Showing papers on "Power station published in 2013"

Future on Power Electronics for Wind Turbine Systems

Abstract: Wind power is still the most promising renewable energy in the year of 2013. The wind turbine system (WTS) started with a few tens of kilowatt power in the 1980s. Now, multimegawatt wind turbines are widely installed even up to 6-8 MW. There is a widespread use of wind turbines in the distribution networks and more and more wind power stations, acting as power plants, are connected directly to the transmission networks. As the grid penetration and power level of the wind turbines increase steadily, the wind power starts to have significant impacts to the power grid system. Therefore, more advanced generators, power electronic systems, and control solutions have to be introduced to improve the characteristics of the wind power plant and make it more suitable to be integrated into the power grid. Meanwhile, there are also some emerging technology challenges, which need to be further clarified and investigated. This paper gives an overview and discusses some development trends in the technologies used for wind power systems. First, the developments of technology and market are generally discussed. Next, several state-of-the-art wind turbine concepts, as well as the corresponding power electronic converters and control structures, are reviewed, respectively. Furthermore, grid requirements and the technology challenges for the future WTS are also addressed.

Life cycle water use for electricity generation: a review and harmonization of literature estimates

Abstract: This article provides consolidated estimates of water withdrawal and water consumption for the full life cycle of selected electricity generating technologies, which includes component manufacturing, fuel acquisition, processing, and transport, and power plant operation and decommissioning. Estimates were gathered through a broad search of publicly available sources, screened for quality and relevance, and harmonized for methodological differences. Published estimates vary substantially, due in part to differences in production pathways, in defined boundaries, and in performance parameters. Despite limitations to available data, we find that: water used for cooling of thermoelectric power plants dominates the life cycle water use in most cases; the coal, natural gas, and nuclear fuel cycles require substantial water per megawatt-hour in most cases; and, a substantial proportion of life cycle water use per megawatt-hour is required for the manufacturing and construction of concentrating solar, geothermal, photovoltaic, and wind power facilities. On the basis of the best available evidence for the evaluated technologies, total life cycle water use appears lowest for electricity generated by photovoltaics and wind, and highest for thermoelectric generation technologies. This report provides the foundation for conducting water use impact assessments of the power sector while also identifying gaps in data that could guide future research.

Value of Energy Storage for Grid Applications

Abstract: This analysis evaluates several operational benefits of electricity storage, including load-leveling, spinning contingency reserves, and regulation reserves. Storage devices were simulated in a utility system in the western United States, and the operational costs of generation was compared to the same system without the added storