility Model employed in economics to study consumer choice. The model is tested against empirical data collected from field demonstration projects and is shown to perform better than alternative models commonly used to forecast demand in normal operating conditions. The results suggest that (1) existing utility tariffs appear to be inadequate to incentivize demand response, particularly in the presence of high renewables, and (2) existing load control systems run the risk of becoming unstable if utilities close the loop on real-time prices.

A System Architecture for Autonomous Demand Side Load Management in Smart Buildings

DEFF Research Database (Denmark)

Costanzo, Giuseppe Tommaso; Zhu, Guchuan; Anjos, Miguel F.

2012-01-01

This paper presents a system architecture for load management in smart buildings which enables autonomous demand side load management in the smart grid. Being of a layered structure composed of three main modules for admission control, load balancing, and demand response management...... in multiple time-scales and allows seamless integration of diverse techniques for online operation control, optimal scheduling, and dynamic pricing. The design of a home energy manager based on this architecture is illustrated and the simulation results with Matlab/Simulink confirm the viability...

Demand response driven load pattern elasticity analysis for smart households

NARCIS (Netherlands)

Paterakis, N.G.; Catalao, J.P.S.; Tascikaraoglu, A.; Bakirtzis, A.G.; Erdinc, O.

2015-01-01

The recent interest in smart grid vision enables several smart applications in different parts of the power grid structure, where specific importance should be given to the demand side. As a result, changes in load patterns due to demand response (DR) activities at end-user premises, such as smart

Influence of sweeping detonation-wave loading on damage evolution during spallation loading of tantalum in both a planar and curved geometry

Energy Technology Data Exchange (ETDEWEB)

Gray, George Thompson III [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hull, Lawrence Mark [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Livescu, Veronica [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Faulkner, James [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Briggs, Matthew E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Meyer, Ross Keith [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Andrews, Heather Lynn [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hare, Steven John [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Jakulewicz, Micah Shawn [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Shinas, Michael A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2015-03-30

Widespread research over the past five decades has provided a wealth of experimental data and insight concerning the shock hardening, damage evolution, and the spallation response of materials subjected to square-topped shock-wave loading profiles. However, fewer quantitative studies have been conducted on the effect of direct, in-contact, high explosive (HE)-driven Taylor wave (unsupported shocks) loading on the shock hardening, damage evolution, or spallation response of materials. Systematic studies quantifying the effect of sweeping-detonation wave loading are yet sparser. In this study, the damage evolution and spallation response of Ta is shown to be critically dependent on the peak shock stress, the geometry of the sample (flat or curved plate geometry), and the shock obliquity during sweeping-detonation-wave shock loading. Sweepingwave loading in the flat-plate geometry is observed to: a) yield a lower spall strength than previously documented for 1-D supported-shock-wave loading, b) exhibit increased shock hardening as a function of increasing obliquity, and c) lead to an increased incidence of deformation twin formation with increasing shock obliquity. Sweeping-wave loading of a 10 cm radius curved Ta plate is observed to: a) lead to an increase in the shear stress as a function of increasing obliquity, b) display a more developed level of damage evolution, extensive voids and coalescence, and lower spall strength with obliquity in the curved plate than seen in the flat-plate sweeping-detonation wave loading for an equivalent HE loading, and c) no increased propensity for deformation twin formation with increasing obliquity as seen in the flat-plate geometry. The overall observations comparing and contrasting the flat versus curved sweeping-wave spall experiments with 1D loaded spallation behavior suggests a coupled influence of obliquity and geometry on dynamic shock-induced damage evolution and spall strength. Coupled experimental and modeling research

Development of p-y curves of laterally loaded piles in cohesionless soil.

Science.gov (United States)

Khari, Mahdy; Kassim, Khairul Anuar; Adnan, Azlan

2014-01-01

The research on damages of structures that are supported by deep foundations has been quite intensive in the past decade. Kinematic interaction in soil-pile interaction is evaluated based on the p-y curve approach. Existing p-y curves have considered the effects of relative density on soil-pile interaction in sandy soil. The roughness influence of the surface wall pile on p-y curves has not been emphasized sufficiently. The presented study was performed to develop a series of p-y curves for single piles through comprehensive experimental investigations. Modification factors were studied, namely, the effects of relative density and roughness of the wall surface of pile. The model tests were subjected to lateral load in Johor Bahru sand. The new p-y curves were evaluated based on the experimental data and were compared to the existing p-y curves. The soil-pile reaction for various relative density (from 30% to 75%) was increased in the range of 40-95% for a smooth pile at a small displacement and 90% at a large displacement. For rough pile, the ratio of dense to loose relative density soil-pile reaction was from 2.0 to 3.0 at a small to large displacement. Direct comparison of the developed p-y curve shows significant differences in the magnitude and shapes with the existing load-transfer curves. Good comparison with the experimental and design studies demonstrates the multidisciplinary applications of the present method.

Development of p-y Curves of Laterally Loaded Piles in Cohesionless Soil

Science.gov (United States)

Khari, Mahdy; Kassim, Khairul Anuar; Adnan, Azlan

2014-01-01

The research on damages of structures that are supported by deep foundations has been quite intensive in the past decade. Kinematic interaction in soil-pile interaction is evaluated based on the p-y curve approach. Existing p-y curves have considered the effects of relative density on soil-pile interaction in sandy soil. The roughness influence of the surface wall pile on p-y curves has not been emphasized sufficiently. The presented study was performed to develop a series of p-y curves for single piles through comprehensive experimental investigations. Modification factors were studied, namely, the effects of relative density and roughness of the wall surface of pile. The model tests were subjected to lateral load in Johor Bahru sand. The new p-y curves were evaluated based on the experimental data and were compared to the existing p-y curves. The soil-pile reaction for various relative density (from 30% to 75%) was increased in the range of 40–95% for a smooth pile at a small displacement and 90% at a large displacement. For rough pile, the ratio of dense to loose relative density soil-pile reaction was from 2.0 to 3.0 at a small to large displacement. Direct comparison of the developed p-y curve shows significant differences in the magnitude and shapes with the existing load-transfer curves. Good comparison with the experimental and design studies demonstrates the multidisciplinary applications of the present method. PMID:24574932

Development of p-y Curves of Laterally Loaded Piles in Cohesionless Soil

Directory of Open Access Journals (Sweden)

Mahdy Khari

2014-01-01

Full Text Available The research on damages of structures that are supported by deep foundations has been quite intensive in the past decade. Kinematic interaction in soil-pile interaction is evaluated based on the p-y curve approach. Existing p-y curves have considered the effects of relative density on soil-pile interaction in sandy soil. The roughness influence of the surface wall pile on p-y curves has not been emphasized sufficiently. The presented study was performed to develop a series of p-y curves for single piles through comprehensive experimental investigations. Modification factors were studied, namely, the effects of relative density and roughness of the wall surface of pile. The model tests were subjected to lateral load in Johor Bahru sand. The new p-y curves were evaluated based on the experimental data and were compared to the existing p-y curves. The soil-pile reaction for various relative density (from 30% to 75% was increased in the range of 40–95% for a smooth pile at a small displacement and 90% at a large displacement. For rough pile, the ratio of dense to loose relative density soil-pile reaction was from 2.0 to 3.0 at a small to large displacement. Direct comparison of the developed p-y curve shows significant differences in the magnitude and shapes with the existing load-transfer curves. Good comparison with the experimental and design studies demonstrates the multidisciplinary applications of the present method.

Conceptual framework for load controlling : with demand reduction bidding & consumer retention

NARCIS (Netherlands)

Babar, M.; Ahamed, I.; Al-Ammar, E.A.

2013-01-01

Advancement in demand side management strategies enables smart grid to cope with the increasing energy demand and provide economic benefit to all of its stakeholders. Moreover, emerging concept of smart pricing and advances in load control and communication generate new business opportunities as a

Community-driven demand creation for the use of routine viral load testing: a model to scale up routine viral load testing.

Science.gov (United States)

Killingo, Bactrin M; Taro, Trisa B; Mosime, Wame N

2017-11-01

HIV treatment outcomes are dependent on the use of viral load measurement. Despite global and national guidelines recommending the use of routine viral load testing, these policies alone have not translated into widespread implementation or sufficiently increased access for people living with HIV (PLHIV). Civil society and communities of PLHIV recognize the need to close this gap and to enable the scale up of routine viral load testing. The International Treatment Preparedness Coalition (ITPC) developed an approach to community-led demand creation for the use of routine viral load testing. Using this Community Demand Creation Model, implementers follow a step-wise process to capacitate and empower communities to address their most pressing needs. This includes utlizing a specific toolkit that includes conducting a baseline assessment, developing a treatment education toolkit, organizing mobilization workshops for knowledge building, provision of small grants to support advocacy work and conducting benchmark evaluations. The Community Demand Creation Model to increase demand for routine viral load testing services by PLHIV has been delivered in diverse contexts including in the sub-Saharan African, Asian, Latin American and the Caribbean regions. Between December 2015 and December 2016, ITPC trained more than 240 PLHIV activists, and disbursed US$90,000 to network partners in support of their national advocacy work. The latter efforts informed a regional, community-driven campaign calling for domestic investment in the expeditious implementation of national viral load testing guidelines. HIV treatment education and community mobilization are critical components of demand creation for access to optimal HIV treatment, especially for the use of routine viral load testing. ITPC's Community Demand Creation Model offers a novel approach to achieving this goal. © 2017 The Authors. Journal of the International AIDS Society published by John Wiley & sons Ltd on behalf of

Load curve modelling of the residential segment electric power consumption applying a demand side energy management program; Modelagem da curva de carga das faixas de consumo de energia eletrica residencial a partir da aplicacao de um programa de gerenciamento de energia pelo lado da demanda

Energy Technology Data Exchange (ETDEWEB)

Rahde, Sergio Barbosa [Pontificia Univ. Catolica do Rio Grande do Sul, Porto Alegre (Brazil). Dept. de Engenharia Mecanica e Mecatronica]. E-mail: sergio@em.pucrs.br; Kaehler, Jose Wagner [Pontificia Univ. Catolica do Rio Grande do Sul, Porto Alegre (Brazil). Faculdade de Engenharia]. E-mail: kaehlerjw@pucrs.br

2000-07-01

The dissertation aims to offer a current vision on the use of electrical energy inside CEEE's newly defined area of operation. It also intends to propose different alternatives to set up a Demand Side Management (DSM) project to be carried out on the same market segment, through a Residential Load Management program. Starting from studies developed by DNAEE (the Brazilian federal government's agency for electrical energy), to establish the load curve characteristics, as well as from a research on electrical equipment ownership and electricity consumption habits, along with the contribution supplied by other utilities, especially in the US, an evaluation is offered, concerning several approaches to residential energy management, setting up conditions that simulate the residential segment's scenarios and their influence on the general system's load. (author)

Loads as a Resource: Frequency Responsive Demand

Energy Technology Data Exchange (ETDEWEB)

Kalsi, Karanjit [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Williams, Tess L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Marinovici, Laurentiu D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Elizondo, Marcelo A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lian, Jianming [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2015-11-30

Demand-side frequency control can complement traditional generator controls to maintain the stability of large electric systems in the face of rising uncertainty and variability associated with renewable energy resources. This report presents a hierarchical frequency-based load control strategy that uses a supervisor to flexibly adjust control gains that a population of end-use loads respond to in a decentralized manner to help meet the NERC BAL-003-1 frequency response standard at both the area level and interconnection level. The load model is calibrated and used to model populations of frequency-responsive water heaters in a PowerWorld simulation of the U.S. Western Interconnection (WECC). The proposed design is implemented and demonstrated on physical water heaters in a laboratory setting. A significant fraction of the required frequency response in the WECC could be supplied by electric water heaters alone at penetration levels of less than 15%, while contributing to NERC requirements at the interconnection and area levels.

Approaches to Enable Demand Response by Industrial Loads for Ancillary Services Provision

Science.gov (United States)

Zhang, Xiao

Demand response has gained significant attention in recent years as it demonstrates potentials to enhance the power system's operational flexibility in a cost-effective way. Industrial loads such as aluminum smelters, steel manufacturers, and cement plants demonstrate advantages in supporting power system operation through demand response programs, because of their intensive power consumption, already existing advanced monitoring and control infrastructure, and the strong economic incentive due to the high energy costs. In this thesis, we study approaches to efficiently integrate each of these types of manufacturing processes as demand response resources. The aluminum smelting process is able to change its power consumption both accurately and quickly by controlling the pots' DC voltage, without affecting the production quality. Hence, an aluminum smelter has both the motivation and the ability to participate in demand response. First, we focus on determining the optimal regulation capacity that such a manufacturing plant should provide. Next, we focus on determining its optimal bidding strategy in the day-ahead energy and ancillary services markets. Electric arc furnaces (EAFs) in steel manufacturing consume a large amount of electric energy. However, a steel plant can take advantage of time-based electricity prices by optimally arranging energy-consuming activities to avoid peak hours. We first propose scheduling methods that incorporate the EAFs' flexibilities to reduce the electricity cost. We then propose methods to make the computations more tractable. Finally, we extend the scheduling formulations to enable the provision of spinning reserve. Cement plants are able to quickly adjust their power consumption rate by switching on/off the crushers. However, switching on/off the loading units only achieves discrete power changes, which restricts the load from offering valuable ancillary services such as regulation and load following, as continuous power changes

Deep Neural Network Based Demand Side Short Term Load Forecasting

Directory of Open Access Journals (Sweden)

Seunghyoung Ryu

2016-12-01

Full Text Available In the smart grid, one of the most important research areas is load forecasting; it spans from traditional time series analyses to recent machine learning approaches and mostly focuses on forecasting aggregated electricity consumption. However, the importance of demand side energy management, including individual load forecasting, is becoming critical. In this paper, we propose deep neural network (DNN-based load forecasting models and apply them to a demand side empirical load database. DNNs are trained in two different ways: a pre-training restricted Boltzmann machine and using the rectified linear unit without pre-training. DNN forecasting models are trained by individual customer’s electricity consumption data and regional meteorological elements. To verify the performance of DNNs, forecasting results are compared with a shallow neural network (SNN, a double seasonal Holt–Winters (DSHW model and the autoregressive integrated moving average (ARIMA. The mean absolute percentage error (MAPE and relative root mean square error (RRMSE are used for verification. Our results show that DNNs exhibit accurate and robust predictions compared to other forecasting models, e.g., MAPE and RRMSE are reduced by up to 17% and 22% compared to SNN and 9% and 29% compared to DSHW.

A Method for Formulizing Disaster Evacuation Demand Curves Based on SI Model

Directory of Open Access Journals (Sweden)

Yulei Song

2016-10-01

Full Text Available The prediction of evacuation demand curves is a crucial step in the disaster evacuation plan making, which directly affects the performance of the disaster evacuation. In this paper, we discuss the factors influencing individual evacuation decision making (whether and when to leave and summarize them into four kinds: individual characteristics, social influence, geographic location, and warning degree. In the view of social contagion of decision making, a method based on Susceptible-Infective (SI model is proposed to formulize the disaster evacuation demand curves to address both social influence and other factors’ effects. The disaster event of the “Tianjin Explosions” is used as a case study to illustrate the modeling results influenced by the four factors and perform the sensitivity analyses of the key parameters of the model. Some interesting phenomena are found and discussed, which is meaningful for authorities to make specific evacuation plans. For example, due to the lower social influence in isolated communities, extra actions might be taken to accelerate evacuation process in those communities.

Integration scenarios of Demand Response into electricity markets: Load shifting, financial savings and policy implications

International Nuclear Information System (INIS)

Feuerriegel, Stefan; Neumann, Dirk

2016-01-01

Demand Response allows for the management of demand side resources in real-time; i.e. shifting electricity demand according to fluctuating supply. When integrated into electricity markets, Demand Response can be used for load shifting and as a replacement for both control reserve and balancing energy. These three usage scenarios are compared based on historic German data from 2011 to determine that load shifting provides the highest benefit: its annual financial savings accumulate to €3.110 M for both households and the service sector. This equals to relative savings of 2.83% compared to a scenario without load shifting. To improve Demand Response integration, the proposed model suggests policy implications: reducing bid sizes, delivery periods and the time-lag between market transactions and delivery dates in electricity markets. - Highlights: •Comparison of 3 scenarios to integrate Demand Response into electricity markets. •These are: optimize procurement, offer as control reserve, avoid balancing energy. •Ex post simulation to quantify financial impact and policy implications. •Highest savings from load shifting with a cost reduction of 3%. •Model suggests reducing bid sizes, delivery periods and time lags as policy issues.

Experimental J estimation from a load-cmod curve for mis-matched SENB and CCT specimens

International Nuclear Information System (INIS)

Hornet, P.; Eripret, Ch.; Hao, S.

1997-01-01

This paper addresses the problem of the determination of the J-integral from experimentally measured quantities for mismatched Single Notched Bend specimens (SENB) or through thickness Centre Cracked panels loaded in Tension (CCT). Commonly, the experimental J-integral is calculated from the area under the load versus load-line displacement curve. Nevertheless, in the case of gross-section yielding, which can occur for short cracked specimens or overmatching cases, this methodology mis-estimates the effective J-integral. A new proposal, based on analytical considerations is made to estimate the J-integral from the area under load versus CMOD curves. This proposal is validated by 2D and 3D finite element analyses. (authors)

An EMD-ANN based prediction methodology for DR driven smart household load demand

NARCIS (Netherlands)

Tascikaraoglu, A.; Paterakis, N.G.; Catalaõ, J.P.S.; Erdinç, O.; Bakirtzis, A.G.

2015-01-01

This study proposes a model for the prediction of smart household load demand influenced by a dynamic pricing demand response (DR) program. Price-based DR programs have a considerable impact on household demand pattern due to the expected choice of customers or their home energy management systems

Control for large scale demand response of thermostatic loads

DEFF Research Database (Denmark)

Totu, Luminita Cristiana; Leth, John; Wisniewski, Rafal

2013-01-01

appliances with on/off operation. The objective is to reduce the consumption peak of a group of loads composed of both flexible and inflexible units. The power flexible units are the thermostat-based appliances. We discuss a centralized, model predictive approach and a distributed structure with a randomized......Demand response is an important Smart Grid concept that aims at facilitating the integration of volatile energy resources into the electricity grid. This paper considers a residential demand response scenario and specifically looks into the problem of managing a large number thermostatbased...

Evaluation of the Electric Vehicle Impact in the Power Demand Curve in a Smart Grid Environment

DEFF Research Database (Denmark)

Morais, Hugo; Sousa, Tiago; Vale, Zita

2014-01-01

be beneficially used to address this problem; the massive use of electric vehicles, particularly of vehicle-to-grid (usually referred as gridable vehicles or V2G), becomes a very relevant issue. This paper addresses the impact of Electric Vehicles (EVs) in system operation costs and in power demand curve...... for a distribution network with large penetration of Distributed Generation (DG) units. An efficient management methodology for EVs charging and discharging is proposed, considering a multi-objective optimization problem. The main goals of the proposed methodology are: to minimize the system operation costs...... and to minimize the difference between the minimum and maximum system demand (leveling the power demand curve). The proposed methodology perform the day-ahead scheduling of distributed energy resources in a distribution network with high penetration of DG and a large number of electric vehicles. It is used a 32...

Stress analysis in curved composites due to thermal loading

Science.gov (United States)

Polk, Jared Cornelius

Many structures in aircraft, cars, trucks, ships, machines, tools, bridges, and buildings, consist of curved sections. These sections vary from straight line segments that have curvature at either one or both ends, segments with compound curvatures, segments with two mutually perpendicular curvatures or Gaussian curvatures, and segments with a simple curvature. With the advancements made in multi-purpose composites over the past 60 years, composites slowly but steadily have been appearing in these various vehicles, compound structures, and buildings. These composite sections provide added benefits over isotropic, polymeric, and ceramic materials by generally having a higher specific strength, higher specific stiffnesses, longer fatigue life, lower density, possibilities in reduction of life cycle and/or acquisition cost, and greater adaptability to intended function of structure via material composition and geometry. To be able to design and manufacture a safe composite laminate or structure, it is imperative that the stress distributions, their causes, and effects are thoroughly understood in order to successfully accomplish mission objectives and manufacture a safe and reliable composite. The objective of the thesis work is to expand upon the knowledge of simply curved composite structures by exploring and ascertaining all pertinent parameters, phenomenon, and trends in stress variations in curved laminates due to thermal loading. The simply curved composites consist of composites with one radius of curvature throughout the span of the specimen about only one axis. Analytical beam theory, classical lamination theory, and finite element analysis were used to ascertain stress variations in a flat, isotropic beam. An analytical method was developed to ascertain the stress variations in an isotropic, simply curved beam under thermal loading that is under both free-free and fixed-fixed constraint conditions. This is the first such solution to Author's best knowledge

Demand for power in Calcutta Electricity Supply Corporation area

Energy Technology Data Exchange (ETDEWEB)

Banerjee, N

1980-07-01

Since the early 1970's there has been a continuous crisis of power supply to the Calcutta industrial region. Historical records show that only the peak demand has grown and has a potential for growth, which, with an unchanging base demand, results in a low load factor and consequently inefficient power system operation. Attempts to shift industrial loads by operating industrial plants during non-peak hours are described. Adverse economic conditions eliminated the need for extra working shifts. It is concluded that the power system supplying the Calcutta region has an insufficient peak load generating capacity and an uneconomic load curve and that stricter hourly schedules for power use by industries should be adhered to in order to minimize these problems. (LCL)

Optimal Load Response to Time-of-Use Power Price for Demand Side Management in Denmark

DEFF Research Database (Denmark)

Hu, Weihao; Chen, Zhe; Bak-Jensen, Birgitte

2010-01-01

-of-use power price for demand side management in order to save the energy costs as much as possible. 3 typical different kinds of loads (industrial load, residential load and commercial load) in Denmark are chosen as study cases. The energy costs decrease up to 9.6% with optimal load response to time......-of-use power price for different loads. Simulation results show that the optimal load response to time-of-use power price for demand side management generates different load profiles and reduces the load peaks. This kind of load patterns may also have significant effects on the power system normal operation.......Since the hourly spot market price is available one day ahead in Denmark, the price could be transferred to the consumers and they may shift their loads from high price periods to the low price periods in order to save their energy costs. This paper presents a load optimization method to time...

Transposing Concentration-Discharge Curves onto Unmonitored Catchments to Estimate Seasonal Nutrient Loads

Science.gov (United States)

Minaudo, C.; Moatar, F.; Abbott, B. W.; Dupas, R.; Gascuel-Odoux, C.; Pinay, G.; Roubeix, V.; Danis, P. A.

2017-12-01

Many lakes and reservoirs in Europe suffer from severe eutrophication. Accurate quantification of nutrient loads are critical for effective mitigation measures, but this information is often unknown. For example, in France, only 50 out of 481 lakes and reservoirs have national monitoring allowing estimation of interannual nitrogen and phosphorus loads, and even these loads are computed from low-frequency data. To address this lack of data, we developed a straightforward method to predict seasonal loads in lake tributaries. First, we analyzed concentration-discharge (C-Q) curves in monitored catchments and identified slopes, intercepts, and coefficient of variation of the log(C)-log(Q) regressions determined for both low and high flows, separated by the median daily flow [Moatar et al., 2017]. Then, we used stepwise multiple linear regression models to empirically link the characteristics of C-Q curves with a set of catchment descriptors such as land use, lithology, morphology indices, climate, and hydrological indicators. Modeled C-Q relationships were then used to estimate annual and seasonal nutrient loads in nearby and similar unmonitored catchments. We implemented this approach on a large dataset from France where stream flow was surveyed daily and water quality (suspended solids, nitrate, total phosphorus, and orthophosphate concentrations) was measured on a monthly basis at 233 stations over the past 20 years in catchments from 10 to 3000 km². The concentration at the median daily flow (seen here as a metric of the general level of contamination in a catchment) was predicted with uncertainty ranging between 30 and 100 %, depending on the variable. C-Q slopes were predicted with large errors, but a sensitivity analysis was conducted to determine the impact of C-Q slopes uncertainties on computed annual and seasonal loads. This approach allows estimation of seasonal and annual nutrient loads and could be potentially implemented to improve protection and

Loads as a Resource: Frequency Responsive Demand

Energy Technology Data Exchange (ETDEWEB)

Kalsi, Karanjit [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lian, Jianming [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Marinovici, Laurentiu D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Elizondo, Marcelo A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Zhang, Wei [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Moya, Christian [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2014-10-08

Frequency control plays an important role in preserving the power balance of a multi-machine power system. Generators modify their power output when a non-zero frequency deviation is presented in order to restore power balance across the network. However, with plans for large-scale penetration of renewable energy resources, performing primary frequency control using only supply-side resources becomes not only prohibitively expensive, but also technically difficult. Frequency control from the demand side or load control presents a novel and viable way for providing the desired frequency response. Loads can measure frequency locally and change their power consumption after a non-zero frequency deviation is presented in order to achieve power balance between generation and consumption. The specific objectives of this project are to: •Provide a framework to facilitate large-scale deployment of frequency responsive end-use devices •Systematically design decentralized frequency-based load control strategies for enhanced stability performance •Ensure applicability over wide range of operating conditions while accounting for unpredictable end-use behavior and physical device constraints •Test and validate control strategy using large-scale simulations and field demonstrations •Create a level-playing field for smart grid assets with conventional generators

Elastic stability of laminated, flat and curved, long rectangular plates subjected to combined inplane loads

Science.gov (United States)

Viswanathan, A. V.; Tamekuni, M.; Baker, L. L.

1974-01-01

A method is presented to predict theoretical buckling loads of long, rectangular flat and curved laminated plates with arbitrary orientation of orthotropic axes each lamina. The plate is subjected to combined inplane normal and shear loads. Arbitrary boundary conditions may be stipulated along the longitudinal sides of the plate. In the absence of inplane shear loads and extensional-shear coupling, the analysis is also applicable to finite length plates. Numerical results are presented for curved laminated composite plates with boundary conditions and subjected to various loadings. These results indicate some of the complexities involved in the numerical solution of the analysis for general laminates. The results also show that the reduced bending stiffness approximation when applied to buckling problems could lead to considerable error in some cases and therefore must be used with caution.

Load building versus conservation as demand-side management objectives

International Nuclear Information System (INIS)

Kexel, D.T.

1994-01-01

This paper examines the economics of load building versus conservation as demand-side management objectives. Economic criteria to be used in evaluating each type of program from the perspectives of all impacted parties are provided. The impact of DSM programs on electric rates is shown to be a key focal point of a thorough evaluation

Field Testing of Telemetry for Demand Response Control of Small Loads

Energy Technology Data Exchange (ETDEWEB)

Lanzisera, Steven [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Weber, Adam [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Liao, Anna [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Schetrit, Oren [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Kiliccote, Sila [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Piette, Mary Ann [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2018-01-30

The electricity system in California, from generation through loads, must be prepared for high renewable penetration and increased electrification of end uses while providing increased resilience and lower operating cost. California has an aggressive renewable portfolio standard that is complemented by world-leading greenhouse gas goals. The goal of this project was to evaluate methods of enabling fast demand response (DR) signaling to small loads for low-cost site enablement. We used OpenADR 2.0 to meet telemetry requirements for providing ancillary services, and we used a variety of low-cost devices coupled with open-source software to enable an end-to-end fast DR. The devices, architecture, implementation, and testing of the system is discussed in this report. We demonstrate that the emerging Internet of Things (IoT) and Smart Home movements provide an opportunity for diverse small loads to provide fast, low-cost demand response. We used Internet-connected lights, thermostats, load interruption devices, and water heaters to demonstrate an ecosystem of controllable devices. The system demonstrated is capable of providing fast load shed for between 20 dollars and $300 per kilowatt (kW) of available load. The wide range results from some loads may have very low cost but also very little shed capability (a 10 watt [W] LED light can only shed a maximum of 10 W) while some loads (e.g., water heaters or air conditioners) can shed several kilowatts but have a higher initial cost. These costs, however, compare well with other fast demand response costs, with typically are over $100/kilowatt of shed. We contend these loads are even more attractive than their price suggests because many of them will be installed for energy efficiency or non-energy benefits (e.g., improved lighting quality or controllability), and the ability to use them for fast DR is a secondary benefit. Therefore the cost of enabling them for DR may approach zero if a software-only solution can be

Multi-Objective Demand Response Model Considering the Probabilistic Characteristic of Price Elastic Load

Directory of Open Access Journals (Sweden)

Shengchun Yang

2016-01-01

Full Text Available Demand response (DR programs provide an effective approach for dealing with the challenge of wind power output fluctuations. Given that uncertain DR, such as price elastic load (PEL, plays an important role, the uncertainty of demand response behavior must be studied. In this paper, a multi-objective stochastic optimization problem of PEL is proposed on the basis of the analysis of the relationship between price elasticity and probabilistic characteristic, which is about stochastic demand models for consumer loads. The analysis aims to improve the capability of accommodating wind output uncertainty. In our approach, the relationship between the amount of demand response and interaction efficiency is developed by actively participating in power grid interaction. The probabilistic representation and uncertainty range of the PEL demand response amount are formulated differently compared with those of previous research. Based on the aforementioned findings, a stochastic optimization model with the combined uncertainties from the wind power output and the demand response scenario is proposed. The proposed model analyzes the demand response behavior of PEL by maximizing the electricity consumption satisfaction and interaction benefit satisfaction of PEL. Finally, a case simulation on the provincial power grid with a 151-bus system verifies the effectiveness and feasibility of the proposed mechanism and models.

Electricity demand load forecasting of the Hellenic power system using an ARMA model

Energy Technology Data Exchange (ETDEWEB)

Pappas, S.Sp. [ASPETE - School of Pedagogical and Technological Education Department of Electrical Engineering Educators N. Heraklion, 141 21 Athens (Greece); Ekonomou, L.; Chatzarakis, G.E.; Skafidas, P.D. [ASPETE-School of Pedagogical and Technological Education, Department of Electrical Engineering Educators, N. Heraklion, 141 21 Athens (Greece); Karampelas, P. [Hellenic American University, IT Department, 12 Kaplanon Str., 106 80 Athens (Greece); Karamousantas, D.C. [Technological Educational Institute of Kalamata, Antikalamos, 24 100 Kalamata (Greece); Katsikas, S.K. [University of Piraeus, Department of Technology Education and Digital Systems, 150 Androutsou St., 18 532 Piraeus (Greece)

2010-03-15

Effective modeling and forecasting requires the efficient use of the information contained in the available data so that essential data properties can be extracted and projected into the future. As far as electricity demand load forecasting is concerned time series analysis has the advantage of being statistically adaptive to data characteristics compared to econometric methods which quite often are subject to errors and uncertainties in model specification and knowledge of causal variables. This paper presents a new method for electricity demand load forecasting using the multi-model partitioning theory and compares its performance with three other well established time series analysis techniques namely Corrected Akaike Information Criterion (AICC), Akaike's Information Criterion (AIC) and Schwarz's Bayesian Information Criterion (BIC). The suitability of the proposed method is illustrated through an application to actual electricity demand load of the Hellenic power system, proving the reliability and the effectiveness of the method and making clear its usefulness in the studies that concern electricity consumption and electricity prices forecasts. (author)

Load/resource matching for period-of-record computer simulation

International Nuclear Information System (INIS)

Lindsey, E.D. Jr.; Robbins, G.E. III

1991-01-01

The Southwestern Power Administration (Southwestern), an agency of the Department of Energy, is responsible for marketing the power and energy produced at Federal hydroelectric power projects developed by the U.S. Army Corps of Engineers in the southwestern United States. This paper reports that in order to maximize benefits from limited resources, to evaluate proposed changes in the operation of existing projects, and to determine the feasibility and marketability of proposed new projects, Southwestern utilizes a period-of-record computer simulation model created in the 1960's. Southwestern is constructing a new computer simulation model to take advantage of changes in computers, policy, and procedures. Within all hydroelectric power reservoir systems, the ability of the resources to match the load demand is critical and presents complex problems. Therefore, the method used to compare available energy resources to energy load demands is a very important aspect of the new model. Southwestern has developed an innovative method which compares a resource duration curve with a load duration curve, adjusting the resource duration curve to make the most efficient use of the available resources

Using of residential load curves obtained for determination of the load diversity, and loading of distribution transformers; Utilizacao de curvas de carga de consumidores industriais medidas para determinacao de diversidade de carga, e carregamento de transformadores de distribuicao

Energy Technology Data Exchange (ETDEWEB)

Ferrari, Eduardo Luiz; Jardini, Jose Antonio

1996-07-01

This work presents some applications of the residential loads, obtained from measurements conducted by the electric power utilities in the state of Sao Paulo , Brazil. During the first application, curve of coincidence of load peaks occurrence, as function of the number of consumers simultaneously connected to a specific residential distribution transformer. This curve provides a information on the number of consumers presenting coincident load peaks coincident relative to the total numbers of consumers connected to the distribution transformer. Those curves allow to obtain the diversity curves. The second application focused the calculation of the distribution transformer life reduction.

Dynamic Response and Optimal Design of Curved Metallic Sandwich Panels under Blast Loading

Science.gov (United States)

Yang, Shu; Han, Shou-Hong; Lu, Zhen-Hua

2014-01-01

It is important to understand the effect of curvature on the blast response of curved structures so as to seek the optimal configurations of such structures with improved blast resistance. In this study, the dynamic response and protective performance of a type of curved metallic sandwich panel subjected to air blast loading were examined using LS-DYNA. The numerical methods were validated using experimental data in the literature. The curved panel consisted of an aluminum alloy outer face and a rolled homogeneous armour (RHA) steel inner face in addition to a closed-cell aluminum foam core. The results showed that the configuration of a “soft” outer face and a “hard” inner face worked well for the curved sandwich panel against air blast loading in terms of maximum deflection (MaxD) and energy absorption. The panel curvature was found to have a monotonic effect on the specific energy absorption (SEA) and a nonmonotonic effect on the MaxD of the panel. Based on artificial neural network (ANN) metamodels, multiobjective optimization designs of the panel were carried out. The optimization results revealed the trade-off relationships between the blast-resistant and the lightweight objectives and showed the great use of Pareto front in such design circumstances. PMID:25126606

Dynamic response and optimal design of curved metallic sandwich panels under blast loading.

Science.gov (United States)

Qi, Chang; Yang, Shu; Yang, Li-Jun; Han, Shou-Hong; Lu, Zhen-Hua

2014-01-01

It is important to understand the effect of curvature on the blast response of curved structures so as to seek the optimal configurations of such structures with improved blast resistance. In this study, the dynamic response and protective performance of a type of curved metallic sandwich panel subjected to air blast loading were examined using LS-DYNA. The numerical methods were validated using experimental data in the literature. The curved panel consisted of an aluminum alloy outer face and a rolled homogeneous armour (RHA) steel inner face in addition to a closed-cell aluminum foam core. The results showed that the configuration of a "soft" outer face and a "hard" inner face worked well for the curved sandwich panel against air blast loading in terms of maximum deflection (MaxD) and energy absorption. The panel curvature was found to have a monotonic effect on the specific energy absorption (SEA) and a nonmonotonic effect on the MaxD of the panel. Based on artificial neural network (ANN) metamodels, multiobjective optimization designs of the panel were carried out. The optimization results revealed the trade-off relationships between the blast-resistant and the lightweight objectives and showed the great use of Pareto front in such design circumstances.

Dynamic Response and Optimal Design of Curved Metallic Sandwich Panels under Blast Loading

Directory of Open Access Journals (Sweden)

Chang Qi

2014-01-01

Full Text Available It is important to understand the effect of curvature on the blast response of curved structures so as to seek the optimal configurations of such structures with improved blast resistance. In this study, the dynamic response and protective performance of a type of curved metallic sandwich panel subjected to air blast loading were examined using LS-DYNA. The numerical methods were validated using experimental data in the literature. The curved panel consisted of an aluminum alloy outer face and a rolled homogeneous armour (RHA steel inner face in addition to a closed-cell aluminum foam core. The results showed that the configuration of a “soft” outer face and a “hard” inner face worked well for the curved sandwich panel against air blast loading in terms of maximum deflection (MaxD and energy absorption. The panel curvature was found to have a monotonic effect on the specific energy absorption (SEA and a nonmonotonic effect on the MaxD of the panel. Based on artificial neural network (ANN metamodels, multiobjective optimization designs of the panel were carried out. The optimization results revealed the trade-off relationships between the blast-resistant and the lightweight objectives and showed the great use of Pareto front in such design circumstances.

Statistical evaluation of low cycle loading curves parameters for structural materials by mechanical characteristics

International Nuclear Information System (INIS)

Daunys, Mykolas; Sniuolis, Raimondas

2006-01-01

About 300 welded joint materials that are used in nuclear power energy were tested under monotonous tension and low cycle loading in Kaunas University of Technology together with St. Peterburg Central Research Institute of Structural Materials in 1970-2000. The main mechanical, low cycle loading and fracture characteristics of base metals, weld metals and some heat-affected zones of welded joints metals were determined during these experiments. Analytical dependences of low cycle fatigue parameters on mechanical characteristics of structural materials were proposed on the basis of a large number of experimental data, obtained by the same methods and testing equipment. When these dependences are used, expensive low cycle fatigue tests may be omitted and it is possible to compute low cycle loading curves parameters and lifetime for structural materials according to the main mechanical characteristics given in technical manuals. Dependences of low cycle loading curves parameters on mechanical characteristics for several groups of structural materials used in Russian nuclear power energy are obtained by statistical methods and proposed in this paper

The demand for environmental quality and the environmental Kuznets Curve hypothesis

International Nuclear Information System (INIS)

Khanna, Neha; Plassmann, Florenz

2004-01-01

Household demand for better environmental quality is the key factor in the long-term global applicability of the Environmental Kuznets Curve (EKC) hypothesis. We argue that, for given consumer preferences, the threshold income level at which the EKC turns downwards or the equilibrium income elasticity changes sign from positive to negative depends on the ability to spatially separate production and consumption. We test our hypothesis by estimating the equilibrium income elasticities of five pollutants, using 1990 data for the United States. We find that the change in sign occurs at lower income levels for pollutants for which spatial separation is relatively easy as compared to pollutants for which spatial separation is difficult. Our results suggest that even high-income households in the United States have not yet reached the income level at which their demand for better environmental quality is high enough to cause the income-pollution relationship to turn downwards for all the pollutants that we analyzed

The demand for environmental quality and the environmental Kuznets Curve hypothesis

Energy Technology Data Exchange (ETDEWEB)

Khanna, Neha [Department of Economics and Environmental Studies Program, Binghamton, University (LT 1004), P.O. Box 6000, Binghamton, NY 13902-6000 (United States); Plassmann, Florenz [Department of Economics, Binghamton University (LT 904), P.O. Box 6000, Binghamton, NY 13902-6000 (United States)

2004-12-01

Household demand for better environmental quality is the key factor in the long-term global applicability of the Environmental Kuznets Curve (EKC) hypothesis. We argue that, for given consumer preferences, the threshold income level at which the EKC turns downwards or the equilibrium income elasticity changes sign from positive to negative depends on the ability to spatially separate production and consumption. We test our hypothesis by estimating the equilibrium income elasticities of five pollutants, using 1990 data for the United States. We find that the change in sign occurs at lower income levels for pollutants for which spatial separation is relatively easy as compared to pollutants for which spatial separation is difficult. Our results suggest that even high-income households in the United States have not yet reached the income level at which their demand for better environmental quality is high enough to cause the income-pollution relationship to turn downwards for all the pollutants that we analyzed.

Demand controllers with optimized programing; Controladores de demanda com programacao otimizada

Energy Technology Data Exchange (ETDEWEB)

Santos, A.H.M.; Haddad, J.; Almeida, A.T.L. [Escola Federal de Engenharia de Itajuba, MG (Brazil); Devienne, R.F. [Universidade de Taubate (UNITAU), SP (Brazil)

1995-12-31

This work presents a methodological proposal for load re-allocation strategy in opposition to the empiric methodology presently used by demand controllers. Through the utilization of dynamic programing techniques associated to fuzzy theory it is possible to modulate the electric power consumers load curve, incorporating different objectives resulting in the global energy consumption rationing 6 figs., 5 tabs., 8 refs.

Least square regression based integrated multi-parameteric demand modeling for short term load forecasting

International Nuclear Information System (INIS)

Halepoto, I.A.; Uqaili, M.A.

2014-01-01

Nowadays, due to power crisis, electricity demand forecasting is deemed an important area for socioeconomic development and proper anticipation of the load forecasting is considered essential step towards efficient power system operation, scheduling and planning. In this paper, we present STLF (Short Term Load Forecasting) using multiple regression techniques (i.e. linear, multiple linear, quadratic and exponential) by considering hour by hour load model based on specific targeted day approach with temperature variant parameter. The proposed work forecasts the future load demand correlation with linear and non-linear parameters (i.e. considering temperature in our case) through different regression approaches. The overall load forecasting error is 2.98% which is very much acceptable. From proposed regression techniques, Quadratic Regression technique performs better compared to than other techniques because it can optimally fit broad range of functions and data sets. The work proposed in this paper, will pave a path to effectively forecast the specific day load with multiple variance factors in a way that optimal accuracy can be maintained. (author)

Microcogeneration in buildings with low energy demand in load sharing application

International Nuclear Information System (INIS)

Angrisani, Giovanni; Canelli, Michele; Roselli, Carlo; Sasso, Maurizio

2015-01-01

Highlights: • The use of microcogenerator (MCHP) in buildings with low energy demand is evaluated. • The load sharing approach leads to suitable thermal and electric loads for MCHP. • Dynamic simulations are carried out considering two different climates. • A sensitivity analysis with respect to the self-consumed electricity is performed. • MCHPs with internal combustion engine perfectly match with well-insulated buildings. - Abstract: The paper investigates the introduction of a MCHP (Micro Combined Heat and Power) system in buildings with low energy demand with respect to the current building stock. A load sharing approach between a multifamily residential building and an office one is taken into account. Dynamic simulations are carried out in order to evaluate the thermo-economic performance of the analyzed system. Particular attention is given to the estimation of the electric load of the different users, as the economic profitability of a MCHP system is strongly influenced by the amount of self-consumed electricity. In order to analyze the influence of climatic conditions, two different geographical locations in Italy (Naples and Turin, having 1034 and 2617 heating degree days, respectively) are considered. The results of this study indicate that the installation of MCHP systems in buildings with low energy demand allows to increase the percentage of self-consumed electricity reducing the bidirectional electricity flow between the users and the external grid, as well as the impact on the grid itself due to the large diffusion of distributed generation systems. Moreover this study shows that the load sharing approach between users with different load profile leads to better energy, environmental and economic results with respect to a conventional system. The climatic conditions play an important role on the MCHP operational hours and hence on the thermo-economic performance of the system. The primary energy saving of the system located in Turin is

Loads as a Resource: Frequency Responsive Demand

Energy Technology Data Exchange (ETDEWEB)

Kalsi, Karanjit [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hansen, Jacob [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Fuller, Jason C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Marinovici, Laurentiu D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Elizondo, Marcelo A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Williams, Tess L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lian, Jianming [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Sun, Yannan [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2015-12-01

Current power grid operation predominantly relies on scheduling and regulating generation resources to supply loads and balance load changes. Due to the inherent intermittency of renewable energy, more flexible and fast ramping capacity is required to compensate for the uncertainty and variability introduced by renewable energy resources. With the advancement of information technologies, power system end-use loads are becoming more agile and can participate in provision of balancing energy and other grid services. The use of demand response can greatly reduce the required generation reserve in a clean and environmentally friendly way. In this report, a new frequency responsive load (FRL) controller was proposed based on the GFA controller, which can respond to both over and under-frequency events. A supervisory control was introduced to coordinate the autonomous response from FRLs in order to overcome the issues of excessive system response due to high penetration of FRLs. The effectiveness of the proposed FRL controller was demonstrated by large-scale simulation studies on the WECC system. Specifically, the FRLs were deployed in the WECC system at different penetration levels to analyze the performance of the proposed strategy both with and without supervisory level control. While both methods have their own advantages, the case without supervisory control could lead to system-wide instability depending on the size of the contingency and the number of FRLs deployed in the system. In addition, the voltage impacts of this controller on distribution system were also carefully investigated. Finally, a preliminary measurement and verification approach was also developed.

The dispatch and load duration curve of the interconnected electrical system, in the hypothetical context of the 450ppm scenario of the Iea

International Nuclear Information System (INIS)

Villanueva M, C.

2017-09-01

The concept of the annual load duration curve of the national interconnected system is presented, which by means of a quadrature procedure becomes a 3-block diagram: one for the base load that occurs at 8,760 hours of the year; another for intermediate load, above the minimum that occurs in a variable number of hours of the year, and another for the peak demand that only happens a few hours of the year. The data of the table of capacity and generation of electric power in 2014, according to Annex A of the Mexico Energy Outlook document of the International Energy Agency (Iea), are converted into a block diagram adjusted to the annual curve of load duration of that year. The procedure is repeated with the capacity and electric power generation data projected by the Iea at 2030 and 2040, according to the 450ppm scenario, which is considered necessary to stabilize the concentration of CO 2 in the atmosphere at 450 parts per million and ensure that the increase in the global temperature of the planet does not exceed 2 degrees Celsius, compared to pre-industrial levels. Then, the same capacity and generation data projected by the Iea by 2040 are tabulated by technology type, grouped now within the base, intermediate and peak blocks of the annual load duration curve for that year, and ordered from according to its plant factor, indicative of its availability to be dispatched. The above, in order to estimate the aggregate result of the annual dispatch that could be made by CENACE, if the projections of electric power generation to the year 2040 foreseen in the ambitious 450ppm scenario were given. Finally, an exercise is carried out to estimate, at 2015 prices, the unit costs of technologies generation in the year 2040, expressed in US D (2015)/ MWh and broken down into fixed and variable reference costs. (Author)

Investigating Theoretical PV Energy Generation Patterns with Their Relation to the Power Load Curve in Poland

Directory of Open Access Journals (Sweden)

Jakub Jurasz

2016-01-01

Full Text Available Polish energy sector is (almost from its origin dominated by fossil fuel feed power. This situation results from an abundance of relatively cheap coal (hard and lignite. Brown coal due to its nature is the cheapest energy source in Poland. However, hard coal which fuels 60% of polish power plants is picking up on prices and is susceptible to the coal imported from neighboring countries. Forced by the European Union (EU regulations, Poland is struggling at achieving its goal of reaching 15% of energy consumption from renewable energy sources (RES by 2020. Over the year 2015, RES covered 11.3% of gross energy consumption but this generation was dominated by solid biomass (over 80%. The aim of this paper was to answer the following research questions: What is the relation of irradiation values to the power load on a yearly and daily basis? and how should photovoltaics (PV be integrated in the polish power system? Conducted analysis allowed us to state that there exists a negative correlation between power demand and irradiation values on a yearly basis, but this is likely to change in the future. Secondly, on average, daily values of irradiation tend to follow power load curve over the first hours of the day.

An assessment of household electricity load curves and corresponding CO2 marginal abatement cost curves for Gujarat state, India

International Nuclear Information System (INIS)

Garg, Amit; Shukla, P.R.; Maheshwari, Jyoti; Upadhyay, Jigeesha

2014-01-01

Gujarat, a large industrialized state in India, consumed 67 TWh of electricity in 2009–10, besides experiencing a 4.5% demand–supply short-fall. Residential sector accounted for 15% of the total electricity consumption. We conducted load research survey across 21 cities and towns of the state to estimate residential electricity load curves, share of appliances by type and usage patterns for all types of household appliances at utility, geographic, appliance, income and end-use levels. The results indicate that a large scope exists for penetration of energy efficient devices in residential sector. Marginal Abatement Cost (MAC) curves for electricity and CO 2 were generated to analyze relative attractiveness of energy efficient appliance options. Results indicate that up to 7.9 TWh of electricity can be saved per year with 6.7 Mt-CO 2 emissions mitigation at negative or very low CO 2 prices of US$ 10/t-CO 2 . Despite such options existing, their penetration is not realized due to myriad barriers such as financial, institutional or awareness and therefore cannot be taken as baseline options for CO 2 emission mitigation regimes. - Highlights: • Residential sector provides focused mitigation opportunities. • Energy efficient space cooling is the main technology transition required. • Almost 26% residential load could be reduced by DSM measures. • Myriad barriers limit penetration of negative marginal cost efficient options

Construction of estimated flow- and load-duration curves for Kentucky using the Water Availability Tool for Environmental Resources (WATER)

Science.gov (United States)

Unthank, Michael D.; Newson, Jeremy K.; Williamson, Tanja N.; Nelson, Hugh L.

2012-01-01

Flow- and load-duration curves were constructed from the model outputs of the U.S. Geological Survey's Water Availability Tool for Environmental Resources (WATER) application for streams in Kentucky. The WATER application was designed to access multiple geospatial datasets to generate more than 60 years of statistically based streamflow data for Kentucky. The WATER application enables a user to graphically select a site on a stream and generate an estimated hydrograph and flow-duration curve for the watershed upstream of that point. The flow-duration curves are constructed by calculating the exceedance probability of the modeled daily streamflows. User-defined water-quality criteria and (or) sampling results can be loaded into the WATER application to construct load-duration curves that are based on the modeled streamflow results. Estimates of flow and streamflow statistics were derived from TOPographically Based Hydrological MODEL (TOPMODEL) simulations in the WATER application. A modified TOPMODEL code, SDP-TOPMODEL (Sinkhole Drainage Process-TOPMODEL) was used to simulate daily mean discharges over the period of record for 5 karst and 5 non-karst watersheds in Kentucky in order to verify the calibrated model. A statistical evaluation of the model's verification simulations show that calibration criteria, established by previous WATER application reports, were met thus insuring the model's ability to provide acceptably accurate estimates of discharge at gaged and ungaged sites throughout Kentucky. Flow-duration curves are constructed in the WATER application by calculating the exceedence probability of the modeled daily flow values. The flow-duration intervals are expressed as a percentage, with zero corresponding to the highest stream discharge in the streamflow record. Load-duration curves are constructed by applying the loading equation (Load = Flow*Water-quality criterion) at each flow interval.

Energy management for vehicle power net with flexible electric load demand

NARCIS (Netherlands)

Kessels, J.T.B.A.; Bosch, van den P.P.J.; Koot, M.W.T.; Jager, de A.G.

2005-01-01

The electric power demand in road vehicles increases rapidly and to supply all electric loads efficiently, energy management (EM) turns out to be a necessity. In general, EM exploits the storage capacity of a buffer connected to the vehicle's power net, such that energy is stored or retrieved at

Optimum community energy storage system for demand load shifting

International Nuclear Information System (INIS)

Parra, David; Norman, Stuart A.; Walker, Gavin S.; Gillott, Mark

2016-01-01

Highlights: • PbA-acid and lithium-ion batteries are optimised up to a 100-home community. • A 4-period real-time pricing and Economy 7 (2-period time-of-use) are compared. • Li-ion batteries perform worse with Economy 7 for small communities and vice versa. • The community approach reduced the levelised cost by 56% compared to a single home. • Heat pumps reduced the levelised cost and increased the profitability of batteries. - Abstract: Community energy storage (CES) is becoming an attractive technological option to facilitate the use of distributed renewable energy generation, manage demand loads and decarbonise the residential sector. There is strong interest in understanding the techno-economic benefits of using CES systems, which energy storage technology is more suitable and the optimum CES size. In this study, the performance including equivalent full cycles and round trip efficiency of lead-acid (PbA) and lithium-ion (Li-ion) batteries performing demand load shifting are quantified as a function of the size of the community using simulation-based optimisation. Two different retail tariffs are compared: a time-of-use tariff (Economy 7) and a real-time-pricing tariff including four periods based on the electricity prices on the wholesale market. Additionally, the economic benefits are quantified when projected to two different years: 2020 and a hypothetical zero carbon year. The findings indicate that the optimum PbA capacity was approximately twice the optimum Li-ion capacity in the case of the real-time-pricing tariff and around 1.6 times for Economy 7 for any community size except a single home. The levelised cost followed a negative logarithmic trend while the internal rate of return followed a positive logarithmic trend as a function of the size of the community. PbA technology reduced the levelised cost down to 0.14 £/kW h when projected to the year 2020 for the retail tariff Economy 7. CES systems were sized according to the demand load and

Capacity market design and renewable energy: Performance incentives, qualifying capacity, and demand curves

Energy Technology Data Exchange (ETDEWEB)

Botterud, Audun; Levin, Todd; Byers, Conleigh

2018-01-01

A review of capacity markets in the United States in the context of increasing levels of variable renewable energy finds substantial differences with respect to incentives for operational performance, methods to calculate qualifying capacity for variable renewable energy and energy storage, and demand curves for capacity. The review also reveals large differences in historical capacity market clearing prices. The authors conclude that electricity market design must continue to evolve to achieve cost-effective policies for resource adequacy.

Injury risk curves for the skeletal knee-thigh-hip complex for knee-impact loading.

Science.gov (United States)

Rupp, Jonathan D; Flannagan, Carol A C; Kuppa, Shashi M

2010-01-01

Injury risk curves for the skeletal knee-thigh-hip (KTH) relate peak force applied to the anterior aspect of the flexed knee, the primary source of KTH injury in frontal motor-vehicle crashes, to the probability of skeletal KTH injury. Previous KTH injury risk curves have been developed from analyses of peak knee-impact force data from studies where knees of whole cadavers were impacted. However, these risk curves either neglect the effects of occupant gender, stature, and mass on KTH fracture force, or account for them using scaling factors derived from dimensional analysis without empirical support. A large amount of experimental data on the knee-impact forces associated with KTH fracture are now available, making it possible to estimate the effects of subject characteristics on skeletal KTH injury risk by statistically analyzing empirical data. Eleven studies were identified in the biomechanical literature in which the flexed knees of whole cadavers were impacted. From these, peak knee-impact force data and the associated subject characteristics were reanalyzed using survival analysis with a lognormal distribution. Results of this analysis indicate that the relationship between peak knee-impact force and the probability of KTH fracture is a function of age, total body mass, and whether the surface that loads the knee is rigid. Comparisons between injury risk curves for the midsize adult male and small adult female crash test dummies defined in previous studies and new risk curves for these sizes of occupants developed in this study suggest that previous injury risk curves generally overestimate the likelihood of KTH fracture at a given peak knee-impact force. Future work should focus on defining the relationships between impact force at the human knee and peak axial compressive forces measured by load cells in the crash test dummy KTH complex so that these new risk curves can be used with ATDs.

Peak load demand forecasting using two-level discrete wavelet decomposition and neural network algorithm

Science.gov (United States)

Bunnoon, Pituk; Chalermyanont, Kusumal; Limsakul, Chusak

2010-02-01

This paper proposed the discrete transform and neural network algorithms to obtain the monthly peak load demand in mid term load forecasting. The mother wavelet daubechies2 (db2) is employed to decomposed, high pass filter and low pass filter signals from the original signal before using feed forward back propagation neural network to determine the forecasting results. The historical data records in 1997-2007 of Electricity Generating Authority of Thailand (EGAT) is used as reference. In this study, historical information of peak load demand(MW), mean temperature(Tmean), consumer price index (CPI), and industrial index (economic:IDI) are used as feature inputs of the network. The experimental results show that the Mean Absolute Percentage Error (MAPE) is approximately 4.32%. This forecasting results can be used for fuel planning and unit commitment of the power system in the future.

Analysis of axisymmetric shells subjected to asymmetric loads using field consistent shear flexible curved element

Energy Technology Data Exchange (ETDEWEB)

Balakrishna, C; Sarma, B S [Defence Research and Development Laboratory, Hyderabad (India)

1989-02-01

A formulation for axisymmetric shell analysis under asymmetric load based on Fourier series representation and using field consistent 3 noded curved axisymmetric shell element is presented. Different field inconsistent/consistent interpolations for an element based on shear flexible theory have been studied for thick and thin shells under asymmetric loads. Various examples covering axisymmetric as well as asymmetric loading cases have been analyzed and numerical results show a good agreement with the available results in the case of thin shells. 12 refs.

A new elasto-plastic spring element for cyclic loading of piles using the p-y curve concept

DEFF Research Database (Denmark)

Hededal, Ole; Klinkvort, Rasmus Tofte

2010-01-01

Modeling the response of large diameter piles subjected to lateral loading is most often done by means of p-y-curves in combination withWinkler beam models. Traditionally the p-y curves are formulated as non-linear (elastic) relations between the lateral movement y and the soil response pressure p....... The present model can account for effects like pre-consolidation and creation of gaps between pile and soil at reversed loading. Results indicate that the model is able to capture hysteresis during loading with full cycles and model the accumulated displacement observed on piles subjected to “half cycles......” as e.g. seen from centrifuge tests carried out. This article presents the theoretical formulations, discusses numerical implementation and finally presents simulations....

An Improved Fuzzy C-Means Algorithm for the Implementation of Demand Side Management Measures

Directory of Open Access Journals (Sweden)

Ioannis Panapakidis

2017-09-01

Full Text Available Load profiling refers to a procedure that leads to the formulation of daily load curves and consumer classes regarding the similarity of the curve shapes. This procedure incorporates a set of unsupervised machine learning algorithms. While many crisp clustering algorithms have been proposed for grouping load curves into clusters, only one soft clustering algorithm is utilized for the aforementioned purpose, namely the Fuzzy C-Means (FCM algorithm. Since the benefits of soft clustering are demonstrated in a variety of applications, the potential of introducing a novel modification of the FCM in the electricity consumer clustering process is examined. Additionally, this paper proposes a novel Demand Side Management (DSM strategy for load management of consumers that are eligible for the implementation of Real-Time Pricing (RTP schemes. The DSM strategy is formulated as a constrained optimization problem that can be easily solved and therefore, making it a useful tool for retailers’ decision-making framework in competitive electricity markets.

Energy and electricity demand forecasting for nuclear power planning in developing countries

International Nuclear Information System (INIS)

1988-07-01

This Guidebook is designed to be a reference document to forecast energy and electricity demand. It presents concepts and methodologies that have been developed to make an analytical approach to energy/electricity demand forecasting as part of the planning process. The Guidebook is divided into 6 main chapters: (Energy demand and development, energy demand analysis, electric load curve analysis, energy and electricity demand forecasting, energy and electricity demand forecasting tools used in various organizations, IAEA methodologies for energy and electricity demand forecasting) and 3 appendices (experience with case studies carried out by the IAEA, reference technical data, reference economic data). A bibliography and a glossary complete the Guidebook. Refs, figs and tabs

Modelling the Load Curve of Aggregate Electricity Consumption Using Principal Components

OpenAIRE

Matteo Manera; Angelo Marzullo

2003-01-01

Since oil is a non-renewable resource with a high environmental impact, and its most common use is to produce combustibles for electricity, reliable methods for modelling electricity consumption can contribute to a more rational employment of this hydrocarbon fuel. In this paper we apply the Principal Components (PC) method to modelling the load curves of Italy, France and Greece on hourly data of aggregate electricity consumption. The empirical results obtained with the PC approach are compa...

Automatic demand response referred to electricity spot price. Demo description

International Nuclear Information System (INIS)

Grande, Ove S.; Livik, Klaus; Hals, Arne

2006-05-01

This report presents background, technical solution and results from a test project (Demo I) developed in the DRR Norway) project. Software and technology from two different vendors, APAS and Powel ASA, are used to demonstrate a scheme for Automatic Demand Response (ADR) referred to spot price level and a system for documentation of demand response and cost savings. Periods with shortage of energy supply and hardly any investments in new production capacity have turned focus towards the need for increased price elasticity on the demand side in the Nordic power market. The new technology for Automatic Meter Reading (AMR) and Remote Load Control (RLC) provides an opportunity to improve the direct market participation from the demand side by introducing automatic schemes that reduce the need for customer attention to hourly market prices. The low prioritized appliances, and not the total load, are in this report defined as the Demand Response Objects, based on the assumption that there is a limit for what the customers are willing to pay for different uses of electricity. Only disconnection of residential water heaters is included in the demo, due to practical limitations. The test was performed for a group of single family houses over a period of 2 months. All the houses were equipped with a radio controlled 'Ebox' unit attached to the water heater socket. The settlement and invoicing were based on hourly metered values (kWh/h), which means that the customer benefit is equivalent to the accumulated changes in the electricity cost per hour. The actual load reduction is documented by comparison between the real meter values for the period and a reference curve. The curves show significant response to the activated control in the morning hours. In the afternoon it is more difficult to register the response, probably due to 'disturbing' activities like cooking etc. Demo I shows that load reduction referred to spot price level can be done in a smooth way. The experiences

Experimental analysis of waveform effects on satellite and ligament behavior via in situ measurement of the drop-on-demand drop formation curve and the instantaneous jetting speed curve

International Nuclear Information System (INIS)

Kwon, Kye-Si

2010-01-01

In situ techniques to measure the drop-on-demand (DOD) drop formation curve and the instantaneous jetting speed curve are developed such that ligament behavior and satellite behavior of inkjet droplets can be analyzed effectively. It is known that the droplet jetting behavior differs by ink properties and the driving waveform voltage. In this study, to reduce possible droplet placement errors due to satellite drops or long ligaments during printing, waveform effects on drop formation are investigated based on the measured DOD drop formation curve and the instantaneous jetting speed curve. Experimental results show that a dwell time greater than the so-called efficient dwell time was effective in reducing placement errors due to satellite drops during the printing process

A Novel Prosumer-Based Energy Sharing and Management (PESM) Approach for Cooperative Demand Side Management (DSM) in Smart Grid

OpenAIRE

Sohail Razzaq; Rehman Zafar; Naveed Ahmed Khan; Asif Raza Butt; Anzar Mahmood

2016-01-01

Increasing population and modern lifestyle have raised energy demands globally. Demand Side Management (DSM) is one important tool used to manage energy demands. It employs an advanced power infrastructure along with bi-directional information flow among utilities and users in order to achieve a balanced load curve and minimize demand-supply mismatch. Traditionally, this involves shifting the electricity demand from peak hours to other times of the day in an optimized manner. Multiple users e...

Simultaneous Provision of Flexible Ramping Product and Demand Relief by Interruptible Loads Considering Economic Incentives

Directory of Open Access Journals (Sweden)

Jiahua Hu

2017-12-01

Full Text Available To cope with the net load variability in real time, sufficient ramp capability from controllable resources is required. To address the issue of insufficient ramp capacity in real time operations, flexible ramping products (FRPs have been adopted by some Independent System Operators (ISOs in the USA as a new market design. The inherent variability and uncertainty caused by renewable energy sources (RESs call for new FRP providers apart from conventional generating units. The so-called interruptible load (IL has proved to be useful in maintaining the supply-demand balance by providing demand relief and can be a viable FRP provider in practice. Given this background, this work presents a stochastic real-time unit commitment model considering ramp requirement and simultaneous provision of IL for FRP and demand relief. Load serving entities (LSEs are included in the proposed model and act as mediators between the ISO and multiple ILs. In particular, incentive compatible contracts are designed to encourage customers to reveal their true outage costs. Case studies indicate both the system and LSEs can benefit by employing the proposed method and ILs can gain the highest profits by signing up a favorable contract.

Demand side management for remote area power supply systems incorporating solar irradiance model

International Nuclear Information System (INIS)

Al-Alawi, A.; Islam, S.M.

2004-01-01

This paper presents a technique for generating the daily electricity load profile for remote areas in the Middle East from first principles, using diversified demand. The generated load profile includes the energy required to run a small desalination unit to provide the necessary freshwater. Demand side management (DSM) is used in this study to smooth out the daily peaks and fill valleys in the load curve to make the most efficient use of energy resources. Finally, the load profile is compared with real data for six houses collected from Safri area in the Sultanate of Oman. These data may be used as the basis to obtain load profiles of other remote areas of the Middle East since the weather and social factors are similar. The modified hourly variation factor based on weather and economic and social factors of the Middle East is obtained. (author)

Demand Response on domestic thermostatically controlled loads

DEFF Research Database (Denmark)

Lakshmanan, Venkatachalam

. For a safe and reliable operation of electric power systems, the balance between electricity generation and consumption has to be maintained. The conventional fossil fuel based power generation achieves this balance by adjusting the generation to follow the consumption. In the electric power system......Electricity has become an inevitable part of human life in present day world. In the past two centuries, the electric power system has undergone a lot of changes. Due to the awareness about the adverse impact of the fossil fuels, the power industry is adopting green and sustainable energy sources....... In general, the electricity consumers are classified as industrial, commercial and domestic. In this dissertation, only the thermostatically controlled loads (TCLs) in the domestic segment are considered for the demand response study. The study is funded by Danish Council for Strategic Research (DCSR...

Designing an application for managing distribution transformer load

Directory of Open Access Journals (Sweden)

Olga Liliana Sánchez

2006-09-01

Full Text Available This paper presents a software application for distribution transformer load management and calculating the elec- tricity distribution network service quality index (i.e. EDS and EFS indexes. Transformer operation state, calculating core and coil losses and selecting distribution transformers based on technical-economic criteria using daily-load curves are the load management strategies presented here. The application consists of a programme allowing to data acquisition input, an Excel-based spread-sheet having the equations for calculating load management data and a user-interface presenting the load management application’s results. The application was validated by technical-economic evaluation of three distribution transformers when supplying demand.

Demand Side Management for the European Supergrid: Occupancy variances of European single-person households

International Nuclear Information System (INIS)

Torriti, Jacopo

2012-01-01

The prospect of a European Supergrid calls for research on aggregate electricity peak demand and Europe-wide Demand Side Management. No attempt has been made as yet to represent a time-related demand curve of residential electricity consumption at the European level. This article assesses how active occupancy levels of single-person households vary in single-person household in 15 European countries. It makes use of occupancy time-series data from the Harmonised European Time Use Survey database to build European occupancy curves; identify peak occupancy periods; construct time-related electricity demand curves for TV and video watching activities and assess occupancy variances of single-person households. - Highlights: ► Morning peak occupancies of European single households tale place between 7h30 and 7h40. ► Evening peaks take place between 20h10 and 20h20. ► TV and video activities during evening peaks make up about 3.1 GWh of European peak electricity load. ► Baseline and peak occupancy variances vary across countries. ► Baseline and peak occupancy variances can be used as input for Demand Side Management choices.

A novel method for decomposing electricity feeder load into elementary profiles from customer information

International Nuclear Information System (INIS)

Gerossier, Alexis; Barbier, Thibaut; Girard, Robin

2017-01-01

Highlights: •Use of aggregated electricity load profiles and customer description at feeder level. •Statistical recovery of elementary load profiles with customer categorization. •Generation of load demand profiles for unknown feeders and new local areas. •Relevancy of the different categorizations. -- Abstract: To plan a distribution grid involves making a long-term forecast of sub-hourly demand, which requires modeling the demand and its dynamics with aggregated measurement data. Distribution system operators (DSOs) have been recording electricity sub-hourly demand delivered by their medium-voltage feeders (around 1000—10,000 customers) for several years. Demand profiles differ widely among the various considered feeders. This is partly due to the varying mix of customer categories from one feeder to another. To overcome this issue, elementary demand profiles are often associated with customer categories and then combined according to a mix description. This paper presents a novel method to estimate elementary profiles that only requires several feeder demand curves and a description of customers. The method relies on a statistical blind source model and a new estimation procedure based on the augmented Lagrangian method. The use of feeders to estimate elementary profiles means that measurements are fully representative and continuously updated. We illustrate the proposed method through a case study comprising around 1000 feeder demand curves operated by the main French DSO Enedis. We propose an application o that uses the obtained profiles to evaluate the contribution of any set of new customers to a feeder peak load. We show that profiles enable a simulation of new unmeasured areas with errors of around 20%. We also show how our method can be used to evaluate the relevancy of different customer categorizations.

Online AMR Domestic Load Profile Characteristic Change Monitor to Support Ancillary Demand Services

DEFF Research Database (Denmark)

Stephen, Bruce; Isleifsson, Fridrik Rafn; Galloway, Stuart

2014-01-01

of small loads is presented. This would allow them to be assessed for their availability to provide demand services to the grid. In the method presented, significant changes in behavior are detected using Bayesian changepoint analysis which tracks a multivariate Gaussian representation of a residential...... in remote rural communities, are currently modeled with homogenous and coarse load profiles developed from aggregated data. An objective of AMR deployment is to clarify the nature and variability of the residential LV customer. In this paper, an algorithm for tracking the consistency of the behavior...

Optimal stochastic short-term thermal and electrical operation of fuel cell/photovoltaic/battery/grid hybrid energy system in the presence of demand response program

International Nuclear Information System (INIS)

Majidi, Majid; Nojavan, Sayyad; Zare, Kazem

2017-01-01

Highlights: • On-grid photovoltaic/battery/fuel cell system is considered as hybrid system. • Thermal and electrical operation of hybrid energy system is studied. • Hybrid energy system is used to reduce dependency on upstream grid for load serving. • Demand response program is proposed to manage the electrical load. • Demand response program is proposed to reduce hybrid energy system’s operation cost. - Abstract: In this paper, cost-efficient operation problem of photovoltaic/battery/fuel cell hybrid energy system has been evaluated in the presence of demand response program. Each load curve has off-peak, mid and peak time periods in which the energy prices are different. Demand response program transfers some amount of load from peak periods to other periods to flatten the load curve and minimize total cost. So, the main goal is to meet the energy demand and propose a cost-efficient approach to minimize system’s total cost including system’s electrical cost and thermal cost and the revenue from exporting power to the upstream grid. A battery has been utilized as an electrical energy storage system and a heat storage tank is used as a thermal energy storage system to save energy in off-peak and mid-peak hours and then supply load in peak hours which leads to reduction of cost. The proposed cost-efficient operation problem of photovoltaic/battery/fuel cell hybrid energy system is modeled by a mixed-integer linear program and solved by General algebraic modeling system optimization software under CPLEX solver. Two case studies are investigated to show the effects of demand response program on reduction of total cost.

The determination of load-time curve for a reactor containment which undergoes the impact of an airplane

International Nuclear Information System (INIS)

Wang Yuangong; Yu Aiping

1991-01-01

It is apparent that there exist some differences between the rigid load function of a reactor containment and the verified load function for undisturbed zone of deformative target when they undergo the impact of an airplane. The local non-linear behavior of impact zone is considered in the later situation, and a modified and better load function is obtained, which gives a value of the dynamic response of the structure 30% to 50% lower. In order to make engineering design more convenient and to simplify the calculation of non-linear behavior of the local zone, and based on the verified load function, several polygonal approximate curves are suggested for calculating the load functions of some typical structures

Distribution load forecast with interactive correction of horizon loads

International Nuclear Information System (INIS)

Glamochanin, V.; Andonov, D.; Gagovski, I.

1994-01-01

This paper presents the interactive distribution load forecast application that performs the distribution load forecast with interactive correction of horizon loads. It consists of two major parts implemented in Fortran and Visual Basic. The Fortran part is used for the forecasts computations. It consists of two methods: Load Transfer Coupling Curve Fitting (LTCCF) and load Forecast Using Curve Shape Clustering (FUCSC). LTCCF is used to 'correct' the contaminated data because of load transfer among neighboring distribution areas. FUCSC uses curve shape clustering to forecast the distribution loads of small areas. The forecast for each small area is achieved by using the shape of corresponding cluster curve. The comparison of forecasted loads of the area with historical data will be used as a tool for the correction of the estimated horizon load. The Visual Basic part is used to provide flexible interactive user-friendly environment. (author). 5 refs., 3 figs

Letter to the Editor: Electric Vehicle Demand Model for Load Flow Studies

DEFF Research Database (Denmark)

Garcia-Valle, Rodrigo; Vlachogiannis, Ioannis (John)

2009-01-01

This paper introduces specific and simple model for electric vehicles suitable for load flow studies. The electric vehicles demand system is modelled as PQ bus with stochastic characteristics based on the concept of queuing theory. All appropriate variables of stochastic PQ buses are given...... with closed formulae as a function of charging time. Specific manufacturer model of electric vehicles is used as study case....

Evaluation of high temperature gas reactor for demanding cogeneration load follow

International Nuclear Information System (INIS)

Yan, Xing L.; Sato, Hiroyuki; Tachibana, Yukio; Kunitomi, Kazuhiko; Hino, Ryutaro

2012-01-01

Modular nuclear reactor systems are being developed around the world for new missions among which is cogeneration for industries and remote areas. Like existing fossil energy counterpart in these markets, a nuclear plant would need to demonstrate the feasibility of load follow including (1) the reliability to generate power and heat simultaneously and alone and (2) the flexibility to vary cogeneration rates concurrent to demand changes. This article reports the results of JAEA's evaluation on the high temperature gas reactor (HTGR) to perform these duties. The evaluation results in a plant design based on the materials and design codes developed with JAEA's operating test reactor and from additional equipment validation programs. The 600 MWt-HTGR plant generates electricity efficiently by gas turbine and 900degC heat by a topping heater. The heater couples via a heat transport loop to industrial facility that consumes the high temperature heat to yield heat product such as hydrogen fuel, steel, or chemical. Original control methods are proposed to automate transition between the load duties. Equipment challenges are addressed for severe operation conditions. Performance limits of cogeneration load following are quantified from the plant system simulation to a range of bounding events including a loss of either load and a rapid peaking of electricity. (author)

Research of Charging(Discharging Orderly and Optimizing Load Curve for Electric Vehicles Based on Dynamic Electric Price and V2G

Directory of Open Access Journals (Sweden)

Yang Shuai

2016-01-01

Full Text Available Firstly, using the Monte Carlo method and simulation analysis, this paper builds models for the behaviour of electric vehicles, the conventional charging model and the fast charging model. Secondly, this paper studies the impact that the number of electric vehicles which get access to power grid has on the daily load curve. Then, the paper put forwards a dynamic pricing mechanism of electricity, and studies how this dynamic pricing mechanism guides the electric vehicles to charge orderly. Last but not the least, the paper presents a V2G mechanism. Under this mechanism, electric vehicles can charge orderly and take part in the peak shaving. Research finds that massive electric vehicles’ access to the power grid will increase the peak-valley difference of daily load curve. Dynamic pricing mechanism and V2G mechanism can effectively lead the electric vehicles to take part in peak-shaving, and optimize the daily load curve.

Two-stage discrete-continuous multi-objective load optimization: An industrial consumer utility approach to demand response

International Nuclear Information System (INIS)

Abdulaal, Ahmed; Moghaddass, Ramin; Asfour, Shihab

2017-01-01

Highlights: •Two-stage model links discrete-optimization to real-time system dynamics operation. •The solutions obtained are non-dominated Pareto optimal solutions. •Computationally efficient GA solver through customized chromosome coding. •Modest to considerable savings are achieved depending on the consumer’s preference. -- Abstract: In the wake of today’s highly dynamic and competitive energy markets, optimal dispatching of energy sources requires effective demand responsiveness. Suppliers have adopted a dynamic pricing strategy in efforts to control the downstream demand. This method however requires consumer awareness, flexibility, and timely responsiveness. While residential activities are more flexible and schedulable, larger commercial consumers remain an obstacle due to the impacts on industrial performance. This paper combines methods from quadratic, stochastic, and evolutionary programming with multi-objective optimization and continuous simulation, to propose a two-stage discrete-continuous multi-objective load optimization (DiCoMoLoOp) autonomous approach for industrial consumer demand response (DR). Stage 1 defines discrete-event load shifting targets. Accordingly, controllable loads are continuously optimized in stage 2 while considering the consumer’s utility. Utility functions, which measure the loads’ time value to the consumer, are derived and weights are assigned through an analytical hierarchy process (AHP). The method is demonstrated for an industrial building model using real data. The proposed method integrates with building energy management system and solves in real-time with autonomous and instantaneous load shifting in the hour-ahead energy price (HAP) market. The simulation shows the occasional existence of multiple load management options on the Pareto frontier. Finally, the computed savings, based on the simulation analysis with real consumption, climate, and price data, ranged from modest to considerable amounts

Comparison of heavy metal loads in stormwater runoff from major and minor urban roads using pollutant yield rating curves

International Nuclear Information System (INIS)

Davis, Brett; Birch, Gavin

2010-01-01

Trace metal export by stormwater runoff from a major road and local street in urban Sydney, Australia, is compared using pollutant yield rating curves derived from intensive sampling data. The event loads of copper, lead and zinc are well approximated by logarithmic relationships with respect to total event discharge owing to the reliable appearance of a first flush in pollutant mass loading from urban roads. Comparisons of the yield rating curves for these three metals show that copper and zinc export rates from the local street are comparable with that of the major road, while lead export from the local street is much higher, despite a 45-fold difference in traffic volume. The yield rating curve approach allows problematic environmental data to be presented in a simple yet meaningful manner with less information loss. - A simple method for representing data onroad runoff pollution allows comparisons among dissimilar sites and could form the basis for a pollution database.

Initial studies on the variations of load-displacement curves of in vivo human healthy heel pads

DEFF Research Database (Denmark)

Matteoli, Sara; Wilhjelm, Jens E.; Virga, Antonio

2011-01-01

The aim of this study was to quantify on the measurement variation of in vivo load-displacement curves by using a group of human healthy heel pads. The recordings were done with a compression device measuring force and displacement. Twenty three heel pads, one from each of 23 subjects aged 20...

Assessment of demand-response-driven load pattern elasticity using a combined approach for smart households

NARCIS (Netherlands)

Paterakis, N.G.; Tascikaraoglu, A.; Erdinç, O.; Bakirtzis, A.G.; Catalaõ, J.P.S.

2016-01-01

The recent interest in the smart grid vision and the technological advancement in the communication and control infrastructure enable several smart applications at different levels of the power grid structure, while specific importance is given to the demand side. As a result, changes in load

Price elasticity matrix of demand in power system considering demand response programs

Science.gov (United States)

Qu, Xinyao; Hui, Hongxun; Yang, Shengchun; Li, Yaping; Ding, Yi

2018-02-01

The increasing renewable energy power generations have brought more intermittency and volatility to the electric power system. Demand-side resources can improve the consumption of renewable energy by demand response (DR), which becomes one of the important means to improve the reliability of power system. In price-based DR, the sensitivity analysis of customer’s power demand to the changing electricity prices is pivotal for setting reasonable prices and forecasting loads of power system. This paper studies the price elasticity matrix of demand (PEMD). An improved PEMD model is proposed based on elasticity effect weight, which can unify the rigid loads and flexible loads. Moreover, the structure of PEMD, which is decided by price policies and load types, and the calculation method of PEMD are also proposed. Several cases are studied to prove the effectiveness of this method.

Oil prices: demand and supply. Lesson plan

OpenAIRE

anonymous

2005-01-01

Upon completion of this lesson, students will be able to list the determinants of demand and supply, recognize which factors will cause demand curves or supply curves to shift, determine equilibrium using a demand/supply graph, and show the effects on price and quantity when equilibrium changes.

Estimating the Impacts of Direct Load Control Programs Using GridPIQ, a Web-Based Screening Tool

Energy Technology Data Exchange (ETDEWEB)

Pal, Seemita; Thayer, Brandon L.; Barrett, Emily L.; Studarus, Karen E.

2017-11-13

In direct load control (DLC) programs, utilities can curtail the demand of participating loads to contractually agreed-upon levels during periods of critical peak load, thereby reducing stress on the system, generation cost, and required transmission and generation capacity. Participating customers receive financial incentives. The impacts of implementing DLC programs extend well beyond peak shaving. There may be a shift of load proportional to the interrupted load to the times before or after a DLC event, and different load shifts have different consequences. Tools that can quantify the impacts of such programs on load curves, peak demand, emissions, and fossil fuel costs are currently lacking. The Grid Project Impact Quantification (GridPIQ) screening tool includes a Direct Load Control module, which takes into account project-specific inputs as well as the larger system context in order to quantify the impacts of a given DLC program. This allows users (utilities, researchers, etc.) to test and compare different program specifications and their impacts.

Numerical Derivation of Iso-Damaged Curve for a Reinforced Concrete Beam Subjected to Blast Loading

Directory of Open Access Journals (Sweden)

Temsah Yehya

2018-01-01

Full Text Available Many engineering facilities are severely damaged by blast loading. Therefore, many manufacturers of sensitive, breakable, and deformed structures (such as facades of glass buildings carry out studies and set standards for these installations to withstand shock waves caused by explosions. Structural engineers also use these standards in their designs for various structural elements by following the ISO Damage Carve, which links pressure and Impulse. As all the points below this curve means that the structure is safe and will not exceed the degree of damage based on the various assumptions made. This research aims to derive the Iso-Damage curve of a reinforced concrete beam exposed to blast wave. An advanced volumetric finite element program (ABAQUS will be used to perform the derivation.

Comparing passive angle-torque curves recorded simultaneously with a load cell versus an isokinetic dynamometer during dorsiflexion stretch tolerance assessments.

Science.gov (United States)

Buckner, Samuel L; Jenkins, Nathaniel D M; Costa, Pablo B; Ryan, Eric D; Herda, Trent J; Cramer, Joel T

2015-05-01

The purpose of the present study was to compare the passive angle-torque curves and the passive stiffness (PS, N m °(-)(1)) values recorded simultaneously from a load cell versus an isokinetic dynamometer during dorsiflexion stretch tolerance assessments in vivo. Nine healthy men (mean ± SD age = 21.4 ± 1.6 years) completed stretch tolerance assessments on a custom-built apparatus where passive torque was measured simultaneously from an isokinetic dynamometer and a load cell. Passive torque values that corresponded with the last 10° of dorsiflexion, verified by surface electromyographic amplitude, were analyzed for each device (θ1, θ2, θ3, …, θ10). Passive torque values measured with the load cell were greater (p ≤ 0.05) than the dynamometer torque values for θ4 through θ10. There were more statistical differentiations among joint angles for passive torque measured by the load cell, and the load cell measured a greater (p ≤ 0.01) increase in passive torque and PS than the isokinetic dynamometer. These findings suggested that when examining the angle-torque curves from passive dorsiflexion stretch tolerance tests, a load cell placed under the distal end of the foot may be more sensitive than the torque recorded from an isokinetic dynamometer. Copyright © 2015 IPEM. Published by Elsevier Ltd. All rights reserved.

Load demand profile for a large charging station of a fleet of all-electric plug-in buses

Directory of Open Access Journals (Sweden)

Mario A. Rios

2014-08-01

Full Text Available This study proposes a general procedure to compute the load demand profile from a parking lot where a fleet of buses with electric propulsion mechanisms are charged. Such procedure is divided in three different stages, the first one models the daily energy utilisation of the batteries based on Monte Carlo simulations and route characteristics. The second one models the process in the charging station based on discrete event simulation of queues of buses served by a lot of available chargers. The third step computes the final demand profile in the parking lot because of the charging process based on the power consumption of batteries’ chargers and the utilisation of the available charges. The proposed procedure allows the computation of the number of required batteries’ chargers to be installed in a charging station placed at a parking lot in order to satisfy and ensure the operation of the fleet, the computation of the power demand profile and the peak load and the computation of the general characteristics of electrical infrastructure to supply the power to the station.

Demand response in energy markets

International Nuclear Information System (INIS)

Skytte, K.; Birk Mortensen, J.

2004-11-01

Improving the ability of energy demand to respond to wholesale prices during critical periods of the spot market can reduce the total costs of reliably meeting demand, and the level and volatility of the prices. This fact has lead to a growing interest in the short-run demand response. There has especially been a growing interest in the electricity market where peak-load periods with high spot prices and occasional local blackouts have recently been seen. Market concentration at the supply side can result in even higher peak-load prices. Demand response by shifting demand from peak to base-load periods can counteract the market power in the peak-load. However, demand response has so far been modest since the current short-term price elasticity seems to be small. This is also the case for related markets, for example, green certificates where the demand is determined as a percentage of the power demand, or for heat and natural gas markets. This raises a number of interesting research issues: 1) Demand response in different energy markets, 2) Estimation of price elasticity and flexibility, 3) Stimulation of demand response, 4) Regulation, policy and modelling aspects, 5) Demand response and market power at the supply side, 6) Energy security of supply, 7) Demand response in forward, spot, ancillary service, balance and capacity markets, 8) Demand response in deviated markets, e.g., emission, futures, and green certificate markets, 9) Value of increased demand response, 10) Flexible households. (BA)

Evaluation of flexible demand-side load-following reserves in power systems with high wind generation penetration

NARCIS (Netherlands)

Paterakis, N.G.; Catalao, J.P.S.; Ntomaris, A.V.; Erdinc, O.

2015-01-01

In this study, a two-stage stochastic programming joint energy and reserve day-ahead market structure is proposed in order to procure the required load-following reserves to tackle with wind power production uncertainty. Reserves can be procured both from generation and demand-side. Responsive

Electricity demand loads modeling using AutoRegressive Moving Average (ARMA) models

Energy Technology Data Exchange (ETDEWEB)

Pappas, S.S. [Department of Information and Communication Systems Engineering, University of the Aegean, Karlovassi, 83 200 Samos (Greece); Ekonomou, L.; Chatzarakis, G.E. [Department of Electrical Engineering Educators, ASPETE - School of Pedagogical and Technological Education, N. Heraklion, 141 21 Athens (Greece); Karamousantas, D.C. [Technological Educational Institute of Kalamata, Antikalamos, 24100 Kalamata (Greece); Katsikas, S.K. [Department of Technology Education and Digital Systems, University of Piraeus, 150 Androutsou Srt., 18 532 Piraeus (Greece); Liatsis, P. [Division of Electrical Electronic and Information Engineering, School of Engineering and Mathematical Sciences, Information and Biomedical Engineering Centre, City University, Northampton Square, London EC1V 0HB (United Kingdom)

2008-09-15

This study addresses the problem of modeling the electricity demand loads in Greece. The provided actual load data is deseasonilized and an AutoRegressive Moving Average (ARMA) model is fitted on the data off-line, using the Akaike Corrected Information Criterion (AICC). The developed model fits the data in a successful manner. Difficulties occur when the provided data includes noise or errors and also when an on-line/adaptive modeling is required. In both cases and under the assumption that the provided data can be represented by an ARMA model, simultaneous order and parameter estimation of ARMA models under the presence of noise are performed. The produced results indicate that the proposed method, which is based on the multi-model partitioning theory, tackles successfully the studied problem. For validation purposes the produced results are compared with three other established order selection criteria, namely AICC, Akaike's Information Criterion (AIC) and Schwarz's Bayesian Information Criterion (BIC). The developed model could be useful in the studies that concern electricity consumption and electricity prices forecasts. (author)

Calculation of cooling internal circuits loss of load curve in giant electric machines; Calculo da curva de perda de carga dos circuitos axiais internos de refrigeracao de maquinas eletricas gigantes

Energy Technology Data Exchange (ETDEWEB)

Silva, Hilton Penha [Parana Univ., Curitiba, PR (Brazil). Dept. de Engenharia Mecanica. Dept. de Engenharia do Produto; Passos, Alex Sandro Barbosa [Parana Univ., Curitiba, PR (Brazil). Dept. de Engenharia Mecanica. Dept. de Pesquisa e Desenvolvimento do Produto

2001-07-01

This article describes a method for calculation of the loss of load curve for the ventilation axial circuits. The method assumes the ventilation circuit representation in a way similar to the electrical circuits. The great difficulty of circuit solution resides in the non linearity of the loss of load resistances and the equations relating the pressures and flows. The method is based on the association of the resistance curves of loss of load in a such way that, when the resistance curve of the total circuit loss of load is obtained, the blower operation point can be easily obtained and, consequently, the individual flows for each section of the circuit.

Spatial–Temporal Analysis of the Heat and Electricity Demand of the Swiss Building Stock

Directory of Open Access Journals (Sweden)

Stefan Schneider

2017-08-01

Full Text Available In 2015, space heating and domestic hot water production accounted for around 40% of the Swiss final energy consumption. Reaching the goals of the 2050 energy strategy will require significantly reducing this share despite the growing building stock. Renewables are numerous but subject to spatial–temporal constraints. Territorial planning of energy distribution systems enabling the integration of renewables requires having a spatial–temporal characterization of the energy demand. This paper presents two bottom-up statistical extrapolation models for the estimation of the geo-dependent heat and electricity demand of the Swiss building stock. The heat demand is estimated by means of a statistical bottom-up model applied at the building level. At the municipality level, the electricity load curve is estimated by combining socio-economic indicators with average consumption per activity and/or electric device. This approach also allows to break down the estimated electricity demand according to activity type (e.g., households, various industry, and service activities and appliance type (e.g., lighting, motor force, fridges. The total estimated aggregated demand is 94 TWh for heat and 58 TWh for electricity, which represent a deviation of 2.9 and 0.5%, respectively compared to the national energy consumption statistics. In addition, comparisons between estimated and measured electric load curves are done to validate the proposed approach. Finally, these models are used to build a geo-referred database of heat and electricity demand for the entire Swiss territory. As an application of the heat demand model, a realistic saving potential is estimated for the existing building stock; this potential could be achieved through by a deep retrofit program. One advantage of the statistical bottom-up model approach is that it allows to simulate a building stock that replicates the diversity of building demand. This point is important in order to

Cognitive Load and Attentional Demands during Objects' Position Change in Real and Digital Environments

Science.gov (United States)

Zacharis, Georgios K.; Mikropoulos, Tassos Anastasios; Kalyvioti, Katerina

2016-01-01

Studies showed that two-dimensional (2D) and three-dimensional (3D) educational content contributes to learning. Although there were many studies with 3D stereoscopic learning environments, only a few studies reported on the differences between real, 2D, and 3D scenes, as far as cognitive load and attentional demands were concerned. We used…

Analysis of demand curves in the stock and financial markets of monopolistic competition

Directory of Open Access Journals (Sweden)

Mikhail I. Geras’kin

2016-01-01

Full Text Available Objective to identify patterns of monopolistic competition as applied to markets of household appliances consumer loans and insurance products in Russia. Methods econometric modeling trending regression analysis analysis of statistical significance. Results the statistical analysis of trends in the market of household appliances insurance and credit markets has been carried out the statistical significance and adequacy of the models has been assessed adequate and accurate regression models of price trends of household appliances and electronics have been developed as well as of the interest rates of consumer loans and insurance rates for loan debts. Scientific novelty the actual patterns of decreasing demand curves for household appliances consumer loans and insurance products were found for the relevant markets in the Russian Federation in 2009ndash2014. Practical significance the model can be used for solving problems of optimal planning strategies of retailers insurers and banks. nbsp

Energy Systems Scenario Modelling and Long Term Forecasting of Hourly Electricity Demand

DEFF Research Database (Denmark)

Alberg Østergaard, Poul; Møller Andersen, Frits; Kwon, Pil Seok

2015-01-01

. The results show that even with a limited short term electric car fleet, these will have a significant effect on the energy system; the energy system’s ability to integrate wind power and the demand for condensing power generation capacity in the system. Charging patterns and flexibility have significant...... or inflexible electric vehicles and individual heat pumps, and in the long term it is investigated what the effects of changes in the load profiles due to changing weights of demand sectors are. The analyses are based on energy systems simulations using EnergyPLAN and demand forecasting using the Helena model...... effects on this. Likewise, individual heat pumps may affect the system operation if they are equipped with heat storages. The analyses also show that the long term changes in electricity demand curve profiles have little impact on the energy system performance. The flexibility given by heat pumps...

Identifying interactive effects of task demands in lifting on estimates of in vivo low back joint loads.

Science.gov (United States)

Gooyers, Chad E; Beach, Tyson A C; Frost, David M; Howarth, Samuel J; Callaghan, Jack P

2018-02-01

This investigation examined interactions between the magnitude of external load, movement speed and (a)symmetry of load placement on estimates of in vivo joint loading in the lumbar spine during simulated occupational lifting. Thirty-two participants with manual materials handling experience were included in the study. Three-dimensional motion data, ground reaction forces, and activation of six bilateral trunk muscle groups were captured while participants performed lifts with two loads at two movement speeds and using two load locations. L4-L5 joint compression and shear force-time histories were estimated using an EMG-assisted musculoskeletal model of the lumbar spine. Results from this investigation provide strong evidence that known mechanical low back injury risk factors should not be viewed in isolation. Rather, injury prevention efforts need to consider the complex interactions that exist between external task demands and their combined influence on internal joint loading. Copyright © 2017 Elsevier Ltd. All rights reserved.

Simple utility functions with Giffen demand

DEFF Research Database (Denmark)

Sørensen, Peter Norman

2007-01-01

Simple utility functions with the Giffen property are presented: locally, the demand curve for a good is upward sloping. The utility functions represent continuous, monotone, convex preferences......Simple utility functions with the Giffen property are presented: locally, the demand curve for a good is upward sloping. The utility functions represent continuous, monotone, convex preferences...

Modeling and prioritizing demand response programs in power markets

International Nuclear Information System (INIS)

Aalami, H.A.; Moghaddam, M. Parsa; Yousefi, G.R.

2010-01-01

One of the responsibilities of power market regulator is setting rules for selecting and prioritizing demand response (DR) programs. There are many different alternatives of DR programs for improving load profile characteristics and achieving customers' satisfaction. Regulator should find the optimal solution which reflects the perspectives of each DR stakeholder. Multi Attribute Decision Making (MADM) is a proper method for handling such optimization problems. In this paper, an extended responsive load economic model is developed. The model is based on price elasticity and customer benefit function. Prioritizing of DR programs can be realized by means of Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) method. Considerations of ISO/utility/customer regarding the weighting of attributes are encountered by entropy method. An Analytical Hierarchy Process (AHP) is used for selecting the most effective DR program. Numerical studies are conducted on the load curve of the Iranian power grid in 2007. (author)

Peak load-impulse characterization of critical pulse loads in structural dynamics

International Nuclear Information System (INIS)

Abrahamson, G.R.; Lindberg, H.E.

1975-01-01

In presenting the characterization scheme, some general features are described first. A detailed analysis is given for the rigid-plastic system of one degree of freedom to illustrate the calculation of critical load curves in terms of peak load and impulse. This is followed by the presentation of critical load curves for uniformly loaded rigid-plastic beams and plates and for dynamic buckling of cylindrical shells under uniform lateral loads. The peak load-impulse characterization of critical pulse loads is compared with the dynamic load factor characterization, and some aspects of the history of the peak load-pulse scheme are presented. (orig./HP) [de

Managing charging loads of electric vehicles by monetary incentives. A model-based optimization; Monetaere Anreize zur Steuerung der Ladelast von Elektrofahrzeugen. Eine modellgestuetzte Optimierung

Energy Technology Data Exchange (ETDEWEB)

Paetz, Alexandra-Gwyn; Kaschub, Thomas; Kopp, Martin; Jochem, Patrick; Fichtner, Wolf [Karlsruher Institut fuer Technologie, Karlsruhe (Germany). Inst. fuer Industriebetriebslehre und Industrielle Produktion

2013-03-15

Electric mobility is supposed to contribute to climate policy targets by reducing CO{sub 2}-emissions in the transportation sector. Increasing penetration rates of electric vehicles (EV) can lead to new challenges in the electricity sector, especially with regard to local distribution networks. Thus the management of charging loads is discussed as a key issue in energy economics. Due to their long parking times, high electricity and power demand, EV seem to be predestined for load management. Monetary incentives as dynamic pricing can be suitable for that: They reflect the current supply situation, pass the information to the consumers and can thus lead to a corresponding charging behaviour. In this article we analyse this interaction between dynamic pricing and charging loads. For this reason we have developed the optimization model DS-Opt+. It models a total number of 4,000 households in two residential areas of a major city with regard to its electricity demand, its mobility behaviour and its equipment of photovoltaic systems. Four different pricing models are tested for their effects on charging behaviour and thus the total load of the residential area. The results illustrate that only fairly high penetration rates of EV lead to remarkably higher electricity demand and require some load management. The tested dynamic pricing models are suitable for influencing charging loads; load-based tariffs are best in achieving a balanced load curve. In our analysis uncontrolled charging strategies are superior regarding a balanced load curve than controlled strategies by time-varying tariffs. Our results lead to several implications relevant for the energy industry and further research.

Forward-looking report of the electricity supply-demand balance in France. 2011

International Nuclear Information System (INIS)

2011-01-01

After an introduction presenting the objective of this report and the method used for its predictions, this document proposes an analysis of energy consumption: past trends, context of predictions, building up of predictions, global predictions, impact of demand control, comparison with a previous forward-looking assessment, comparison with other scenarios and other European countries. It analyses and discusses power consumption predictions (electricity consumption time variations, load curve evolution perspectives, peak power), production supply (current stock, thermal nuclear, thermal fossil, thermal decentralized, hydroelectric, wind energy, and photovoltaic production), the evolution of the supply-demand balance on a medium term for France and for two French regions. It finally proposes a long term prospective vision regarding energy

Load kick-back effects due to activation of demand response in view of distribution grid operation

DEFF Research Database (Denmark)

Han, Xue; Sossan, Fabrizio; Bindner, Henrik W.

2014-01-01

. The paper has shown how aggregated consumption dynamics introduce new peaks in the system due to the synchronous behaviors of a portfolio of homogeneous DSRs, which is instructed by the flexibility management system. This dynamic effect is recognized as load kick-back effect. The impact of load kick......-back effects onto the distribution grid is analysed in this paper by establishing scenarios based on the estimation of DSR penetration levels from the system operator. The results indicate some risks that the activation of demand response may create critical peaks in the local grid due to kick-back effects....

Development of Load Duration Curve System in Data Scarce Watersheds Based on a Distributed Hydrological Model

Science.gov (United States)

WANG, J.

2017-12-01

In stream water quality control, the total maximum daily load (TMDL) program is very effective. However, the load duration curves (LDC) of TMDL are difficult to be established because no sufficient observed flow and pollutant data can be provided in data-scarce watersheds in which no hydrological stations or consecutively long-term hydrological data are available. Although the point sources or a non-point sources of pollutants can be clarified easily with the aid of LDC, where does the pollutant come from and to where it will be transported in the watershed cannot be traced by LDC. To seek out the best management practices (BMPs) of pollutants in a watershed, and to overcome the limitation of LDC, we proposed to develop LDC based on a distributed hydrological model of SWAT for the water quality management in data scarce river basins. In this study, firstly, the distributed hydrological model of SWAT was established with the scarce-hydrological data. Then, the long-term daily flows were generated with the established SWAT model and rainfall data from the adjacent weather station. Flow duration curves (FDC) was then developed with the aid of generated daily flows by SWAT model. Considering the goal of water quality management, LDC curves of different pollutants can be obtained based on the FDC. With the monitored water quality data and the LDC curves, the water quality problems caused by the point or non-point source pollutants in different seasons can be ascertained. Finally, the distributed hydrological model of SWAT was employed again to tracing the spatial distribution and the origination of the pollutants of coming from what kind of agricultural practices and/or other human activities. A case study was conducted in the Jian-jiang river, a tributary of Yangtze river, of Duyun city, Guizhou province. Results indicate that this kind of method can realize the water quality management based on TMDL and find out the suitable BMPs for reducing pollutant in a watershed.

Plug-in Hybrid Electric Vehicles in the Smart Grid Environment: An Economic Model of Load Management by Demand Response

Directory of Open Access Journals (Sweden)

Poudineh R.

2012-10-01

Full Text Available Environmental concern regarding the consumption of fossil fuels is among the most serious challenges facing the world. As a result, utilisation of more renewable resources and promotion of a clean transport system such as the use of Plug in Hybrid Electric Vehicles (PHEVs became the forefront of the new energy policies. However, the breakthrough of PHEVs in the automotive fleet increases concerns around the stability of power system and in particular, the power network. This research simulates the aggregate load profile of the UK with presence of PHEVs based upon different price scenarios. The results show that under the fixed rate and time of use programmes in the current grid, the extra load of the electric vehicles intensifies the consumption profile and also creates new critical points. Thus, there should always be excess standby capacity to satisfy peak demand even for a short period of time. On the other hand, when the consumers do not pay the price based on the actual cost of supply, those who consume less in peak hours subsidise the ones who consume more and this cross subsidy raises a regulatory issue. On the contrary, a smart grid can accommodate PHEVs without creating technical and regulatory problems. This positive consequence is the result of demand response to the real time pricing. From a technical point of view, the biggest chunk of PHEVs' load will be shifted to the late evening and the hours of minimum demand. Besides, from a welfare analysis standpoint, real time pricing creates no deadweight losses and corresponding demand response will limit the ability of suppliers to increase the spot market clearing price above its equilibrium level.

Refrigerated Warehouse Demand Response Strategy Guide

Energy Technology Data Exchange (ETDEWEB)

Scott, Doug [VaCom Technologies, San Luis Obispo, CA (United States); Castillo, Rafael [VaCom Technologies, San Luis Obispo, CA (United States); Larson, Kyle [VaCom Technologies, San Luis Obispo, CA (United States); Dobbs, Brian [VaCom Technologies, San Luis Obispo, CA (United States); Olsen, Daniel [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2015-11-01

This guide summarizes demand response measures that can be implemented in refrigerated warehouses. In an appendix, it also addresses related energy efficiency opportunities. Reducing overall grid demand during peak periods and energy consumption has benefits for facility operators, grid operators, utility companies, and society. State wide demand response potential for the refrigerated warehouse sector in California is estimated to be over 22.1 Megawatts. Two categories of demand response strategies are described in this guide: load shifting and load shedding. Load shifting can be accomplished via pre-cooling, capacity limiting, and battery charger load management. Load shedding can be achieved by lighting reduction, demand defrost and defrost termination, infiltration reduction, and shutting down miscellaneous equipment. Estimation of the costs and benefits of demand response participation yields simple payback periods of 2-4 years. To improve demand response performance, it’s suggested to install air curtains and another form of infiltration barrier, such as a rollup door, for the passageways. Further modifications to increase efficiency of the refrigeration unit are also analyzed. A larger condenser can maintain the minimum saturated condensing temperature (SCT) for more hours of the day. Lowering the SCT reduces the compressor lift, which results in an overall increase in refrigeration system capacity and energy efficiency. Another way of saving energy in refrigerated warehouses is eliminating the use of under-floor resistance heaters. A more energy efficient alternative to resistance heaters is to utilize the heat that is being rejected from the condenser through a heat exchanger. These energy efficiency measures improve efficiency either by reducing the required electric energy input for the refrigeration system, by helping to curtail the refrigeration load on the system, or by reducing both the load and required energy input.

Load-Displacement Curves of Spot Welded, Bonded, and Weld-Bonded Joints for Dissimilar Materials and Thickness

Directory of Open Access Journals (Sweden)

E.A. Al-Bahkali

2011-12-01

Full Text Available Three-dimensional finite element models of spot welded, bonded and weld-bonded joints are developed using ABAQUS software. Each model consists of two strips with dissimilar materials and thickness and is subjected to an axial loading. The bonded and weld-bonded joints have specific adhesive thickness. A detailed experimental plan to define many properties and quantities such as, the elastic - plastic properties, modulus of elasticity, fracture limit, and properties of the nugget and heat affected zones are carried out. Experiments include standard testing of the base metal, the adhesive, the nugget and heat affected zone. They also include employing the indentation techniques, and ductile fracture limits criteria, using the special notch tests. Complete load-displacement curves are obtained for all joining models and a comparison is made to determine the best combination.

Interdependent demands, regulatory constraint, and peak-load pricing. [Assessment of Bailey's model

Energy Technology Data Exchange (ETDEWEB)

Nguyen, D T; Macgregor-Reid, G J

1977-06-01

A model of a regulated firm which includes an analysis of peak-load pricing has been formulated by E. E. Bailey in which three alternative modes of regulation on a profit-maximizing firm are considered. The main conclusion reached is that under a regulation limiting the rate of return on capital investment, price reductions are received solely by peak-users and that when regulation limiting the profit per unit of output or the return on costs is imposed, there are price reductions for all users. Bailey has expressly assumed that the demands in different periods are interdependent but has somehow failed to derive the correct price and welfare implications of this empirically highly relevant assumption. Her conclusions would have been perfectly correct for marginal revenues but are quite incorrect for prices, even if her assumption that price exceeds marginal revenues in every period holds. This present paper derives fully and rigorously the implications of regulation for prices, outputs, capacity, and social welfare for a profit-maximizing firm with interdependent demands. In section II, Bailey's model is reproduced and the optimal conditions are given. In section III, it is demonstrated that under the conditions of interdependent demands assumed by Bailey herself, her often-quoted conclusion concerning the effects of the return-on-investment regulation on the off-peak price is invalid. In section IV, the effects of the return-on-investment regulation on the optimal prices, outputs, capacity, and social welfare both for the case in which the demands in different periods are substitutes and for the case in which they are complements are examined. In section V, the pricing and welfare implications of the return-on-investment regulation are compared with the two other modes of regulation considered by Bailey. Section VI is a summary of all sections. (MCW)

Variability of electricity load patterns and its effect on demand response: A critical peak pricing experiment on Korean commercial and industrial customers

International Nuclear Information System (INIS)

Jang, Dongsik; Eom, Jiyong; Jae Park, Min; Jeung Rho, Jae

2016-01-01

To the extent that demand response represents an intentional electricity usage adjustment to price changes or incentive payments, consumers who exhibit more-variable load patterns on normal days may be capable of altering their loads more significantly in response to dynamic pricing plans. This study investigates the variation in the pre-enrollment load patterns of Korean commercial and industrial electricity customers and their impact on event-day loads during a critical peak pricing experiment in the winter of 2013. Contrary to conventional approaches to profiling electricity loads, this study proposes a new clustering technique based on variability indices that collectively represent the potential demand–response resource that these customers would supply. Our analysis reveals that variability in pre-enrollment load patterns does indeed have great predictive power for estimating their impact on demand–response loads. Customers in relatively low-variability clusters provided limited or no response, whereas customers in relatively high-variability clusters consistently presented large load impacts, accounting for most of the program-level peak reductions. This study suggests that dynamic pricing programs themselves may not offer adequate motivation for meaningful adjustments in load patterns, particularly for customers in low-variability clusters. - Highlights: • A method of clustering customers by variability indices is developed. • Customers in high-variability clusters provide substantial peak reductions. • Low-variability clusters exhibit limited reductions. • For low-variability customers, alternative policy instruments is well advised. • A model of discerning customer's demand response potential is suggested.

Analysis on learning curves of end-use appliances for the establishment of price-sensitivity load model in competitive electricity market

Energy Technology Data Exchange (ETDEWEB)

Hwang, Sung Wook; Kim, Jung Hoon [Hongik University (Korea); Song, Kyung Bin [Keimyung University (Korea); Choi, Joon Young [Jeonju University (Korea)

2001-07-01

The change of the electricity charge from cost base to price base due to the introduction to the electricity market competition causes consumer to choose a variety of charge schemes and a portion of loads to be affected by this change. Besides, it is required the index that consolidate the price volatility experienced on the power exchange with gaming and strategic bidding by suppliers to increase profits. Therefore, in order to find a mathematical model of the sensitively-responding to-price loads, the price-sensitive load model is needed. And the development of state-of- the-art technologies affects the electricity price, so the diffusion of high-efficient end-uses and these price affect load patterns. This paper shows the analysis on learning curves algorithms which is used to investigate the correlation of the end-uses' price and load patterns. (author). 6 refs., 4 figs., 4 tabs.

Addressing Energy Demand through Demand Response. International Experiences and Practices

Energy Technology Data Exchange (ETDEWEB)

Shen, Bo [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Ghatikar, Girish [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Ni, Chun Chun [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Dudley, Junqiao [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Martin, Phil [Enernoc, Inc., Boston, MA (United States); Wikler, Greg

2012-06-01

Demand response (DR) is a load management tool which provides a cost-effective alternative to traditional supply-side solutions to address the growing demand during times of peak electrical load. According to the US Department of Energy (DOE), demand response reflects “changes in electric usage by end-use customers from their normal consumption patterns in response to changes in the price of electricity over time, or to incentive payments designed to induce lower electricity use at times of high wholesale market prices or when system reliability is jeopardized.” 1 The California Energy Commission (CEC) defines DR as “a reduction in customers’ electricity consumption over a given time interval relative to what would otherwise occur in response to a price signal, other financial incentives, or a reliability signal.” 2 This latter definition is perhaps most reflective of how DR is understood and implemented today in countries such as the US, Canada, and Australia where DR is primarily a dispatchable resource responding to signals from utilities, grid operators, and/or load aggregators (or DR providers).

Integration of Methodologies for the Evaluation of Offer Curves in Energy and Capacity Markets through Energy Efficiency and Demand Response

Directory of Open Access Journals (Sweden)

Antonio Gabaldón

2018-02-01

Full Text Available The objectives of improving the efficiency, and integration, of renewable sources by 2030–2050 are complex in practice and should be linked to an increase of demand-side flexibility. The main challenges to achieving this flexibility are the lack of incentives and an adequate framework. For instance, customers’ revenue is usually low, the volatility of prices is high and there is not any practical feedback to customers from smart meters. The possibility of increasing customer revenue could reduce the uncertainty with respect to economic concerns, improving investments in efficiency, enabling technology and thus, engaging more customers in these policies. This objective could be achieved by the participation of customers in several markets. Moreover, Demand Response and Energy Efficiency can share ICT technologies but this participation needs to perform an aggregation of demand. The idea of this paper is to present some methodologies for facilitating the definition and evaluation of energy versus cost curves; and subsequently to estimate potential revenues due to Demand Response. This can be accomplished by models that estimate: demand and energy aggregation; economic opportunities and benefits; impacts on customer convenience; customer feedback and price analysis. By doing so, we would have comprehensive information that can help customers and aggregators to define energy packages and their monetary value with the objective of fostering their market participation.

Demand oriented biogas production to cover peak load; Bedarfsorientierte Biogasproduktion zur Erzeugung von Spitzenlaststrom. Weiterentwicklung der Biogastechnologie von Grundlast- zur Regelenergieerzeugung

Energy Technology Data Exchange (ETDEWEB)

Wallmann, Rainer; Ganagin, Waldemar; Loewe, Kirsten; Loewen, Achim [HAWK - Hochschule fuer angewandte Wissenschaft und Kunst, Fachhochschule Hildesheim, Holzminden, Goettingen (Germany)

2010-08-15

In contrast to solar and wind energy, biogas production is independent from environmental influences. The better part of biogas plants provide almost constant power and, thus, cover base load. However, it is possible to match biogas production with changing demand in different ways. Besides installing sufficiently dimensioned storages, a flexible generation of gas is possible by adjusting the digestion processes and installing appropriate control technologies. This enables flexible biogas production oriented towards customer demand. Peak load energy can be produced and marketed even without the advantage of reimbursement guaranteed by the renewable energy law. The Department of Sustainable Energy and Environmental Technology NEUTec at the University of Applied Science and Arts HAWK in Goettingen has carried out a research project to prove this concept of flexible biogas production. Operating a two-stage digestion plant, the capability to cover peak load was investigated by digesting energyrich liquid substrate in fixed bed reactors that represented the methanogenesis stage. These reactors showed extreme stability and flexibility. The promising results let expect a great potential of fixed bed reactors for on-demand biogas production from liquid substrates. In addition, with up to 80 % very high methane contents could be achieved in the produced gas. (orig.)

Visualized study on specific points on demand curves and flow patterns in a single-side heated narrow rectangular channel

International Nuclear Information System (INIS)

Wang Junfeng; Huang Yanping; Wang Yanlin

2011-01-01

Highlights: → Specific points on the demand curve and flow patterns are visually studied. → Bubbly, churn, and annular flows were observed. → Onset of flow instability and bubbly-churn transition occurs at the same time. → The evolution of specific points and flow pattern transitions were examined. - Abstract: A simultaneous visualization and measurement study on some specific points on demand curves, such as onset of nucleate boiling (ONB), onset of significant void (OSV), onset of flow instability (OFI), and two-phase flow patterns in a single-side heated narrow rectangular channel, having a width of 40 mm and a gap of 3 mm, was carried out. New experimental approaches were adopted to identify OSV and OFI in a narrow rectangular channel. Under experimental conditions, the ONB could be predicted well by the Sato and Matsumura model. The OSV model of Bowring can reasonably predict the OSV if the single-side heated condition is considered. The OFI was close to the saturated boiling point and could be described accurately by Kennedy's correlation. The two-phase flow patterns observed in this experiment could be classified into bubbly, churn, and annular flow. Slug flow was never observed. The OFI always occurred when the bubbles at the channel exit began to coalesce, which corresponded to the beginning of the bubbly-churn transition in flow patterns. Finally, the evolution of specific points and flow pattern transitions were examined in a single-side heated narrow rectangular channel.

Review of current Southern California edison load management programs and proposal for a new market-driven, mass-market, demand-response program

Energy Technology Data Exchange (ETDEWEB)

Weller, G.H.

2002-01-01

Utility load management programs, including direct load control and interruptible load programs, constitute a large installed base of controllable loads that are employed by utilities as system reliability resources. In response to energy supply shortfalls expected during the summer of 2001, the California Public Utilities Commission in spring 2001 authorized new utility load management programs as well as revisions to existing programs. This report provides an independent review of the designs of these new programs for a large utility (Southern California Edison) and suggests possible improvements to enhance the price responsiveness of the customer actions influenced by these programs. The report also proposes a new program to elicit a mass-market demand response to utility price signals.

Optimum residential load management strategy for real time pricing (RTP) demand response programs

International Nuclear Information System (INIS)

Lujano-Rojas, Juan M.; Monteiro, Cláudio; Dufo-López, Rodolfo; Bernal-Agustín, José L.

2012-01-01

This paper presents an optimal load management strategy for residential consumers that utilizes the communication infrastructure of the future smart grid. The strategy considers predictions of electricity prices, energy demand, renewable power production, and power-purchase of energy of the consumer in determining the optimal relationship between hourly electricity prices and the use of different household appliances and electric vehicles in a typical smart house. The proposed strategy is illustrated using two study cases corresponding to a house located in Zaragoza (Spain) for a typical day in summer. Results show that the proposed model allows users to control their diary energy consumption and adapt their electricity bills to their actual economical situation. - Highlights: ► This work shows an optimal load management strategy for residential consumers. ► It has been considered the communication infrastructure of the future smart grid. ► A study case shows the optimal utilization of some appliances and electric vehicles. ► Results showed that the proposed model allows users to reduce their electricity bill.

Metabolic Demand and Internal Training Load in Technical-Tactical Training Sessions of Professional Futsal Players.

Science.gov (United States)

Wilke, Carolina F; Ramos, Guilherme P; Pacheco, Diogo A S; Santos, Weslley H M; Diniz, Mateus S L; Gonçalves, Gabriela G P; Marins, João C B; Wanner, Samuel P; Silami-Garcia, Emerson

2016-08-01

Wilke, CF, Ramos, GP, Pacheco, DAS, Santos, WHM, Diniz, MSL, Gonçalves, GGP, Marins, JCB, Wanner, SP, and Silami-Garcia, E. Metabolic demand and internal training load in technical-tactical training sessions of professional futsal players. J Strength Cond Res 30(8): 2330-2340, 2016-The aim of the study was to characterize aspects of technical-tactical training sessions of a professional futsal team. We addressed 4 specific aims: characterize the metabolic demands and intensity of these training sessions, compare the training intensity among players of different positions, compare the intensity of different futsal-specific activities (4 × 4, 6 × 4, and match simulation), and investigate the association between an objective (training impulse; TRIMP) and a subjective method (session rating of perceived exertion; sRPE) of measuring a player's internal training load. Twelve top-level futsal players performed an incremental exercise to determine their maximal oxygen consumption, maximal heart rate (HRmax), ventilatory threshold (VT), and respiratory compensation point (RCP). Each player's HR and RPE were measured and used to calculate energy expenditure, TRIMP, and sRPE during 37 training sessions over 8 weeks. The average intensity was 74 ± 4% of HRmax, which corresponded to 9.3 kcal·min. The players trained at intensities above the RCP, between the RCP and VT and below the VT for 20 ± 8%, 28 ± 6%, and 51 ± 10% of the session duration, respectively. Wingers, defenders, and pivots exercised at a similar average intensity but with different intensity distributions. No difference in intensity was found between the 3 typical activities. A strong correlation between the average daily TRIMP and sRPE was observed; however, this relationship was significant for only 4 of 12 players, indicating that sRPE is a useful tool for monitoring training loads but that it should be interpreted for each player individually rather than collectively.

Automatic generation and analysis of solar cell IV curves

Science.gov (United States)

Kraft, Steven M.; Jones, Jason C.

2014-06-03

A photovoltaic system includes multiple strings of solar panels and a device presenting a DC load to the strings of solar panels. Output currents of the strings of solar panels may be sensed and provided to a computer that generates current-voltage (IV) curves of the strings of solar panels. Output voltages of the string of solar panels may be sensed at the string or at the device presenting the DC load. The DC load may be varied. Output currents of the strings of solar panels responsive to the variation of the DC load are sensed to generate IV curves of the strings of solar panels. IV curves may be compared and analyzed to evaluate performance of and detect problems with a string of solar panels.

Demand forecasting: methodology used to electric power consumers for irrigation

International Nuclear Information System (INIS)

Gangi, R.D.; Atmann, J.L.

1989-01-01

The utilization of load curves on the evaluation of systems behaviour, consumers and in the owners and users brought a new subsidy for the performance of forecast techniques. This paper shows how we can use these forecasting techniques and load curves in a specify situation joined to Guaira Substation, where the predominance is rural consumers with large activities in irrigation. The main objective of this study is bring by load curve modulation and the expansion of consumer market, a optimized view of load for the future years. (C.G.C.)

Flexible Transmission Network Expansion Planning Considering Uncertain Renewable Generation and Load Demand Based on Hybrid Clustering Analysis

Directory of Open Access Journals (Sweden)

Yun-Hao Li

2015-12-01

Full Text Available This paper presents a flexible transmission network expansion planning (TNEP approach considering uncertainty. A novel hybrid clustering technique, which integrates the graph partitioning method and rough fuzzy clustering, is proposed to cope with uncertain renewable generation and load demand. The proposed clustering method is capable of recognizing the actual cluster distribution of complex datasets and providing high-quality clustering results. By clustering the hourly data for renewable generation and load demand, a multi-scenario model is proposed to consider the corresponding uncertainties in TNEP. Furthermore, due to the peak distribution characteristics of renewable generation and heavy investment in transmission, the traditional TNEP, which caters to rated renewable power output, is usually uneconomic. To improve the economic efficiency, the multi-objective optimization is incorporated into the multi-scenario TNEP model, while the curtailment of renewable generation is considered as one of the optimization objectives. The solution framework applies a modified NSGA-II algorithm to obtain a set of Pareto optimal planning schemes with different levels of investment costs and renewable generation curtailments. Numerical results on the IEEE RTS-24 system demonstrated the robustness and effectiveness of the proposed approach.

Retiring the Short-Run Aggregate Supply Curve

Science.gov (United States)

Elwood, S. Kirk

2010-01-01

The author argues that the aggregate demand/aggregate supply (AD/AS) model is significantly improved--although certainly not perfected--by trimming it of the short-run aggregate supply (SRAS) curve. Problems with the SRAS curve are shown first for the AD/AS model that casts the AD curve as identifying the equilibrium level of output associated…

Flexible demand in the GB domestic electricity sector in 2030

International Nuclear Information System (INIS)

Drysdale, Brian; Wu, Jianzhong; Jenkins, Nick

2015-01-01

Highlights: • Annual domestic demand by category and daily flexible load profiles are shown to 2030. • Valuable flexible demand requires loads to be identifiable, accessible, and useful. • The extent of flexible demand varies significantly on a diurnal and seasonal basis. • Barriers to accessing domestic demand include multiple low value loads and apathy. • Existing market structure a barrier to fully rewarding individual load flexibility. - Abstract: In order to meet greenhouse gas emissions targets the Great Britain (GB) future electricity supply will include a higher fraction of non-dispatchable generation, increasing opportunities for demand side management to maintain a supply/demand balance. This paper examines the extent of flexible domestic demand (FDD) in GB, its usefulness in system balancing and appropriate incentives to encourage consumers to participate. FDD, classified as electric space and water heating (ESWH), and cold and wet appliances, amounts to 59 TW h in 2012 (113 TW h total domestic demand) and is calculated to increase to 67 TW h in 2030. Summer and winter daily load profiles for flexible loads show significant seasonal and diurnal variations in the total flexible load and between load categories. Low levels of reflective consumer engagement with electricity consumption and a resistance to automation present barriers to effective access to FDD. A value of £1.97/household/year has been calculated for cold appliance loads used for frequency response in 2030, using 2013 market rates. The introduction of smart meters in GB by 2020 will allow access to FDD for system balancing. The low commercial value of individual domestic loads increases the attractiveness of non-financial incentives to fully exploit FDD. It was shown that appliance loads have different characteristics which can contribute to an efficient power system in different ways

Improved Short-Term Load Forecasting Based on Two-Stage Predictions with Artificial Neural Networks in a Microgrid Environment

Directory of Open Access Journals (Sweden)

Jaime Lloret

2013-08-01

Full Text Available Short-Term Load Forecasting plays a significant role in energy generation planning, and is specially gaining momentum in the emerging Smart Grids environment, which usually presents highly disaggregated scenarios where detailed real-time information is available thanks to Communications and Information Technologies, as it happens for example in the case of microgrids. This paper presents a two stage prediction model based on an Artificial Neural Network in order to allow Short-Term Load Forecasting of the following day in microgrid environment, which first estimates peak and valley values of the demand curve of the day to be forecasted. Those, together with other variables, will make the second stage, forecast of the entire demand curve, more precise than a direct, single-stage forecast. The whole architecture of the model will be presented and the results compared with recent work on the same set of data, and on the same location, obtaining a Mean Absolute Percentage Error of 1.62% against the original 2.47% of the single stage model.

Energy systems scenario modelling and long term forecasting of hourly electricity demand

Directory of Open Access Journals (Sweden)

Poul Alberg Østergaard

2015-06-01

Full Text Available The Danish energy system is undergoing a transition from a system based on storable fossil fuels to a system based on fluctuating renewable energy sources. At the same time, more of and more of the energy system is becoming electrified; transportation, heating and fuel usage in industry and elsewhere. This article investigates the development of the Danish energy system in a medium year 2030 situation as well as in a long-term year 2050 situation. The analyses are based on scenario development by the Danish Climate Commission. In the short term, it is investigated what the effects will be of having flexible or inflexible electric vehicles and individual heat pumps, and in the long term it is investigated what the effects of changes in the load profiles due to changing weights of demand sectors are. The analyses are based on energy systems simulations using EnergyPLAN and demand forecasting using the Helena model. The results show that even with a limited short-term electric car fleet, these will have a significant effect on the energy system; the energy system’s ability to integrated wind power and the demand for condensing power generation capacity in the system. Charging patterns and flexibility have significant effects on this. Likewise, individual heat pumps may affect the system operation if they are equipped with heat storages. The analyses also show that the long-term changes in electricity demand curve profiles have little impact on the energy system performance. The flexibility given by heat pumps and electric vehicles in the long-term future overshadows any effects of changes in hourly demand curve profiles.

Data model for Demand Side Management

Directory of Open Access Journals (Sweden)

Simona-Vasilica OPREA

2017-08-01

Full Text Available Demand Side Management (DSM is a portfolio of measures to improve the energy system mainly at the consumption level. In this paper we propose a data model for DSM stating from the optimization methods approach in SMARTRADE project from different perspectives of several entities that include: Transmission System Operator (TSO/Distribution System Operators (DSOs perspectives in case of security/reliability concerns: minimum amount of load (or generation shedding; aggregators perspective in case of demand or generation shedding request: Which demand (or generators should be shed?; consumers perspective: load shifting (time-of-use (ToU tariffs and optimum contract strategies with the aggregators (also known as balancing responsible parties- BRP for load shedding.

Plastic limit loads for cylindrical shell intersections under combined loading

International Nuclear Information System (INIS)

Skopinsky, V.N.; Berkov, N.A.; Vogov, R.A.

2015-01-01

In this research, applied methods of nonlinear analysis and results of determining the plastic limit loads for shell intersection configurations under combined internal pressure, in-plane moment and out-plane moment loadings are presented. The numerical analysis of shell intersections is performed using the finite element method, geometrically nonlinear shell theory in quadratic approximation and plasticity theory. For determining the load parameter of proportional combined loading, the developed maximum criterion of rate of change of relative plastic work is employed. The graphical results for model of cylindrical shell intersection under different two-parameter combined loadings (as generalized plastic limit load curves) and three-parameter combined loading (as generalized plastic limit load surface) are presented on the assumption that the internal pressure, in-plane moment and out-plane moment loads were applied in a proportional manner. - Highlights: • This paper presents nonlinear two-dimensional FE analysis for shell intersections. • Determining the plastic limit loads under combined loading is considered. • Developed maximum criterion of rate of change of relative plastic work is employed. • Plastic deformation mechanism in shell intersections is discussed. • Results for generalized plastic limit load curves of branch intersection are presented

Modelling the Stem Curve of a Palm in a Strong Wind

DEFF Research Database (Denmark)

Philipsen, Claus; Markvorsen, Steen; Kliem, Wolfhard

1996-01-01

Nonlinear differential equations governing the stem curve of a wind-loaded palm are derived and solved numerically.......Nonlinear differential equations governing the stem curve of a wind-loaded palm are derived and solved numerically....

Program Design Analysis using BEopt Building Energy Optimization Software: Defining a Technology Pathway Leading to New Homes with Zero Peak Cooling Demand; Preprint

Energy Technology Data Exchange (ETDEWEB)

Anderson, R.; Christensen, C.; Horowitz, S.

2006-08-01

An optimization method based on the evaluation of a broad range of different combinations of specific energy efficiency and renewable-energy options is used to determine the least-cost pathway to the development of new homes with zero peak cooling demand. The optimization approach conducts a sequential search of a large number of possible option combinations and uses the most cost-effective alternatives to generate a least-cost curve to achieve home-performance levels ranging from a Title 24-compliant home to a home that uses zero net source energy on an annual basis. By evaluating peak cooling load reductions on the least-cost curve, it is then possible to determine the most cost-effective combination of energy efficiency and renewable-energy options that both maximize annual energy savings and minimize peak-cooling demand.

Load curves analysis under operational and economics focus; Analise de curvas de carga sob enfoques operativos e economicos

Energy Technology Data Exchange (ETDEWEB)

Matos, R S; Cardoso, A F; Fleury, M E.V. [Companhia Energetica de Minas Gerais (CEMIG), Belo Horizonte, MG (Brazil)

1988-12-31

This work aims to present the analysis of load curves performed by the short term planning sectors of several subsidiaries, independently of the methodologies used. In order to do so some peculiar occurrences were selected which show the influence of factors that are external to the electric power system. In such way, the analysis of past situations proves to be an important tool in the forecasting work so that a better planning may be achieved. 13 figs., 2 tabs.

Voltage Controlled Dynamic Demand Response

DEFF Research Database (Denmark)

Bhattarai, Bishnu Prasad; Bak-Jensen, Birgitte; Mahat, Pukar

2013-01-01

Future power system is expected to be characterized by increased penetration of intermittent sources. Random and rapid fluctuations in demands together with intermittency in generation impose new challenges for power balancing in the existing system. Conventional techniques of balancing by large...... central or dispersed generations might not be sufficient for future scenario. One of the effective methods to cope with this scenario is to enable demand response. This paper proposes a dynamic voltage regulation based demand response technique to be applied in low voltage (LV) distribution feeders....... An adaptive dynamic model has been developed to determine composite voltage dependency of an aggregated load on feeder level. Following the demand dispatch or control signal, optimum voltage setting at the LV substation is determined based on the voltage dependency of the load. Furthermore, a new technique...

Household electricity demand profiles

DEFF Research Database (Denmark)

Marszal, Anna Joanna; Heiselberg, Per Kvols; Larsen, Olena Kalyanova

2016-01-01

Highlights •A 1-min resolution household electricity load model is presented. •Model adapts a bottom-up approach with single appliance as the main building block. •Load profiles are used to analyse the flexibility potential of household appliances. •Load profiles can be applied in other domains, .......g. building energy simulations. •The demand level of houses with different number of occupants is well captured....

A Comparative Study of Electric Load Curve Changes in an Urban Low-Voltage Substation in Spain during the Economic Crisis (2008–2013)

Science.gov (United States)

Lara-Santillán, Pedro M.; Mendoza-Villena, Montserrat; Fernández-Jiménez, L. Alfredo; Mañana-Canteli, Mario

2014-01-01

This paper presents a comparative study of the electricity consumption (EC) in an urban low-voltage substation before and during the economic crisis (2008–2013). This low-voltage substation supplies electric power to near 400 users. The EC was measured for an 11-year period (2002–2012) with a sampling time of 1 minute. The study described in the paper consists of detecting the changes produced in the load curves of this substation along the time due to changes in the behaviour of consumers. The EC was compared using representative curves per time period (precrisis and crisis). These representative curves were obtained after a computational process, which was based on a search for days with similar curves to the curve of a determined (base) date. This similitude was assessed by the proximity on the calendar, day of the week, daylight time, and outdoor temperature. The last selection parameter was the error between the nearest neighbour curves and the base date curve. The obtained representative curves were linearized to determine changes in their structure (maximum and minimum consumption values, duration of the daily time slot, etc.). The results primarily indicate an increase in the EC in the night slot during the summer months in the crisis period. PMID:24895677

A Comparative Study of Electric Load Curve Changes in an Urban Low-Voltage Substation in Spain during the Economic Crisis (2008–2013

Directory of Open Access Journals (Sweden)

Pedro M. Lara-Santillán

2014-01-01

Full Text Available This paper presents a comparative study of the electricity consumption (EC in an urban low-voltage substation before and during the economic crisis (2008–2013. This low-voltage substation supplies electric power to near 400 users. The EC was measured for an 11-year period (2002–2012 with a sampling time of 1 minute. The study described in the paper consists of detecting the changes produced in the load curves of this substation along the time due to changes in the behaviour of consumers. The EC was compared using representative curves per time period (precrisis and crisis. These representative curves were obtained after a computational process, which was based on a search for days with similar curves to the curve of a determined (base date. This similitude was assessed by the proximity on the calendar, day of the week, daylight time, and outdoor temperature. The last selection parameter was the error between the nearest neighbour curves and the base date curve. The obtained representative curves were linearized to determine changes in their structure (maximum and minimum consumption values, duration of the daily time slot, etc.. The results primarily indicate an increase in the EC in the night slot during the summer months in the crisis period.

Heat demand profiles of energy conservation measures in buildings and their impact on a district heating system

International Nuclear Information System (INIS)

Lundström, Lukas; Wallin, Fredrik

2016-01-01

Highlights: • Energy savings impact on an low CO 2 emitting district heating system. • Heat profiles of eight building energy conservation measures. • Exhaust air heat pump, heat recovery ventilation, electricity savings etc. • Heat load weather normalisation with segmented multivariable linear regression. - Abstract: This study highlights the forthcoming problem with diminishing environmental benefits from heat demand reducing energy conservation measures (ECM) of buildings within district heating systems (DHS), as the supply side is becoming “greener” and more primary energy efficient. In this study heat demand profiles and annual electricity-to-heat factors of ECMs in buildings are computed and their impact on system efficiency and greenhouse gas emissions of a Swedish biomass fuelled and combined heat and power utilising DHS are assessed. A weather normalising method for the DHS heat load is developed, combining segmented multivariable linear regressions with typical meteorological year weather data to enable the DHS model and the buildings model to work under the same weather conditions. Improving the buildings’ envelope insulation level and thereby levelling out the DHS heat load curve reduces greenhouse gas emissions and improves primary energy efficiency. Reducing household electricity use proves to be highly beneficial, partly because it increases heat demand, allowing for more cogeneration of electricity. However the other ECMs considered may cause increased greenhouse gas emissions, mainly because of their adverse impact on the cogeneration of electricity. If biomass fuels are considered as residuals, and thus assigned low primary energy factors, primary energy efficiency decreases when implementing ECMs that lower heat demand.

DISCOVERING AND LABELLING OF TEMPORAL GRANULARITY PATTERNS IN ELECTRIC POWER DEMAND WITH A BRAZILIAN CASE STUDY

Directory of Open Access Journals (Sweden)

Gabriela Servidone

Full Text Available ABSTRACT Clustering is commonly used to group data in order to represent the behaviour of a system as accurately as possible by obtaining patterns and profiles. In this paper, clustering is applied with partitioning-clustering techniques, specifically, Partitioning around Medoids (PAM to analyse load curves from a city of South-eastern Brazil in São Paulo state. A top-down approach in time granularity is performed to detect and to label profiles which could be affected by seasonal trends and daily/hourly time blocks. Time-granularity patterns are useful to support the improvement of activities related to distribution, transmission and scheduling of energy supply. Results indicated four main patterns which were post-processed in hourly blocks by using shades of grey to help final-user to understand demand thresholds according to the meaning of dark grey, light grey and white colours. A particular and different behaviour of load curve was identified for the studied city if it is compared to the classical behaviour of urban cities.

Latent factor structure of a behavioral economic marijuana demand curve.

Science.gov (United States)

Aston, Elizabeth R; Farris, Samantha G; MacKillop, James; Metrik, Jane

2017-08-01

Drug demand, or relative value, can be assessed via analysis of behavioral economic purchase task performance. Five demand indices are typically obtained from drug purchase tasks. The goal of this research was to determine whether metrics of marijuana reinforcement from a marijuana purchase task (MPT) exhibit a latent factor structure that efficiently characterizes marijuana demand. Participants were regular marijuana users (n = 99; 37.4% female, 71.5% marijuana use days [5 days/week], 15.2% cannabis dependent) who completed study assessments, including the MPT, during a baseline session. Principal component analysis was used to examine the latent structure underlying MPT indices. Concurrent validity was assessed via examination of relationships between latent factors and marijuana use, past quit attempts, and marijuana expectancies. A two-factor solution was confirmed as the best fitting structure, accounting for 88.5% of the overall variance. Factor 1 (65.8% variance) reflected "Persistence," indicating sensitivity to escalating marijuana price, which comprised four MPT indices (elasticity, O max , P max , and breakpoint). Factor 2 (22.7% variance) reflected "Amplitude," indicating the amount consumed at unrestricted price (intensity). Persistence factor scores were associated with fewer past marijuana quit attempts and lower expectancies of negative use outcomes. Amplitude factor scores were associated with more frequent use, dependence symptoms, craving severity, and positive marijuana outcome expectancies. Consistent with research on alcohol and cigarette purchase tasks, the MPT can be characterized with a latent two-factor structure. Thus, demand for marijuana appears to encompass distinct dimensions of price sensitivity and volumetric consumption, with differential relations to other aspects of marijuana motivation.

Solar + Storage Synergies for Managing Commercial-Customer Demand Charges

Energy Technology Data Exchange (ETDEWEB)

Gagnon, P. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Govindarajan, A. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Bird, L. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Barbose, G. L. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Darghouth, N. R. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Mills, A. D. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2017-10-18

Demand charges, which are based on a customer’s maximum demand in kilowatts (kW), are a common element of electricity rate structures for commercial customers. Customer-sited solar photovoltaic (PV) systems can potentially reduce demand charges, but the level of savings is difficult to predict, given variations in demand charge designs, customer loads, and PV generation profiles. Lawrence Berkeley National Laboratory (Berkeley Lab) and the National Renewable Energy Laboratory (NREL) are collaborating on a series of studies to understand how solar PV can impact demand charges. Prior studies in the series examined demand charge reductions from solar on a stand-alone basis for residential and commercial customers. Those earlier analyses found that solar, alone, has limited ability to reduce demand charges depending on the specific design of the demand charge and on the shape of the customer’s load profile. This latest analysis estimates demand charge savings from solar in commercial buildings when co-deployed with behind-the-meter storage, highlighting the complementary roles of the two technologies. The analysis is based on simulated loads, solar generation, and storage dispatch across a wide variety of building types, locations, system configurations, and demand charge designs.

Study of a conceptual nuclear energy center at Green River, Utah. Power demand, load center assessment and transmission

Energy Technology Data Exchange (ETDEWEB)

Smith, D.R.; Thaik, A.; Pingel, P.

1982-02-01

This document constitutes a segment of a feasibility study investigating the ramification of constructing a nuclear energy center in an arid western region. In this phase of the study. The projected power demands and load center locations were reviewed and assessed. Alternative transmission systems were analysed and a conceptual transmission for bulk power transportation is proposed with potential line routes. Environmental impacts of the proposed transmission were also identified.

Study of a conceptual nuclear energy center at Green River, Utah. Power demand, load center assessment and transmission

International Nuclear Information System (INIS)

Smith, D.R.; Thaik, A.; Pingel, P.

1982-02-01

This document constitutes a segment of a feasibility study investigating the ramification of constructing a nuclear energy center in an arid western region. In this phase of the study. The projected power demands and load center locations were reviewed and assessed. Alternative transmission systems were analysed and a conceptual transmission for bulk power transportation is proposed with potential line routes. Environmental impacts of the proposed transmission were also identified

A sustainable development of a city electrical grid via a non-contractual Demand-Side Management

Science.gov (United States)

Samoylenko, Vladislav O.; Pazderin, Andrew V.

2017-06-01

An increasing energy consumption of large cities as well as an extreme high density of city electrical loads leads to the necessity to search for an alternative approaches to city grid development. The ongoing implementation of the energy accounting tariffs with differentiated rates depending upon the market conditions and changing in a short-term perspective, provide the possibility to use it as a financial incentive base of a Demand-Side Management (DSM). Modern hi-technology energy metering and accounting systems with a large number of functions and consumer feedback are supposed to be the good means of DSM. Existing systems of Smart Metering (SM) billing usually provide general information about consumption curve, bills and compared data, but not the advanced statistics about the correspondence of financial and electric parameters. Also, consumer feedback is usually not fully used. So, the efforts to combine the market principle, Smart Metering and a consumer feedback for an active non-contractual load control are essential. The paper presents the rating-based multi-purpose system of mathematical statistics and algorithms of DSM efficiency estimation useful for both the consumers and the energy companies. The estimation is performed by SM Data processing systems. The system is aimed for load peak shaving and load curve smoothing. It is focused primarily on a retail market support. The system contributes to the energy efficiency and a distribution process improvement by the manual management or by the automated Smart Appliances interaction.

Option value of electricity demand response

Energy Technology Data Exchange (ETDEWEB)

Sezgen, Osman; Goldman, C.A. [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley CA 94720 (United States); Krishnarao, P. [Citigroup Energy Inc., 1301 Fannin St, Houston, TX 77002 (United States)

2007-02-15

As electricity markets deregulate and energy tariffs increasingly expose customers to commodity price volatility, it is difficult for energy consumers to assess the economic value of investments in technologies that manage electricity demand in response to changing energy prices. The key uncertainties in evaluating the economics of demand-response technologies are the level and volatility of future wholesale energy prices. In this paper, we demonstrate that financial engineering methodologies originally developed for pricing equity and commodity derivatives (e.g., futures, swaps, options) can be used to estimate the value of demand-response technologies. We adapt models used to value energy options and assets to value three common demand-response strategies: load curtailment, load shifting or displacement, and short-term fuel substitution-specifically, distributed generation. These option models represent an improvement to traditional discounted cash flow methods for assessing the relative merits of demand-side technology investments in restructured electricity markets. (author)

Option value of electricity demand response

International Nuclear Information System (INIS)

Sezgen, Osman; Goldman, C.A.; Krishnarao, P.

2007-01-01

As electricity markets deregulate and energy tariffs increasingly expose customers to commodity price volatility, it is difficult for energy consumers to assess the economic value of investments in technologies that manage electricity demand in response to changing energy prices. The key uncertainties in evaluating the economics of demand-response technologies are the level and volatility of future wholesale energy prices. In this paper, we demonstrate that financial engineering methodologies originally developed for pricing equity and commodity derivatives (e.g., futures, swaps, options) can be used to estimate the value of demand-response technologies. We adapt models used to value energy options and assets to value three common demand-response strategies: load curtailment, load shifting or displacement, and short-term fuel substitution-specifically, distributed generation. These option models represent an improvement to traditional discounted cash flow methods for assessing the relative merits of demand-side technology investments in restructured electricity markets. (author)

Comparison of wind turbines based on power curve analysis

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-02-01

In the study measured power curves for 46 wind turbines were analyzed with the purpose to establish the basis for a consistent comparison of the efficiency of the wind turbines. Emphasis is on wind turbines above 500 kW rated power, with power curves measured after 1994 according to international recommendations. The available power curves fulfilling these requirements were smoothened according to a procedure developed for the purpose in such a way that the smoothened power curves are equally representative as the measured curves. The resulting smoothened power curves are presented in a standardized format for the subsequent processing. Using wind turbine data from the power curve documentation the analysis results in curves for specific energy production (kWh/M{sup 2}/yr) versus specific rotor load (kW/M{sup 2}) for a range of mean wind speeds. On this basis generalized curves for specific annual energy production versus specific rotor load are established for a number of generalized wind turbine concepts. The 46 smoothened standardized power curves presented in the report, the procedure developed to establish them, and the results of the analysis based on them aim at providers of measured power curves as well as users of them including manufacturers, advisors and decision makers. (au)

The dispatch and load duration curve of the interconnected electrical system, in the hypothetical context of the 450ppm scenario of the Iea; El despacho y la curva de duracion de carga del sistema electrico interconectado, en el contexto hipotetico del escenario 450 ppm de la IEA

Energy Technology Data Exchange (ETDEWEB)

Villanueva M, C. [CVM-Consultor, Ciudad de Mexico (Mexico)

2017-09-15

The concept of the annual load duration curve of the national interconnected system is presented, which by means of a quadrature procedure becomes a 3-block diagram: one for the base load that occurs at 8,760 hours of the year; another for intermediate load, above the minimum that occurs in a variable number of hours of the year, and another for the peak demand that only happens a few hours of the year. The data of the table of capacity and generation of electric power in 2014, according to Annex A of the Mexico Energy Outlook document of the International Energy Agency (Iea), are converted into a block diagram adjusted to the annual curve of load duration of that year. The procedure is repeated with the capacity and electric power generation data projected by the Iea at 2030 and 2040, according to the 450ppm scenario, which is considered necessary to stabilize the concentration of CO{sub 2} in the atmosphere at 450 parts per million and ensure that the increase in the global temperature of the planet does not exceed 2 degrees Celsius, compared to pre-industrial levels. Then, the same capacity and generation data projected by the Iea by 2040 are tabulated by technology type, grouped now within the base, intermediate and peak blocks of the annual load duration curve for that year, and ordered from according to its plant factor, indicative of its availability to be dispatched. The above, in order to estimate the aggregate result of the annual dispatch that could be made by CENACE, if the projections of electric power generation to the year 2040 foreseen in the ambitious 450ppm scenario were given. Finally, an exercise is carried out to estimate, at 2015 prices, the unit costs of technologies generation in the year 2040, expressed in US D (2015)/ MWh and broken down into fixed and variable reference costs. (Author)

Definitional-mission report: Demand-side management program for the Tenaga Nasional Berhad in Malaysia. Export trade information

Energy Technology Data Exchange (ETDEWEB)

1992-03-01

A definitional mission evaluated the prospects of the US Trade and Development Program (TDP) funding a market demonstration of a Demand Side Management (DSM) program being developed by the Tenaga Nasional Berhad (TNB) in Malaysia. TNB is the national electric utility of Malaysia with the responsibility to promote economically efficient supply of electricity needed for the economic development of Peninsular Malaysia. DSM is a utility-financed program to affect energy savings at the enduse level thereby reducing peak and base loads. Historically, TNB has taken the peak load and the load duration curves as given in planning and implementing the least-cost generation expansion strategy. It has refrained from influencing the pattern of energy use by the customer through any means other than tariff structures and levels. The experience of many utilities with DSM in the U.S. offers TNB an opportunity to develop a suitable DSM program for Malaysia.

Formulation of Forming Load in V-Bending

Directory of Open Access Journals (Sweden)

Koumura Yuki

2016-01-01

Full Text Available A novel method is described to calculate the forming load in V-bending by a press brake. The data of forming load are collected by FEM analysis. With an increase of the punch stroke in V-bending, the forming load increases gradually after the elastic limit, and then decreases after showing the maximum value. The proposal formulation to trace the variations in the forming load curve includes the calculating method of the load of the elastic limit, the maximum load in air bending and the variations of the forming load before/after the bending stroke of the maximum load. The calculated precision is confirmed by comparing with the measured load-stroke curves in V-bending with a press brake.

Opportunities for Demand Response in California Agricultural Irrigation: A Scoping Study

Energy Technology Data Exchange (ETDEWEB)

Marks, Gary [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Wilcox, Edmund [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Olsen, Daniel [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Goli, Sasank [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2013-01-02

California agricultural irrigation consumes more than ten billion kilowatt hours of electricity annually and has significant potential for contributing to a reduction of stress on the grid through demand response, permanent load shifting, and energy efficiency measures. To understand this potential, a scoping study was initiated for the purpose of determining the associated opportunities, potential, and adoption challenges in California agricultural irrigation. The primary research for this study was conducted in two ways. First, data was gathered and parsed from published sources that shed light on where the best opportunities for load shifting and demand response lie within the agricultural irrigation sector. Secondly, a small limited survey was conducted as informal face-to-face interviews with several different California growers to get an idea of their ability and willingness to participate in permanent load shifting and/or demand response programs. Analysis of the data obtained from published sources and the survey reveal demand response and permanent load shifting opportunities by growing region, irrigation source, irrigation method, grower size, and utility coverage. The study examines some solutions for demand response and permanent load shifting in agricultural irrigation, which include adequate irrigation system capacity, automatic controls, variable frequency drives, and the contribution from energy efficiency measures. The study further examines the potential and challenges for grower acceptance of demand response and permanent load shifting in California agricultural irrigation. As part of the examination, the study considers to what extent permanent load shifting, which is already somewhat accepted within the agricultural sector, mitigates the need or benefit of demand response for agricultural irrigation. Recommendations for further study include studies on how to gain grower acceptance of demand response as well as other related studies such as

Structural load inventory database for the Kansas City Plant

International Nuclear Information System (INIS)

Hashimoto, P.S.; Johnson, M.W.; Nakaki, D.K.; Wilson, J.J.; Lynch, D.T.; Drury, M.A.

1993-01-01

A structural load inventory database (LID) has been developed to support configuration management at the DOE Kansas City Plant (KCP). The objective of the LID is to record loads supported by the plant structures and to provide rapid assessments of the impact of future facility modifications on structural adequacy. Development of the LID was initiated for the KCP's Main Manufacturing Building. Field walkdowns were performed to determine all significant loads supported by the structure, including the weight of piping, service equipment, etc. These loads were compiled in the LID. Structural analyses for natural phenomena hazards were performed in accordance with UCRL-15910. Software to calculate demands on the structural members due to gravity loads, total demands including both gravity and seismic loads, and structural member demand-to-capacity ratios were also developed and integrated into the LID. Operation of the LID is menu-driven. The LID user has options to review and print existing loads and corresponding demand-to-capacity ratios, and to update the supported loads and demand-to-capacity ratios for any future facility modifications

Seismic Performance Evaluation of Reinforced Concrete Frames Subjected to Seismic Loads

Science.gov (United States)

Zameeruddin, Mohd.; Sangle, Keshav K.

2017-06-01

Ten storied-3 bays reinforced concrete bare frame designed for gravity loads following the guidelines of IS 456 and IS 13920 for ductility is subjected to seismic loads. The seismic demands on this building were calculated by following IS 1893 for response spectra of 5% damping (for hard soil type). Plastic hinges were assigned to the beam and column at both ends to represent the failure mode, when member yields. Non-linear static (pushover) analysis was performed to evaluate the performance of the building in reference to first (ATC 40), second (FEMA 356) and next-generation (FEMA 440) performance based seismic design procedures. Base shear against top displacement curve of structure, known as pushover curve was obtained for two actions of plastic hinge behavior, force-controlled (brittle) and deformation-controlled (ductile) actions. Lateral deformation corresponding to performance point proves the building capability to sustain a certain level of seismic loads. The failure is represented by a sequence of formation of plastic hinges. Deformation-controlled action of hinges showed that building behaves like strong-column-weak-beam mechanism, whereas force-controlled action showed formation of hinges in the column. The study aims to understand the first, second and next generation performance based design procedure in prediction of actual building responses and their conservatism into the acceptance criteria.

Acquirement of true stress-strain curve using true fracture strain obtained by tensile test and FE analysis

International Nuclear Information System (INIS)

Lee, Kyoung Yoon; Kim, Tae Hyung; Lee, Hyung Yil

2009-01-01

In this work, we predict a true fracture strain using load-displacement curves from tensile test and Finite Element Analysis (FEA), and suggest a method for acquiring true Stress-Strain (SS) curves by predicted fracture strain. We first derived the true SS curve up to necking point from load-displacement curve. As the beginning, the posterior necking part of true SS curve is linearly extrapolated with the slope at necking point. The whole SS curve is then adopted for FE simulation of tensile test. The Bridgman factor or suitable plate correction factors are applied to pre and post FEA. In the load-true strain curve from FEA, the true fracture strain is determined as the matching point to test fracture load. The determined true strain is validated by comparing with test fracture strain. Finally, we complete the true SS curve by combining the prior necking part and linear part, the latter of which connects necking and predicted fracture points.

Acquirement of true stress-strain curve using true fracture strain obtained by tensile test and FE analysis

Energy Technology Data Exchange (ETDEWEB)

Lee, Kyoung Yoon; Kim, Tae Hyung; Lee, Hyung Yil [Sogang University, Seoul (Korea, Republic of)

2009-07-01

In this work, we predict a true fracture strain using load-displacement curves from tensile test and Finite Element Analysis (FEA), and suggest a method for acquiring true Stress-Strain (SS) curves by predicted fracture strain. We first derived the true SS curve up to necking point from load-displacement curve. As the beginning, the posterior necking part of true SS curve is linearly extrapolated with the slope at necking point. The whole SS curve is then adopted for FE simulation of tensile test. The Bridgman factor or suitable plate correction factors are applied to pre and post FEA. In the load-true strain curve from FEA, the true fracture strain is determined as the matching point to test fracture load. The determined true strain is validated by comparing with test fracture strain. Finally, we complete the true SS curve by combining the prior necking part and linear part, the latter of which connects necking and predicted fracture points.

Acquirement of True Stress-strain Curve Using True Fracture Strain Obtained by Tensile Test and FE Analysis

Energy Technology Data Exchange (ETDEWEB)

Lee, Kyoung Yoon; Lee, Hyung Yil [Sogang University, Seoul (Korea, Republic of); Kim, Tae Hyung [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2009-10-15

In this work, we predict a true fracture strain using load-displacement curves from tensile test and finite element analysis (FEA), and suggest a method for acquiring true stress-strain (SS) curves by predicted fracture strain. We first derived the true SS curve up to necking point from load-displacement curve. As the beginning, the posterior necking part of true SS curve is linearly extrapolated with the slope at necking point. The whole SS curve is then adopted for FE simulation of tensile test. The Bridgman factor or suitable plate correction factors are applied to pre and post FEA. In the load-true strain curve from FEA, the true fracture strain is determined as the matching point to test fracture load. The determined true strain is validated by comparing with test fracture strain. Finally, we complete the true SS curve by combining the prior necking part and linear part, the latter of which connects necking and predicted fracture points.

Large Scale Demand Response of Thermostatic Loads

DEFF Research Database (Denmark)

Totu, Luminita Cristiana

This study is concerned with large populations of residential thermostatic loads (e.g. refrigerators, air conditioning or heat pumps). The purpose is to gain control over the aggregate power consumption in order to provide balancing services for the electrical grid. Without affecting the temperat......This study is concerned with large populations of residential thermostatic loads (e.g. refrigerators, air conditioning or heat pumps). The purpose is to gain control over the aggregate power consumption in order to provide balancing services for the electrical grid. Without affecting....... The control architecture is defined by parsimonious communication requirements that also have a high level data privacy, and it furthermore guarantees a robust and secure local operation. Mathematical models are put forward, and the effectiveness is shown by numerical simulations. A case study of 10000...

Impact of thermostatically controlled loads' demand response activation on aggregated power: A field experiment

DEFF Research Database (Denmark)

Lakshmanan, Venkatachalam; Marinelli, Mattia; Kosek, Anna Magdalena

2015-01-01

activation. The outcome of this experimental study quantifies the actual flexibility of household TCLs and the consequence for the different parties with respect to power behaviour. Each DR activation method adopts different scenarios to meet the power reduction, and has different impacts on the parameters......This paper describes the impacts of different types of DR (demand response) activation on TCLs' (thermostatically controlled loads) aggregated power. The different parties: power system operators, DR service providers (or aggregators) and consumers, have different objectives in relation to DR....... The experiments are conducted with real domestic refrigerators representing TCL. Activating refrigerators for DR with a delay reduces the ISE (integral square error) in power limitation by 28.46%, overshoot by 7.69%. The delay in refrigerator activation causes reduction in power ramp down rate by 39.90%, ramp up...

Environmental Aspects of Load Management

International Nuclear Information System (INIS)

Abaravicius, Juozas

2004-02-01

This study approaches load management from an environmental perspective. It identifies and discusses the possible environmental benefits of load management and evaluates their significance, primary focusing on CO 2 emissions reduction. The analysis is carried out on two levels: national - the Swedish electricity market, and local - one electric utility in southern Sweden. Our results show the importance of considering the influence of site-specific or level-specific conditions on the environmental effects of load management. On the national level, load management measures can hardly provide significant environmental benefits, due to the high hydropower production in Sweden, which is the demand following production source. Emission reductions will rather be the result of energy efficiency measures, which will cut the load demand as well as the energy demand. However, when it comes to a local (utility) level, where load management is considered as an alternative to an installation of peak diesel power plant, the benefits are clear. It is demonstrated that significant CO 2 emissions savings can be achieved due to avoided peak diesel power production

Demand Response as a System Reliability Resource

Energy Technology Data Exchange (ETDEWEB)

Eto, Joseph H. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division; Lewis, Nancy Jo [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division; Watson, David [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division; Kiliccote, Sila [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Environmental Energy Technologies Division; Auslander, David [Univ. of California, Berkeley, CA (United States); Paprotny, Igor [Univ. of California, Berkeley, CA (United States); Makarov, Yuri [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2012-12-31

The Demand Response as a System Reliability Resource project consists of six technical tasks: • Task 2.1. Test Plan and Conduct Tests: Contingency Reserves Demand Response (DR) Demonstration—a pioneering demonstration of how existing utility load-management assets can provide an important electricity system reliability resource known as contingency reserve. • Task 2.2. Participation in Electric Power Research Institute (EPRI) IntelliGrid—technical assistance to the EPRI IntelliGrid team in developing use cases and other high-level requirements for the architecture. • Task 2.3. Research, Development, and Demonstration (RD&D) Planning for Demand Response Technology Development—technical support to the Public Interest Energy Research (PIER) Program on five topics: Sub-task 1. PIER Smart Grid RD&D Planning Document; Sub-task 2. System Dynamics of Programmable Controllable Thermostats; Sub-task 3. California Independent System Operator (California ISO) DR Use Cases; Sub-task 4. California ISO Telemetry Requirements; and Sub-task 5. Design of a Building Load Data Storage Platform. • Task 2.4. Time Value of Demand Response—research that will enable California ISO to take better account of the speed of the resources that it deploys to ensure compliance with reliability rules for frequency control. • Task 2.5. System Integration and Market Research: Southern California Edison (SCE)—research and technical support for efforts led by SCE to conduct demand response pilot demonstrations to provide a contingency reserve service (known as non-spinning reserve) through a targeted sub-population of aggregated residential and small commercial customers enrolled in SCE’s traditional air conditioning (AC) load cycling program, the Summer Discount Plan. • Task 2.6. Demonstrate Demand Response Technologies: Pacific Gas and Electric (PG&E)—research and technical support for efforts led by PG&E to conduct a demand response pilot demonstration to provide non

Modeling of demand response in electricity markets : effects of price elasticity

International Nuclear Information System (INIS)

Banda, E.C.; Tuan, L.A.

2007-01-01

A design mechanism for the optimal participation of customer load in electricity markets was presented. In particular, this paper presented a modified market model for the optimal procurement of interruptible loads participating in day-ahead electricity markets. The proposed model considers the effect of price elasticity and demand-response functions. The objective was to determine the role that price elasticity plays in electricity markets. The simulation model can help the Independent System Operator (ISO) identify customers offering the lowest price of interruptible loads and load flow patterns that avoid problems associated with transmission congestion and transmission losses. Various issues associated with procurement of demand-response offerings such as advance notification, locational aspect of load, and power factor of the loads, were considered. It was shown that demand response can mitigate price volatility by allowing the ISO to maintain operating reserves during peak load periods. It was noted that the potential benefits of the demand response program would be reduced when price elasticity of demand is taken into account. This would most likely occur in actual developed open electricity markets, such as Nordpool. This study was based on the CIGRE 32-bus system, which represents the Swedish high voltage power system. It was modified for this study to include a broad range of customer characteristics. 18 refs., 2 tabs., 14 figs

Simulation, Experimental and Analitical Study of Deflection at End Curved Beam Affected by Single Concentrated Load

Directory of Open Access Journals (Sweden)

Dewa Ngakan Ketut Putra Negara

2012-11-01

Full Text Available Deflection has an important role in order to design structure or machine component, beside consideration of stresscalculation. This is due to although stress is still smaller then stress allowed by material strength, but probably happen thatdeflection exceeds limit allowed. That condition affects serious hazard on machine elements or structure due to it can affectof component deviate from its main function. One of element which is often experience of deflection is beam. Beams playsignificant roles in many engineering applications, including buildings, bridges, automobiles, and airplane structures. In thisresearch, material to be used was Steel ASTM 1060, with specimen in the form of curved beam. Physical condition of beamwas modeled use of BEAM3 2D. Variation of loads to be applied were W = 100, 150, 200, 250, 300, 350, 400, 450, 500, and550 gr in vertical direction. The result of simulation was verificated by analytical and experimental data. Evaluation wascarried out by statistical test (t-test. The result of simulation is categorized to be good if the result of simulation is samewith analytical and experimental data. The result of research shows that loading has a significant effect on the deflection.The higher load affect the higher of deflection Modeling use of BEAM3 2D gave good result of deflection. This is showedfrom t-test have done, where the result of simulation was same with analytical and experimental data. Other advantage ofsimulation was deflection result obtained was not limited only at the end of beam, but it can predict of deflection at eachnode or point desired

User-Preference-Driven Model Predictive Control of Residential Building Loads and Battery Storage for Demand Response: Preprint

Energy Technology Data Exchange (ETDEWEB)

Jin, Xin [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Baker, Kyri A. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Christensen, Dane T. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Isley, Steven C. [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

2017-08-21

This paper presents a user-preference-driven home energy management system (HEMS) for demand response (DR) with residential building loads and battery storage. The HEMS is based on a multi-objective model predictive control algorithm, where the objectives include energy cost, thermal comfort, and carbon emission. A multi-criterion decision making method originating from social science is used to quickly determine user preferences based on a brief survey and derive the weights of different objectives used in the optimization process. Besides the residential appliances used in the traditional DR programs, a home battery system is integrated into the HEMS to improve the flexibility and reliability of the DR resources. Simulation studies have been performed on field data from a residential building stock data set. Appliance models and usage patterns were learned from the data to predict the DR resource availability. Results indicate the HEMS was able to provide a significant amount of load reduction with less than 20% prediction error in both heating and cooling cases.

The Use of Artificial Neural Networks for Forecasting the Electric Demand of Stand-Alone Consumers

Science.gov (United States)

Ivanin, O. A.; Direktor, L. B.

2018-05-01

The problem of short-term forecasting of electric power demand of stand-alone consumers (small inhabited localities) situated outside centralized power supply areas is considered. The basic approaches to modeling the electric power demand depending on the forecasting time frame and the problems set, as well as the specific features of such modeling, are described. The advantages and disadvantages of the methods used for the short-term forecast of the electric demand are indicated, and difficulties involved in the solution of the problem are outlined. The basic principles of arranging artificial neural networks are set forth; it is also shown that the proposed method is preferable when the input information necessary for prediction is lacking or incomplete. The selection of the parameters that should be included into the list of the input data for modeling the electric power demand of residential areas using artificial neural networks is validated. The structure of a neural network is proposed for solving the problem of modeling the electric power demand of residential areas. The specific features of generation of the training dataset are outlined. The results of test modeling of daily electric demand curves for some settlements of Kamchatka and Yakutia based on known actual electric demand curves are provided. The reliability of the test modeling has been validated. A high value of the deviation of the modeled curve from the reference curve obtained in one of the four reference calculations is explained. The input data and the predicted power demand curves for the rural settlement of Kuokuiskii Nasleg are provided. The power demand curves were modeled for four characteristic days of the year, and they can be used in the future for designing a power supply system for the settlement. To enhance the accuracy of the method, a series of measures based on specific features of a neural network's functioning are proposed.

Data-based method for creating electricity use load profiles using large amount of customer-specific hourly measured electricity use data

International Nuclear Information System (INIS)

Raesaenen, Teemu; Voukantsis, Dimitrios; Niska, Harri; Karatzas, Kostas; Kolehmainen, Mikko

2010-01-01

The recent technological developments monitoring the electricity use of small customers provides with a whole new view to develop electricity distribution systems, customer-specific services and to increase energy efficiency. The analysis of customer load profile and load estimation is an important and popular area of electricity distribution technology and management. In this paper, we present an efficient methodology, based on self-organizing maps (SOM) and clustering methods (K-means and hierarchical clustering), capable of handling large amounts of time-series data in the context of electricity load management research. The proposed methodology was applied on a dataset consisting of hourly measured electricity use data, for 3989 small customers located in Northern-Savo, Finland. Information for the hourly electricity use, for a large numbers of small customers, has been made available only recently. Therefore, this paper presents the first results of making use of these data. The individual customers were classified into user groups based on their electricity use profile. On this basis, new, data-based load curves were calculated for each of these user groups. The new user groups as well as the new-estimated load curves were compared with the existing ones, which were calculated by the electricity company, on the basis of a customer classification scheme and their annual demand for electricity. The index of agreement statistics were used to quantify the agreement between the estimated and observed electricity use. The results indicate that there is a clear improvement when using data-based estimations, while the new-estimated load curves can be utilized directly by existing electricity power systems for more accurate load estimates.

Data-based method for creating electricity use load profiles using large amount of customer-specific hourly measured electricity use data

Energy Technology Data Exchange (ETDEWEB)

Raesaenen, Teemu; Niska, Harri; Kolehmainen, Mikko [Department of Environmental Sciences, University of Eastern Finland P.O. Box 1627, FIN-70211 Kuopio (Finland); Voukantsis, Dimitrios; Karatzas, Kostas [Department of Mechanical Engineering, Aristotle University of Thessaloniki, GR-54124 Thessaloniki (Greece)

2010-11-15

The recent technological developments monitoring the electricity use of small customers provides with a whole new view to develop electricity distribution systems, customer-specific services and to increase energy efficiency. The analysis of customer load profile and load estimation is an important and popular area of electricity distribution technology and management. In this paper, we present an efficient methodology, based on self-organizing maps (SOM) and clustering methods (K-means and hierarchical clustering), capable of handling large amounts of time-series data in the context of electricity load management research. The proposed methodology was applied on a dataset consisting of hourly measured electricity use data, for 3989 small customers located in Northern-Savo, Finland. Information for the hourly electricity use, for a large numbers of small customers, has been made available only recently. Therefore, this paper presents the first results of making use of these data. The individual customers were classified into user groups based on their electricity use profile. On this basis, new, data-based load curves were calculated for each of these user groups. The new user groups as well as the new-estimated load curves were compared with the existing ones, which were calculated by the electricity company, on the basis of a customer classification scheme and their annual demand for electricity. The index of agreement statistics were used to quantify the agreement between the estimated and observed electricity use. The results indicate that there is a clear improvement when using data-based estimations, while the new-estimated load curves can be utilized directly by existing electricity power systems for more accurate load estimates. (author)

Measuring and controlling unfairness in decentralized planning of energy demand

NARCIS (Netherlands)

Pournaras, E.; Vasirani, M.; Kooij, R.E.; Aberer, K.

2014-01-01

Demand-side energy management improves robustness and efficiency in Smart Grids. Load-adjustment and load-shifting are performed to match demand to available supply. These operations come at a discomfort cost for consumers as their lifestyle is influenced when they adjust or shift in time their

Elasticity of Demand for Tuition Fees at an Institution of Higher Education

Science.gov (United States)

Langelett, George; Chang, Kuo-Liang; Ola' Akinfenwa, Samson; Jorgensen, Nicholas; Bhattarai, Kopila

2015-01-01

Using a conjoint survey of 161 students at South Dakota State University (SDSU), we mapped a probability-of-enrolment curve for SDSU students, consistent with demand theory. A quasi-demand curve was created from the conditional-logit model. This study shows that along with the price of tuition fees, distance from home, availability of majors, and…

High-resolution mapping of yield curve shape and evolution for high porosity sandstones

Science.gov (United States)

Bedford, J. D.; Faulkner, D.; Wheeler, J.; Leclere, H.

2017-12-01

The onset of permanent inelastic deformation for porous rock is typically defined by a yield curve plotted in P-Q space, where P is the effective mean stress and Q is the differential stress. Sandstones usually have broadly elliptical shaped yield curves, with the low pressure side of the ellipse associated with localized brittle faulting (dilation) and the high pressure side with distributed ductile deformation (compaction). However recent works have shown that these curves might not be perfectly elliptical and that significant evolution in shape occurs with continued deformation. We therefore use a novel stress-probing methodology to map in high-resolution the yield curve shape for Boise and Idaho Gray sandstones (36-38% porosity) and also investigate curve evolution with increasing deformation. The data reveal yield curves with a much flatter geometry than previously recorded for porous sandstone and that the compactive side of the curve is partly comprised of a near vertical limb. The yield curve evolution is found to be strongly dependent on the nature of inelastic strain. Samples that were compacted under a deviatoric load, with a component of inelastic shear strain, were found to have yield curves with peaks that are approximately 50% higher than similar porosity samples that were hydrostatically compacted (i.e. purely volumetric strain). The difference in yield curve evolution along the different loading paths is attributed to mechanical anisotropy that develops during deviatoric loading by the closure of preferentially orientated fractures. Increased shear strain also leads to the formation of a plateau at the peak of the yield curve as samples deform along the deviatoric loading path. These results have important implications for understanding how the strength of porous rock evolves along different stress paths, including during fluid extraction from hydrocarbon reservoirs where the stress state is rarely isotropic.

Demand response from the non-domestic sector: Early UK experiences and future opportunities

International Nuclear Information System (INIS)

Grünewald, Philipp; Torriti, Jacopo

2013-01-01

Demand response is believed by some to become a major contributor towards system balancing in future electricity networks. Shifting or reducing demand at critical moments can reduce the need for generation capacity, help with the integration of renewables, support more efficient system operation and thereby potentially lead to cost and carbon reductions for the entire energy system. In this paper we review the nature of the response resource of consumers from different non-domestic sectors in the UK, based on extensive half hourly demand profiles and observed demand responses. We further explore the potential to increase the demand response capacity through changes in the regulatory and market environment. The analysis suggests that present demand response measures tend to stimulate stand-by generation capacity in preference to load shifting and we propose that extended response times may favour load based demand response, especially in sectors with significant thermal loads. - Highlights: • Empirical demand response data from non-domestic sector evaluated. • Load profiles suggest strong sector dependence on availability response at system peak. • Majority of aggregated demand response still stems from stand-by generation, not from demand turn down. • Scope for substantial increase in demand response capacity if response times were extended

Structural load inventory database for the Kansas City federal complex

International Nuclear Information System (INIS)

Hashimoto, P.S.; Johnson, M.W.; Nakaki, D.K.; Lynch, D.T.; Drury, M.A.

1995-01-01

A structural load inventory database (LID) has been developed to support configuration management at the DOE Kansas City Plant (KCP). The objective of the LID is to record loads supported by the plant structures and to provide rapid assessments of the impact of future facility modifications on structural adequacy. Development of the LID was initiated for the KCP's Main Manufacturing Building. Field walkdowns were performed to determine all significant loads supported by the structure, including the weight of piping, service equipment, etc. These loads were compiled in the LID. Structural analyses for natural phenomena hazards were performed in accordance with UCRL-15910. Software to calculate demands on the structural members due to gravity loads, total demands including both gravity and seismic loads, and structural member demand-to-capacity ratios were also developed and integrated into the LID. Operation of the LID is menu-driven. The LID user has options to review and print existing loads and corresponding demand-to-capacity ratios, and to update the supported loads and demand-to-capacity ratios for any future facility modifications

A supply and demand based volatility model for energy prices

International Nuclear Information System (INIS)

Kanamura, Takashi

2009-01-01

This paper proposes a new volatility model for energy prices using the supply-demand relationship, which we call a supply and demand based volatility model. We show that the supply curve shape in the model determines the characteristics of the volatility in energy prices. It is found that the inverse Box-Cox transformation supply curve reflecting energy markets causes the inverse leverage effect, i.e., positive correlation between energy prices and volatility. The model is also used to show that an existing (G)ARCH-M model has the foundations on the supply-demand relationship. Additionally, we conduct the empirical studies analyzing the volatility in the U.S. natural gas prices. (author)

A supply and demand based volatility model for energy prices

Energy Technology Data Exchange (ETDEWEB)

Kanamura, Takashi [J-POWER, 15-1, Ginza 6-Chome, Chuo-ku, Tokyo 104-8165 (Japan)

2009-09-15

This paper proposes a new volatility model for energy prices using the supply-demand relationship, which we call a supply and demand based volatility model. We show that the supply curve shape in the model determines the characteristics of the volatility in energy prices. It is found that the inverse Box-Cox transformation supply curve reflecting energy markets causes the inverse leverage effect, i.e., positive correlation between energy prices and volatility. The model is also used to show that an existing (G)ARCH-M model has the foundations on the supply-demand relationship. Additionally, we conduct the empirical studies analyzing the volatility in the U.S. natural gas prices. (author)

Lighting Systems Control for Demand Response

NARCIS (Netherlands)

Husen, S.A.; Pandharipande, A.; Tolhuizen, L.M.G.; Wang, Y.; Zhao, M.

2012-01-01

Lighting is a major part of energy consumption in buildings. Lighting systems will thus be one of the important component systems of a smart grid for dynamic load management services like demand response.In the scenario considered in this paper, under a demand response request, lighting systems in a

Demand Response Integration Through Agent-Based Coordination of Consumers in Virtual Power Plants

DEFF Research Database (Denmark)

Clausen, Anders; Umair, Aisha; Ma, Zheng

2016-01-01

of industrial loads. Coordination happens in response to Demand Response events, while considering local objectives in the industrial domain. We illustrate the applicability of our approach on a Virtual Power Plant scenario with three simulated greenhouses. The results suggest that the proposed design is able...... Power Plant design that is able to balance the demand of energy-intensive, industrial loads with the supply situation in the electricity grid. The proposed Virtual Power Plant design uses a novel inter-agent, multi-objective, multi-issue negotiation mechanism, to coordinate the electricity demands...... to coordinate the electricity demands of industrial loads, in compliance with external Demand Response events....

Day-ahead stochastic economic dispatch of wind integrated power system considering demand response of residential hybrid energy system

International Nuclear Information System (INIS)

Jiang, Yibo; Xu, Jian; Sun, Yuanzhang; Wei, Congying; Wang, Jing; Ke, Deping; Li, Xiong; Yang, Jun; Peng, Xiaotao; Tang, Bowen

2017-01-01

Highlights: • Improving the utilization of wind power by the demand response of residential hybrid energy system. • An optimal scheduling of home energy management system integrating micro-CHP. • The scattered response capability of consumers is aggregated by demand bidding curve. • A stochastic day-ahead economic dispatch model considering demand response and wind power. - Abstract: As the installed capacity of wind power is growing, the stochastic variability of wind power leads to the mismatch of demand and generated power. Employing the regulating capability of demand to improve the utilization of wind power has become a new research direction. Meanwhile, the micro combined heat and power (micro-CHP) allows residential consumers to choose whether generating electricity by themselves or purchasing from the utility company, which forms a residential hybrid energy system. However, the impact of the demand response with hybrid energy system contained micro-CHP on the large-scale wind power utilization has not been analyzed quantitatively. This paper proposes an operation optimization model of the residential hybrid energy system based on price response, integrating micro-CHP and smart appliances intelligently. Moreover, a novel load aggregation method is adopted to centralize scattered response capability of residential load. At the power grid level, a day-ahead stochastic economic dispatch model considering demand response and wind power is constructed. Furthermore, simulation is conducted respectively on the modified 6-bus system and IEEE 118-bus system. The results show that with the method proposed, the wind power curtailment of the system decreases by 78% in 6-bus system. In the meantime, the energy costs of residential consumers and the operating costs of the power system reduced by 10.7% and 11.7% in 118-bus system, respectively.

Generation adequacy report on the electricity supply-demand balance in France. 2016 edition + executive summary

International Nuclear Information System (INIS)

2016-01-01

After a presentation of the elaboration framework of this generation adequacy report, and of the objectives of the risk analysis, this report proposes a detailed analysis of electricity consumption in France. It describes the main determining factors of electric power consumption: energy efficiency, economic growth, demography, and transfers and new uses of electricity. It proposes a sector-based analysis of energy demand (housing sector, office building sector, industrial sector, transport, energy and agriculture sectors), and an assessment of perspectives for power consumption. It also proposes a power-based analysis of electricity consumption: influence of temperature on electricity consumption, analysis of the load curve, perspectives for electricity consumption peak. The next part addresses the evolution of electricity supply in France. It presents the existing production fleet, proposes an overview of renewable energies (ground-based wind energy, offshore wind energy and marine energies, solar photovoltaic energy, bio-energies, hydraulic energy), presents some characteristics of the French nuclear fleet (installed capacity, availability), analyses the flame-based thermal fleet (oil-based, coal-based, gas-based combined, combustion turbine, and decentralised thermal installations). It also discusses the issue of load management, and proposes a synthetic overview of the electricity production fleet (supply evolutions on the medium term, evolutions with respect to the 2015 provisional assessment). The next chapter reports a risk analysis on the medium term by presenting indicators of supply safety, by proposing a failure risk analysis (diagnosis on the medium term, comparison with the previous provisional assessment, sensitivity to extreme events), by presenting energy assessments, by reporting sensitivity analysis (to consumption hypotheses, to hypotheses related to the development of renewable energies, to hypotheses related to the nuclear fleet), by reporting

A New Strategy for Short-Term Load Forecasting

Directory of Open Access Journals (Sweden)

Yi Yang

2013-01-01

Full Text Available Electricity is a special energy which is hard to store, so the electricity demand forecasting remains an important problem. Accurate short-term load forecasting (STLF plays a vital role in power systems because it is the essential part of power system planning and operation, and it is also fundamental in many applications. Considering that an individual forecasting model usually cannot work very well for STLF, a hybrid model based on the seasonal ARIMA model and BP neural network is presented in this paper to improve the forecasting accuracy. Firstly the seasonal ARIMA model is adopted to forecast the electric load demand day ahead; then, by using the residual load demand series obtained in this forecasting process as the original series, the follow-up residual series is forecasted by BP neural network; finally, by summing up the forecasted residual series and the forecasted load demand series got by seasonal ARIMA model, the final load demand forecasting series is obtained. Case studies show that the new strategy is quite useful to improve the accuracy of STLF.

Price, environment and security: Exploring multi-modal motivation in voluntary residential peak demand response

International Nuclear Information System (INIS)

Gyamfi, Samuel; Krumdieck, Susan

2011-01-01

Peak demand on electricity grids is a growing problem that increases costs and risks to supply security. Residential sector loads often contribute significantly to seasonal and daily peak demand. Demand response projects aim to manage peak demand by applying price signals and automated load shedding technologies. This research investigates voluntary load shedding in response to information about the security of supply, the emission profile and the cost of meeting critical peak demand in the customers' network. Customer willingness to change behaviour in response to this information was explored through mail-back survey. The diversified demand modelling method was used along with energy audit data to estimate the potential peak load reduction resulting from the voluntary demand response. A case study was conducted in a suburb of Christchurch, New Zealand, where electricity is the main source for water and space heating. On this network, all water heating cylinders have ripple-control technology and about 50% of the households subscribe to differential day/night pricing plan. The survey results show that the sensitivity to supply security is on par with price, with the emission sensitivity being slightly weaker. The modelling results show potential 10% reduction in critical peak load for aggregate voluntary demand response. - Highlights: → Multiple-factor behaviour intervention is necessarily for effective residential demand response. → Security signals can achieve result comparable to price. → The modelling results show potential 10% reduction in critical peak load for aggregate voluntary demand response. → New Zealand's energy policy should include innovation and development of VDR programmes and technologies.

An Intuitive Definition of Demand Flexibility in Direct Load Control

DEFF Research Database (Denmark)

Tahersima, Fatemeh; Madsen, Per Printz; Andersen, Palle

2013-01-01

Two control approaches: direct and indirect control of demand side energy management in a smart grid are studied. Indirect control of energy demands is based on economic incentives. In this approach, consumers will shift their energy consumption with the benefit of a cut down in the electricity b...

The Role of Demand Resources In Regional Transmission Expansion Planning and Reliable Operations

Energy Technology Data Exchange (ETDEWEB)

Kirby, Brendan J [ORNL

2006-07-01

Investigating the role of demand resources in regional transmission planning has provided mixed results. On one hand there are only a few projects where demand response has been used as an explicit alternative to transmission enhancement. On the other hand there is a fair amount of demand response in the form of energy efficiency, peak reduction, emergency load shedding, and (recently) demand providing ancillary services. All of this demand response reduces the need for transmission enhancements. Demand response capability is typically (but not always) factored into transmission planning as a reduction in the load which must be served. In that sense demand response is utilized as an alternative to transmission expansion. Much more demand response is used (involuntarily) as load shedding under extreme conditions to prevent cascading blackouts. The amount of additional transmission and generation that would be required to provide the current level of reliability if load shedding were not available is difficult to imagine and would be impractical to build. In a very real sense demand response solutions are equitably treated in every region - when proposed, demand response projects are evaluated against existing reliability and economic criteria. The regional councils, RTOs, and ISOs identify needs. Others propose transmission, generation, or responsive load based solutions. Few demand response projects get included in transmission enhancement plans because few are proposed. But this is only part of the story. Several factors are responsible for the current very low use of demand response as a transmission enhancement alternative. First, while the generation, transmission, and load business sectors each deal with essentially the same amount of electric power, generation and transmission companies are explicitly in the electric power business but electricity is not the primary business focus of most loads. This changes the institutional focus of each sector. Second

In-plane impulse response of a curved bar with varying cross-section

International Nuclear Information System (INIS)

Suzuki, Katsuyoshi; Kosawada, Tadashi; Takahashi, Shin; Miyashita, Yasushi.

1984-01-01

The vibration problem of a curved bar, of which the center line is represented with a plane curve, is important for the aseismatic design of the piping system and structures in chemical and nuclear plants. The dynamic response problem of an in-plane curved bar has not been sufficiently examined. In this study, the in-plane impact response of an in-plane curved bar having varying cross section when impact load acts in the direction of the center of curvature was analyzed. First, the Lagrangian of a curved bar with varying cross section when general exciting distributed load acts in the direction of the center of curvature along the center line was determined by the classic theory, and from its stationary condition, the equations of motion and boundary conditions were derived. Next, the equations of motion were analyzed by eigen-function development method. In the example of numerical calculation, the variation of displacement and bending moment in course of time when stepwise concentrated impact load acts on a both ends fixed symmetric semi-elliptic arc bar was determined. Besides, the change of response due to the change of cross section and the change of the point of impact load application was clarified. Displacement and bending moment varied at a certain period with static value at the center. (Kako, I.)

Effects of demand elasticity and price variation on load profile

NARCIS (Netherlands)

Maqbool, S.D.; Babar, M.; Al-Ammar, E.A.

2011-01-01

Optimizing the operation of power generation systems is one of the core objectives of Smart Grid. The area of Smart Grid focuses on this issue is Demand Response (DR). DR is an essential tool to limit the demand to flatten spikes. This can reduce the need of peak power generation units which

Demand Response Spinning Reserve Demonstration

Energy Technology Data Exchange (ETDEWEB)

Eto, Joseph H.; Nelson-Hoffman, Janine; Torres, Carlos; Hirth,Scott; Yinger, Bob; Kueck, John; Kirby, Brendan; Bernier, Clark; Wright,Roger; Barat, A.; Watson, David S.

2007-05-01

The Demand Response Spinning Reserve project is a pioneeringdemonstration of how existing utility load-management assets can providean important electricity system reliability resource known as spinningreserve. Using aggregated demand-side resources to provide spinningreserve will give grid operators at the California Independent SystemOperator (CAISO) and Southern California Edison (SCE) a powerful, newtool to improve system reliability, prevent rolling blackouts, and lowersystem operating costs.

Balancing supply and demand resources

International Nuclear Information System (INIS)

Sinha, J.; Saleeby, R.G.

1990-01-01

This article deals with using demand-side management (DSM) resources as an effective means of balancing supply and demand as a part of least-cost planning. The authors present a more sophisticated application of the load forecast adjustment method that reduces the number of DSM programs that need to be evaluated and provides blocks large enough to eliminate resolution problems in production costing models

A master curve-mechanism based approach to modeling the effects of constraint, loading rate and irradiation on the toughness-temperature behavior of a V-4Cr-4Ti alloy

International Nuclear Information System (INIS)

Odette, G.R.; Donahue, E.; Lucas, G.E.; Sheckherd, J.W.

1996-01-01

The influence of loading rate and constraint on the effective fracture toughness as a function of temperature [K e (T)] of the fusion program heat of V-4Cr-4Ti was measured using subsized, three point bend specimens. The constitutive behavior was characterized as a function of temperature and strain rate using small tensile specimens. Data in the literature on this alloy was also analysed to determine the effect of irradiation on K e (T) and the energy temperature (E-T) curves measured in subsized Charpy V-notch tests. It was found that V-4Cr-4Ti undergoes open-quotes normalclose quotes stress-controlled cleavage fracture below a temperature marking a sharp ductile-to-brittle transition. The transition temperature is increased by higher loading rates, irradiation hardening and triaxial constraint. Shifts in a reference transition temperature due to higher loading rates and irradiation can be reasonably predicted by a simple equivalent yield stress model. These results also suggest that size and geometry effects, which mediate constraint, can be modeled by combining local critical stressed area σ*/A* fracture criteria with finite element method simulations of crack tip stress fields. The fundamental understanding reflected in these models will be needed to develop K e (T) curves for a range of loading rates, irradiation conditions, structural size scales and geometries relying (in large part) on small specimen tests. Indeed, it may be possible to develop a master K e (T) curve-shift method to account for these variables. Such reliable and flexible failure assessment methods are critical to the design and safe operation of defect tolerant vanadium structures

A Novel Prosumer-Based Energy Sharing and Management (PESM Approach for Cooperative Demand Side Management (DSM in Smart Grid

Directory of Open Access Journals (Sweden)

Sohail Razzaq

2016-10-01

Full Text Available Increasing population and modern lifestyle have raised energy demands globally. Demand Side Management (DSM is one important tool used to manage energy demands. It employs an advanced power infrastructure along with bi-directional information flow among utilities and users in order to achieve a balanced load curve and minimize demand-supply mismatch. Traditionally, this involves shifting the electricity demand from peak hours to other times of the day in an optimized manner. Multiple users equipped with renewable resources work in coordination with each other in order to achieve mutually beneficial energy management. This, in turn, has generated the concept of cooperative DSM. Such users, called prosumers, consume and produce energy using renewable resources (solar, wind etc.. Prosumers with surplus energy sell to the grid as well as to other consumers. In this paper, a novel Prosumer-based Energy Sharing and Management (PESM scheme for cooperative DSM has been proposed. A simulation model has been developed for testing the proposed method. Different variations of the proposed methodology have been experimented with different criteria. The results show that the proposed energy sharing scheme achieves DSM purposes in a useful manner.

Correlated wind-power production and electric load scenarios for investment decisions

International Nuclear Information System (INIS)

Baringo, L.; Conejo, A.J.

2013-01-01

Highlights: ► Investment models require an accurate representation of the involved uncertainty. ► Demand and wind power production are correlated and uncertain parameters. ► Two methodologies are provided to represent uncertainty and correlation. ► An accurate uncertainty representation is crucial to get optimal results. -- Abstract: Stochastic programming constitutes a useful tool to address investment problems. This technique represents uncertain input data using a set of scenarios, which should accurately describe the involved uncertainty. In this paper, we propose two alternative methodologies to efficiently generate electric load and wind-power production scenarios, which are used as input data for investment problems. The two proposed methodologies are based on the load- and wind-duration curves and on the K-means clustering technique, and allow representing the uncertainty of and the correlation between electric load and wind-power production. A case study pertaining to wind-power investment is used to show the interest of the proposed methodologies and to illustrate how the selection of scenarios has a significant impact on investment decisions.

How to obtain J-R curve from one test on one sample

International Nuclear Information System (INIS)

Roche, Roland.

1981-01-01

Operational definition of J concept is first examined. Then it is shown that conventional methods of experimental determination of J values are based on the following assumption: if the load-deflexion curve is known for one value of the crack length it is possible to know the load-deflexion curve for any value of the crack length. This assumption is generalized with the help of scale functions and formula giving J are deduced. Attention is given to the effect of crack propagation on J values. The same assumption is used to extract the crack length from the load-deflexion curve. As the real crack lengths are known before propagation occurs and at the end of the test, it is possible to achieve a good calibration of the material characteristic [fr

DEVELOPING AN EXCELLENT SEDIMENT RATING CURVE FROM ONE HYDROLOGICAL YEAR SAMPLING PROGRAMME DATA: APPROACH

Directory of Open Access Journals (Sweden)

Preksedis M. Ndomba

2008-01-01

Full Text Available This paper presents preliminary findings on the adequacy of one hydrological year sampling programme data in developing an excellent sediment rating curve. The study case is a 1DD1 subcatchment in the upstream of Pangani River Basin (PRB, located in the North Eastern part of Tanzania. 1DD1 is the major runoff-sediment contributing tributary to the downstream hydropower reservoir, the Nyumba Ya Mungu (NYM. In literature sediment rating curve method is known to underestimate the actual sediment load. In the case of developing countries long-term sediment sampling monitoring or conservation campaigns have been reported as unworkable options. Besides, to the best knowledge of the authors, to date there is no consensus on how to develop an excellent rating curve. Daily-midway and intermittent-cross section sediment samples from Depth Integrating sampler (D-74 were used to calibrate the subdaily automatic sediment pumping sampler (ISCO 6712 near bank point samples for developing the rating curve. Sediment load correction factors were derived from both statistical bias estimators and actual sediment load approaches. It should be noted that the ongoing study is guided by findings of other studies in the same catchment. For instance, long term sediment yield rate estimated based on reservoir survey validated the performance of the developed rating curve. The result suggests that excellent rating curve could be developed from one hydrological year sediment sampling programme data. This study has also found that uncorrected rating curve underestimates sediment load. The degreeof underestimation depends on the type of rating curve developed and data used.

Short-Term Multiple Forecasting of Electric Energy Loads for Sustainable Demand Planning in Smart Grids for Smart Homes

Directory of Open Access Journals (Sweden)

Adeshina Y. Alani

2017-10-01

Full Text Available Energy consumption in the form of fuel or electricity is ubiquitous globally. Among energy types, electricity is crucial to human life in terms of cooking, warming and cooling of shelters, powering of electronic devices as well as commercial and industrial operations. Users of electronic devices sometimes consume fluctuating amounts of electricity generated from smart-grid infrastructure owned by the government or private investors. However, frequent imbalance is noticed between the demand and supply of electricity, hence effective planning is required to facilitate its distribution among consumers. Such effective planning is stimulated by the need to predict future consumption within a short period. Although several interesting classical techniques have been used for such predictions, they still require improvement for the purpose of reducing significant predictive errors when used for short-term load forecasting. This research develops a near-zero cooperative probabilistic scenario analysis and decision tree (PSA-DT model to address the lacuna of enormous predictive error faced by the state-of-the-art models. The PSA-DT is based on a probabilistic technique in view of the uncertain nature of electricity consumption, complemented by a DT to reinforce the collaboration of the two techniques. Based on detailed experimental analytics on residential, commercial and industrial data loads, the PSA-DT model outperforms the state-of-the-art models in terms of accuracy to a near-zero error rate. This implies that its deployment for electricity demand planning will be of great benefit to various smart-grid operators and homes.

Co-optimization of Energy and Demand-Side Reserves in Day-Ahead Electricity Markets

Science.gov (United States)

Surender Reddy, S.; Abhyankar, A. R.; Bijwe, P. R.

2015-04-01

This paper presents a new multi-objective day-ahead market clearing (DAMC) mechanism with demand-side reserves/demand response (DR) offers, considering realistic voltage-dependent load modeling. The paper proposes objectives such as social welfare maximization (SWM) including demand-side reserves, and load served error (LSE) minimization. In this paper, energy and demand-side reserves are cleared simultaneously through co-optimization process. The paper clearly brings out the unsuitability of conventional SWM for DAMC in the presence of voltage-dependent loads, due to reduction of load served (LS). Under such circumstances multi-objective DAMC with DR offers is essential. Multi-objective Strength Pareto Evolutionary Algorithm 2+ (SPEA 2+) has been used to solve the optimization problem. The effectiveness of the proposed scheme is confirmed with results obtained from IEEE 30 bus system.

A methodology for Electric Power Load Forecasting

Directory of Open Access Journals (Sweden)

Eisa Almeshaiei

2011-06-01

Full Text Available Electricity demand forecasting is a central and integral process for planning periodical operations and facility expansion in the electricity sector. Demand pattern is almost very complex due to the deregulation of energy markets. Therefore, finding an appropriate forecasting model for a specific electricity network is not an easy task. Although many forecasting methods were developed, none can be generalized for all demand patterns. Therefore, this paper presents a pragmatic methodology that can be used as a guide to construct Electric Power Load Forecasting models. This methodology is mainly based on decomposition and segmentation of the load time series. Several statistical analyses are involved to study the load features and forecasting precision such as moving average and probability plots of load noise. Real daily load data from Kuwaiti electric network are used as a case study. Some results are reported to guide forecasting future needs of this network.

Simulation of a curved flume bed-load experiment

NARCIS (Netherlands)

Talmon, A.M.

1988-01-01

The mathematical model for river bend morphology, as developed by Olesen, for bed-load transport is discussed, by comparing the results with some new experimental data. The model consists of a two-dimensional depth-averaged flow model together with a sediment balance and can be used to compute the

Modeling storage and demand management in power distribution grids

International Nuclear Information System (INIS)

Schroeder, Andreas

2011-01-01

Grahical abstract: The model informs an optimal investment sizing decision as regards specific 'smart grid' applications such as storage facilities and meters enabling load control. Results indicate that central storage facilities are a more promising option for generation cost reductions as compared to demand management. Highlights: → Stochastic versus deterministic model increases investment efficiency up to 5%. → Deterministic model under-estimates value of load control and storage. → Battery storage is beneficial at investment cost below 850 EUR/MW h. → Demand management equipment is not beneficial at cost beyond 200 EUR. → The stylized 10 kV grid constitutes no shortage factor. -- Abstract: Storage devices and demand control may constitute beneficial tools to optimize electricity generation with a large share of intermittent resources through inter-temporal substitution of load. This paper quantifies the related cost reductions in a simulation model of a simplified stylized medium-voltage grid (10 kV) under uncertain demand and wind output. Benders Decomposition Method is applied to create a two-stage stochastic optimization program. The model informs an optimal investment sizing decision as regards specific 'smart' applications such as storage facilities and meters enabling load control. Model results indicate that central storage facilities are a more promising option for generation cost reductions as compared to demand management. Grid extensions are not appropriate in any of the scenarios. A sensitivity analysis is applied with respect to the market penetration of uncoordinated Plug-In Electric Vehicles which are found to strongly encourage investment into load control equipment for 'smart' charging and slightly improve the case for central storage devices.

A comparison of economic demand and conditioned-cued reinstatement of methamphetamine- or food-seeking in rats

Science.gov (United States)

Galuska, Chad M.; Banna, Kelly M.; Willse, Lena Vaughn; Yahyavi-Firouz-Abadi, Noushin; See, Ronald E.

2011-01-01

The present study examined whether continued access to methamphetamine or food reinforcement changed economic demand for both. The relationship between demand elasticity and cue-induced reinstatement was also determined. Male Long-Evans rats lever-pressed under increasing fixed-ratio requirements for either food pellets or methamphetamine (20 μg/50 μl infusion). For two groups, demand curves were obtained before and after continued access (12 days, 2-hr sessions) to the reinforcer under a fixed-ratio 3 schedule. A third group was given continued access to methamphetamine between determinations of food demand and a fourth group abstained from methamphetamine between determinations. All groups underwent extinction sessions, followed by a cue-induced reinstatement test. Although food demand was less elastic than methamphetamine demand, continued access to methamphetamine shifted the methamphetamine demand curve upward and the food demand curve downward. In some rats, methamphetamine demand also became less elastic. Continued access to food had no effect on food demand. Reinstatement was higher after continued access to methamphetamine relative to food. For methamphetamine, elasticity and reinstatement measures were correlated. We conclude that continued access to methamphetamine – but not food – alters demand in ways suggestive of methamphetamine accruing reinforcing strength. Demand elasticity and reinstatement measures appear to be related indices of drug-seeking. PMID:21597363

Laterally Loaded Nail-Plates

DEFF Research Database (Denmark)

Nielsen, Jacob; Rathkjen, Arne

Load-displacement curves from about 200 short-term and laterally loaded nail-plate joints are analysed. The nail-plates are from Gang-Nail Systems, type GNA 20 S. The test specimens and the measuring systems are described. The tests are divided into 32 different series. The influence of the number...

Responsive demand to mitigate slow recovery voltage sags

DEFF Research Database (Denmark)

Garcia-Valle, Rodrigo; da Silva, Luiz Carlos Pereira; Xu, Zhao

2012-01-01

, and reactive power reserve for peak load management through price responsive methods and also as energy providers through embedded generation technologies. This article introduces a new technology, called demand as voltagecontrolled reserve, which can help mitigation of momentary voltage sags. The technology...... faults. This article presents detailed models, discussion, and simulation tests to demonstrate the technical viability and effectiveness of the demand as voltage-controlled reserve technology for mitigating voltage sags....... can be provided by thermostatically controlled loads as well as other types of load. This technology has proven to be effective in distribution systems with a large composition of induction motors, when voltage sags present slow recovery characteristics because of the deceleration of the motors during...

Spreading the load

International Nuclear Information System (INIS)

Hay, Greg

1999-01-01

This article examines the management of power demand by the regional electricity companies in the United Kingdom so that consumers use most power at times when the pool price is at its lowest. The use of teleswitching for load management, the control of the heating of large residential buildings, the power demand of supermarkets with 24hr opening, financial incentives, and the forecasting of demand are discussed. Details are given of the work of the operational forecasting team, and the matching of demand with generators availability by the scheduling team of the National Grid. (UK)

Demand modelling for central heating systems

Energy Technology Data Exchange (ETDEWEB)

Heller, A.

2000-07-01

Most researchers in the field of heat demand estimation have focussed on explaning the load for a given plant based on rather few measurements. This approach is simply the only one adaptable with the very limited data material and limited computer power. This way of dealing with the subject is here called the top-down approach, due to the fact that one tries to explain the load from the overall data. The results of such efforts are discussed in the report, leading to inspiration for own work. Also the significance of the findings to the causes for given heat loads are discussed and summarised. Contrary to the top-down approach applied in literature, a here-called bottom-up approach is applied in this work, describing the causes of a given partial load in detail and combining them to explain the total load for the system. Three partial load 'components' are discussed: 1) Space heating. 2) Hot-Water Consumption. 3) Heat losses in pipe networks. The report is aimed at giving an introduction to these subjects, but at the same time at collecting the previous work done by the author. Space heating is shortly discussed and loads are generated by an advanced simulation model. A hot water consumption model is presented and heat loads, generated by this model, utilised in the overall work. Heat loads due to heat losses in district heating a given a high priority in the current work. Hence a detailed presentation and overview of the subject is given to solar heating experts normally not dealing with district heating. Based on the 'partial' loads generated by the above-mentioned method, an overall load model is built in the computer simulation environment TRNSYS. The final tool is then employed for the generation of time series for heat demand, representing a district heating area. The results are compared to alternative methods for the generation of heat demand profiles. Results form this comparison will be presented. Computerised modelling of systems

Future residential loads profiles : scenario-based analysis of high penetration of heavy loads and distributed generation

NARCIS (Netherlands)

Asare-Bediako, B.; Kling, W.L.; Ribeiro, P.F.

2014-01-01

Electric load profiles are useful for accurate load forecasting, network planning and optimal generation capacity. They represent electricity demand patterns and are to a large extent predictable. However, new and heavier loads (heat pumps and electric vehicles), distributed generation, and home

Calculating load factors for the transatlantic airline market using supply and demand data: a note on the identification of gaps in the available airline statistics

NARCIS (Netherlands)

Devriendt, L.; Burghouwt, G.; Derudder, B.; de Wit, J.; Witlox, F.

2009-01-01

This paper takes a critical view of the verification of load factors for the direct transatlantic airline market by combining supply and demand-data. The supply-related data originate from the Official Airline Guide, a well-known data source that contains information on scheduled flights. The

Co-Planning of Demand Response and Distributed Generators in an Active Distribution Network

Directory of Open Access Journals (Sweden)

Yi Yu

2018-02-01

Full Text Available The integration of renewables is fast-growing, in light of smart grid technology development. As a result, the uncertain nature of renewables and load demand poses significant technical challenges to distribution network (DN daily operation. To alleviate such issues, price-sensitive demand response and distributed generators can be coordinated to accommodate the renewable energy. However, the investment cost for demand response facilities, i.e., load control switch and advanced metering infrastructure, cannot be ignored, especially when the responsive demand is large. In this paper, an optimal coordinated investment for distributed generator and demand response facilities is proposed, based on a linearized, price-elastic demand response model. To hedge against the uncertainties of renewables and load demand, a two-stage robust investment scheme is proposed, where the investment decisions are optimized in the first stage, and the demand response participation with the coordination of distributed generators is adjusted in the second stage. Simulations on the modified IEEE 33-node and 123-node DN demonstrate the effectiveness of the proposed model.

Preliminary guidelines for electricity distributor conservation and demand management activities : a guide for conservation and demand management investment

International Nuclear Information System (INIS)

2004-01-01

In May 2004, electricity distributors in Ontario were asked to submit deferral accounts to the Ontario Energy Board to track expenditures on conservation and demand management initiatives. The deferral accounts must be established before the distributor could recover the costs through the next installment of the allowable return on equity in March 2004. The Board will determine the appropriateness of the actual expenditures. These guidelines offer short-term assistance to distributors in establishing conservation and demand management plans and initiatives. The following specific measures may be supported by the Board: energy efficiency; operational changes to smart control systems; load management measures which facilitate interruptible and dispatchable loads, dual fuel applications, thermal storage and demand response; fuel switching measures; programs targeted to low income and hard to reach consumers; and, distributed energy options such as tri-generation, cogeneration, ground source heat pumps, wind and biomass systems. These guidelines described the regulatory treatment of conservation and demand management investments along with cost effectiveness, allocation of costs, monitoring, evaluation, and implementation. 1 appendix

Buckling Capacity Curves for Steel Spherical Shells Loaded by the External Pressure

Science.gov (United States)

Błażejewski, Paweł; Marcinowski, Jakub

2015-03-01

Assessment of buckling resistance of pressurised spherical cap is not an easy task. There exist two different approaches which allow to achieve this goal. The first approach involves performing advanced numerical analyses in which material and geometrical nonlinearities would be taken into account as well as considering the worst imperfections of the defined amplitude. This kind of analysis is customarily called GMNIA and is carried out by means of the computer software based on FEM. The other, comparatively easier approach, relies on the utilisation of earlier prepared procedures which enable determination of the critical resistance pRcr, the plastic resistance pRpl and buckling parameters a, b, h, l 0 needed to the definition of the standard buckling resistance curve. The determination of the buckling capacity curve for the particular class of spherical caps is the principal goal of this work. The method of determination of the critical pressure and the plastic resistance were described by the authors in [1] whereas the worst imperfection mode for the considered class of spherical shells was found in [2]. The determination of buckling parameters defining the buckling capacity curve for the whole class of shells is more complicated task. For this reason the authors focused their attention on spherical steel caps with the radius to thickness ratio of R/t = 500, the semi angle j = 30o and the boundary condition BC2 (the clamped supporting edge). Taking into account all imperfection forms considered in [2] and different amplitudes expressed by the multiple of the shell thickness, sets of buckling parameters defining the capacity curve were determined. These parameters were determined by the methods proposed by Rotter in [3] and [4] where the method of determination of the exponent h by means of additional parameter k was presented. As a result of the performed analyses the standard capacity curves for all considered imperfection modes and amplitudes 0.5t, 1.0t, 1.5t

Analysis of the relationship between economic growth and industrial pollution in Zaozhuang, China-based on the hypothesis of the environmental Kuznets curve.

Science.gov (United States)

Liu, Xiao-Hui; Wang, Wei-Liang; Lu, Shao-Yong; Wang, Yu-Fan; Ren, Zongming

2016-08-01

In Zaozhuang, economic development affects the discharge amount of industrial wastewater, chemical oxygen demand (COD), and ammonia nitrogen (NH3-N). To reveal the trend of water environmental quality related to the economy in Zaozhuang, this paper simulated the relationships between industrial wastewater discharge, COD, NH3-N load, and gross domestic product (GDP) per capita for Zaozhuang (2002-2012) using environmental Kuznets curve (EKC) models. The results showed that the added value of industrial GDP, the per capita GDP, and wastewater emission had average annual growth rates of 16.62, 16.19, and 17.89 %, respectively, from 2002 to 2012, while COD and NH3-N emission in 2012, compared with 2002, showed average annual decreases of 10.70 and 31.12 %, respectively. The export of EKC models revealed that industrial wastewater discharge had a typical inverted-U-shaped relationship with per capita GDP. However, both COD and NH3-N showed the binding curve of the left side of the "U" curve and left side U-shaped curve. The economy in Zaozhuang had been at the "fast-growing" stage, with low environmental pollution according to the industrial pollution level. In recent years, Zaozhuang has abated these heavy-pollution industries emphatically, so pollutants have been greatly reduced. Thus, Zaozhuang industrial wastewater treatment has been quite effective, with water quality improved significantly. The EKC models provided scientific evidence for estimating industrial wastewater discharge, COD, and NH3-N load as well as their changeable trends for Zaozhuang from an economic perspective.

A bi-level integrated generation-transmission planning model incorporating the impacts of demand response by operation simulation

International Nuclear Information System (INIS)

Zhang, Ning; Hu, Zhaoguang; Springer, Cecilia; Li, Yanning; Shen, Bo

2016-01-01

Highlights: • We put forward a novel bi-level integrated power system planning model. • Generation expansion planning and transmission expansion planning are combined. • The effects of two sorts of demand response in reducing peak load are considered. • Operation simulation is conducted to reflect the actual effects of demand response. • The interactions between the two levels can guarantee a reasonably optimal result. - Abstract: If all the resources in power supply side, transmission part, and power demand side are considered together, the optimal expansion scheme from the perspective of the whole system can be achieved. In this paper, generation expansion planning and transmission expansion planning are combined into one model. Moreover, the effects of demand response in reducing peak load are taken into account in the planning model, which can cut back the generation expansion capacity and transmission expansion capacity. Existing approaches to considering demand response for planning tend to overestimate the impacts of demand response on peak load reduction. These approaches usually focus on power reduction at the moment of peak load without considering the situations in which load demand at another moment may unexpectedly become the new peak load due to demand response. These situations are analyzed in this paper. Accordingly, a novel approach to incorporating demand response in a planning model is proposed. A modified unit commitment model with demand response is utilized. The planning model is thereby a bi-level model with interactions between generation-transmission expansion planning and operation simulation to reflect the actual effects of demand response and find the reasonably optimal planning result.

Seismic Fragility Curves of Industrial Buildings by Using Nonlinear Analysis

Directory of Open Access Journals (Sweden)

Mohamed Nazri Fadzli

2017-01-01

Full Text Available This study presents the steel fragility curves and performance curves of industrial buildings of different geometries. The fragility curves were obtained for different building geometries, and the performance curves were developed based on lateral load, which is affected by the geometry of the building. Three records of far-field ground motion were used for incremental dynamic analysis (IDA, and the design lateral loads for pushover analysis (POA. All designs were based on British Standard (BS 5950; however, Eurocode 8 was preferred for seismic consideration in the analysis because BS 5950 does not specify any seismic provision. The five levels of performance stated by FEMA-273, namely, operational phase, immediate occupancy, damage control, life safety, and collapse prevention (CP were used as main guidelines for evaluating structural performance. For POA, Model 2 had highest base shear, followed by Model 1 and Model 3, even though Model 2 has a smaller structure compared with Model 3. Meanwhile, the fragility curves showed that the probability of reaching or exceeding the CP level of Model 2 is the highest, followed by that of Models 1 and 3.

Harmonic Force Spectroscopy Reveals a Force-Velocity Curve from a Single Human Beta Cardiac Myosin Motor

DEFF Research Database (Denmark)

Sung, Jongmin; Nag, Suman; Vestergaard, Christian L.

2014-01-01

human beta cardiac myosin S1. We also compare load-velocity curves for wild-type motors with load-velocity curves of mutant forms that cause hypertrophic or dilated-cardiomyopathy (HCM or DCM), in order to understand the effects of mutations on the contractile cycle at the single molecule level....

Social implications of residential demand response in cool temperate climates

International Nuclear Information System (INIS)

Darby, Sarah J.; McKenna, Eoghan

2012-01-01

Residential electrical demand response (DR) offers the prospect of reducing the environmental impact of electricity use, and also the supply costs. However, the relatively small loads and numerous actors imply a large effort: response ratio. Residential DR may be an essential part of future smart grids, but how viable is it in the short to medium term? This paper reviews some DR concepts, then evaluates the propositions that households in cool temperate climates will be in a position to contribute to grid flexibility within the next decade, and that that they will allow some automated load control. Examples of demand response from around the world are discussed in order to assess the main considerations for cool climates. Different tariff types and forms of control are assessed in terms of what is being asked of electricity users, with a focus on real-time pricing and direct load control in energy systems with increasingly distributed resources. The literature points to the significance of thermal loads, supply mix, demand-side infrastructure, market regulation, and the framing of risks and opportunities associated with DR. In concentrating on social aspects of residential demand response, the paper complements the body of work on technical and economic potential. - Highlights: ► Demand response implies major change in governance of electricity systems. ► Households in cool temperate climates can be flexible, mainly with thermal loads. ► DR requires simple tariffs, appropriate enabling technology, education, and feedback. ► Need to test consumer acceptance of DR in specific conditions. ► Introduce tariffs with technologies e.g., TOU tariff plus DLC with electric vehicles.

Electricity Crisis and Load Management in Bangladesh

Directory of Open Access Journals (Sweden)

Rajib Kanti Das

2012-09-01

Full Text Available Bangladesh is a densely populated country. Only a small part of her area is electrified which cover around 18% of total population. The people who are in the electrified area are suffering from severe load shedding. A systematic load management procedure related to demand side may improve the situation is the research problem. The major objectives serve by the research are to analyze contemporary electricity status with a view to drawing inference about demand supply gap and extracting benefits from load management. Data supplied by the Bangladesh Power Development Board, World Bank and outcome of survey are analyzed with some simple statistical tools to test the hypothesis. Analysis discloses that with properly managed uses of electricity with load switch and rotation week-end can improve the concurrent condition of electricity. Moreover, introducing smart distribution system, reducing system loss, shifting load to off-peak, large scale use of prepaid mete, observing energy week and using energy efficient home and office appliance are recommended to improve load through demand side management. Some other recommendations such as introducing alternative energy, public private partnership and using renewable energy development and producing energy locally are made for load management from the supply side.

Cognitive task demands, self-control demands and the mental well-being of office workers.

Science.gov (United States)

Bridger, Robert S; Brasher, Kate

2011-09-01

The cognitive task demands of office workers and the self-control demands of their work roles were measured in a sample of 196 employees in two different office layouts using a self-report questionnaire, which was circulated electronically. Multiple linear regression analysis revealed that both factors were associated with mental well-being, but not with physical well-being, while controlling for exposure to psychosocial stressors. The interaction between cognitive task demands and self-control demands had the strongest association with mental well-being, suggesting that the deleterious effect of one was greater when the other was present. An exploratory analysis revealed that the association was stronger for employees working in a large open-plan office than for those working in smaller offices with more privacy. Frustration of work goals was the cognitive task demand having the strongest negative impact on mental well-being. Methodological limitations and scale psychometrics (particularly the use of the NASA Task Load Index) are discussed. STATEMENT OF RELEVANCE: Modern office work has high mental demands and low physical demands and there is a need to design offices to prevent adverse psychological reactions. It is shown that cognitive task demands interact with self-control demands to degrade mental well-being. The association was stronger in an open-plan office.

A pattern recognition methodology for evaluation of load profiles and typical days of large electricity customers

International Nuclear Information System (INIS)

Tsekouras, G.J.; Kotoulas, P.B.; Tsirekis, C.D.; Dialynas, E.N.; Hatziargyriou, N.D.

2008-01-01

This paper describes a pattern recognition methodology for the classification of the daily chronological load curves of each large electricity customer, in order to estimate his typical days and his respective representative daily load profiles. It is based on pattern recognition methods, such as k-means, self-organized maps (SOM), fuzzy k-means and hierarchical clustering, which are theoretically described and properly adapted. The parameters of each clustering method are properly selected by an optimization process, which is separately applied for each one of six adequacy measures. The results can be used for the short-term and mid-term load forecasting of each consumer, for the choice of the proper tariffs and the feasibility studies of demand side management programs. This methodology is analytically applied for one medium voltage industrial customer and synoptically for a set of medium voltage customers of the Greek power system. The results of the clustering methods are presented and discussed. (author)

Demand Response of Thermostatic Loads by Optimized Switching-Fraction Broadcast

DEFF Research Database (Denmark)

Totu, Luminita Cristiana; Wisniewski, Rafal

2014-01-01

Demand response is an important Smart Grid concept that aims at facilitating the integration of volatile energy resources into the electricity grid. This paper considers the problem of managing large populations of thermostat-based devices with on/off operation. The objective is to enable demand...... Method is used to spatially discretize these equations. Next, a broadcast strategy with two switching-fraction signals is proposed for actuating the population. This is applied in an open-loop scenario for tracking a power reference by running an optimization with a multilinear objective....

Training anesthesiology residents in providing anesthesia for awake craniotomy: learning curves and estimate of needed case load.

Science.gov (United States)

Bilotta, Federico; Titi, Luca; Lanni, Fabiana; Stazi, Elisabetta; Rosa, Giovanni

2013-08-01

To measure the learning curves of residents in anesthesiology in providing anesthesia for awake craniotomy, and to estimate the case load needed to achieve a "good-excellent" level of competence. Prospective study. Operating room of a university hospital. 7 volunteer residents in anesthesiology. Residents underwent a dedicated training program of clinical characteristics of anesthesia for awake craniotomy. The program was divided into three tasks: local anesthesia, sedation-analgesia, and intraoperative hemodynamic management. The learning curve for each resident for each task was recorded over 10 procedures. Quantitative assessment of the individual's ability was based on the resident's self-assessment score and the attending anesthesiologist's judgment, and rated by modified 12 mm Likert scale, reported ability score visual analog scale (VAS). This ability VAS score ranged from 1 to 12 (ie, very poor, mild, moderate, sufficient, good, excellent). The number of requests for advice also was recorded (ie, resident requests for practical help and theoretical notions to accomplish the procedures). Each task had a specific learning rate; the number of procedures necessary to achieve "good-excellent" ability with confidence, as determined by the recorded results, were 10 procedures for local anesthesia, 15 to 25 procedures for sedation-analgesia, and 20 to 30 procedures for intraoperative hemodynamic management. Awake craniotomy is an approach used increasingly in neuroanesthesia. A dedicated training program based on learning specific tasks and building confidence with essential features provides "good-excellent" ability. © 2013 Elsevier Inc. All rights reserved.

Deliberation's blindsight: how cognitive load can improve judgments.

Science.gov (United States)

Hoffmann, Janina A; von Helversen, Bettina; Rieskamp, Jörg

2013-06-01

Multitasking poses a major challenge in modern work environments by putting the worker under cognitive load. Performance decrements often occur when people are under high cognitive load because they switch to less demanding--and often less accurate--cognitive strategies. Although cognitive load disturbs performance over a wide range of tasks, it may also carry benefits. In the experiments reported here, we showed that judgment performance can increase under cognitive load. Participants solved a multiple-cue judgment task in which high performance could be achieved by using a similarity-based judgment strategy but not by using a more demanding rule-based judgment strategy. Accordingly, cognitive load induced a shift to a similarity-based judgment strategy, which consequently led to more accurate judgments. By contrast, shifting to a similarity-based strategy harmed judgments in a task best solved by using a rule-based strategy. These results show how important it is to consider the cognitive strategies people rely on to understand how people perform in demanding work environments.

A comparison of economic demand and conditioned-cued reinstatement of methamphetamine-seeking or food-seeking in rats.

Science.gov (United States)

Galuska, Chad M; Banna, Kelly M; Willse, Lena Vaughn; Yahyavi-Firouz-Abadi, Noushin; See, Ronald E

2011-08-01

This study examined whether continued access to methamphetamine or food reinforcement changed economic demand for both. The relationship between demand elasticity and cue-induced reinstatement was also determined. Male Long-Evans rats were lever pressed under increasing fixed-ratio requirements for either food pellets or methamphetamine (20 μg/50 μl infusion). For two groups, demand curves were obtained before and after continued access (12 days, 2-h sessions) to the reinforcer under a fixed-ratio 3 schedule. A third group was given continued access to methamphetamine between determinations of food demand and a fourth group abstained from methamphetamine between determinations. All groups underwent extinction sessions, followed by a cue-induced reinstatement test. Although food demand was less elastic than methamphetamine demand, continued access to methamphetamine shifted the methamphetamine demand curve upward and the food demand curve downward. In some rats, methamphetamine demand also became less elastic. Continued access to food had no effect on food demand. Reinstatement was higher after continued access to methamphetamine relative to food. For methamphetamine, elasticity and reinstatement measures were correlated. Continued access to methamphetamine, but not food, alters demand in ways suggestive of methamphetamine accruing reinforcing strength. Demand elasticity thus provides a useful measure of abuse liability that may predict future relapse to renewed drug-seeking and drug use.

Evaluation of automated residential demand response with flat and dynamic pricing

International Nuclear Information System (INIS)

Swisher, Joel; Wang, Kitty; Stewart, Stewart

2005-01-01

This paper reviews the performance of two recent automated load management programs for residential customers of electric utilities in two American states. Both pilot programs have been run with about 200 participant houses each, and both programs have control populations of similar customers without the technology or program treatment. In both cases, the technology used in the pilot is GoodWatts, an advanced, two-way, real-time, comprehensive home energy management system. The purpose of each pilot is to determine the household kW reduction in coincident peak electric load from the energy management technology. Nevada Power has conducted a pilot program for Air-Conditioning Load Management (ACLM), in which customers are sent an electronic curtailment signal for three-hour intervals during times of maximum peak demand. The participating customers receive an annual incentive payment, but otherwise they are on a conventional utility tariff. In California, three major utilities are jointly conducting a pilot demonstration of an Automated Demand Response System (ADRS). Customers are on a time-of-use (ToU) tariff, which includes a critical peak pricing (CPP) element. During times of maximum peak demand, customers are sent an electronic price signal that is three times higher than the normal on-peak price. Houses with the automated GoodWatts technology reduced their demand in both the ACLM and the ADRS programs by about 50% consistently across the summer curtailment or super peak events, relative to homes without the technology or any load management program or tariff in place. The absolute savings were greater in the ACLM program, due to the higher baseline air conditioning loads in the hotter Las Vegas climate. The results suggest that either automated technology or dynamic pricing can deliver significant demand response in low-consumption houses. However, for high-consumption houses, automated technology can reduce load by a greater absolute kWh difference. Targeting

Load Management in Residential Buildings Considering Techno-Economic and Environmental Aspects

Energy Technology Data Exchange (ETDEWEB)

Abaravicius, Juozas

2004-12-01

Load problems in electricity markets occur both on the supply and demand side and can have technical, economic and even political causes. Commonly, such problems have been solved by expanding production and/or distribution capacity, importing electricity or by load management. Load management is a techno-economic measure for harmonizing the relations between supply and demand sides, optimizing power generation and transmission and increasing security of supply. Interest in load management differs depending on the perspective of the actors involved: from customer, utility, or producer to state policy maker. The problem of load demand and load management in residential sector is in this thesis approached from different perspectives, i.e. technical, economic, and environmental. The study does not go deep into detailed analyses of each perspective, but rather aims to establish and analyze the links between them. This trans-disciplinary approach is the key methodological moment used in the research work performed by the research group for load management in buildings at the Lund Institute of Technology. The key objective of this study is to analyze load demand variation and load management possibilities in residential sector, particularly detached and semi-detached houses, to experimentally test and analyze the conditions and potential of direct load management from customer and utility viewpoint. Techno-economic and environmental aspects are investigated. The study was performed in collaboration with one electric utility in Southern Sweden. Ten electric-heated houses were equipped with extra meters, enabling hourly load measurements for heating, hot water and total electricity use. Household heating and hot water systems were controlled by the utility using an existing remote reading and monitoring system. The residents noticed some of the control periods, although they didn't express any larger discomfort. The experiments proved that direct load management might

Emerging technologies for demand side management. Demand side management jitsugen no tame no saishin gijutsu

Energy Technology Data Exchange (ETDEWEB)

Suzuki, H; Iyoda, I [Mitsubishi Electric Corp., Tokyo (Japan)

1993-11-05

This paper explains the latest situation in hardware technologies to realize the demand side management, divided into the following technologies: communications technology, measurement technology, client information system technology, load controlling technology, home automation technology, and energy storing and saving technologies. Speaking of the communications technology, information exchange between the supply side and the demand side is important in the demand side management, whereas a technology intended of automatic power distribution and automatic meter-reading is advancing in development. The technology covers transmissions using from power lines and telephone lines to optical cables and wireless communications. Power line communications using power transmission lines as communication lines are simple and economical, but weak against noise, and not suitable for long-distance communications. Wireless communications have been drawing attentions along with the development of mobile communication device technologies. These technologies will give benefits to electric power companies in the initial stage of their use, such as for load investigation and general automation in power distribution. They would shift to benefiting users in about 2010 covering from security information such as about power interruption to publicity information and educations. 8 refs., 8 figs., 1 tab.

Assessment of p-y Curves from Numerical Methods for a non-Slender Monopile in Cohesionless Soil

DEFF Research Database (Denmark)

Ibsen, Lars Bo; Roesen, Hanne Ravn; Wolf, Torben K.

2013-01-01

In current design the stiff large diameter monopile is a widely used solution as foundation of offshore wind turbines. Winds and waves subject the monopile to considerable lateral loads. The current design guidances apply the p-y curve method with formulations for the curves based on slender piles....... However, the behaviour of the stiff monopiles during lateral loading is not fully understood. In this paper case study from Barrow Offshore Wind Farm is used in a 3D finite element model. The analysis forms a basis for extraction of p-y curves which are used in an evaluation of the traditional curves...

Assessment of p-y Curves from Numerical Methods for a non-Slender Monopile in Cohesionless Soil

DEFF Research Database (Denmark)

Wolf, Torben K.; Rasmussen, Kristian L.; Hansen, Mette

In current design the stiff large diameter monopile is a widely used solution as foundation of offshore wind turbines. Winds and waves subject the monopile to considerable lateral loads. The current design guidances apply the p-y curve method with formulations for the curves based on slender piles....... However, the behaviour of the stiff monopiles during lateral loading is not fully understood. In this paper case study from Barrow Offshore Wind Farm is used in a 3D finite element model. The analysis forms a basis for extraction of p-y curves which are used in an evaluation of the traditional curves...

Reactor pressure elevation preventing device upon interruption of load

International Nuclear Information System (INIS)

Ota, Yasuo; Okukawa, Ryutaro.

1996-01-01

In a power load imbalance circuit of a steam turbine control device, a power load imbalance occurrence signal is outputted for a predetermined period of time upon occurrence of load interruption. A function for suppressing increase of number of rotation of a turbine due to load interruption is not disturbed, and the power load imbalance circuit is not operated at least after a primary peak where the number of rotation of the turbine is increased. Since a steam control valve flow rate demand signal and a turbine bypass valve flow rate demand signals are corporated subsequently to control the opening degree of the steam control valve and the turbine bypass valve, elevation of reactor pressure is always suppressed and maintained constant, as well as abrupt opening of the steam control valve due to cancel of the power load imbalance circuit when steam control valve opening demand is outputted can be prevented. (N.H.)

Demand flexibility from residential heat pump

DEFF Research Database (Denmark)

Bhattarai, Bishnu Prasad; Bak-Jensen, Birgitte; Pillai, Jayakrishnan Radhakrishna

2014-01-01

Demand response (DR) is considered as a potentially effective tool to compensate generation intermittency imposed by renewable sources. Further, DR can instigate to offer optimum asset utilization and to avoid or delay the need for new infrastructure investment. Being a sizable load together...... with high thermal time constant, heat pumps (HP) can offer a great deal of flexibility in the future intelligent grids especially to compensate fluctuating generation. However, the HP flexibility is highly dependent on thermal demand profile, namely hot water and space heating demand. This paper proposes...... price based scheduling followed by a demand dispatch based central control and a local voltage based adaptive control, to realize HP demand flexibility. Two-step control architecture, namely local primary control encompassed by the central coordinative control, is proposed to implement...

Development and validation of I x V curve tracer for photovoltaic modules

OpenAIRE

MÃrcio Leal Macedo Luna

2016-01-01

The IxV curves tracers for PV modules are used as a method of diagnosis of problems such as shadowing, faulty connections and degradation conditions. There are several types and brands tracers commercially available, but their costs are quite high in the Brazilian market due to the need to import. This thesis describes the development and validation of a IxV curve tracer for PV modules based on the electronic load method using MOSFET as load to the module. By appropriate variation of the MOSF...

A mathematical programming framework for energy planning in services' sector buildings under uncertainty in load demand: The case of a hospital in Athens

International Nuclear Information System (INIS)

Mavrotas, George; Diakoulaki, Danae; Florios, Kostas; Georgiou, Paraskevas

2008-01-01

The aim of this paper is to provide an integrated modeling and optimization framework for energy planning in large consumers of the services' sector based on mathematical programming. The power demand is vaguely known and the underlying uncertainty is modeled using elements from fuzzy set theory. The defined fuzzy programming model is subsequently transformed to an equivalent multi-objective problem, where the minimization of cost and the maximization of demand satisfaction are the objective functions. The Pareto optimal solutions of this problem are obtained using a novel version of the ε-constraint method and represent the possibly optimal solutions of the original problem under uncertainty. In the present case, in order to select the most preferred Pareto optimal solution, the minimax regret criterion is properly used to indicate the preferred configuration of the system (i.e. the size of the installed units) given the load uncertainty. Furthermore, the paper proposes a model reduction technique that can be used in similar cases and further examines its effect in the final results. The above methodology is applied to the energy rehabilitation of a hospital in the Athens area. The technologies under consideration include a combined heat and power unit for providing power and heat, an absorption unit and/or a compression unit for providing cooling load. The obtained results demonstrate that, increasing the degree of demand satisfaction, the total annual cost increases almost linearly. Although data compression allows obtaining realistic results, the size of the proposed units might be slightly changed

Opportunities for Automated Demand Response in Wastewater Treatment Facilities in California - Southeast Water Pollution Control Plant Case Study

Energy Technology Data Exchange (ETDEWEB)

Olsen, Daniel [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Goli, Sasank [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Faulkner, David [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); McKane, Aimee [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2012-12-20

This report details a study into the demand response potential of a large wastewater treatment facility in San Francisco. Previous research had identified wastewater treatment facilities as good candidates for demand response and automated demand response, and this study was conducted to investigate facility attributes that are conducive to demand response or which hinder its implementation. One years' worth of operational data were collected from the facility's control system, submetered process equipment, utility electricity demand records, and governmental weather stations. These data were analyzed to determine factors which affected facility power demand and demand response capabilities The average baseline demand at the Southeast facility was approximately 4 MW. During the rainy season (October-March) the facility treated 40% more wastewater than the dry season, but demand only increased by 4%. Submetering of the facility's lift pumps and centrifuges predicted load shifts capabilities of 154 kW and 86 kW, respectively, with large lift pump shifts in the rainy season. Analysis of demand data during maintenance events confirmed the magnitude of these possible load shifts, and indicated other areas of the facility with demand response potential. Load sheds were seen to be possible by shutting down a portion of the facility's aeration trains (average shed of 132 kW). Load shifts were seen to be possible by shifting operation of centrifuges, the gravity belt thickener, lift pumps, and external pump stations These load shifts were made possible by the storage capabilities of the facility and of the city's sewer system. Large load reductions (an average of 2,065 kW) were seen from operating the cogeneration unit, but normal practice is continuous operation, precluding its use for demand response. The study also identified potential demand response opportunities that warrant further study: modulating variable-demand aeration loads, shifting

Processing Capacity under Perceptual and Cognitive Load: A Closer Look at Load Theory

Science.gov (United States)

Fitousi, Daniel; Wenger, Michael J.

2011-01-01

Variations in perceptual and cognitive demands (load) play a major role in determining the efficiency of selective attention. According to load theory (Lavie, Hirst, Fockert, & Viding, 2004) these factors (a) improve or hamper selectivity by altering the way resources (e.g., processing capacity) are allocated, and (b) tap resources rather than…

The Influence of Load and Speed on Individuals' Movement Behavior.

Science.gov (United States)

Frost, David M; Beach, Tyson A C; Callaghan, Jack P; McGill, Stuart M

2015-09-01

Because individuals' movement patterns have been linked to their risk of future injury, movement evaluations have become a topic of interest. However, if individuals adapt their movement behavior in response to the demands of a task, the utility of evaluations comprising only low-demand activities could have limited application with regard to the prediction of future injury. This investigation examined the impact of load and speed on individuals' movement behavior. Fifty-two firefighters performed 5 low-demand (i.e., light load, low movement speed) whole-body tasks (i.e., lift, squat, lunge, push, and pull). Each task was then modified by increasing the speed, external load, or speed and load. Select measures of motion were used to characterize the performance of each task, and comparisons were made between conditions. The participants adapted their movement behavior in response to the external demands of a task (64 and 70% of all the variables were influenced [p ≤ 0.05] by changing the load and speed, respectively), but in a manner unique to the task and type of demand. The participants exhibited greater spine and frontal plane knee motion in response to an increase in speed when compared with increasing loads. However, there were a large number of movement strategies exhibited by individual firefighters that differed from the group's response. The data obtained here imply that individuals may not be physically prepared to perform safely or effectively when a task's demands are elevated simply because they exhibit the ability to perform a low-demand activity with competence. Therefore, movement screens comprising only low-demand activities may not adequately reflect an individual's capacity, or their risk of injury, and could adversely affect any recommendations that are made for training or job performance.

Novel algorithm for aggregated demand response strategy for smart distribution network

NARCIS (Netherlands)

Babar, M.; Ahamed, I.; Shah, A.; Al-Ammar, E.A.; Malik, N.H.

2013-01-01

Advancement in demand side management strategies enables smart grid to cope with the ever increasing energy demand and provide economic benefit to all of it's stakeholders. Moreover, emerging concept of smart pricing and advances in load control can provide new business opportunities for demand side

Probabilistic Quantification of Potentially Flexible Residential Demand

DEFF Research Database (Denmark)

Kouzelis, Konstantinos; Mendaza, Iker Diaz de Cerio; Bak-Jensen, Birgitte

2014-01-01

The balancing of power systems with high penetration of renewable energy is a serious challenge to be faced in the near future. One of the possible solutions, recently capturing a lot of attention, is demand response. Demand response can only be achieved by power consumers holding loads which allow...... them to modify their normal power consumption pattern, namely flexible consumers. However flexibility, despite being constantly mentioned, is usually not properly defined and even rarer quantified. This manuscript introduces a methodology to identify and quantify potentially flexible demand...

Magneto-electro-elastic buckling analysis of nonlocal curved nanobeams

Science.gov (United States)

Ebrahimi, Farzad; Reza Barati, Mohammad

2016-09-01

In this work, a size-dependent curved beam model is developed to take into account the effects of nonlocal stresses on the buckling behavior of curved magneto-electro-elastic FG nanobeams for the first time. The governing differential equations are derived based on the principle of virtual work and Euler-Bernoulli beam theory. The power-law function is employed to describe the spatially graded magneto-electro-elastic properties. By extending the radius of the curved nanobeam to infinity, the results of straight nonlocal FG beams can be rendered. The effects of magnetic potential, electric voltage, opening angle, nonlocal parameter, power-law index and slenderness ratio on buckling loads of curved MEE-FG nanobeams are studied.

Breaking through the hydrogen cost barrier by using electrolysis loads to access ancillary services and demand response programs

International Nuclear Information System (INIS)

Wilson, D.; McGillivray, R.

2009-01-01

This presentation described the use of hydrogen electrolysis as a load resource for handling grid instability resulting from the increased penetration of intermittent renewable power. In particular, it focused on Hydrogenics, the leading global supplier of industrial scale electrolysis equipment and fuel cells. The presentation included an overview of the current incentive and market value of ancillary services provided by the company and demand responses in a number of grids around the world. There is a link between the amount of ancillary services required by the grid and the penetration level of renewable energy power such as wind and solar. The ability of hydrogen generation from electrolysis to satisfy all the requirements of ancillary services markets was also demonstrated. The economic analysis of hydrogen generation was discussed with particular reference to the cost of hydrogen fully loading all capital, energy and operating costs. The resulting reduction in the cost of hydrogen was compared to the existing markets for hydrogen, including use of hydrogen as a fuel for municipal bus fleets relative to the existing cost of fossil fuel fleets. Current industrial hydrogen merchant and bulk market prices were also compared

Optimal Dispatching of Active Distribution Networks Based on Load Equilibrium

Directory of Open Access Journals (Sweden)

Xiao Han

2017-12-01

Full Text Available This paper focuses on the optimal intraday scheduling of a distribution system that includes renewable energy (RE generation, energy storage systems (ESSs, and thermostatically controlled loads (TCLs. This system also provides time-of-use pricing to customers. Unlike previous studies, this study attempts to examine how to optimize the allocation of electric energy and to improve the equilibrium of the load curve. Accordingly, we propose a concept of load equilibrium entropy to quantify the overall equilibrium of the load curve and reflect the allocation optimization of electric energy. Based on this entropy, we built a novel multi-objective optimal dispatching model to minimize the operational cost and maximize the load curve equilibrium. To aggregate TCLs into the optimization objective, we introduced the concept of a virtual power plant (VPP and proposed a calculation method for VPP operating characteristics based on the equivalent thermal parameter model and the state-queue control method. The Particle Swarm Optimization algorithm was employed to solve the optimization problems. The simulation results illustrated that the proposed dispatching model can achieve cost reductions of system operations, peak load curtailment, and efficiency improvements, and also verified that the load equilibrium entropy can be used as a novel index of load characteristics.

Monopoly Output and Welfare: The Role of Curvature of the Demand Function.

Science.gov (United States)

Malueg, David A.

1994-01-01

Discusses linear demand functions and constant marginal costs related to a monopoly in a market economy. Illustrates the demand function by using a curve. Includes an appendix with two figures and accompanying mathematical formulae illustrating the concepts presented in the article. (CFR)

Force Curves to Demonstrate Methods to Increase Musculoskeletal Loading with the ARED

Data.gov (United States)

National Aeronautics and Space Administration — Current resistance exercises on ISS do not meet the requirements set by expert panels in that the eccentric loads are less than concentric loads, forces are variable...

Optimal real time cost-benefit based demand response with intermittent resources

International Nuclear Information System (INIS)

Zareen, N.; Mustafa, M.W.; Sultana, U.; Nadia, R.; Khattak, M.A.

2015-01-01

Ever-increasing price of conventional energy resources and related environmental concern enforced to explore alternative energy sources. Inherent uncertainty of power generation and demand being strongly influenced by the electricity market has posed severe challenges for DRPs (Demand Response Programs). Definitely, the success of such uncertain energy systems under new market structures is critically decided by the advancement of innovative technical and financial tools. Recent exponential growth of DG (distributed generations) demanded both the grid reliability and financial cost–benefits analysis for deregulated electricity market stakeholders. Based on the SGT (signaling game theory), the paper presents a novel user-aware demand-management approach where the price are colligated with grid condition uncertainties to manage the peak residential loads. The degree of information disturbances are considered as a key factor for evaluating electricity bidding mechanisms in the presence of independent multi-generation resources and price-elastic demand. A correlation between the cost–benefit price and variable reliability of grid is established under uncertain generation and demand conditions. Impacts of the strategies on load shape, benefit of customers and the reduction of energy consumption are inspected and compared with Time-of-Used based DRPs. Simulation results show that the proposed DRP can significantly reduce or even eliminate peak-hour energy consumption, leading to a substantial raise of revenues with 18% increase in the load reduction and a considerable improvement in system reliability is evidenced. - Highlights: • Proposed an optimal real time cost-benefit based demand response model. • Used signaling game theory for the information disturbances in deregulated market. • Introduced a correlation between the cost–benefit price and variable grid reliability. • Derive robust bidding strategies for utility/customers successful participation. �

Ontario demand response scenarios

International Nuclear Information System (INIS)

Rowlands, I.H.

2005-09-01

Strategies for demand management in Ontario were examined via 2 scenarios for a commercial/institutional building with a normal summertime peak load of 300 kW between 14:00 and 18:00 during a period of high electricity demand and high electricity prices. The first scenario involved the deployment of a 150 kW on-site generator fuelled by either diesel or natural gas. The second scenario involved curtailing load by 60 kW during the same periods. Costs and benefits of both scenarios were evaluated for 3 groups: consumers, system operators and society. Benefits included electricity cost savings, deferred transmission capacity development, lower system prices for electricity, as well as environmental changes, economic development, and a greater sense of corporate social responsibility. It was noted that while significant benefits were observed for all 3 groups, they were not substantial enough to encourage action, as the savings arising from deferred generation capacity development do not accrue to individual players. The largest potential benefit was identified as lower prices, spread across all users of electricity in Ontario. It was recommended that representative bodies cooperate so that the system-wide benefits can be reaped. It was noted that if 10 municipal utilities were able to have 250 commercial or institutional customers engaged in distributed response, then a total peak demand reduction of 375 MW could be achieved, representing more than 25 per cent of Ontario's target for energy conservation. It was concluded that demand response often involves the investment of capital and new on-site procedures, which may affect reactions to various incentives. 78 refs., 10 tabs., 5 figs

Market integration of flexible demand and DG-RES supply. A new approach for demand response

International Nuclear Information System (INIS)

Warmer, C.J.; Hommelberg, M.P.F.; Kamphuis, I.G.; Kok, J.K.

2007-06-01

In this paper we discuss the shortcomings of traditional Demand Response programs in an environment in which a large amount of distributed generation is available. An innovative approach is given in which true Customer Site Integration is obtained in the spirit of the liberalized electricity market, by making use of the load flexibility of underlying processes of production and consumption devices. The approach is based on distributed control mechanisms and incorporates new market models for distribution and aggregation costs, load losses, and network constraints

Economic demand and essential value.

Science.gov (United States)

Hursh, Steven R; Silberberg, Alan

2008-01-01

The strength of a rat's eating reflex correlates with hunger level when strength is measured by the response frequency that precedes eating (B. F. Skinner, 1932a, 1932b). On the basis of this finding, Skinner argued response frequency could index reflex strength. Subsequent work documented difficulties with this notion because responding was affected not only by the strengthening properties of the reinforcer but also by the rate-shaping effects of the schedule. This article obviates this problem by measuring strength via methods from behavioral economics. This approach uses demand curves to map how reinforcer consumption changes with changes in the "price" different ratio schedules impose. An exponential equation is used to model these demand curves. The value of this exponential's rate constant is used to scale the strength or essential value of a reinforcer, independent of the scalar dimensions of the reinforcer. Essential value determines the consumption level to be expected at particular prices and the response level that will occur to support that consumption. This approach permits comparing reinforcers that differ in kind, contributing toward the goal of scaling reinforcer value. (c) 2008 APA, all rights reserved

Pigeons' demand and preference for specific and generalized conditioned reinforcers in a token economy.

Science.gov (United States)

Tan, Lavinia; Hackenberg, Timothy D

2015-11-01

Pigeons' demand and preference for specific and generalized tokens was examined in a token economy. Pigeons could produce and exchange different colored tokens for food, for water, or for food or water. Token production was measured across three phases, which examined: (1) across-session price increases (typical demand curve method); (2) within-session price increases (progressive-ratio, PR, schedule); and (3) concurrent pairwise choices between the token types. Exponential demand curves were fitted to the response data and accounted for over 90% total variance. Demand curve parameter values, Pmax , Omax and α showed that demand was ordered in the following way: food tokens, generalized tokens, water tokens, both in Phase 1 and in Phase 3. This suggests that the preferences were predictable on the basis of elasticity and response output from the demand analysis. Pmax and Omax values failed to consistently predict breakpoints and peak response rates in the PR schedules in Phase 2, however, suggesting limits on a unitary conception of reinforcer efficacy. The patterns of generalized token production and exchange in Phase 3 suggest that the generalized tokens served as substitutes for the specific food and water tokens. Taken together, the present findings demonstrate the utility of behavioral economic concepts in the analysis of generalized reinforcement. © Society for the Experimental Analysis of Behavior.

Functional dynamic factor models with application to yield curve forecasting

KAUST Repository

Hays, Spencer

2012-09-01

Accurate forecasting of zero coupon bond yields for a continuum of maturities is paramount to bond portfolio management and derivative security pricing. Yet a universal model for yield curve forecasting has been elusive, and prior attempts often resulted in a trade-off between goodness of fit and consistency with economic theory. To address this, herein we propose a novel formulation which connects the dynamic factor model (DFM) framework with concepts from functional data analysis: a DFM with functional factor loading curves. This results in a model capable of forecasting functional time series. Further, in the yield curve context we show that the model retains economic interpretation. Model estimation is achieved through an expectation- maximization algorithm, where the time series parameters and factor loading curves are simultaneously estimated in a single step. Efficient computing is implemented and a data-driven smoothing parameter is nicely incorporated. We show that our model performs very well on forecasting actual yield data compared with existing approaches, especially in regard to profit-based assessment for an innovative trading exercise. We further illustrate the viability of our model to applications outside of yield forecasting.

Demand as Frequency-controlled Reserve

DEFF Research Database (Denmark)

Bang, Christian; Rasmussen, Christian Brandt; Østergaard, Jacob

with great enthusiasm from all DFR project members who have shown a memorable dedication to their work. Active control of electricity demand is a key technology when creating a more dynamic, wind power friendly energy system. In this demonstration project, we have developed and tested devices, which use...... electric loads to provide frequency controlled primary reserves. The devices collected data from domestic households and industrial loads covering i.e. circulation pumps, electrical domestic heating, bottle coolers, a wastewater treatment plant etc., that have been analysed and used for the papers...

Demand response policies for the implementation of smart grids

NARCIS (Netherlands)

Koliou, E.

2016-01-01

With the grasp of a smart grid in sight, discussions have shifted the focus of system security measures away from generation capacity; apart from modifying the supply side, demand may also be exploited to keep the system in balance. Specifically, Demand Response (DR) is the concept of consumer load

Fragility curves for bridges under differential support motions

DEFF Research Database (Denmark)

Konakli, Katerina

2012-01-01

This paper employs the notion of fragility to investigate the seismic vulnerability of bridges subjected to spatially varying support motions. Fragility curves are developed for four highway bridges in California with vastly different structural characteristics. The input in this analysis consists...... of simulated ground motion arrays with temporal and spectral nonstationarities, and consistent with prescribed spatial variation patterns. Structural damage is quantified through displacement ductility demands obtained from nonlinear time-history analysis. The potential use of the ‘equal displacement’ rule...... to approximately evaluate displacement demands from analysis of the equivalent linear systems is examined....

High cycle fatigue of austenitic stainless steels under random loading

International Nuclear Information System (INIS)

Gauthier, J.P.; Petrequin, P.

1987-08-01

To investigate reactor components, load control random fatigue tests were performed at 300 0 C and 550 0 C, on specimens from austenitic stainless steels plates in the transverse orientation. Random solicitations are produced on closed loop servo-hydraulic machines by a mini computer which generates random load sequence by the use of reduced Markovian matrix. The method has the advantage of taking into account the mean load for each cycle. The solicitations generated are those of a stationary gaussian process. Fatigue tests have been mainly performed in the endurance region of fatigue curve, with scattering determination using stair case method. Experimental results have been analysed aiming at determining design curves for components calculations, depending on irregularity factor and temperature. Analysis in term of mean square root fatigue limit calculation, shows that random loading gives more damage than constant amplitude loading. Damage calculations following Miner rule have been made using the probability density function for the case where the irregularity factor is nearest to 100 %. The Miner rule is too conservative for our results. A method using design curves including random loading effects with irregularity factor as an indexing parameter is proposed

Opportunities for Energy Efficiency and Automated Demand Response in Industrial Refrigerated Warehouses in California

Energy Technology Data Exchange (ETDEWEB)

Lekov, Alex; Thompson, Lisa; McKane, Aimee; Rockoff, Alexandra; Piette, Mary Ann

2009-05-11

This report summarizes the Lawrence Berkeley National Laboratory's research to date in characterizing energy efficiency and open automated demand response opportunities for industrial refrigerated warehouses in California. The report describes refrigerated warehouses characteristics, energy use and demand, and control systems. It also discusses energy efficiency and open automated demand response opportunities and provides analysis results from three demand response studies. In addition, several energy efficiency, load management, and demand response case studies are provided for refrigerated warehouses. This study shows that refrigerated warehouses can be excellent candidates for open automated demand response and that facilities which have implemented energy efficiency measures and have centralized control systems are well-suited to shift or shed electrical loads in response to financial incentives, utility bill savings, and/or opportunities to enhance reliability of service. Control technologies installed for energy efficiency and load management purposes can often be adapted for open automated demand response (OpenADR) at little additional cost. These improved controls may prepare facilities to be more receptive to OpenADR due to both increased confidence in the opportunities for controlling energy cost/use and access to the real-time data.

The duration perception of loading applications in smartphone: Effects of different loading types.

Science.gov (United States)

Zhao, Wenguo; Ge, Yan; Qu, Weina; Zhang, Kan; Sun, Xianghong

2017-11-01

The loading time of a smartphone application is an important issue, which affects the satisfaction of phone users. This study evaluated the effects of black loading screen (BLS) and animation loading screen (ALS) during application loading on users' duration perception and satisfaction. A total of 43 volunteers were enrolled. They were asked to complete several tasks by clicking the icons of each application, such as camera or message. The duration of loading time for each application was manipulated. The participants were asked to estimate the duration, evaluate the loading speed and their satisfaction. The results showed that the estimated duration increased and the satisfaction for loading period declined along with the loading time increased. Compared with the BLS, the ALS prolonged the estimated duration, and lowered the evaluation of speed and satisfaction. We also discussed the tendency and key inflection points of the curves involving the estimated duration, speed evaluation and satisfaction with the loading time. Copyright © 2017 Elsevier Ltd. All rights reserved.

Econophysics: Master curve for price-impact function

Science.gov (United States)

Lillo, Fabrizio; Farmer, J. Doyne; Mantegna, Rosario N.

2003-01-01

The price reaction to a single transaction depends on transaction volume, the identity of the stock, and possibly many other factors. Here we show that, by taking into account the differences in liquidity for stocks of different size classes of market capitalization, we can rescale both the average price shift and the transaction volume to obtain a uniform price-impact curve for all size classes of firm for four different years (1995-98). This single-curve collapse of the price-impact function suggests that fluctuations from the supply-and-demand equilibrium for many financial assets, differing in economic sectors of activity and market capitalization, are governed by the same statistical rule.

Thermo-Electro-Mechanical Analysis of a Curved Functionally Graded Piezoelectric Actuator with Sandwich Structure

Directory of Open Access Journals (Sweden)

Liying Jiang

2011-12-01

Full Text Available In this work, the problem of a curved functionally graded piezoelectric (FGP actuator with sandwich structure under electrical and thermal loads is investigated. The middle layer in the sandwich structure is functionally graded with the piezoelectric coefficient g31 varying continuously along the radial direction of the curved actuator. Based on the theory of linear piezoelectricity, analytical solutions are obtained by using Airy stress function to examine the effects of material gradient and heat conduction on the performance of the curved actuator. It is found that the material gradient and thermal load have significant influence on the electroelastic fields and the mechanical response of the curved FGP actuator. Without the sacrifice of actuation deflection, smaller internal stresses are generated by using the sandwich actuator with functionally graded piezoelectric layer instead of the conventional bimorph actuator. This work is very helpful for the design and application of curved piezoelectric actuators under thermal environment.

Thermo-Electro-Mechanical Analysis of a Curved Functionally Graded Piezoelectric Actuator with Sandwich Structure.

Science.gov (United States)

Yan, Zhi; Zaman, Mostafa; Jiang, Liying

2011-12-12

In this work, the problem of a curved functionally graded piezoelectric (FGP) actuator with sandwich structure under electrical and thermal loads is investigated. The middle layer in the sandwich structure is functionally graded with the piezoelectric coefficient g 31 varying continuously along the radial direction of the curved actuator. Based on the theory of linear piezoelectricity, analytical solutions are obtained by using Airy stress function to examine the effects of material gradient and heat conduction on the performance of the curved actuator. It is found that the material gradient and thermal load have significant influence on the electroelastic fields and the mechanical response of the curved FGP actuator. Without the sacrifice of actuation deflection, smaller internal stresses are generated by using the sandwich actuator with functionally graded piezoelectric layer instead of the conventional bimorph actuator. This work is very helpful for the design and application of curved piezoelectric actuators under thermal environment.

DeMand: A tool for evaluating and comparing device-level demand and supply forecast models

DEFF Research Database (Denmark)

Neupane, Bijay; Siksnys, Laurynas; Pedersen, Torben Bach

2016-01-01

Fine-grained device-level predictions of both shiftable and non-shiftable energy demand and supply is vital in order to take advantage of Demand Response (DR) for efficient utilization of Renewable Energy Sources. The selection of an effective device-level load forecast model is a challenging task......, mainly due to the diversity of the models and the lack of proper tools and datasets that can be used to validate them. In this paper, we introduce the DeMand system for fine-tuning, analyzing, and validating the device-level forecast models. The system offers several built-in device-level measurement...... datasets, forecast models, features, and errors measures, thus semi-automating most of the steps of the forecast model selection and validation process. This paper presents the architecture and data model of the DeMand system; and provides a use-case example on how one particular forecast model...

Predictive Control of a Domestic Freezer for Real-Time Demand Response Applications

NARCIS (Netherlands)

Baghina, N.G.; Lampropoulos, I.; Asare-Bediako, B.; Kling, W.L.; Ribeiro, P.F.

2012-01-01

Demand side management and demand response aim to maximize the efficiency of the electricity delivery process by exploiting the flexibility of customers. At residential level, demand response can be applied only to a limited number of appliances, through load management, due to user intervention or

Towards building a neural network model for predicting pile static load test curves

Directory of Open Access Journals (Sweden)

Alzo’ubi A. K.

2018-01-01

Full Text Available In the United Arab Emirates, Continuous Flight Auger piles are the most widely used type of deep foundation. To test the pile behaviour, the Static Load Test is routinely conducted in the field by increasing the dead load while monitoring the displacement. Although the test is reliable, it is expensive to conduct. This test is usually conducted in the UAE to verify the pile capacity and displacement as the load increase and decreases in two cycles. In this paper we will utilize the Artificial Neural Network approach to build a model that can predict a complete Static Load Pile test. We will show that by integrating the pile configuration, soil properties, and ground water table in one artificial neural network model, the Static Load Test can be predicted with confidence. We believe that based on this approach, the model is able to predict the entire pile load test from start to end. The suggested approach is an excellent tool to reduce the cost associated with such expensive tests or to predict pile’s performance ahead of the actual test.

Price responsive load programs: U.S. experience in creating markets for peak demand reductions

International Nuclear Information System (INIS)

Goldberg, Miriam L.; Michelman, Thomas; Rosenberg, Mitchell

2003-01-01

Demand response programs use a variety of pricing mechanisms to induce end-use customers to reduce demand at specified periods. U.S. distribution utilities, regional market operators, and their regulators have implemented demand response programs with the objectives of improving electric system reliability, avoiding price spikes, and relieving local transmission congestion. This paper reviews the design and performance of market-linked demand response programs operated in 2001 and 2002, focusing on the relationship between program design and customer participation and the development of accurate and feasible methods to measure demand response at the facility level

Exploring Demand Charge Savings from Commercial Solar

Energy Technology Data Exchange (ETDEWEB)

Darghouth, Naim [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Barbose, Galen [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Mills, Andrew [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Wiser, Ryan [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Gagnon, Pieter [National Renewable Energy Lab. (NREL), Golden, CO (United States); Bird, Lori [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2017-07-31

Commercial retail electricity rates commonly include a demand charge component, based on some measure of the customer’s peak demand. Customer-sited solar PV can potentially reduce demand charges, but the magnitude of these savings can be difficult to predict, given variations in demand charge designs, customer loads, and PV generation profiles. Moreover, depending on the circumstances, demand charges from solar may or may not align well with associated utility cost savings. Lawrence Berkeley National Laboratory (Berkeley Lab) and the National Renewable Energy Laboratory (NREL) are collaborating in a series of studies to understand how solar PV can reduce demand charge levels for a variety of customer types and demand charges designs. Previous work focused on residential customs with solar. This study, instead, focuses on commercial customers and seeks to understand the extent and conditions under which rooftop can solar reduce commercial demand charges. To answer these questions, we simulate demand charge savings for a broad range of commercial customer types, demand charge designs, locations, and PV system characteristics. This particular analysis does not include storage, but a subsequent analysis in this series will evaluate demand charge savings for commercial customers with solar and storage.

Why do successful restaurants not raise their prices? : Market forces of demand and the all-or-nothing demand curve

NARCIS (Netherlands)

Folmer, Henk; Leen, Auke

Becker (J Political Econ 99:1109-1116, 1991) addresses the problem of persistent queues at popular restaurants. He poses the question why such restaurants do not raise their prices, thus reducing the queues while expanding profits. He presents a solution based on the assumption that demand by a

Domestic demand-side management (DSM): Role of heat pumps and thermal energy storage (TES) systems

International Nuclear Information System (INIS)

Arteconi, A.; Hewitt, N.J.; Polonara, F.

2013-01-01

Heat pumps are seen as a promising technology for load management in the built environment, in combination with the smart grid concept. They can be coupled with thermal energy storage (TES) systems to shift electrical loads from high-peak to off-peak hours, thus serving as a powerful tool in demand-side management (DSM). This paper analyzes heat pumps with radiators or underfloor heating distribution systems coupled with TES with a view to showing how a heat pump system behaves and how it influences the building occupants' thermal comfort under a DSM strategy designed to flatten the shape of the electricity load curve by switching off the heat pump during peak hours (16:00–19:00). The reference scenario for the analysis was Northern Ireland (UK). The results showed that the heat pump is a good tool for the purposes of DSM, also thanks to the use of TES systems, in particular with heating distribution systems that have a low thermal inertia, e.g. radiators. It proved possible to achieve a good control of the indoor temperature, even if the heat pump was turned off for 3 h, and to reduce the electricity bill if a “time of use” tariff structure was adopted. -- Highlights: ► Heat pump heating systems with thermal energy storage are considered. ► System behavior is investigated during a DSM strategy for reducing peak energy demand. ► Heat pump heating systems demonstrate to be able to have an active role in DSM programs. ► A TES system must be coupled with the heat pump in presence of low thermal inertia heating distribution systems. ► Central role played by incentives schemes to promote this technology

Experimental verification of different parameters influencing the fatigue S/N-curve

International Nuclear Information System (INIS)

Roos, E.; Maile, K.; Herter, K.-H.; Schuler, X.

2005-01-01

For the construction, design and operation of nuclear components the appropriate technical codes and standards provide detailed stress analysis procedures, material data and a design philosophy which guarantees a reliable behavior throughout the specified lifetime. Especially for cyclic stress evaluation the different codes and standards provide different fatigue analyses procedures to be performed considering the various (specified or measured) loading histories which are of mechanical and/or thermal origin and the geometric complexities of the components. In order to fully understand the background of the fatigue analysis included in the codes and standards as well as of the fatigue design curves used as a limiting criteria (to determine the fatigue life usage factor), it is important to understand the history, background as well as the methodologies which are important for the design engineers to get reliable results. The design rules according to the technical codes and standards provide for explicit consideration of cyclic operation, using design fatigue curves of allowable alternating loads (allowable stress or strain amplitudes) vs. number of loading cycles (S/N-curves), specific rules for assessing the cumulative fatigue damage (cumulative fatigue life usage factor) caused by different specified or monitored load cycles. The influence of different factors like welds, environment, surface finish, temperature, mean stress and size must be taken into consideration. In the paper parameters influencing the S/N-curves used within a fatigue analysis, like different type of material, the surface finish, the temperature, the difference between unwelded and welded areas, the strain rate as well as the influences of notches are verified on the basis of experimental results obtained by specimens testing in the LCF regime for high strain amplitudes. Thus safety margins relevant for the assessment of fatigue life depending on the different influencing parameters are

Determiantion of elasticity coefficient of demand for suburban passenger transport

Directory of Open Access Journals (Sweden)

Тетяна Михайлівна Григорова

2015-06-01

Full Text Available The regularity of changes in demand for suburban passenger road transport, depending on the value, is investigated. The results of the survey of passengers about changes of fare on the chosen route are given. It is built the curve of elasticity of demand for suburban bus transport use in labor and cultural and social movements. The equilibrium tariff for suburban road transport is defined

Impacts of demand response and renewable generation in electricity power market

Science.gov (United States)

Zhao, Zhechong

This thesis presents the objective of the research which is to analyze the impacts of uncertain wind power and demand response on power systems operation and power market clearing. First, in order to effectively utilize available wind generation, it is usually given the highest priority by assigning zero or negative energy bidding prices when clearing the day-ahead electric power market. However, when congestion occurs, negative wind bidding prices would aggravate locational marginal prices (LMPs) to be negative in certain locations. A load shifting model is explored to alleviate possible congestions and enhance the utilization of wind generation, by shifting proper amount of load from peak hours to off peaks. The problem is to determine proper amount of load to be shifted, for enhancing the utilization of wind generation, alleviating transmission congestions, and making LMPs to be non-negative values. The second piece of work considered the price-based demand response (DR) program which is a mechanism for electricity consumers to dynamically manage their energy consumption in response to time-varying electricity prices. It encourages consumers to reduce their energy consumption when electricity prices are high, and thereby reduce the peak electricity demand and alleviate the pressure to power systems. However, it brings additional dynamics and new challenges on the real-time supply and demand balance. Specifically, price-sensitive DR load levels are constantly changing in response to dynamic real-time electricity prices, which will impact the economic dispatch (ED) schedule and in turn affect electricity market clearing prices. This thesis adopts two methods for examining the impacts of different DR price elasticity characteristics on the stability performance: a closed-loop iterative simulation method and a non-iterative method based on the contraction mapping theorem. This thesis also analyzes the financial stability of DR load consumers, by incorporating

Forecasting monthly peak demand of electricity in India—A critique

International Nuclear Information System (INIS)

Rallapalli, Srinivasa Rao; Ghosh, Sajal

2012-01-01

The nature of electricity differs from that of other commodities since electricity is a non-storable good and there have been significant seasonal and diurnal variations of demand. Under such condition, precise forecasting of demand for electricity should be an integral part of the planning process as this enables the policy makers to provide directions on cost-effective investment and on scheduling the operation of the existing and new power plants so that the supply of electricity can be made adequate enough to meet the future demand and its variations. Official load forecasting in India done by Central Electricity Authority (CEA) is often criticized for being overestimated due to inferior techniques used for forecasting. This paper tries to evaluate monthly peak demand forecasting performance predicted by CEA using trend method and compare it with those predicted by Multiplicative Seasonal Autoregressive Integrated Moving Average (MSARIMA) model. It has been found that MSARIMA model outperforms CEA forecasts both in-sample static and out-of-sample dynamic forecast horizons in all five regional grids in India. For better load management and grid discipline, this study suggests employing sophisticated techniques like MSARIMA for peak load forecasting in India. - Highlights: ► This paper evaluates monthly peak demand forecasting performance by CEA. ► Compares CEA forecasts it with those predicted by MSARIMA model. ► MSARIMA model outperforms CEA forecasts in all five regional grids in India. ► Opportunity exists to improve the performance of CEA forecasts.

Supply and demand elasticities in the U.S. ethanol fuel market

International Nuclear Information System (INIS)

Luchansky, Matthew S.; Monks, James

2009-01-01

The market for ethanol has grown from approximately 1.2 billion gallons in 1997 to almost 5 billion gallons in 2006. With the huge increase in ethanol demand in recent years, the growth in derived demand for corn has driven up many food prices. This paper uses monthly data from 1997-2006 to estimate the market supply and demand for ethanol at the national level. The simultaneous determination of the supply and demand curves using two-stage least squares allows for the calculation of supply and demand-side elasticities, which are important results in light of the tremendous growth in this market and recent legislation concerning ethanol. (author)

Supply and demand elasticities in the U.S. ethanol fuel market

Energy Technology Data Exchange (ETDEWEB)

Luchansky, Matthew S. [University of Illinois at Urbana-Champaign49 Roger Adams Lab, 81-5600 S. Mathews Ave., Urbana, IL 61801 (United States); Monks, James [Robins School of Business, University of Richmond, Richmond, VA 23173 (United States)

2009-05-15

The market for ethanol has grown from approximately 1.2 billion gallons in 1997 to almost 5 billion gallons in 2006. With the huge increase in ethanol demand in recent years, the growth in derived demand for corn has driven up many food prices. This paper uses monthly data from 1997-2006 to estimate the market supply and demand for ethanol at the national level. The simultaneous determination of the supply and demand curves using two-stage least squares allows for the calculation of supply and demand-side elasticities, which are important results in light of the tremendous growth in this market and recent legislation concerning ethanol. (author)

Considerations for reference pump curves

International Nuclear Information System (INIS)

Stockton, N.B.

1992-01-01

This paper examines problems associated with inservice testing (IST) of pumps to assess their hydraulic performance using reference pump curves to establish acceptance criteria. Safety-related pumps at nuclear power plants are tested under the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (the Code), Section 11. The Code requires testing pumps at specific reference points of differential pressure or flow rate that can be readily duplicated during subsequent tests. There are many cases where test conditions cannot be duplicated. For some pumps, such as service water or component cooling pumps, the flow rate at any time depends on plant conditions and the arrangement of multiple independent and constantly changing loads. System conditions cannot be controlled to duplicate a specific reference value. In these cases, utilities frequently request to use pump curves for comparison of test data for acceptance. There is no prescribed method for developing a pump reference curve. The methods vary and may yield substantially different results. Some results are conservative when compared to the Code requirements; some are not. The errors associated with different curve testing techniques should be understood and controlled within reasonable bounds. Manufacturer's pump curves, in general, are not sufficiently accurate to use as reference pump curves for IST. Testing using reference curves generated with polynomial least squares fits over limited ranges of pump operation, cubic spline interpolation, or cubic spline least squares fits can provide a measure of pump hydraulic performance that is at least as accurate as the Code required method. Regardless of the test method, error can be reduced by using more accurate instruments, by correcting for systematic errors, by increasing the number of data points, and by taking repetitive measurements at each data point

Introduction effect of a load levelling system in an electric power system with a photovoltaic and wind system; Taiyoko/furyoku hatsuden wo donyu shita denryoku keito ni okeru fuka heijunka shisutemu no donyu koka

Energy Technology Data Exchange (ETDEWEB)

Kenmoku, Y.; Sakakibara, T. [Toyohashi University of Technology, Aichi (Japan); Nakagawa, S. [Maizuru College of Technology, Kyoto (Japan); Kawamoto, T. [Shizuoka University, Shizuoka (Japan)

1998-12-05

Introduction effect of load levelling system by a battery in an electric power system by a battery in an electric power system with a PV and wind system is investigated. Charge and discharge power of the battery are determined from a load curve and every hour data of PV and wind output. Annual cost of the power system is calculated from the generating power and the capacity of each source via the installed utility capacity and the capacity factor. It is found that (1) the battery system reduces the maximum demand and improves the load factor, (2) the cost effect of the battery system when introducing the PV system is higher than that when introducing the wind system. (author)

The design of optimal electric power demand management contracts

Science.gov (United States)

Fahrioglu, Murat

1999-11-01

Our society derives a quantifiable benefit from electric power. In particular, forced outages or blackouts have enormous consequences on society, one of which is loss of economic surplus. Electric utilities try to provide reliable supply of electric power to their customers. Maximum customer benefit derives from minimum cost and sufficient supply availability. Customers willing to share in "availability risk" can derive further benefit by participating in controlled outage programs. Specifically, whenever utilities foresee dangerous loading patterns, there is a need for a rapid reduction in demand either system-wide or at specific locations. The utility needs to get relief in order to solve its problems quickly and efficiently. This relief can come from customers who agree to curtail their loads upon request in exchange for an incentive fee. This thesis shows how utilities can get efficient load relief while maximizing their economic benefit. This work also shows how estimated customer cost functions can be calibrated, using existing utility data, to help in designing efficient demand management contracts. In order to design such contracts, optimal mechanism design is adopted from "Game Theory" and applied to the interaction between a utility and its customers. The idea behind mechanism design is to design an incentive structure that encourages customers to sign up for the right contract and reveal their true value of power. If a utility has demand management contracts with customers at critical locations, most operational problems can be solved efficiently. This thesis illustrates how locational attributes of customers incorporated into demand management contract design can have a significant impact in solving system problems. This kind of demand management contracts can also be used by an Independent System Operator (ISO). During times of congestion a loss of economic surplus occurs. When the market is too slow or cannot help relieve congestion, demand management

Impact of oil prices, economic diversification policies and energy conservation programs on the electricity and water demands in Kuwait

International Nuclear Information System (INIS)

Wood, Michael; Alsayegh, Osamah A.

2014-01-01

This paper describes the influences of oil revenue and government's policies toward economic developments and energy efficiency on the electricity and water demands. A Kuwait-specific electricity and water demand model was developed based on historic data of oil income, gross domestic product (GDP), population and electric load and water demand over the past twelve years (1998–2010). Moreover, the model took into account the future mega projects, annual new connected loads and expected application of energy conservation programs. It was run under six circumstances representing the combinations of three oil income scenarios and two government action policies toward economic diversification and energy conservation. The first government policy is the status quo with respect to economic diversification and applying energy conservation programs. The second policy scenario is the proactive strategy of raising the production of the non-oil sector revenue and enforcing legislations toward energy demand side management and conservation. In the upcoming 20 years, the average rates of change of the electric load and water demand increase are 0.13 GW and 3.0 MIGD, respectively, per US dollar oil price increase. Moreover, through proactive policy, the rates of average load and water demand decrease are 0.13 GW and 2.9 MIGD per year, respectively. - Highlights: • Kuwait-specific electricity and water demand model is presented. • Strong association between oil income and electricity and water demands. • Rate of change of electric load per US dollar oil price change is 0.13 GW. • Rate of change of water demand per US dollar oil price change is 3.0 MIGD. • By 2030, efficiency lowers electric load and water demand by 10 and 6%, respectively

Assessment of p-y curves from numerical methods for a non-slender monopile in cohesionless soil

Energy Technology Data Exchange (ETDEWEB)

Ibsen, L. B.; Ravn Roesen, H. [Aalborg Univ. Dept. of Civil Engineering, Aalborg (Denmark); Hansen, Mette; Kirk Wolf, T. [COWI, Kgs. Lyngby (Denmark); Lange Rasmussen, K. [Niras, Aalborg (Denmark)

2013-06-15

In current design the monopile is a widely used solution as foundation of offshore wind turbines. Winds and waves subject the monopile to considerable lateral loads. The behaviour of monopiles under lateral loading is not fully understood and the current design guidances apply the p-y curve method in a Winkler model approach. The p-y curve method was originally developed for jag-piles used in the oil and gas industry which are much more slender than the monopile foundation. In recent years the 3D finite element analysis has become a tool in the investigation of complex geotechnical situations, such as the laterally loaded monopile. In this paper a 3D FEA is conducted as basis of an extraction of p-y curves, as a basis for an evaluation of the traditional curves. Two different methods are applied to create a list of data points used for the p-y curves: A force producing a similar response as seen in the ULS situation is applied stepwise; hereby creating the most realistic soil response. This method, however, does not generate sufficient data points around the rotation point of the pile. Therefore, also a forced horizontal displacement of the entire pile is applied, whereby displacements are created over the entire length of the pile. The response is extracted from the interface and the nearby soil elements respectively, as to investigate the influence this has on the computed curves. p-y curves are obtained near the rotation point by evaluation of soil response during a prescribed displacement but the response is not in clear agreement with the response during an applied load. Two different material models are applied. It is found that the applied material models have a significant influence on the stiffness of the evaluated p-y curves. The p-y curves evaluated by means of FEA are compared to the conventional p-y curve formulation which provides a much stiffer response. It is found that the best response is computed by implementing the Hardening Soil model and

Two-Stage Electricity Demand Modeling Using Machine Learning Algorithms

Directory of Open Access Journals (Sweden)

Krzysztof Gajowniczek

2017-10-01

Full Text Available Forecasting of electricity demand has become one of the most important areas of research in the electric power industry, as it is a critical component of cost-efficient power system management and planning. In this context, accurate and robust load forecasting is supposed to play a key role in reducing generation costs, and deals with the reliability of the power system. However, due to demand peaks in the power system, forecasts are inaccurate and prone to high numbers of errors. In this paper, our contributions comprise a proposed data-mining scheme for demand modeling through peak detection, as well as the use of this information to feed the forecasting system. For this purpose, we have taken a different approach from that of time series forecasting, representing it as a two-stage pattern recognition problem. We have developed a peak classification model followed by a forecasting model to estimate an aggregated demand volume. We have utilized a set of machine learning algorithms to benefit from both accurate detection of the peaks and precise forecasts, as applied to the Polish power system. The key finding is that the algorithms can detect 96.3% of electricity peaks (load value equal to or above the 99th percentile of the load distribution and deliver accurate forecasts, with mean absolute percentage error (MAPE of 3.10% and resistant mean absolute percentage error (r-MAPE of 2.70% for the 24 h forecasting horizon.

Demand Response Resource Quantification with Detailed Building Energy Models

Energy Technology Data Exchange (ETDEWEB)

Hale, Elaine; Horsey, Henry; Merket, Noel; Stoll, Brady; Nag, Ambarish

2017-04-03

Demand response is a broad suite of technologies that enables changes in electrical load operations in support of power system reliability and efficiency. Although demand response is not a new concept, there is new appetite for comprehensively evaluating its technical potential in the context of renewable energy integration. The complexity of demand response makes this task difficult -- we present new methods for capturing the heterogeneity of potential responses from buildings, their time-varying nature, and metrics such as thermal comfort that help quantify likely acceptability of specific demand response actions. Computed with an automated software framework, the methods are scalable.

A residual life prediction model based on the generalized σ -N curved surface

Directory of Open Access Journals (Sweden)

Zongwen AN

2016-06-01

Full Text Available In order to investigate change rule of the residual life of structure under random repeated load, firstly, starting from the statistic meaning of random repeated load, the joint probability density function of maximum stress and minimum stress is derived based on the characteristics of order statistic (maximum order statistic and minimum order statistic; then, based on the equation of generalized σ -N curved surface, considering the influence of load cycles number on fatigue life, a relationship among minimum stress, maximum stress and residual life, that is the σmin(n- σmax(n-Nr(n curved surface model, is established; finally, the validity of the proposed model is demonstrated by a practical case. The result shows that the proposed model can reflect the influence of maximum stress and minimum stress on residual life of structure under random repeated load, which can provide a theoretical basis for life prediction and reliability assessment of structure.

Daily Air Temperature and Electricity Load in Spain.

Science.gov (United States)

Valor, Enric; Meneu, Vicente; Caselles, Vicente

2001-08-01

Weather has a significant impact on different sectors of the economy. One of the most sensitive is the electricity market, because power demand is linked to several weather variables, mainly the air temperature. This work analyzes the relationship between electricity load and daily air temperature in Spain, using a population-weighted temperature index. The electricity demand shows a significant trend due to socioeconomic factors, in addition to daily and monthly seasonal effects that have been taken into account to isolate the weather influence on electricity load. The results indicate that the relationship is nonlinear, showing a `comfort interval' of ±3°C around 18°C and two saturation points beyond which the electricity load no longer increases. The analysis has also revealed that the sensitivity of electricity load to daily air temperature has increased along time, in a higher degree for summer than for winter, although the sensitivity in the cold season is always more significant than in the warm season. Two different temperature-derived variables that allow a better characterization of the observed relationship have been used: the heating and cooling degree-days. The regression of electricity data on them defines the heating and cooling demand functions, which show correlation coefficients of 0.79 and 0.87, and predicts electricity load with standard errors of estimate of ±4% and ±2%, respectively. The maximum elasticity of electricity demand is observed at 7 cooling degree-days and 9 heating degree-days, and the saturation points are reached at 11 cooling degree-days and 13 heating degree-days, respectively. These results are helpful in modeling electricity load behavior for predictive purposes.

Description of Concrete Creep under Time-Varying Stress Using Parallel Creep Curve

OpenAIRE

Park, Yeong-Seong; Lee, Yong-Hak; Lee, Youngwhan

2016-01-01

An incremental format of creep model was presented to take account of the development of concrete creep due to loading at different ages. The formulation was attained by introducing a horizontal parallel assumption of creep curves and combining it with the vertical parallel creep curve of the rate of creep method to remedy the disadvantage of the rate of creep method that significantly underestimates the amount of creep strain, regardless of its simple format. Two creep curves were combined b...

Data-Driven Optimization of Incentive-based Demand Response System with Uncertain Responses of Customers

Directory of Open Access Journals (Sweden)

Jimyung Kang

2017-10-01

Full Text Available Demand response is nowadays considered as another type of generator, beyond just a simple peak reduction mechanism. A demand response service provider (DRSP can, through its subcontracts with many energy customers, virtually generate electricity with actual load reduction. However, in this type of virtual generator, the amount of load reduction includes inevitable uncertainty, because it consists of a very large number of independent energy customers. While they may reduce energy today, they might not tomorrow. In this circumstance, a DSRP must choose a proper set of these uncertain customers to achieve the exact preferred amount of load curtailment. In this paper, the customer selection problem for a service provider that consists of uncertain responses of customers is defined and solved. The uncertainty of energy reduction is fully considered in the formulation with data-driven probability distribution modeling and stochastic programming technique. The proposed optimization method that utilizes only the observed load data provides a realistic and applicable solution to a demand response system. The performance of the proposed optimization is verified with real demand response event data in Korea, and the results show increased and stabilized performance from the service provider’s perspective.

Automated Dynamic Demand Response Implementation on a Micro-grid

Energy Technology Data Exchange (ETDEWEB)

Kuppannagari, Sanmukh R.; Kannan, Rajgopal; Chelmis, Charalampos; Prasanna, Viktor K.

2016-11-16

In this paper, we describe a system for real-time automated Dynamic and Sustainable Demand Response with sparse data consumption prediction implemented on the University of Southern California campus microgrid. Supply side approaches to resolving energy supply-load imbalance do not work at high levels of renewable energy penetration. Dynamic Demand Response (D²R) is a widely used demand-side technique to dynamically adjust electricity consumption during peak load periods. Our D²R system consists of accurate machine learning based energy consumption forecasting models that work with sparse data coupled with fast and sustainable load curtailment optimization algorithms that provide the ability to dynamically adapt to changing supply-load imbalances in near real-time. Our Sustainable DR (SDR) algorithms attempt to distribute customer curtailment evenly across sub-intervals during a DR event and avoid expensive demand peaks during a few sub-intervals. It also ensures that each customer is penalized fairly in order to achieve the targeted curtailment. We develop near linear-time constant-factor approximation algorithms along with Polynomial Time Approximation Schemes (PTAS) for SDR curtailment that minimizes the curtailment error defined as the difference between the target and achieved curtailment values. Our SDR curtailment problem is formulated as an Integer Linear Program that optimally matches customers to curtailment strategies during a DR event while also explicitly accounting for customer strategy switching overhead as a constraint. We demonstrate the results of our D²R system using real data from experiments performed on the USC smartgrid and show that 1) our prediction algorithms can very accurately predict energy consumption even with noisy or missing data and 2) our curtailment algorithms deliver DR with extremely low curtailment errors in the 0.01-0.05 kWh range.

Opportunities for Automated Demand Response in California Wastewater Treatment Facilities

Energy Technology Data Exchange (ETDEWEB)

Aghajanzadeh, Arian [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Wray, Craig [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); McKane, Aimee [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2015-08-30

Previous research over a period of six years has identified wastewater treatment facilities as good candidates for demand response (DR), automated demand response (Auto-­DR), and Energy Efficiency (EE) measures. This report summarizes that work, including the characteristics of wastewater treatment facilities, the nature of the wastewater stream, energy used and demand, as well as details of the wastewater treatment process. It also discusses control systems and automated demand response opportunities. Furthermore, this report summarizes the DR potential of three wastewater treatment facilities. In particular, Lawrence Berkeley National Laboratory (LBNL) has collected data at these facilities from control systems, submetered process equipment, utility electricity demand records, and governmental weather stations. The collected data were then used to generate a summary of wastewater power demand, factors affecting that demand, and demand response capabilities. These case studies show that facilities that have implemented energy efficiency measures and that have centralized control systems are well suited to shed or shift electrical loads in response to financial incentives, utility bill savings, and/or opportunities to enhance reliability of service. In summary, municipal wastewater treatment energy demand in California is large, and energy-­intensive equipment offers significant potential for automated demand response. In particular, large load reductions were achieved by targeting effluent pumps and centrifuges. One of the limiting factors to implementing demand response is the reaction of effluent turbidity to reduced aeration at an earlier stage of the process. Another limiting factor is that cogeneration capabilities of municipal facilities, including existing power purchase agreements and utility receptiveness to purchasing electricity from cogeneration facilities, limit a facility’s potential to participate in other DR activities.

On using the dynamic snap-through motion of MEMS initially curved microbeams for filtering applications

KAUST Repository

Ouakad, Hassen M.; Younis, Mohammad I.

2014-01-01

Numerical and experimental investigations of the dynamics of micromachined shallow arches (initially curved microbeams) and the possibility of using their dynamic snap-through motion for filtering purposes are presented. The considered MEMS arches are actuated by a DC electrostatic load along with an AC harmonic load. Their dynamics is examined numerically using a Galerkin-based reduced-order model when excited near both their first and third natural frequencies. Several simulation results are presented demonstrating interesting jumps and dynamic snap-through behavior of the MEMS arches and their attractive features for uses as band-pass filters, such as their sharp roll-off from pass-bands to stop-bands and their flat response. Experimental work is conducted to test arches realized of curved polysilicon microbeams when excited by DC and AC loads. Experimental data of the micromachined curved beams are shown for the softening and hardening behavior near the first and third natural frequencies, respectively, as well as dynamic snap-through motion. © 2013 Elsevier Ltd.

Reducing Demand Charges and Onsite Generation Variability Using Behind-the-Meter Energy Storage

Energy Technology Data Exchange (ETDEWEB)

Bhattarai, Bishnu P.; Myers, Kurt S.; Bush, Jason W.

2017-04-01

Electric utilities in the United States are increasingly employing demand charges and/or real-time pricing. This directive is bringing potential opportunities in deploying behindthe-meter energy storage (BMES) systems for various grid functionalities. This study quantifies techno-economic benefits of BMES in reducing demand charge and smoothing load/generation intermittencies, and determines how those benefits vary with onsite distributed photovoltaic. We proposed a two-stage control algorithm, whereby the first stage proactively determines costoptimal BMES configuration for reducing peak-demands and demand charges, and the second stage adaptively compensates intermittent generations and short load spikes that may otherwise increase the demand charges. The performance of the proposed algorithm is evaluated through a 24 hours time sweep simulation performed using data from smart microgrid testbed at Idaho National Laboratory (INL). The simulation results demonstrated that this research provides a simple but effective solution for peak shaving, demand charge reductions, and smoothing onsite PV variability.

Households under the impression of the energy turnaround. Development of electricity demand and load profiles; Die Haushalte im Zeichen der Energiewende. Entwicklung der Stromnachfrage und Lastprofile

Energy Technology Data Exchange (ETDEWEB)

Elsland, Rainer; Bossmann, Tobias; Gnann, Till; Wietschel, Martin [Fraunhofer-Institut fuer System- und Innovationsforschung (ISI), Karlsruhe (Germany); Hartel, Rupert; Fichtner, Wolf [Karlsruher Institut fuer Technologie (KIT), Karlsruhe (Germany). Inst. fuer Industriebetriebslehre und Industrielle Produktion (IIP)

2013-01-15

One of the central components of the energy turnaround is the improvement of energy efficiency. Households play a key role in this connection, not only due to their high potentials for saving energy and shifting loads, but also because of the growing importance of electricity as an energy carrier. This makes it interesting to explore how the continuing dissemination of efficient energy applications, electromobility and decentralised electricity production through photovoltaics will impact on load and electricity production profiles in the German household sector until the year 2040. The results show that with ambitious energy policy goals it will be possible to lower the electricity demand of households by 30%. However, this decrease could be more than undone by electromobility.

Smart Grid as advanced technology enabler of demand response

Energy Technology Data Exchange (ETDEWEB)

Gellings, C.W.; Samotyj, M. [Electric Power Research Institute (EPRI), Palo Alto, CA (United States)

2013-11-15

Numerous papers and articles presented worldwide at different conferences and meetings have already covered the goals, objectives, architecture, and business plans of Smart Grid. The number of electric utilities worldwide has followed up with demonstration and deployment efforts. Our initial assumptions and expectations of Smart Grid functionality have been confirmed. We have indicated that Smart Grid will fulfill the following goals: enhance customer service, improve operational efficiency, enhance demand response and load control, transform customer energy use behavior, and support new utility business models. For the purpose of this paper, we shall focus on which of those above-mentioned Smart Grid functionalities are going to facilitate the ever-growing need for enhanced demand response and load control.

On-demand Antimicrobial Treatment with Antibiotic-Loaded Porous Silicon Capped with a pH-Responsive Dual Plasma Polymer Barrier.

Science.gov (United States)

Vasani, Roshan B; Szili, Endre J; Rajeev, Gayathri; Voelcker, Nicolas H

2017-07-04

Chronic wounds are a major socio-economic problem. Bacterial infections in such wounds are a major contributor to lack of wound healing. An early indicator of wound infection is an increase in pH of the wound fluid. Herein, we describe the development of a pH-responsive drug delivery device that can potentially be used for wound decontamination in situ and on-demand in response to an increase in the pH of the wound environment. The device is based on a porous silicon film that provides a reservoir for encapsulation of an antibiotic within the pores. Loaded porous silicon is capped with dual plasma polymer layers of poly(1,7-octadiene) and poly(acrylic acid), which provide a pH-responsive barrier for on-demand release of the antibiotic. We demonstrate that release of the antibiotic is inhibited in aqueous buffer at pH 5, whereas the drug is released in a sustainable manner at pH 8. Importantly, the released drug was bacteriostatic against the Pseudomonas aeruginosa wound pathogen. In the future, incorporation of the delivery device into wound dressings could potentially be utilized for non-invasive decontamination of wounds. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Demand controlled ventilation for multi-family dwellings

DEFF Research Database (Denmark)

Mortensen, Dorthe Kragsig

for centrally balanced DCV systems with heat recovery. A design expected to fulfill this requirement was investigated in detail with regard to its electricity consumption by evaluating a control strategy that resets the static pressure set point at part load. The results showed that this control strategy can......The present thesis “Demand controlled ventilation for multi-family dwellings” constitutes the summary of a three year project period during which demand specification and system design of demand controlled ventilation for residential buildings were studied. Most standards and buildings codes...... can be reduced compared to a system with constant air flow. A literature study on indoor pollutants in homes, their sources and their impact on humans formed the basis for the demand specification. Emission of pollutants in residential buildings roughly fall into constantly emitted background sources...

Demand side management—A simulation of household behavior under variable prices

International Nuclear Information System (INIS)

Gottwalt, Sebastian; Ketter, Wolfgang; Block, Carsten; Collins, John; Weinhardt, Christof

2011-01-01

Within the next years, consumer households will be increasingly equipped with smart metering and intelligent appliances. These technologies are the basis for households to better monitor electricity consumption and to actively control loads in private homes. Demand side management (DSM) can be adopted to private households. We present a simulation model that generates household load profiles under flat tariffs and simulates changes in these profiles when households are equipped with smart appliances and face time-based electricity prices. We investigate the impact of smart appliances and variable prices on electricity bills of a household. We show that for households the savings from equipping them with smart appliances are moderate compared to the required investment. This finding is quite robust with respect to variation of tariff price spreads and to different types of appliance utilization patterns. Finally, our results indicate that electric utilities may face new demand peaks when day-ahead hourly prices are applied. However, a considerable amount of residential load is available for shifting, which is interesting for the utilities to balance demand and supply. - Highlights: ► Our model generates residential load profiles that are based on real world data. ► We simulate changes in load profiles when smart appliances and time-of-use tariffs are applied. ► The economic incentive for households to invest in smart appliances is low. ► Time-of-use tariffs create new, even higher peaks. ► Electric utilities have a large amount of the hourly load available for shifting.

Part-load performance of a high temperature Kalina cycle

International Nuclear Information System (INIS)

Modi, Anish; Andreasen, Jesper Graa; Kærn, Martin Ryhl; Haglind, Fredrik

2015-01-01

Highlights: • Detailed algorithm to solve high temperature Kalina cycle in part load. • A central receiver concentrating solar power plant with direct vapour generation considered as case study. • Part-load performance curves and fitted equations presented. - Abstract: The Kalina cycle has recently seen increased interest as an alternative to the conventional steam Rankine cycle. The cycle has been studied for use with both low and high temperature applications such as geothermal power plants, ocean thermal energy conversion, waste heat recovery, gas turbine bottoming cycle, and solar power plants. The high temperature cycle layouts are inherently more complex than the low temperature layouts due to the presence of a distillation-condensation subsystem, three pressure levels, and several heat exchangers. This paper presents a detailed approach to solve the Kalina cycle in part-load operating conditions for high temperature (a turbine inlet temperature of 500 °C) and high pressure (100 bar) applications. A central receiver concentrating solar power plant with direct vapour generation is considered as a case study where the part-load conditions are simulated by changing the solar heat input to the receiver. Compared with the steam Rankine cycle, the Kalina cycle has an additional degree of freedom in terms of the ammonia mass fraction which can be varied in order to maximize the part-load efficiency of the cycle. The results include the part-load curves for various turbine inlet ammonia mass fractions and the fitted equations for these curves.

Solving unit commitment and economic load dispatch problems ...

African Journals Online (AJOL)

Economic Load Dispatch (ELD) and Unit Commitment (UC) are very important applications to predict the optimized cost of load in a power system. UC determines working states for existing generating units under some operational constraints and then optimizing the operation cost for all running units w.r.t. load demand ...

Impact Analysis of Customized Feedback Interventions on Residential Electricity Load Consumption Behavior for Demand Response

Directory of Open Access Journals (Sweden)

Fei Wang

2018-03-01

Full Text Available Considering the limitations of traditional energy-saving policies, a kind of energy conservation method called the Information Feedback to Residential Electricity Load Customers, which could impact the demand response capacity, has increasingly received more attention. However, most of the current feedback programs provide the same feedback information to all customers regardless of their diverse characteristics, which may reduce the energy-saving effects or even backfire. This paper attempts to investigate how different types of customers may change their behaviors under a set of customized feedback. We conducted a field survey study in Qinhuangdao (QHD, China. First, we conducted semi-structured interviews to classify four groups of customers of different energy-saving awareness, energy-saving potential, and behavioral variability. Then, 156 QHD households were surveyed using scenarios to collect feedback of different scenarios. Social science theories were used to guide the discussion on the behavior changes as a result of different feedback strategies and reveal the reasons for customers’ behaviors. Using the Chi-Square test of independence, the variables that have strong correlations with the categories of residents are extracted to provide references for residents’ classification. Finally, the practical implications and needs for future research are discussed.

Demand side load management using a three step optimization methodology

NARCIS (Netherlands)

Bakker, Vincent; Bosman, M.G.C.; Molderink, Albert; Hurink, Johann L.; Smit, Gerardus Johannes Maria

2010-01-01

In order to keep a proper functional electricity grid and to prevent large investments in the current grid, the creation, transmission and consumption of electricity needs to be controlled and organized in a different way as done nowadays. Smart meters, distributed generation and -storage and demand

The effects of initial rise and axial loads on MEMS arches

KAUST Repository

Tella, Sherif Adekunle

2017-04-07

Arch microbeams have been utilized and proposed for many uses over the past few years due to their large tunability and bistability. However, recent experimental data have shown different mechanical behavior of arches when subjected to axial loads. This paper aims to investigate in depth the influence of the competing effects of initial rise and axial loads on the mechanical behavior of micromachined arches; mainly their static deflection and resonant frequencies. Based on analytical solutions, the static response and eigenvalue problems are analyzed for various values of initial rises and axial loads. Universal curves showing the variation of the first three resonance frequencies of the arch are generated for various values of initial rise under both tensile and compressive axial loads. This study shows that increasing the tensile or compressive axial loads for different values of initial rise may lead to either increase in the stiffness of the beam or initial decrease in the stiffness, which later increases as the axial load is increased depending on the dominant effect of the initial rise of the arch and the axial load. The obtained universal curves represent useful design tools to predict the tunability of arches under axial loads for various values of initial rises. The use of the universal curves is demonstrated with an experimental case study. Analytical formulation is developed to predict the point of minimum where the trend of the resonance frequency versus axial loads changes qualitatively due to the competing effects of axial loads and initial curvature.

Development of a Dynamic Biomechanical Model for Load Carriage: Phase III Part B: Characterization of Load Control During a Human Trials Circuit

National Research Council Canada - National Science Library

Stevenson, J. M; Good, J. A; Devenney, I. A; Morin, E. L; Reid, S. A; Bryant, J. T

2005-01-01

.... The goals of the study were to examine the relationships among aerobic demand, performance time and load as well as the relationships between posture, shoulder and lumbar reaction forces and load...

A novel microgrid demand-side management system for manufacturing facilities

Science.gov (United States)

Harper, Terance J.

Thirty-one percent of annual energy consumption in the United States occurs within the industrial sector, where manufacturing processes account for the largest amount of energy consumption and carbon emissions. For this reason, energy efficiency in manufacturing facilities is increasingly important for reducing operating costs and improving profits. Using microgrids to generate local sustainable power should reduce energy consumption from the main utility grid along with energy costs and carbon emissions. Also, microgrids have the potential to serve as reliable energy generators in international locations where the utility grid is often unstable. For this research, a manufacturing process that had approximately 20 kW of peak demand was matched with a solar photovoltaic array that had a peak output of approximately 3 KW. An innovative Demand-Side Management (DSM) strategy was developed to manage the process loads as part of this smart microgrid system. The DSM algorithm managed the intermittent nature of the microgrid and the instantaneous demand of the manufacturing process. The control algorithm required three input signals; one from the microgrid indicating the availability of renewable energy, another from the manufacturing process indicating energy use as a percent of peak production, and historical data for renewable sources and facility demand. Based on these inputs the algorithm had three modes of operation: normal (business as usual), curtailment (shutting off non-critical loads), and energy storage. The results show that a real-time management of a manufacturing process with a microgrid will reduce electrical consumption and peak demand. The renewable energy system for this research was rated to provide up to 13% of the total manufacturing capacity. With actively managing the process loads with the DSM program alone, electrical consumption from the utility grid was reduced by 17% on average. An additional 24% reduction was accomplished when the microgrid

String dynamics in curved space-time revisited

International Nuclear Information System (INIS)

Marrakchi, A.L.; Singh, L.P.

1989-09-01

The equations of motion of the general background of curved space-time, Einstein's equations, are derived simply by demanding the renormalized energy-momentum tensor of a bosonic string propagating in this background to be traceless. The energy-momentum tensor of such a string is then separable into a holomorphic and an antiholomorphic parts as a consequence of the conformal invariance of the theory regained at the quantum level. (author). 8 refs

Implementation of the Master Curve method in ProSACC

Energy Technology Data Exchange (ETDEWEB)

Feilitzen, Carl von; Sattari-Far, Iradj [Inspecta Technology AB, Stockholm (Sweden)

2012-03-15

Cleavage fracture toughness data display normally large amount of statistical scatter in the transition region. The cleavage toughness data in this region is specimen size-dependent, and should be treated statistically rather than deterministically. Master Curve methodology is a procedure for mechanical testing and statistical analysis of fracture toughness of ferritic steels in the transition region. The methodology accounts for temperature and size dependence of fracture toughness. Using the Master Curve methodology for evaluation of the fracture toughness in the transition region releases the overconservatism that has been observed in using the ASME-KIC curve. One main advantage of using the Master Curve methodology is possibility to use small Charpy-size specimens to determine fracture toughness. Detailed description of the Master Curve methodology is given by Sattari-Far and Wallin [2005). ProSACC is a suitable program in using for structural integrity assessments of components containing crack like defects and for defect tolerance analysis. The program gives possibilities to conduct assessments based on deterministic or probabilistic grounds. The method utilized in ProSACC is based on the R6-method developed at Nuclear Electric plc, Milne et al [1988]. The basic assumption in this method is that fracture in a cracked body can be described by two parameters Kr and Lr. The parameter Kr is the ratio between the stress intensity factor and the fracture toughness of the material. The parameter Lr is the ratio between applied load and the plastic limit load of the structure. The ProSACC assessment results are therefore highly dependent on the applied fracture toughness value in the assessment. In this work, the main options of the Master Curve methodology are implemented in the ProSACC program. Different options in evaluating Master Curve fracture toughness from standard fracture toughness testing data or impact testing data are considered. In addition, the

Implementation of the Master Curve method in ProSACC

International Nuclear Information System (INIS)

Feilitzen, Carl von; Sattari-Far, Iradj

2012-03-01

Cleavage fracture toughness data display normally large amount of statistical scatter in the transition region. The cleavage toughness data in this region is specimen size-dependent, and should be treated statistically rather than deterministically. Master Curve methodology is a procedure for mechanical testing and statistical analysis of fracture toughness of ferritic steels in the transition region. The methodology accounts for temperature and size dependence of fracture toughness. Using the Master Curve methodology for evaluation of the fracture toughness in the transition region releases the overconservatism that has been observed in using the ASME-KIC curve. One main advantage of using the Master Curve methodology is possibility to use small Charpy-size specimens to determine fracture toughness. Detailed description of the Master Curve methodology is given by Sattari-Far and Wallin [2005). ProSACC is a suitable program in using for structural integrity assessments of components containing crack like defects and for defect tolerance analysis. The program gives possibilities to conduct assessments based on deterministic or probabilistic grounds. The method utilized in ProSACC is based on the R6-method developed at Nuclear Electric plc, Milne et al [1988]. The basic assumption in this method is that fracture in a cracked body can be described by two parameters Kr and Lr. The parameter Kr is the ratio between the stress intensity factor and the fracture toughness of the material. The parameter Lr is the ratio between applied load and the plastic limit load of the structure. The ProSACC assessment results are therefore highly dependent on the applied fracture toughness value in the assessment. In this work, the main options of the Master Curve methodology are implemented in the ProSACC program. Different options in evaluating Master Curve fracture toughness from standard fracture toughness testing data or impact testing data are considered. In addition, the

Load management in electrical networks. Objectives, methods, prospects

International Nuclear Information System (INIS)

Gabioud, D.

2008-01-01

This illustrated article takes up the problems related to the variation of the load in electricity networks. How to handle the peak load? Different solutions in the energy demand management are discussed. Method based on the price, method based on the reduction of the load by electric utilities. Information systems are presented which gives the consumer the needed data to participate in the local load management.

Impact of Scheduling Flexibility on Demand Profile Flatness and User Inconvenience in Residential Smart Grid System

Directory of Open Access Journals (Sweden)

Naveed Ul Hassan

2013-12-01

Full Text Available The objective of this paper is to study the impact of scheduling flexibility on both demand profile flatness and user inconvenience in residential smart grid systems. Temporal variations in energy consumption by end users result in peaks and troughs in the aggregated demand profile. In a residential smart grid, some of these peaks and troughs can be eliminated through appropriate load balancing algorithms. However, load balancing requires user participation by allowing the grid to re-schedule some of their loads. In general, more scheduling flexibility can result in more demand profile flatness, however the resulting inconvenience to users would also increase. In this paper, our objective is to help the grid determine an appropriate amount of scheduling flexibility that it should demand from users, based on which, proper incentives can be designed. We consider three different types of scheduling flexibility (delay, advance scheduling and flexible re-scheduling in flexible loads and develop both optimal and sub-optimal scheduling algorithms. We discuss their implementation in centralized and distributed manners. We also identify the existence of a saturation point. Beyond this saturation point, any increase in scheduling flexibility does not significantly affect the flatness of the demand profile while user inconvenience continues to increase. Moreover, full participation of all the households is not required since increasing user participation only marginally increases demand profile flatness.

Water advisory demand evaluation and resource toolkit

OpenAIRE

Paluszczyszyn, D.; Illya, S.; Goodyer, E.; Kubrycht, T.; Ambler, M.

2016-01-01

Cities are living organisms, 24h / 7day, with demands on resources and outputs. Water is a key resource whose management has not kept pace with modern urban life. Demand for clean water and loads on waste water no longer fit diurnal patterns; and they are impacted by events that are outside the normal range of parameters that are taken account of in water management. This feasibility study will determine how the application of computational intelligence can be used to analyse a mix of dat...

Cognitive Load of Learner Control: Extraneous or Germane Load?

Directory of Open Access Journals (Sweden)

Mieke Vandewaetere

2013-01-01

Full Text Available Computer-based learning environments become more tailored when learners can exert control over one or more parts of the learning process. Learner control (LC demands additional efforts of learners because, in addition to learning, they also have to monitor that learning. As a consequence, LC may cause additional cognitive load and even cognitive overload. The central question in this study is what type of cognitive load is induced by LC and whether the experienced load is related to learning outcomes. For this study, half of the students had control over task selection, while the other half had not. Within each condition, students were assigned to a single treatment, with the primary task to solely focus on the learning content, and a dual treatment, comprising a primary task and a secondary task. The results indicate that LC did not impose higher cognitive load as measured by secondary task scores and mental effort ratings.

Experimental analysis of flexibility change with different levels of power reduction by demand response activation on thermostat controlled loads

DEFF Research Database (Denmark)

Lakshmanan, Venkatachalam; Marinelli, Mattia; Hu, Junjie

2017-01-01

This paper studies the flexibility available with thermostatically controlled loads (TCLs) to provide power system services by demand response (DR) activation. Although the DR activation on TCLs can provide power system ancillary services, it is important to know how long such services can...... be provided for when different levels of power reduction are imposed. The flexibility change with different levels of power reduction is tested experimentally with domestic fridges used by real customers with unknown user interaction. The investigation quantifies the flexibility of household fridges...... and the impact of DR activation in terms of deviation in the average temperature. The maximum possible power reduction with the cluster of refrigerators is 67% and the available flexibility with the cluster of refrigerators is 10%. The resulting deviation in the average temperature is 14%....

Energy-environment policy goals and instruments and electricity demand response. A framework for the analysis

International Nuclear Information System (INIS)

Rio, Pablo del; Hernandez, F.

2004-01-01

The environment and energy realms have traditionally been two major focus of attention of EU and Member State (MS) policy. This attention has intensified in recent years as a response to, both, internal and external events and strategies (i.e., the Kyoto Protocol). In this context, the EU and its MS have set ambitious goals in the environmental and energy contexts and are already implementing packages of policies and measures. Both policies interact. Although there might be conflicts between both, there are also mutually reinforcing effects with significant policy implications. Actually, as stated in the Amsterdam Treaty, environmental protection is one of the major goals of energy policy (together with 'security of supply' and 'competitive energy systems'). On the other hand, the energy sector is instrumental in the success of environmental policy. In this context, a wide array of measures are currently being implemented in the EU and its MS which have a more or less direct impact on the electricity market. Particularly, Demand Side Management (DSM) activities, promotion of electricity from renewable energy sources (RES-E) and measures aimed at the mitigation of Greenhouse Gas (GHG) emissions are arguably three major instruments which have the potential to contribute to energy and environmental goals. The effectiveness and impact of there measures depends to a large extent on the demand response in the electricity market. Some of there measures affect the electricity demand curve, while others do not have a direct impact on the demand curve but affect the quantity of electricity demand by displacing the electricity supply curve. In turn, the effectiveness of energy and environmental policies may be different when electricity demand response varies (i.e., different elasticity demand). This paper entails an initial effort to provide a theoretical framework for the analysis of the interactions between electricity demand response and the above mentioned energy

Renewable generation versus demand-side management. A comparison for the Spanish market

International Nuclear Information System (INIS)

Roldán Fernández, Juan Manuel; Burgos Payán, Manuel; Riquelme Santos, Jesús Manuel; Trigo García, Ángel Luis

2016-01-01

Conventionally the required instantaneous balance generation-load is achieved by adjusting production to fit variable consumer demand. Nowadays, a significant and increasing segment of generation is renewable. But renewable production cannot be scheduled on request since its generation is dependent on nature (wind, sun, …). In this context, demand-side management (DSM) would help since it would be advisable for part of the flexibility to be provided by the demand. The integration of renewable production and demand-side management (DSM), are compared in this work for Spain throughout 2008–2014. First a qualitative model, based on the linearization of the wholesale market, is employed to explore some hypotheses. A set of scenarios are then examined to quantify the main effects on the market. The results show that DSM exhibits the best performance in terms of economic efficiency and environmental sustainability, as well as for the reduction of load peaks and losses in the system, what suggests the convenience of promoting plans for the replacement of equipment with other more efficient as well as the implementation of real-time tariffs. - Highlights: •The impact of the integration of renewable production versus DSM has been compared. •Merit-order effect related to energy efficiency and to load-shifting is identified. •Large industries achieve energy efficiency with less CAPEX than renewable generation. •Load-shifting cycle yields a reduction of the traded energy and the economic volume.

Dose and elasticity of demand for self-administered cocaine in rats.

Science.gov (United States)

Kearns, David N; Silberberg, Alan

2016-04-01

The present experiment tested whether the elasticity of demand for self-administered cocaine in rats is dose-dependent. Subjects lever pressed for three different doses of intravenous cocaine - 0.11, 0.33, and 1.0 mg/kg/infusion - on a demand procedure where the number of lever presses required per infusion increased within a session. The main finding was that demand for the 0.11 mg/kg dose was more elastic than it was for the two larger doses. There was no difference in demand elasticity between the 0.33 and 1.0 mg/kg doses. These results parallel findings previously reported in monkeys. The present study also demonstrated that a within-session procedure can be used to generate reliable demand curves.

Loading-unloading pressure-volume curves for rocks

International Nuclear Information System (INIS)

Stephens, D.R.; Lilley, E.M.

1970-01-01

The stress-strain codes (SOC and TENSOR) used to calculate phenomenology of nuclear explosion for the Plowshare Program require inter alia the pressure-volume relationships of the earth media. In this paper we describe a rapid and accurate method to obtain pressure-volume data to 40 kb at 25 deg. C for rocks. These experimental results may also be related to the in situ elastic properties of the rock and to other laboratory measurement of properties, such as ultrasonic experiments with pressure and Hugoniot determinations. Qualitative features of the pressure-volume curves can be related to the initial porosity of the rock. A porous rock is usually quite compressible at low pressures. If the porosity is in the form of narrow cracks, the cracks are closed at a pressure of about 3 to 6 kb, after which the rock is much less compressible. If the porosity is in the form of spherical pores, it is not necessarily removed even at pressures of 40 kb, depending on the strength of the rock, and the compressibility is higher at all pressures than for a similar rock containing no porosity. Data for water-saturated samples show the phase transformation due to free water at about 10 and 22 kb. However, the presence of 'nonliquid' water, which is loosely contained within the lattice of clay or zeolitic minerals or adsorbed on particle surfaces, is also observed. (author)

Loading-unloading pressure-volume curves for rocks

Energy Technology Data Exchange (ETDEWEB)

Stephens, D R; Lilley, E M [Lawrence Radiation Laboratory, University of California, Livermore, CA (United States)

1970-05-01

The stress-strain codes (SOC and TENSOR) used to calculate phenomenology of nuclear explosion for the Plowshare Program require inter alia the pressure-volume relationships of the earth media. In this paper we describe a rapid and accurate method to obtain pressure-volume data to 40 kb at 25 deg. C for rocks. These experimental results may also be related to the in situ elastic properties of the rock and to other laboratory measurement of properties, such as ultrasonic experiments with pressure and Hugoniot determinations. Qualitative features of the pressure-volume curves can be related to the initial porosity of the rock. A porous rock is usually quite compressible at low pressures. If the porosity is in the form of narrow cracks, the cracks are closed at a pressure of about 3 to 6 kb, after which the rock is much less compressible. If the porosity is in the form of spherical pores, it is not necessarily removed even at pressures of 40 kb, depending on the strength of the rock, and the compressibility is higher at all pressures than for a similar rock containing no porosity. Data for water-saturated samples show the phase transformation due to free water at about 10 and 22 kb. However, the presence of 'nonliquid' water, which is loosely contained within the lattice of clay or zeolitic minerals or adsorbed on particle surfaces, is also observed. (author)

A fuzzy inference model for short-term load forecasting

International Nuclear Information System (INIS)

Mamlook, Rustum; Badran, Omar; Abdulhadi, Emad

2009-01-01

This paper is concerned with the short-term load forecasting (STLF) in power system operations. It provides load prediction for generation scheduling and unit commitment decisions, and therefore precise load forecasting plays an important role in reducing the generation cost and the spinning reserve capacity. Short-term electricity demand forecasting (i.e., the prediction of hourly loads (demand)) is one of the most important tools by which an electric utility/company plans, dispatches the loading of generating units in order to meet system demand. The accuracy of the dispatching system, which is derived from the accuracy of the forecasting algorithm used, will determine the economics of the operation of the power system. The inaccuracy or large error in the forecast simply means that load matching is not optimized and consequently the generation and transmission systems are not being operated in an efficient manner. In the present study, a proposed methodology has been introduced to decrease the forecasted error and the processing time by using fuzzy logic controller on an hourly base. Therefore, it predicts the effect of different conditional parameters (i.e., weather, time, historical data, and random disturbances) on load forecasting in terms of fuzzy sets during the generation process. These parameters are chosen with respect to their priority and importance. The forecasted values obtained by fuzzy method were compared with the conventionally forecasted ones. The results showed that the STLF of the fuzzy implementation have more accuracy and better outcomes

Modeling Framework and Validation of a Smart Grid and Demand Response System for Wind Power Integration

Energy Technology Data Exchange (ETDEWEB)

Broeer, Torsten; Fuller, Jason C.; Tuffner, Francis K.; Chassin, David P.; Djilali, Ned

2014-01-31

Electricity generation from wind power and other renewable energy sources is increasing, and their variability introduces new challenges to the power system. The emergence of smart grid technologies in recent years has seen a paradigm shift in redefining the electrical system of the future, in which controlled response of the demand side is used to balance fluctuations and intermittencies from the generation side. This paper presents a modeling framework for an integrated electricity system where loads become an additional resource. The agent-based model represents a smart grid power system integrating generators, transmission, distribution, loads and market. The model incorporates generator and load controllers, allowing suppliers and demanders to bid into a Real-Time Pricing (RTP) electricity market. The modeling framework is applied to represent a physical demonstration project conducted on the Olympic Peninsula, Washington, USA, and validation simulations are performed using actual dynamic data. Wind power is then introduced into the power generation mix illustrating the potential of demand response to mitigate the impact of wind power variability, primarily through thermostatically controlled loads. The results also indicate that effective implementation of Demand Response (DR) to assist integration of variable renewable energy resources requires a diversity of loads to ensure functionality of the overall system.

Including dynamic CO2 intensity with demand response

International Nuclear Information System (INIS)

Stoll, Pia; Brandt, Nils; Nordström, Lars

2014-01-01

Hourly demand response tariffs with the intention of reducing or shifting loads during peak demand hours are being intensively discussed among policy-makers, researchers and executives of future electricity systems. Demand response rates have still low customer acceptance, apparently because the consumption habits requires stronger incentive to change than any proposed financial incentive. An hourly CO 2 intensity signal could give customers an extra environmental motivation to shift or reduce loads during peak hours, as it would enable co-optimisation of electricity consumption costs and carbon emissions reductions. In this study, we calculated the hourly dynamic CO 2 signal and applied the calculation to hourly electricity market data in Great Britain, Ontario and Sweden. This provided a novel understanding of the relationships between hourly electricity generation mix composition, electricity price and electricity mix CO 2 intensity. Load shifts from high-price hours resulted in carbon emission reductions for electricity generation mixes where price and CO 2 intensity were positively correlated. The reduction can be further improved if the shift is optimised using both price and CO 2 intensity. The analysis also indicated that an hourly CO 2 intensity signal can help avoid carbon emissions increases for mixes with a negative correlation between electricity price and CO 2 intensity. - Highlights: • We present a formula for calculating hybrid dynamic CO 2 intensity of electricity generation mixes. • We apply the dynamic CO 2 Intensity on hourly electricity market prices and generation units for Great Britain, Ontario and Sweden. • We calculate the spearman correlation between hourly electricity market price and dynamic CO 2 intensity for Great Britain, Ontario and Sweden. • We calculate carbon footprint of shifting 1 kWh load daily from on-peak hours to off-peak hours using the dynamic CO 2 intensity. • We conclude that using dynamic CO 2 intensity for

Data-driven Demand Response Characterization and Quantification

DEFF Research Database (Denmark)

Le Ray, Guillaume; Pinson, Pierre; Larsen, Emil Mahler

2017-01-01

Analysis of load behavior in demand response (DR) schemes is important to evaluate the performance of participants. Very few real-world experiments have been carried out and quantification and characterization of the response is a difficult task. Nevertheless it will be a necessary tool for portf...

Distributed Variable Droop Curve Control Strategies in Smart Microgrid

Directory of Open Access Journals (Sweden)

Changhong Deng

2017-12-01

Full Text Available In micro grid (MG, active/reactive power sharing for all dis-patchable units is an important issue. To meet fluctuating loads’ active and reactive power demands, the units generally adopt primary P-f and Q-U droop control methods. However, at different state of charge (SOC values, the capability of Lead Acid Battery Bank (LABB based units to take loads varies in a large range; active power should not be shared according to the units P capacities in a constant ratio. Besides, influenced by the output and line impedance between units, reactive power is not able to be shared in proportion to the units Q capacities. Another problem, after MG power balance requirement is satisfied, frequency and voltage are deviating from their rated values thus power quality is reduced. This paper presents a new smart MG which is based on the multi agent system. To solve the problems mentioned above, P-f and Q-U droop curves are adjusted dynamically and autonomously in local agents. To improve the power quality, secondary restoration function is realized in a decentralized way, the computation tasks are assigned to local, the computation capability and communication reliability requirements for central PC are low, and operation reliability is high. Simulation results back the proposed methods.

A bi-level stochastic scheduling optimization model for a virtual power plant connected to a wind–photovoltaic–energy storage system considering the uncertainty and demand response

International Nuclear Information System (INIS)

Ju, Liwei; Tan, Zhongfu; Yuan, Jinyun; Tan, Qingkun; Li, Huanhuan; Dong, Fugui

2016-01-01

replace CGT to provide backup service for the WPP and PV, to smooth the VPP output curve and to improve the WPP and PV grid connection by its charging–discharging characteristics. Meanwhile, IBDR and PBDR could smooth the load curve to the maximum extent, link the generation side with the demand side to minimize abandoned power value and reach the optimum benefit of VPP operation.

Fatigue life of bovine meniscus under longitudinal and transverse tensile loading.

Science.gov (United States)

Creechley, Jaremy J; Krentz, Madison E; Lujan, Trevor J

2017-05-01

The knee meniscus is composed of a fibrous extracellular matrix that is subjected to large and repeated loads. Consequently, the meniscus is frequently torn, and a potential mechanism for failure is fatigue. The objective of this study was to measure the fatigue life of bovine meniscus when applying cyclic tensile loads either longitudinal or transverse to the principal fiber direction. Fatigue experiments consisted of cyclic loads to 60%, 70%, 80% or 90% of the predicted ultimate tensile strength until failure occurred or 20,000 cycles was reached. The fatigue data in each group was fit with a Weibull distribution to generate plots of stress level vs. cycles to failure (S-N curve). Results showed that loading transverse to the principal fiber direction gave a two-fold increase in failure strain, a three-fold increase in creep, and a nearly four-fold increase in cycles to failure (not significant), compared to loading longitudinal to the principal fiber direction. The S-N curves had strong negative correlations between the stress level and the mean cycles to failure for both loading directions, where the slope of the transverse S-N curve was 11% less than the longitudinal S-N curve (longitudinal: S=108-5.9ln(N); transverse: S=112-5.2ln(N)). Collectively, these results suggest that the non-fibrillar matrix is more resistant to fatigue failure than the collagen fibers. Results from this study are relevant to understanding the etiology of atraumatic radial and horizontal meniscal tears, and can be utilized by research groups that are working to develop meniscus implants with fatigue properties that mimic healthy tissue. Copyright © 2017 Elsevier Ltd. All rights reserved.

Short term load forecasting of anomalous load using hybrid soft computing methods

Science.gov (United States)

Rasyid, S. A.; Abdullah, A. G.; Mulyadi, Y.

2016-04-01

Load forecast accuracy will have an impact on the generation cost is more economical. The use of electrical energy by consumers on holiday, show the tendency of the load patterns are not identical, it is different from the pattern of the load on a normal day. It is then defined as a anomalous load. In this paper, the method of hybrid ANN-Particle Swarm proposed to improve the accuracy of anomalous load forecasting that often occur on holidays. The proposed methodology has been used to forecast the half-hourly electricity demand for power systems in the Indonesia National Electricity Market in West Java region. Experiments were conducted by testing various of learning rate and learning data input. Performance of this methodology will be validated with real data from the national of electricity company. The result of observations show that the proposed formula is very effective to short-term load forecasting in the case of anomalous load. Hybrid ANN-Swarm Particle relatively simple and easy as a analysis tool by engineers.

Improved capacitive melting curve measurements

International Nuclear Information System (INIS)

Sebedash, Alexander; Tuoriniemi, Juha; Pentti, Elias; Salmela, Anssi

2009-01-01

Sensitivity of the capacitive method for determining the melting pressure of helium can be enhanced by loading the empty side of the capacitor with helium at a pressure nearly equal to that desired to be measured and by using a relatively thin and flexible membrane in between. This way one can achieve a nanobar resolution at the level of 30 bar, which is two orders of magnitude better than that of the best gauges with vacuum reference. This extends the applicability of melting curve thermometry to lower temperatures and would allow detecting tiny anomalies in the melting pressure, which must be associated with any phenomena contributing to the entropy of the liquid or solid phases. We demonstrated this principle in measurements of the crystallization pressure of isotopic helium mixtures at millikelvin temperatures by using partly solid pure 4 He as the reference substance providing the best possible universal reference pressure. The achieved sensitivity was good enough for melting curve thermometry on mixtures down to 100 μK. Similar system can be used on pure isotopes by virtue of a blocked capillary giving a stable reference condition with liquid slightly below the melting pressure in the reference volume. This was tested with pure 4 He at temperatures 0.08-0.3 K. To avoid spurious heating effects, one must carefully choose and arrange any dielectric materials close to the active capacitor. We observed some 100 pW loading at moderate excitation voltages.

Effects of Demand Response on Retail and Wholesale Power Markets

Energy Technology Data Exchange (ETDEWEB)

Chassin, David P.; Kalsi, Karanjit

2012-07-26

Demand response has grown to be a part of the repertoire of resources used by utilities to manage the balance between generation and load. In recent years, advances in communications and control technology have enabled utilities to consider continuously controlling demand response to meet generation, rather than the other way around. This paper discusses the economic applications of a general method for load resource analysis that parallels the approach used to analyze generation resources and uses the method to examine the results of the US Department of Energy’s Olympic Peninsula Demonstration Testbed. A market-based closed-loop system of controllable assets is discussed with necessary and sufficient conditions on system controllability, observability and stability derived.

A residual life prediction model based on the generalized σ -N curved surface

OpenAIRE

Zongwen AN; Xuezong BAI; Jianxiong GAO

2016-01-01

In order to investigate change rule of the residual life of structure under random repeated load, firstly, starting from the statistic meaning of random repeated load, the joint probability density function of maximum stress and minimum stress is derived based on the characteristics of order statistic (maximum order statistic and minimum order statistic); then, based on the equation of generalized σ -N curved surface, considering the influence of load cycles number on fatigue life, a relation...

Short term load forecasting using neuro-fuzzy networks

Energy Technology Data Exchange (ETDEWEB)

Hoffman, M.; Hassan, A. [South Dakota School of Mines and Technology, Rapid City, SD (United States); Martinez, D. [Black Hills Power and Light, Rapid City, SD (United States)

2005-07-01

Details of a neuro-fuzzy network-based short term load forecasting system for power utilities were presented. The fuzzy logic controller was used to fuzzify inputs representing historical temperature and load curves. The fuzzified inputs were then used to develop the fuzzy rules matrix. Output membership function values were determined by evaluating the fuzzified inputs with the fuzzy rules. Output membership function values were used as inputs for the neural network portion of the system. The training process used a back propagation gradient descent algorithm to adjust the weight values of the neural network in order to reduce the error between the neural network output and the desired output. The neural network was then used to predict future load values. Sample data were taken from a local power company's daily load curve to validate the system. A 10 per cent forecast error was introduced in the temperature values to determine the effect on load prediction. Results of the study suggest that the combined use of fuzzy logic and neural networks provide greater accuracy than studies where either approach is used alone. 6 refs., 6 figs.

Using Microsensor Technology to Quantify Match Demands in Collegiate Women's Volleyball.

Science.gov (United States)

Vlantes, Travis G; Readdy, Tucker

2017-12-01

Vlantes, TG and Readdy, T. Using microsensor technology to quantify match demands in collegiate women's volleyball. J Strength Cond Res 31(12): 3266-3278, 2017-The purpose of this study was to quantify internal and external load demands of women's NCAA Division I collegiate volleyball competitions using microsensor technology and session rating of perceived exertion (S-RPE). Eleven collegiate volleyball players wore microsensor technology (Optimeye S5; Catapult Sports, Chicago, IL, USA) during 15 matches played throughout the 2016 season. Parameters examined include player load (PL), high impact PL, percentage of HI PL, explosive efforts (EEs), and jumps. Session rating of perceived exertion was collected 20 minutes postmatch using a modified Borg scale. The relationship between internal and external load was explored, comparing S-RPE data with the microsensor metrics (PL, HI PL, % HI PL, EEs, and jumps). The setter had the greatest mean PL and highest number of jumps of all positions in a 5-1 system, playing all 6 rotations. Playing 4 sets yielded a mean PL increase of 25.1% over 3 sets, whereas playing 5 sets showed a 31.0% increase in PL. A multivariate analysis of variance revealed significant differences (p < 0.01) across all position groups when examining % HI PL and jumps. Cohen's d analysis revealed large (≥0.8) effect sizes for these differences. Defensive specialists recorded the greatest mean S-RPE values over all 15 matches (886 ± 384.6). Establishing positional load demands allows coaches, trainers, and strength and conditioning professionals to implement training programs for position-specific demands, creating consistent peak performance, and reducing injury risk.

Demand response in a market environment

DEFF Research Database (Denmark)

Larsen, Emil Mahler

This thesis addresses the design, deployment and benefits of demand response in a market environment. Demand response is consumption that can be controlled by an external stimulus in the power system. Flexible consumption is a useful tool for absorbing volatile power from renewable sources like...... this simulation, real power system data from the Danish island of Bornholm is introduced and methods to quantify an aggregated load is developed. These methods can be used for real-time operation and to support investment decisions. More specifically, they can be used to forecast the response to electricity...... pricing and to classify different types of customers. The proposed models are then embedded into new fiveminute electricity markets for system balancing and local congestion management. New market tools for exploiting and maintaining a degree of control over demand are developed, and the value of DR using...

Evaluation of team lifting on work demands, workload and workers' evaluation: an observational field study.

Science.gov (United States)

Visser, Steven; van der Molen, Henk F; Kuijer, P Paul F M; Hoozemans, Marco J M; Frings-Dresen, Monique H W

2014-11-01

The objective of this study was to assess differences in work demands, energetic workload and workers' discomfort and physical effort in two regularly observable workdays in ironwork; one where loads up to 50kg were handled with two persons manually (T50) and one where loads up to 100kg were handled manually with four persons (T100). Differences between these typical workdays were assessed with an observational within-subject field study of 10 ironworkers. No significant differences were found for work demands, energetic workload or discomfort between T50 and T100 workdays. During team lifts, load mass exceeded 25kg per person in 57% (T50 workday) and 68% (T100 workday) of the lifts. Seven ironworkers rated team lifting with two persons as less physically demanding compared with lifting with four persons. When loads heavier than 25kg are lifted manually with a team, regulations of the maximum mass weight are frequently violated. Loads heavier than 25kg are frequently lifted during concrete reinforcement work and should be lifted by a team of persons. However, the field study showed that loads above 25kg are most of the time not lifted with the appropriate number of workers. Therefore, loads heavier than 25kg should be lifted mechanically. Copyright © 2014 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Modeling of Triangular Lattice Space Structures with Curved Battens

Science.gov (United States)

Chen, Tzikang; Wang, John T.

2005-01-01

Techniques for simulating an assembly process of lattice structures with curved battens were developed. The shape of the curved battens, the tension in the diagonals, and the compression in the battens were predicted for the assembled model. To be able to perform the assembly simulation, a cable-pulley element was implemented, and geometrically nonlinear finite element analyses were performed. Three types of finite element models were created from assembled lattice structures for studying the effects of design and modeling variations on the load carrying capability. Discrepancies in the predictions from these models were discussed. The effects of diagonal constraint failure were also studied.

Demand-side management and demand response in the Ontario energy sectors

International Nuclear Information System (INIS)

2003-01-01

In June 2003, the Ontario Energy Board was asked by the Minister of Energy to identify and review options for the delivery of demand-side management (DSM) and demand response (DR) activities within the electricity sector, by consulting with stakeholders. The role of local distribution company (distributor) in such activities was also to be determined. The objective was to balance implementation costs with the benefits to consumers and the entire system. The preliminary research and ideas were presented in this discussion paper. Definitions of both DSM and DR were provided, followed by an overview of economic theory and competitive markets. The framework for discussion was presented, along with a list of issues and other considerations. A spectrum of potential approaches to a DSM and DR framework was included and jurisdictional examples provided. A brief overview of the concept of load aggregation was presented and the next steps for consultations were outlined. 30 refs., 7 tabs

Preclinical endoscopic training using a part-task simulator: learning curve assessment and determination of threshold score for advancement to clinical endoscopy.

Science.gov (United States)

Jirapinyo, Pichamol; Abidi, Wasif M; Aihara, Hiroyuki; Zaki, Theodore; Tsay, Cynthia; Imaeda, Avlin B; Thompson, Christopher C

2017-10-01

Preclinical simulator training has the potential to decrease endoscopic procedure time and patient discomfort. This study aims to characterize the learning curve of endoscopic novices in a part-task simulator and propose a threshold score for advancement to initial clinical cases. Twenty novices with no prior endoscopic experience underwent repeated endoscopic simulator sessions using the part-task simulator. Simulator scores were collected; their inverse was averaged and fit to an exponential curve. The incremental improvement after each session was calculated. Plateau was defined as the session after which incremental improvement in simulator score model was less than 5%. Additionally, all participants filled out questionnaires regarding simulator experience after sessions 1, 5, 10, 15, and 20. A visual analog scale and NASA task load index were used to assess levels of comfort and demand. Twenty novices underwent 400 simulator sessions. Mean simulator scores at sessions 1, 5, 10, 15, and 20 were 78.5 ± 5.95, 176.5 ± 17.7, 275.55 ± 23.56, 347 ± 26.49, and 441.11 ± 38.14. The best fit exponential model was [time/score] = 26.1 × [session #] -0.615 ; r 2  = 0.99. This corresponded to an incremental improvement in score of 35% after the first session, 22% after the second, 16% after the third and so on. Incremental improvement dropped below 5% after the 12th session corresponding to the predicted score of 265. Simulator training was related to higher comfort maneuvering an endoscope and increased readiness for supervised clinical endoscopy, both plateauing between sessions 10 and 15. Mental demand, physical demand, and frustration levels decreased with increased simulator training. Preclinical training using an endoscopic part-task simulator appears to increase comfort level and decrease mental and physical demand associated with endoscopy. Based on a rigorous model, we recommend that novices complete a minimum of 12 training

Load management: Model-based control of aggregate power for populations of thermostatically controlled loads

International Nuclear Information System (INIS)

Perfumo, Cristian; Kofman, Ernesto; Braslavsky, Julio H.; Ward, John K.

2012-01-01

Highlights: ► Characterisation of power response of a population of air conditioners. ► Implementation of demand side management on a group of air conditioners. ► Design of a controller for the power output of a group of air conditioners. ► Quantification of comfort impact of demand side management. - Abstract: Large groups of electrical loads can be controlled as a single entity to reduce their aggregate power demand in the electricity network. This approach, known as load management (LM) or demand response, offers an alternative to the traditional paradigm in the electricity market, where matching supply and demand is achieved solely by regulating how much generation is dispatched. Thermostatically controlled loads (TCLs), such as air conditioners (ACs) and fridges, are particularly suitable for LM, which can be implemented using feedback control techniques to regulate their aggregate power. To achieve high performance, such feedback control techniques require an accurate mathematical model of the TCL aggregate dynamics. Although such models have been developed, they appear too complex to be effectively used in control design. In this paper we develop a mathematical model aimed at the design of a model-based feedback control strategy. The proposed model analytically characterises the aggregate power response of a population of ACs to a simultaneous step change in temperature set points. Based on this model, we then derive, and completely parametrise in terms of the ACs ensemble properties, a reduced-order mathematical model to design an internal-model controller that regulates aggregate power by broadcasting temperature set-point offset changes. The proposed controller achieves high LM performance provided the ACs are equipped with high resolution thermostats. With coarser resolution thermostats, which are typical in present commercial and residential ACs, performance deteriorates significantly. This limitation is overcome by subdividing the population

Load management through agent based coordination of flexible electricity consumers

DEFF Research Database (Denmark)

Clausen, Anders; Demazeau, Yves; Jørgensen, Bo Nørregaard

2015-01-01

Demand Response (DR) offers a cost-effective and carbonfriendly way of performing load balancing. DR describes a change in the electricity consumption of flexible consumers in response to the supply situation. In DR, flexible consumers may perform their own load balancing through load management...

Influence of Shading on Cooling Energy Demand

Science.gov (United States)

Rabczak, Sławomir; Bukowska, Maria; Proszak-Miąsik, Danuta; Nowak, Krzysztof

2017-10-01

The article presents an analysis of the building cooling load taking into account the variability of the factors affecting the size of the heat gains. In order to minimize the demand for cooling, the effect of shading elements installed on the outside on the windows and its effect on size of the cooling capacity of air conditioning system for the building has been estimated. Multivariate building cooling load calculations to determine the size of the reduction in cooling demand has derived. Determination of heat gain from the sun is laborious, but gives a result which reflects the influence of the surface transparent partitions, devices used as sunscreen and its location on the building envelope in relation to the world, as well as to the internal heat gains has great attention in obtained calculation. In this study, included in the balance sheet of solar heat gains are defined in three different shading of windows. Calculating the total demand cooling is made for variants assuming 0% shading baffles transparent, 50% shading baffles transparent external shutters at an angle of 45 °, 100% shading baffles transparent hours 12 from the N and E and from 12 from the S and W of the outer slat blinds. The calculation of the average hourly cooling load was taken into account the option assuming the hypothetical possibility of default by up to 10% of the time assumed the cooling season temperatures in the rooms. To reduce the consumption of electricity energy in the cooling system of the smallest variant identified the need for the power supply for the operation of the cooling system. Also assessed the financial benefits of the temporary default of comfort.

On Usage of Pareto curves to Select Wind Turbine Controller Tunings to the Wind Turbulence Level

DEFF Research Database (Denmark)

Odgaard, Peter Fogh

2015-01-01

Model predictive control has in recently publications shown its potential for lowering of cost of energy of modern wind turbines. Pareto curves can be used to evaluate performance of these controllers with multiple conflicting objectives of power and fatigue loads. In this paper an approach...... to update an model predictive wind turbine controller tuning as the wind turbulence increases, as increased turbulence levels results in higher loads for the same controller tuning. In this paper the Pareto curves are computed using an industrial high fidelity aero-elastic model. Simulations show...

Electrical Load Survey and Forecast for a Decentralized Hybrid ...

African Journals Online (AJOL)

Electrical Load Survey and Forecast for a Decentralized Hybrid Power System at Elebu, Kwara State, Nigeria. ... Nigerian Journal of Technology ... The paper reports the results of electrical load demand and forecast for Elebu rural community ...

Comparison of two methods to determine fan performance curves using computational fluid dynamics

Science.gov (United States)

Onma, Patinya; Chantrasmi, Tonkid

2018-01-01

This work investigates a systematic numerical approach that employs Computational Fluid Dynamics (CFD) to obtain performance curves of a backward-curved centrifugal fan. Generating the performance curves requires a number of three-dimensional simulations with varying system loads at a fixed rotational speed. Two methods were used and their results compared to experimental data. The first method incrementally changes the mass flow late through the inlet boundary condition while the second method utilizes a series of meshes representing the physical damper blade at various angles. The generated performance curves from both methods are compared with an experiment setup in accordance with the AMCA fan performance testing standard.

Impact of Demand Side Management in Active Distribution Networks

DEFF Research Database (Denmark)

Ponnaganti, Pavani; Bak-Jensen, Birgitte; Pillai, Jayakrishnan Radhakrishna

2017-01-01

Demand Side Management (DSM) is an efficient flexible program which helps distribution network operators to meet the future critical peak demand. It is executed in cases of not only technical issues like voltage sag or swell, transformer burdening, cable congestions, but also to increase the degree...... of visibility in the electricity markets. The aim of this paper is to find the optimal flexible demands that can be shifted to another time in order to operate the active distribution system within secure operating limits. A simple mechanism is proposed for finding the flexibility of the loads where electric...

What are the key drivers of MAC curves? A partial-equilibrium modelling approach for the UK

International Nuclear Information System (INIS)

Kesicki, Fabian

2013-01-01

Marginal abatement cost (MAC) curves are widely used for the assessment of costs related to CO 2 emissions reduction in environmental economics, as well as domestic and international climate policy. Several meta-analyses and model comparisons have previously been performed that aim to identify the causes for the wide range of MAC curves. Most of these concentrate on general equilibrium models with a focus on aspects such as specific model type and technology learning, while other important aspects remain almost unconsidered, including the availability of abatement technologies and level of discount rates. This paper addresses the influence of several key parameters on MAC curves for the United Kingdom and the year 2030. A technology-rich energy system model, UK MARKAL, is used to derive the MAC curves. The results of this study show that MAC curves are robust even to extreme fossil fuel price changes, while uncertainty around the choice of the discount rate, the availability of key abatement technologies and the demand level were singled out as the most important influencing factors. By using a different model type and studying a wider range of influencing factors, this paper contributes to the debate on the sensitivity of MAC curves. - Highlights: ► A partial-equilibrium model is employed to test key sensitivities of MAC curves. ► MAC curves are found to be robust to wide-ranging changes in fossil fuel prices. ► Most influencing factors are the discount rate, availability of key technologies. ► Further important uncertainty in MAC curves is related to demand changes

China's energy demand and its characteristics in the industrialization and urbanization process

International Nuclear Information System (INIS)

Jiang Zhujun; Lin Boqiang

2012-01-01

China is currently in the process of industrialization and urbanization, which is the key stage of transition from a low-income country to a middle-income country and requires large amount of energy. The process will not end until 2020, so China's primary energy demand will keep high growth in the mid-term. Although each country is unique considering its particular history and background, all countries are sharing some common rules in energy demand for economic development. Based on the comparison with developed countries, here, we report some rules in the process of industrialization and urbanization as follows: (1) urbanization always goes along with industrialization; (2) the higher economic growth is, the higher energy demand is; (3) economic globalization makes it possible to shorten the time of industrialization, but the shorter the transition phase is, the faster energy demand grows; (4) the change of energy intensity presents as an “inverted U” curve, but whose shape can be changed for different energy policy. The above rules are very important for the Chinese government in framing its energy policy. - Highlights: ► China's energy demand will maintain high growth in mid-term. ► Urbanization always goes along with industrialization. ► Higher economic growth needs more energy. ► The energy intensity presents as an “inverted U” curve.

Efficient Energy Consumption Scheduling: Towards Effective Load Leveling

Directory of Open Access Journals (Sweden)

Yuan Hong

2017-01-01

Full Text Available Different agents in the smart grid infrastructure (e.g., households, buildings, communities consume energy with their own appliances, which may have adjustable usage schedules over a day, a month, a season or even a year. One of the major objectives of the smart grid is to flatten the demand load of numerous agents (viz. consumers, such that the peak load can be avoided and power supply can feed the demand load at anytime on the grid. To this end, we propose two Energy Consumption Scheduling (ECS problems for the appliances held by different agents at the demand side to effectively facilitate load leveling. Specifically, we mathematically model the ECS problems as Mixed-Integer Programming (MIP problems using the data collected from different agents (e.g., their appliances’ energy consumption in every time slot and the total number of required in-use time slots, specific preferences of the in-use time slots for their appliances. Furthermore, we propose a novel algorithm to efficiently and effectively solve the ECS problems with large-scale inputs (which are NP-hard. The experimental results demonstrate that our approach is significantly more efficient than standard benchmarks, such as CPLEX, while guaranteeing near-optimal outputs.

Nonlinear Analysis and Post-Test Correlation for a Curved PRSEUS Panel

Science.gov (United States)

Gould, Kevin; Lovejoy, Andrew E.; Jegley, Dawn; Neal, Albert L.; Linton, Kim, A.; Bergan, Andrew C.; Bakuckas, John G., Jr.

2013-01-01

The Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) concept, developed by The Boeing Company, has been extensively studied as part of the National Aeronautics and Space Administration's (NASA s) Environmentally Responsible Aviation (ERA) Program. The PRSEUS concept provides a light-weight alternative to aluminum or traditional composite design concepts and is applicable to traditional-shaped fuselage barrels and wings, as well as advanced configurations such as a hybrid wing body or truss braced wings. Therefore, NASA, the Federal Aviation Administration (FAA) and The Boeing Company partnered in an effort to assess the performance and damage arrestments capabilities of a PRSEUS concept panel using a full-scale curved panel in the FAA Full-Scale Aircraft Structural Test Evaluation and Research (FASTER) facility. Testing was conducted in the FASTER facility by subjecting the panel to axial tension loads applied to the ends of the panel, internal pressure, and combined axial tension and internal pressure loadings. Additionally, reactive hoop loads were applied to the skin and frames of the panel along its edges. The panel successfully supported the required design loads in the pristine condition and with a severed stiffener. The panel also demonstrated that the PRSEUS concept could arrest the progression of damage including crack arrestment and crack turning. This paper presents the nonlinear post-test analysis and correlation with test results for the curved PRSEUS panel. It is shown that nonlinear analysis can accurately calculate the behavior of a PRSEUS panel under tension, pressure and combined loading conditions.

Logging and Agricultural Residue Supply Curves for the Pacific Northwest

Energy Technology Data Exchange (ETDEWEB)

Kerstetter, James D.; Lyons, John Kim

2001-01-01

This report quantified the volume of logging residues at the county level for current timber harvests. The cost of recovering logging residues was determined for skidding, yearding, loading, chipping and transporting the residues. Supply curves were developed for ten candidate conversion sites in the Pacific Northwest Region. Agricultural field residues were also quantified at the county level using five-year average crop yields. Agronomic constraints were applied to arrive at the volumes available for energy use. Collection costs and transportation costs were determined and supply curves generated for thirteen candidate conversion sites.

Elastic-plastic fracture assessment using a J-R curve by direct method

International Nuclear Information System (INIS)

Asta, E.P.

1996-01-01

In the elastic-plastic evaluation methods, based on J integral and tearing modulus procedures, an essential input is the material fracture resistance (J-R) curve. In order to simplify J-R determination direct, a method from load-load point displacement records of the single specimen tests may be employed. This procedure has advantages such as avoiding accuracy problems of the crack growth measuring devices and reducing testing time. This paper presents a structural integrity assessment approach, for ductile fracture, using the J-R obtained by a direct method from small single specimen fracture tests. The J-R direct method was carried out by means of a developed computational program based on theoretical elastic-plastic expressions. A comparative evaluation between the direct method J resistance curves and those obtained by the standard testing methodology on typical pressure vessel steels has been made. The J-R curves estimated from the direct method give an acceptable agreement with the approach proposed in this study which is reliable to use for engineering determinations. (orig.)

Flexible Demand Control to Enhance the Dynamic Operation of Low Voltage Networks

DEFF Research Database (Denmark)

Diaz de Cerio Mendaza, Iker; Szczesny, Ireneusz Grzegorz; Pillai, Jayakrishnan Radhakrishna

2015-01-01

Moving towards a carbon free energy system has become an objective for many countries nowadays. Among other changes, the electrification of strategic sectors such as heating and transportation is inevitable. As a consequence, the current power system load will substantially increase...... for controlling the demand response of a low voltage grid. This is designed to; i) maximize the grid utilization, thereby reducing the need for reinforcement, ii) accommodate the maximum number of flexible loads and iii) satisfy the power and comfort requirements from each of the consumers in the network....... In this context, the nature of the expected loads (heat pumps, plug-in electric vehicles, etc.) makes the low voltage networks specially targeted. A promising solution to overcome the challenges resulting from their grid integration, is demand response. This paper introduces a hierarchical structure...

Effects of LWR coolant environments on fatigue design curves of carbon and low-alloy steels

International Nuclear Information System (INIS)

Chopra, O.K.; Shack, W.J.

1998-03-01

The ASME Boiler and Pressure Vessel Code provides rules for the construction of nuclear power plant components. Figures I-9.1 through I-9.6 of Appendix I to Section III of the code specify fatigue design curves for structural materials. While effects of reactor coolant environments are not explicitly addressed by the design curves, test data indicate that the Code fatigue curves may not always be adequate in coolant environments. This report summarizes work performed by Argonne National Laboratory on fatigue of carbon and low-alloy steels in light water reactor (LWR) environments. The existing fatigue S-N data have been evaluated to establish the effects of various material and loading variables such as steel type, dissolved oxygen level, strain range, strain rate, temperature, orientation, and sulfur content on the fatigue life of these steels. Statistical models have been developed for estimating the fatigue S-N curves as a function of material, loading, and environmental variables. The results have been used to estimate the probability of fatigue cracking of reactor components. The different methods for incorporating the effects of LWR coolant environments on the ASME Code fatigue design curves are presented

Practical load management - Peak shaving using photovoltaics

International Nuclear Information System (INIS)

Berger, W.

2009-01-01

This article takes a look at how photovoltaic (PV) power generation can be used in a practical way to meet peak demands for electricity. Advice is provided on how photovoltaics can provide peak load 'shaving' through the correlation between its production and the peak loads encountered during the day. The situation regarding feed-in tariffs in Italy is discussed, as are further examples of installations in Germany and Austria. Further, an initiative of the American Southern California Edison utility is discussed which foresees the installation of large PV plant on the roofs of commercial premises to provide local generation of peak energy and thus relieve demands on their power transportation network.

Resident Load Influence Analysis Method for Price Based on Non-intrusive Load Monitoring and Decomposition Data

Science.gov (United States)

Jiang, Wenqian; Zeng, Bo; Yang, Zhou; Li, Gang

2018-01-01

In the non-invasive load monitoring mode, the load decomposition can reflect the running state of each load, which will help the user reduce unnecessary energy costs. With the demand side management measures of time of using price, a resident load influence analysis method for time of using price (TOU) based on non-intrusive load monitoring data are proposed in the paper. Relying on the current signal of the resident load classification, the user equipment type, and different time series of self-elasticity and cross-elasticity of the situation could be obtained. Through the actual household load data test with the impact of TOU, part of the equipment will be transferred to the working hours, and users in the peak price of electricity has been reduced, and in the electricity at the time of the increase Electrical equipment, with a certain regularity.

Development and evaluation of fully automated demand response in large facilities

Energy Technology Data Exchange (ETDEWEB)

Piette, Mary Ann; Sezgen, Osman; Watson, David S.; Motegi, Naoya; Shockman, Christine; ten Hope, Laurie

2004-03-30

This report describes the results of a research project to develop and evaluate the performance of new Automated Demand Response (Auto-DR) hardware and software technology in large facilities. Demand Response (DR) is a set of activities to reduce or shift electricity use to improve electric grid reliability, manage electricity costs, and ensure that customers receive signals that encourage load reduction during times when the electric grid is near its capacity. The two main drivers for widespread demand responsiveness are the prevention of future electricity crises and the reduction of electricity prices. Additional goals for price responsiveness include equity through cost of service pricing, and customer control of electricity usage and bills. The technology developed and evaluated in this report could be used to support numerous forms of DR programs and tariffs. For the purpose of this report, we have defined three levels of Demand Response automation. Manual Demand Response involves manually turning off lights or equipment; this can be a labor-intensive approach. Semi-Automated Response involves the use of building energy management control systems for load shedding, where a preprogrammed load shedding strategy is initiated by facilities staff. Fully-Automated Demand Response is initiated at a building or facility through receipt of an external communications signal--facility staff set up a pre-programmed load shedding strategy which is automatically initiated by the system without the need for human intervention. We have defined this approach to be Auto-DR. An important concept in Auto-DR is that a facility manager is able to ''opt out'' or ''override'' an individual DR event if it occurs at a time when the reduction in end-use services is not desirable. This project sought to improve the feasibility and nature of Auto-DR strategies in large facilities. The research focused on technology development, testing

Demand forecast of turbines in the offshore wind power industry

DEFF Research Database (Denmark)

Martinez-Neri, Ivan

2014-01-01

How important is it for a manufacturing company to be able to predict the demand of their products? How much will it lose in inventory costs due to a bad forecasting technique? And what if the product in question is composed of more than 100,000 parts and costs millions of euros a piece......? This article summarises the reasoning followed by a European manufacturer to determine the demand curve of finished offshore wind turbines and how to forecast it for the purpose of production planning....

Stochastic model of forecasting spare parts demand

Directory of Open Access Journals (Sweden)

Ivan S. Milojević

2012-01-01

hypothesis of the existence of phenomenon change trends, the next step in the methodology of forecasting is the determination of a specific growth curve that describes the regularity of the development in time. These curves of growth are obtained by the analytical representation (expression of dynamic lines. There are two basic stages in the process of expression and they are: - The choice of the type of curve the shape of which corresponds to the character of the dynamic order variation - the determination of the number of values (evaluation of the curve parameters. The most widespread method of forecasting is the trend extrapolation. The basis of the trend extrapolation is the continuing of past trends in the future. The simplicity of the trend extrapolation process, on the one hand, and the absence of other information on the other hand, are the main reasons why the trend extrapolation is used for forecasting. The trend extrapolation is founded on the following assumptions: - The phenomenon development can be presented as an evolutionary trajectory or trend, - General conditions that influenced the trend development in the past will not undergo substantial changes in the future. Spare parts demand forecasting is constantly being done in all warehouses, workshops, and at all levels. Without demand forecasting, neither planning nor decision making can be done. Demand forecasting is the input for determining the level of reserve, size of the order, ordering cycles, etc. The question that arises is the one of the reliability and accuracy of a forecast and its effects. Forecasting 'by feeling' is not to be dismissed if there is nothing better, but in this case, one must be prepared for forecasting failures that cause unnecessary accumulation of certain spare parts, and also a chronic shortage of other spare parts. All this significantly increases costs and does not provide a satisfactory supply of spare parts. The main problem of the application of this model is that each

A Distributed Intelligent Automated Demand Response Building Management System

Energy Technology Data Exchange (ETDEWEB)

Auslander, David [Univ. of California, Berkeley, CA (United States); Culler, David [Univ. of California, Berkeley, CA (United States); Wright, Paul [Univ. of California, Berkeley, CA (United States); Lu, Yan [Siemens Corporate Research Inc., Princeton, NJ (United States); Piette, Mary [Univ. of California, Berkeley, CA (United States)

2013-03-31

The goal of the 2.5 year Distributed Intelligent Automated Demand Response (DIADR) project was to reduce peak electricity load of Sutardja Dai Hall at UC Berkeley by 30% while maintaining a healthy, comfortable, and productive environment for the occupants. We sought to bring together both central and distributed control to provide “deep” demand response1 at the appliance level of the building as well as typical lighting and HVAC applications. This project brought together Siemens Corporate Research and Siemens Building Technology (the building has a Siemens Apogee Building Automation System (BAS)), Lawrence Berkeley National Laboratory (leveraging their Open Automated Demand Response (openADR), Auto-­Demand Response, and building modeling expertise), and UC Berkeley (related demand response research including distributed wireless control, and grid-­to-­building gateway development). Sutardja Dai Hall houses the Center for Information Technology Research in the Interest of Society (CITRIS), which fosters collaboration among industry and faculty and students of four UC campuses (Berkeley, Davis, Merced, and Santa Cruz). The 141,000 square foot building, occupied in 2009, includes typical office spaces and a nanofabrication laboratory. Heating is provided by a district heating system (steam from campus as a byproduct of the campus cogeneration plant); cooling is provided by one of two chillers: a more typical electric centrifugal compressor chiller designed for the cool months (Nov-­ March) and a steam absorption chiller for use in the warm months (April-­October). Lighting in the open office areas is provided by direct-­indirect luminaries with Building Management System-­based scheduling for open areas, and occupancy sensors for private office areas. For the purposes of this project, we focused on the office portion of the building. Annual energy consumption is approximately 8053 MWh; the office portion is estimated as 1924 MWh. The maximum peak load

Stimulation of demand response through evaluation and training

International Nuclear Information System (INIS)

Encinas, N.; Alfonso, D.; Alvarez, C.; Mendez, C.; Rodriguez, J.; Perez-Navarro, A.; Gabaldon, A.

2004-01-01

The objective of Demand Response is to enhance customer choice opportunities by means of price-responsive mechanisms in contrast to direct load control practices and associated revenues based on fixed incentives. In this way, the new approach complements the traditional concept of Demand Side Management by including the voluntary nature to customer participation. This voluntary feature implies a change in customers' traditional behaviour and therefore stimulation and training is needed to achieve an optimal participation. This paper presents a methodology developed to stimulate and train customers for Demand Response practices as well as to identify the suitable products for different customers. Finally, the paper includes an example of the methodology considering a university as a customer. (au)

Biomechanical demands on posterior fusion instrumentation during lordosis restoration procedures.

Science.gov (United States)

Kuo, Calvin C; Martin, Audrey; Telles, Connor; Leasure, Jeremi; Iezza, Alex; Ames, Christopher; Kondrashov, Dimitriy

2016-09-01

OBJECTIVE The goal of this study was to investigate the forces placed on posterior fusion instrumentation by 3 commonly used intraoperative techniques to restore lumbar lordosis: 1) cantilever bending; 2) in situ bending; and 3) compression and/or distraction of screws along posterior fusion rods. METHODS Five cadaveric torsos were instrumented with pedicle screws at the L1-5 levels. Specimens underwent each of the 3 lordosis restoration procedures. The pedicle screw pullout force was monitored in real time via strain gauges that were mounted unilaterally at each level. The degree of correction was noted through fluoroscopic imaging. The peak loads experienced on the screws during surgery, total demand on instrumentation, and resting loads after corrective maneuvers were measured. RESULTS A mean overall lordotic correction of 10.9 ± 4.7° was achieved. No statistically significant difference in lordotic correction was observed between restoration procedures. In situ bending imparted the largest loads intraoperatively with an average of 1060 ± 599.9 N, followed by compression/distraction (971 ± 534.1 N) and cantilever bending (705 ± 413.0 N). In situ bending produced the largest total demand and postoperative loads at L-1 (1879 ± 1064.1 and 487 ± 118.8 N, respectively), which were statistically higher than cantilever bending and compression/distraction (786 ± 272.1 and 138 ± 99.2 N, respectively). CONCLUSIONS In situ bending resulted in the highest mechanical demand on posterior lumbar instrumentation, as well as the largest postoperative loads at L-1. These results suggest that the forces generated with in situ bending indicate a greater chance of intraoperative instrumentation failure and postoperative proximal pedicle screw pullout when compared with cantilever bending and/or compression/distraction options. The results are aimed at optimizing correction and fusion strategies in lordosis restoration cases.

Ontario demand forecast from January 2004 to December 2013

International Nuclear Information System (INIS)

2003-01-01

This document examined the demand forecast for electricity on the Independent Market Operator (IMO)-controlled grid in Ontario for the period 2004-2013. It serves as an assessment tool to determine whether existing and proposed generation and transmission facilities in the province will be sufficient to meet future electricity needs. Changes in methodology have been made to allow for an hourly peak versus the previously reported 20-minute peak value. Actual data through to the end of October 2002 was used to re-estimate energy demand. Compared to other developed countries, the outlook for the Canadian economy is optimistic. In addition, the economic forecast is better than that which formed the basis of the last ten-year forecast. Energy demand in the median growth scenario is increasing at an annual rate of 1.1 per cent rather than 0.9 per cent for the forecasted period of 2003-2012. The combination of a higher growth rate and a higher starting point results in a 2010 forecast of 168 TWh. It is expected that peak demand will grow faster than in the previous forecast. Summer peak demand averaging an annual growth of 1.3 per cent is forecasted for the period 2003-2012, with winter peak demand averaging a growth of 0.8 per cent. Under normal weather conditions, the electricity system is expected to peak in the summer of 2005 due to the continued demand for cooling load. However, under an extreme weather scenario, the system is already summer peaking. The improved economic outlook and higher starting point resulted in a higher forecast for energy. The electricity system is expected to winter peak during the first years of the forecasted period. The heating load is not expected to experience rapid growth in the next few years. 15 tabs., 14 figs

Methods for Analyzing Electric Load Shape and its Variability

Energy Technology Data Exchange (ETDEWEB)

Price, Philip

2010-05-12

Current methods of summarizing and analyzing electric load shape are discussed briefly and compared. Simple rules of thumb for graphical display of load shapes are suggested. We propose a set of parameters that quantitatively describe the load shape in many buildings. Using the example of a linear regression model to predict load shape from time and temperature, we show how quantities such as the load?s sensitivity to outdoor temperature, and the effectiveness of demand response (DR), can be quantified. Examples are presented using real building data.

Assessing the financial impacts of distributed energy on load serving entities

International Nuclear Information System (INIS)

Wang, Zeyu; Negash, Ahlmahz; Kirschen, Daniel

2015-01-01

This article analyzes the financial impact of distributed energy resources (DERs) owned and operated by commercial customers on the load serving entities (LSEs). DERs reduce the customers' electricity bills and hence the revenues collected by their LSE. However, changes in customer demand profiles can potentially reduce the aggregated system demand profile, and therefore, reduce the LSE's costs in wholesale markets. Analysis of these financial impacts indicates that the LSE's lost revenue ultimately outweighs its reduced expenses. This is largely due to a significant reduction in revenue from demand charges. Dispatchable DERs, including energy storages and demand response, result in more financial losses for LSEs than photovoltaics. The financial losses LSEs face indicate that redesigning commercial customer tariffs is necessary in order for LSEs to accommodate customer owned DERs properly. Several suggestions on modifying commercial tariffs are presented. - Highlights: • We analyze the financial impacts on load serving entities of DERs owned by commercial customers. • Under the selected commercial tariff, load serving entities suffer economic losses. • Energy storages and demand response results in more financial losses for LSE than photovoltaics. • We provide some suggestions for tariff modifications.

Commercial equipment loads: End-Use Load and Consumer Assessment Program (ELCAP)

Energy Technology Data Exchange (ETDEWEB)

Pratt, R.G.; Williamson, M.A.; Richman, E.E.; Miller, N.E.

1990-07-01

The Office of Energy Resources of the Bonneville Power Administration is generally responsible for the agency's power and conservation resource planning. As associated responsibility which supports a variety of office functions is the analysis of historical trends in and determinants of energy consumption. The Office of Energy Resources' End-Use Research Section operates a comprehensive data collection program to provide pertinent information to support demand-side planning, load forecasting, and demand-side program development and delivery. Part of this on-going program is known as the End-Use Load and Consumer Assessment Program (ELCAP), an effort designed to collect electricity usage data through direct monitoring of end-use loads in buildings. This program is conducted for Bonneville by the Pacific Northwest Laboratory. This report provides detailed information on electricity consumption of miscellaneous equipment from the commercial portion of ELCAP. Miscellaneous equipment includes all commercial end-uses except heating, ventilating, air conditioning, and central lighting systems. Some examples of end-uses covered in this report are office equipment, computers, task lighting, refrigeration, and food preparation. Electricity consumption estimates, in kilowatt-hours per square food per year, are provided for each end-use by building type. The following types of buildings are covered: office, retail, restaurant, grocery, warehouse, school, university, and hotel/motel. 6 refs., 35 figs., 12 tabs.

Supply and demand in physician markets: a panel data analysis of GP services in Australia.

Science.gov (United States)

McRae, Ian; Butler, James R G

2014-09-01

To understand the trends in any physician services market it is necessary to understand the nature of both supply and demand, but few studies have jointly examined supply and demand in these markets. This study uses aggregate panel data on general practitioner (GP) services at the Statistical Local Area level in Australia spanning eight years to estimate supply and demand equations for GP services. The structural equations of the model are estimated separately using population-weighted fixed effects panel modelling with the two stage least squares formulation of the generalised method of moments approach (GMM (2SLS)). The estimated price elasticity of demand of [Formula: see text] is comparable with other studies. The direct impact of GP density on demand, while significant, proves almost immaterial in the context of near vertical supply curves. Supply changes are therefore due to shifts in the position of the curves, partly determined by a time trend. The model is validated by comparing post-panel model predictions with actual market outcomes over a period of three years and is found to provide surprisingly accurate projections over a period of significant policy change. The study confirms the need to jointly consider supply and demand in exploring the behaviour of physician services markets.

Probabilistic evaluation of design S-N curve and reliability assessment of ASME code-based evaluation

International Nuclear Information System (INIS)

Zhao Yongxiang

1999-01-01

A probabilistic evaluating approach of design S-N curve and a reliability assessment approach of the ASME code-based evaluation are presented on the basis of Langer S-N model-based P-S-N curves. The P-S-N curves are estimated by a so-called general maximum likelihood method. This method can be applied to deal with the virtual stress amplitude-crack initial life data which have a characteristics of double random variables. Investigation of a set of the virtual stress amplitude-crack initial life (S-N) data of 1Cr18Ni9Ti austenitic stainless steel-welded joint reveals that the P-S-N curves can give a good prediction of scatter regularity of the S-N data. Probabilistic evaluation of the design S-N curve with 0.9999 survival probability has considered various uncertainties, besides of the scatter of the S-N data, to an appropriate extent. The ASME code-based evaluation with 20 reduction factor on the mean life is much more conservative than that with 2 reduction factor on the stress amplitude. Evaluation of the latter in 666.61 MPa virtual stress amplitude is equivalent to 0.999522 survival probability and in 2092.18 MPa virtual stress amplitude equivalent to 0.9999999995 survival probability. This means that the evaluation in the low loading level may be non-conservative and in contrast, too conservative in the high loading level. Cause is that the reduction factors are constants and the factors can not take into account the general observation that scatter of the N data increases with the loading level decreasing. This has indicated that it is necessary to apply the probabilistic approach to the evaluation of design S-N curve

SCK-CEN participation to the IAEA CRP-8 - Area topic no. 2: ''Application of the master curve for dynamic testing''. Activity 2005

International Nuclear Information System (INIS)

Lucon, E.

2005-11-01

The latest IAEA Co-ordinated Research Project (CRP-8) focuses on the application of the Master Curve approach to monitor fracture toughness of reactor pressure vessels in nuclear power power plants. Three main work areas have been identified: (a) constraint and geometry effects on Master Curve To values; (b) loading rate effects up to impact conditions; (c) potential changes of Master Curve shape for highly embrittled materials. After the kick-off meeting in Vienna in October 2004, the first Research Coordination Meeting was held in May 2005, hosted by AEKI Budapest. The present document focuses on the participation and contribution of SCK-CEN to Topic Area no. 2 (Loading rate effects on Master Curve - Impact Loading), for which E. Lucon acts as co-task leader. A Round-Robin exercise is planned for early 2006, consisting in 10 tests per participant on precracked Charpy-V specimen of JRQ, tested dynamically using an instrumented pendulum; the results will be analysed using the Master Curve procedure (ASTM E1921-05) and compared to data obtained at other loading rates (quasi-static and/or dynamic). Guidelines and detailed specifications have been produced and circulated after the meeting in Budapest. SCK-CEN has also produced data reporting sheets in EXCEL97 form, which will be used for reporting all fracture toughness test results (at quasi-static, dynamic or impact loading rates) performed in the framework of the CRP-8. (author)

Empirical Investigations of the Opportunity Limits of Automatic Residential Electric Load Shaping: Preprint

Energy Technology Data Exchange (ETDEWEB)

Cruickshank, Robert F.; Henze, Gregor P.; Balaji, Rajagopalan; Hodge, Bri-Mathias S.; Florita, Anthony R.

2017-04-01

Residential electric load shaping is often modeled as infrequent, utility-initiated, short-duration deferral of peak demand through direct load control. In contrast, modeled herein is the potential for frequent, transactive, intraday, consumer-configurable load shaping for storage-capable thermostatically controlled electric loads (TCLs), including refrigerators, freezers, and hot water heaters. Unique to this study are 28 months of 15-minute-interval observations of usage in 101 homes in the Pacific Northwest United States that specify exact start, duration, and usage patterns of approximately 25 submetered loads per home. The magnitudes of the load shift from voluntarily-participating TCL appliances are aggregated to form hourly upper and lower load-shaping limits for the coordination of electrical generation, transmission, distribution, storage, and demand. Empirical data are statistically analyzed to define metrics that help quantify load-shaping opportunities.

Pupillary Response to Cognitive Demand in Parkinson's Disease: A Pilot Study.

Science.gov (United States)

Kahya, Melike; Moon, Sanghee; Lyons, Kelly E; Pahwa, Rajesh; Akinwuntan, Abiodun E; Devos, Hannes

2018-01-01

Previous studies have shown that pupillary response, a physiological measure of cognitive workload, reflects cognitive demand in healthy younger and older adults. However, the relationship between cognitive workload and cognitive demand in Parkinson's disease (PD) remains unclear. The aim of this pilot study was to examine the pupillary response to cognitive demand in a letter-number sequencing (LNS) task between 16 non-demented individuals with PD (age, median (Q1-Q3): 68 (62-72); 10 males) and 10 control participants (age: 63 (59-67); 2 males), matched for age, education, and Montreal Cognitive Assessment (MOCA) scores. A mixed model analysis was employed to investigate cognitive workload changes as a result of incremental cognitive demand for both groups. As expected, no differences were found in cognitive scores on the LNS between groups. Cognitive workload, exemplified by greater pupil dilation, increased with incremental cognitive demand in both groups ( p = 0.003). No significant between-group ( p = 0.23) or interaction effects were found ( p = 0.45). In addition, individuals who achieved to complete the task at higher letter-number (LN) load responded differently to increased cognitive demand compared with those who completed at lower LN load ( p demand in non-demented people with PD and healthy controls. Further research is needed to investigate the pupillary response to incremental cognitive demand of PD patients with dementia compared to non-demented PD and healthy controls. Highlights -Pupillary response reflects cognitive demand in both non-demented people with PD and healthy controls-Although not significant due to insufficient power, non-demented individuals with PD had increased cognitive workload compared to the healthy controls throughout the testing-Pupillary response may be a valid measure of cognitive demand in non-demented individuals with PD-In future, pupillary response might be used to detect cognitive impairment in individuals with PD.

Optimal load scheduling in commercial and residential microgrids

Science.gov (United States)

Ganji Tanha, Mohammad Mahdi

Residential and commercial electricity customers use more than two third of the total energy consumed in the United States, representing a significant resource of demand response. Price-based demand response, which is in response to changes in electricity prices, represents the adjustments in load through optimal load scheduling (OLS). In this study, an efficient model for OLS is developed for residential and commercial microgrids which include aggregated loads in single-units and communal loads. Single unit loads which include fixed, adjustable and shiftable loads are controllable by the unit occupants. Communal loads which include pool pumps, elevators and central heating/cooling systems are shared among the units. In order to optimally schedule residential and commercial loads, a community-based optimal load scheduling (CBOLS) is proposed in this thesis. The CBOLS schedule considers hourly market prices, occupants' comfort level, and microgrid operation constraints. The CBOLS' objective in residential and commercial microgrids is the constrained minimization of the total cost of supplying the aggregator load, defined as the microgrid load minus the microgrid generation. This problem is represented by a large-scale mixed-integer optimization for supplying single-unit and communal loads. The Lagrangian relaxation methodology is used to relax the linking communal load constraint and decompose the independent single-unit functions into subproblems which can be solved in parallel. The optimal solution is acceptable if the aggregator load limit and the duality gap are within the bounds. If any of the proposed criteria is not satisfied, the Lagrangian multiplier will be updated and a new optimal load schedule will be regenerated until both constraints are satisfied. The proposed method is applied to several case studies and the results are presented for the Galvin Center load on the 16th floor of the IIT Tower in Chicago.

Real-Time Demand Side Management Algorithm Using Stochastic Optimization

Directory of Open Access Journals (Sweden)

Moses Amoasi Acquah

2018-05-01

Full Text Available A demand side management technique is deployed along with battery energy-storage systems (BESS to lower the electricity cost by mitigating the peak load of a building. Most of the existing methods rely on manual operation of the BESS, or even an elaborate building energy-management system resorting to a deterministic method that is susceptible to unforeseen growth in demand. In this study, we propose a real-time optimal operating strategy for BESS based on density demand forecast and stochastic optimization. This method takes into consideration uncertainties in demand when accounting for an optimal BESS schedule, making it robust compared to the deterministic case. The proposed method is verified and tested against existing algorithms. Data obtained from a real site in South Korea is used for verification and testing. The results show that the proposed method is effective, even for the cases where the forecasted demand deviates from the observed demand.

Basic analysis on the load management in consumer section

Energy Technology Data Exchange (ETDEWEB)

Tezuka, Tetsuo; Nishikawa, Eiichi

1988-05-01

The load management of the energy (electric power, gas and oil products) in consumer section means to move demand characteristics in desirable directions. The demand characteristics are represented by the energy consumption characteristics along time and their annual sum. The load management is analyzed here from a more practical point of view. As the total thermal demand has been fixed to some extent from the aspect of a total system, the trade-off occurs among objectives of industries. For the quantitative consistency, the model analysis is effective. Changes in the consumers' attitude have been observed as indicated by the cogeneration, heat storage technology and automatic energy management by consumers. Techniques for changing the demand characteristics include the charging system, financial aids for equipment installation, favorable provisions in taxation, law revision and marketing. Stable supply and improved consumption are the future tasks. (2 figs, 6 tabs, 28 refs)

Demand Shifting With Thermal Mass in Large Commercial Buildings:Field Tests, Simulation and Audits

Energy Technology Data Exchange (ETDEWEB)

Xu, Peng; Haves, Philip; Piette, Mary Ann; Zagreus, Leah

2005-09-01

The principle of pre-cooling and demand limiting is to pre-cool buildings at night or in the morning during off-peak hours, storing cooling in the building thermal mass and thereby reducing cooling loads and reducing or shedding related electrical demand during the peak periods. Cost savings are achieved by reducing on-peak energy and demand charges. The potential for utilizing building thermal mass for load shifting and peak demand reduction has been demonstrated in a number of simulation, laboratory, and field studies (Braun 1990, Ruud et al. 1990, Conniff 1991, Andresen and Brandemuehl 1992, Mahajan et al. 1993, Morris et al. 1994, Keeney and Braun 1997, Becker and Paciuk 2002, Xu et al. 2003). This technology appears to have significant potential for demand reduction if applied within an overall demand response program. The primary goal associated with this research is to develop information and tools necessary to assess the viability of and, where appropriate, implement demand response programs involving building thermal mass in buildings throughout California. The project involves evaluating the technology readiness, overall demand reduction potential, and customer acceptance for different classes of buildings. This information can be used along with estimates of the impact of the strategies on energy use to design appropriate incentives for customers.

Improving demand response potential of a supermarket refrigeration system

DEFF Research Database (Denmark)

Pedersen, Rasmus; Schwensen, John; Biegel, Benjamin

2017-01-01

In a smart grid the load shifting capabilities of demand-side devices such as supermarkets are of high interest. In supermarkets this potential is represented by the ability to store energy in the thermal mass of refrigerated foodstuff. To harness the full load shifting potential we propose...... a method for estimating food temperature based on measurements of evaporator expansion valve opening degree. This method requires no additional hardware or system modeling. We demonstrate the estimation method on a real supermarket display case and the applicability of knowing food temperature is shown...... through tests on a full scale supermarket refrigeration system made available by Danfoss A/S. The conducted application test shows that feedback based on food temperature can increase the demand flexibility during a step by approx. 60 % the first 70 minutes and up to 100%over the first 150 minutes...

The application of the consecutive-Woehler-curve-concept in computation of the life values for multi-stage creep

International Nuclear Information System (INIS)

Schott, G.

1991-01-01

It is known that at multi-stage creep load there cannot be calculated any reliable life values by means of linear damage accumulation hypotheses. A practicable non-linear statement was proposed by Pantelakis. Besides the one-stage creep life curve, results from two-stage tests are required for determining the damage exponent. With this exponent, which is a function of temperature and stress in the load stage applied first, the life values can be calculated only for two-stage sequences whose stress stages have to be identical to those of the two-stage tests. For the application of the consecutive Woehler curve concept described in the following there is required the knowledge of the one-stage creep life curve and of the creep function for increasing and decreasing stress sequences derived from two-stage tests. Then, the life values can be calculated for the most different multi-stage loads. The stress stages should lie within the stress range used in the two-stage tests. (orig.) [de

Effects of loading sequences and size of repeated stress block of loads on fatigue life calculated using fatigue functions

International Nuclear Information System (INIS)

Schott, G.

1989-01-01

It is well-known that collective form, stress intensity and loading sequence of individual stresses as well as size of repeated stress blocks can influence fatigue life, significantly. The basic variant of the consecutive Woehler curve concept will permit these effects to be involved into fatigue life computation. The paper presented will demonstrate that fatigue life computations using fatigue functions reflect the loading sequence effect with multilevel loading precisely and provide reliable fatigue life data. Effects of size of repeated stress block and loading sequence on fatigue life as observed with block program tests can be reproduced using the new computation method. (orig.) [de

An Economic Customer-Oriented Demand Response Model in Electricity Markets

DEFF Research Database (Denmark)

Sharifi, Reza; Anvari-Moghaddam, Amjad; Fathi, S. Hamid

2018-01-01

Consumer choice theory is a branch of microeconomics. This theory relates to adjusting consumption expenditures and consumer demand curve. Consumer choice science is trying to realize the buyer's decision-making process. This science studies customer characteristics, such as behavioral criteria......, to understand the consumer’s need. The concept of price elasticity of demand (PED) has also been derived from this theory. In fact, the PED is the percentage of changes in the amount of demand relative to the price changes. In consumer choice theory, for each consumer according to behavioral criteria, a unique...... demand response (DR) models have been developed based on this concept, this will also be deemed as a disadvantage for them. In this paper, we propose an economic DR model based on economic theories and mathematical methods. In addition to abate the defects of price-elasticity based DR models...

An economic welfare analysis of demand response in the PJM electricity market

International Nuclear Information System (INIS)

Walawalkar, Rahul; Blumsack, Seth; Apt, Jay; Fernands, Stephen

2008-01-01

We analyze the economic properties of the economic demand-response (DR) program in the PJM electricity market in the United States using DR market data. PJM's program provided subsidies to customers who reduced load in response to price signals. The program incorporated a 'trigger point', at a locational marginal price of $75/MWh, at or beyond which payments for load reduction included a subsidy payment. Particularly during peak hours, such a program saves money for the system, but the subsidies involved introduce distortions into the market. We simulate demand-side bidding into the PJM market, and compare the social welfare gains with the subsidies paid to price-responsive load using load and price data for year 2006. The largest economic effect is wealth transfers from generators to non price-responsive loads. Based on the incentive payment structure that was in effect through the end of 2007, we estimate that the social welfare gains exceed the distortions introduced by the subsidies. Lowering the trigger point increases the transfer from generators to consumers, but may result in the subsidy outweighing the social welfare gains due to load curtailment. We estimate that the socially optimal range for the incentive trigger point would be $66-77/MWh

Using demand-side management to decrease transformer ageing

NARCIS (Netherlands)

van der Klauw, Thijs; Gerards, Marco Egbertus Theodorus; Hurink, Johann L.

2016-01-01

The introduction of local, often uncontrollable, generation units as well as larger loads such as electric vehicles (EVs) causes an increasing amount of stress on our energy supply chain, specifically on the distribution grids. Demand-side management (DSM) is often seen as a potential technology to

Crack resistance curves determination of tube cladding material

Energy Technology Data Exchange (ETDEWEB)

Bertsch, J. [Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland)]. E-mail: johannes.bertsch@psi.ch; Hoffelner, W. [Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland)

2006-06-30

Zirconium based alloys have been in use as fuel cladding material in light water reactors since many years. As claddings change their mechanical properties during service, it is essential for the assessment of mechanical integrity to provide parameters for potential rupture behaviour. Usually, fracture mechanics parameters like the fracture toughness K {sub IC} or, for high plastic strains, the J-integral based elastic-plastic fracture toughness J {sub IC} are employed. In claddings with a very small wall thickness the determination of toughness needs the extension of the J-concept beyond limits of standards. In the paper a new method based on the traditional J approach is presented. Crack resistance curves (J-R curves) were created for unirradiated thin walled Zircaloy-4 and aluminium cladding tube pieces at room temperature using the single sample method. The procedure of creating sharp fatigue starter cracks with respect to optical recording was optimized. It is shown that the chosen test method is appropriate for the determination of complete J-R curves including the values J {sub 0.2} (J at 0.2 mm crack length), J {sub m} (J corresponding to the maximum load) and the slope of the curve.

Simulation-optimization model of reservoir operation based on target storage curves

Directory of Open Access Journals (Sweden)

Hong-bin Fang

2014-10-01

Full Text Available This paper proposes a new storage allocation rule based on target storage curves. Joint operating rules are also proposed to solve the operation problems of a multi-reservoir system with joint demands and water transfer-supply projects. The joint operating rules include a water diversion rule to determine the amount of diverted water in a period, a hedging rule based on an aggregated reservoir to determine the total release from the system, and a storage allocation rule to specify the release from each reservoir. A simulation-optimization model was established to optimize the key points of the water diversion curves, the hedging rule curves, and the target storage curves using the improved particle swarm optimization (IPSO algorithm. The multi-reservoir water supply system located in Liaoning Province, China, including a water transfer-supply project, was employed as a case study to verify the effectiveness of the proposed join operating rules and target storage curves. The results indicate that the proposed operating rules are suitable for the complex system. The storage allocation rule based on target storage curves shows an improved performance with regard to system storage distribution.

Optimizing electrical load pattern in Kuwait using grid connected photovoltaic systems

International Nuclear Information System (INIS)

Al-Hasan, A.Y.; Ghoneim, A.A.; Abdullah, A.H.

2004-01-01

Grid connected photovoltaic systems is one of the most promising applications of photovoltaic systems. These systems are employed in applications where utility service is already available. In this case, there is no need for battery storage because grid power may be used to supplement photovoltaic systems (PV) when the load exceeds available PV generation. The load receives electricity from both the photovoltaic array and the utility grid. In this system, the load is the total electrical energy consumption. The main objective of the present work is to optimize the electrical load pattern in Kuwait using grid connected PV systems. In this situation, the electric load demand can be satisfied from both the photovoltaic array and the utility grid. The performance of grid connected photovoltaic systems in the Kuwait climate has been evaluated. It was found that the peak load matches the maximum incident solar radiation in Kuwait, which would emphasize the role of using the PV station to minimize the electrical load demand. In addition, a significant reduction in peak load can be achieved with grid connected PV systems

Demand-controlling marketing of electric utilities

Energy Technology Data Exchange (ETDEWEB)

Raffee, H; Fritz, W

1980-01-01

In situations like the shortage of energy resources the particular autonomy of the users concerning energy demand raises more and more aggravating problems for the electric utilities (EU) and, last not least, for society (i.e. the peak-load problem, threatening bottlenecks in the supply situation). Thus the requirement for a demand-controlling marketing strategy of the EU with the help of which the individual demand should be influenced in the following manner is legitimate. The article discusses the targets, strategies, and instruments of marketing performed by the EU under the aspect of their efficiency concerning demand control. The discussion leads to e.g. the following results: that a marketing strategy for the sensible, responsible, and efficent use of energy, in the long-term, serves both the interests of the users and the interests of the EU; that such a marketing programme can have the required controlling effects especially with the help of strategies like market segmentation and cooperation. The discussion makes also clear that a demand-controlling marketing strategy of the EU can hardly be realized without a considerable change within the organization of the EU on one hand and, on the other, without expanding the marketing programme toward a marketing strategy of balance.

Province gets serious about demand management

International Nuclear Information System (INIS)

Anon

2003-01-01

Directives from the Minister to the Ontario Energy Board to review options for demand-side management and demand reduction activities, and discussion papers describing the policy framework needed to implement demand management, are indications of renewed interest by the provincial government in demand-side management of Ontario's electric power supply. This renewed interest comes on the hills of a 5.5 per cent increase in electricity use, a 33 per cent increase in imports, and consumption records broken in 10 of the last 12 months. A 117-page study was released in April by Navigant Consulting, entitled 'Demand response blueprint for Ontario' which estimates that if the Ontario market had 250 MW of additional demand response, customers providing the demand response would have saved $20 million by reducing their demand when HOEP was greater than $120/MWh, while other customers would have saved $170 million due to lower HOEP, and would have enjoyed greater reliability as a result of the increase in reserve margins. Other than price signals to induce customers to save, the Navigant report suggest paying customers not to consume during peak periods. The report estimates that such a policy could generate a total demand response of 350 MW and a $235 million reduction in revenue to generators. The Navigan report also includes a large number of detailed analysis and recommendations. One among them is for the extensive use of interval meters for customers with loads over 200 kW. The report tends to be critical of the recent price freeze ordered by the Ontario government, claiming that the freeze could increase consumption, making prices more volatile and increasing the cost to the government even more. Successful demand response programs from California, New York and the New England states are cited as examples for Ontario to emulate

Study on energy demand function of korea considering replacement among energy sources and the structural changes of demand behavior

Energy Technology Data Exchange (ETDEWEB)

Moon, C.K. [Korea Energy Economics Institute, Euiwang (Korea, Republic of)

1997-08-01

If the necessity of careful study on energy function is mentioned, it should be stressed that energy investment not only needs a long gestation period but also, acts as the bottleneck in the production capacity of an economy when investment is not enough. Thereby, the adverse effect of an energy supply shortage is very big. Especially, the replacement/supplemental relationship between energy and capital which corresponds to the movement on the iso-quanta curve is believed to have a direct relation with the answer as to whether long-term economic development would be possible under an energy crisis and its influence on technology selection. Furthermore, the advantages of technological advances which correspond to the movement on the iso-quanta curve has a direct relation with the question whether long-term economic development would be possible under an energy crisis depending on whether its direction is toward energy-saving or energy-consuming. This study tackles the main issues and outlines of the quantitative approach method based on the accounting approach method for modeling energy demand, quantitative economics approach method, and production model. In order to model energy demand of the Korean manufacturing industry, related data was established and a positive analytical model is completed and presented based on these. 122 refs., 10 tabs.

Lagrangian Curves on Spectral Curves of Monopoles

International Nuclear Information System (INIS)

Guilfoyle, Brendan; Khalid, Madeeha; Ramon Mari, Jose J.

2010-01-01

We study Lagrangian points on smooth holomorphic curves in TP 1 equipped with a natural neutral Kaehler structure, and prove that they must form real curves. By virtue of the identification of TP 1 with the space LE 3 of oriented affine lines in Euclidean 3-space, these Lagrangian curves give rise to ruled surfaces in E 3 , which we prove have zero Gauss curvature. Each ruled surface is shown to be the tangent lines to a curve in E 3 , called the edge of regression of the ruled surface. We give an alternative characterization of these curves as the points in E 3 where the number of oriented lines in the complex curve Σ that pass through the point is less than the degree of Σ. We then apply these results to the spectral curves of certain monopoles and construct the ruled surfaces and edges of regression generated by the Lagrangian curves.

Opportunities for Energy Efficiency and Open Automated Demand Response in Wastewater Treatment Facilities in California -- Phase I Report

Energy Technology Data Exchange (ETDEWEB)

Lekov, Alex; Thompson, Lisa; McKane, Aimee; Song, Katherine; Piette, Mary Ann

2009-04-01

This report summarizes the Lawrence Berkeley National Laboratory?s research to date in characterizing energy efficiency and automated demand response opportunities for wastewater treatment facilities in California. The report describes the characteristics of wastewater treatment facilities, the nature of the wastewater stream, energy use and demand, as well as details of the wastewater treatment process. It also discusses control systems and energy efficiency and automated demand response opportunities. In addition, several energy efficiency and load management case studies are provided for wastewater treatment facilities.This study shows that wastewater treatment facilities can be excellent candidates for open automated demand response and that facilities which have implemented energy efficiency measures and have centralized control systems are well-suited to shift or shed electrical loads in response to financial incentives, utility bill savings, and/or opportunities to enhance reliability of service. Control technologies installed for energy efficiency and load management purposes can often be adapted for automated demand response at little additional cost. These improved controls may prepare facilities to be more receptive to open automated demand response due to both increased confidence in the opportunities for controlling energy cost/use and access to the real-time data.

Findings from Seven Years of Field Performance Data for Automated Demand Response in Commercial Buildings

Energy Technology Data Exchange (ETDEWEB)

Kiliccote, Sila; Piette, Mary Ann; Mathieu, Johanna; Parrish, Kristen

2010-05-14

California is a leader in automating demand response (DR) to promote low-cost, consistent, and predictable electric grid management tools. Over 250 commercial and industrial facilities in California participate in fully-automated programs providing over 60 MW of peak DR savings. This paper presents a summary of Open Automated DR (OpenADR) implementation by each of the investor-owned utilities in California. It provides a summary of participation, DR strategies and incentives. Commercial buildings can reduce peak demand from 5 to 15percent with an average of 13percent. Industrial facilities shed much higher loads. For buildings with multi-year savings we evaluate their load variability and shed variability. We provide a summary of control strategies deployed, along with costs to install automation. We report on how the electric DR control strategies perform over many years of events. We benchmark the peak demand of this sample of buildings against their past baselines to understand the differences in building performance over the years. This is done with peak demand intensities and load factors. The paper also describes the importance of these data in helping to understand possible techniques to reach net zero energy using peak day dynamic control capabilities in commercial buildings. We present an example in which the electric load shape changed as a result of a lighting retrofit.

A stochastic self-scheduling program for compressed air energy storage (CAES) of renewable energy sources (RESs) based on a demand response mechanism

International Nuclear Information System (INIS)

Ghalelou, Afshin Najafi; Fakhri, Alireza Pashaei; Nojavan, Sayyad; Majidi, Majid; Hatami, Hojat

2016-01-01

Highlights: • Optimal stochastic energy management of renewable energy sources (RESs) is proposed. • The compressed air energy storage (CAES) besides RESs is used in the presence of DRP. • Determination charge and discharge of CAES in order to reduce the expected operation cost. • Moreover, demand response program (DRP) is proposed to minimize the operation cost. • The uncertainty modeling of input data are considered in the proposed stochastic framework. - Abstract: In this paper, a stochastic self-scheduling of renewable energy sources (RESs) considering compressed air energy storage (CAES) in the presence of a demand response program (DRP) is proposed. RESs include wind turbine (WT) and photovoltaic (PV) system. Other energy sources are thermal units and CAES. The time-of-use (TOU) rate of DRP is considered in this paper. This DRP shifts the percentage of load from the expensive period to the cheap one in order to flatten the load curve and minimize the operation cost, consequently. The proposed objective function includes minimizing the operation costs of thermal unit and CAES, considering technical and physical constraints. The proposed model is formulated as mixed integer linear programming (MILP) and it is been solved using General Algebraic Modeling System (GAMS) optimization package. Furthermore, CAES and DRP are incorporated in the stochastic self-scheduling problem by a decision maker to reduce the expected operation cost. Meanwhile, the uncertainty models of market price, load, wind speed, temperature and irradiance are considered in the formulation. Finally, to assess the effects of DRP and CAES on self-scheduling problem, four case studies are utilized, and significant results were obtained, which indicate the validity of the proposed stochastic program.

Load Management in District Heating Operation

OpenAIRE

Li, Hongwei; Wang, Stephen Jia

2015-01-01

Smooth operation of district heating system will avoid installation of expensive peak heat boilers, improve plant partial load performance, increase the system redundancy for further network expansion and improve its resilience to ensuresecurity of supply during severe heating seasons. The peak heating load can be reduced through building demand side management. The building thermal mass can be used to shift the heating supply under the circumstance withoutjeopardizing the consumer thermal co...

Framing scenarios of electricity generation and gas use: EPRI report series on gas demands for power generation. Final report

International Nuclear Information System (INIS)

Thumb, S.; Glover, W.; Hughes, W.R.

1996-07-01

Results of three EPRI projects have been combined to analyze power industry consumption of gas and other generating fuels. The report's capstone is a scenario analysis of power industry generation and fuel consumption. The Utility Fuel Consumption Model (UFCM), developed for the project, predicts generating capacity and generation by region and fuel through 2015, based on load duration curves, generation dispatch, and expected capacity additions. Scenarios embody uncertain factors, such as electricity demand growth, fuel switching, coal-gas competition, the merit order of gas-coal dispatch, and retirement of nuclear units, that substantially affect gas consumption. Some factors, especially electricity demand have very large effects. The report includes a consistent database on NUG (non-utility generation) capacity and generation and assesses historical and prospective trends in NUG generation. The report shows that NUG capacity growth will soon decline substantially. The study assesses industry capability for price-induced fuel switching from gas to oil and coal, documenting conversions of coal units to dual coal-gas capability and determining that gas-to-oil switching remains a strong influence on fuel availability and gas prices, though regulation and taxation have increased trigger prices for switching. 61 tabs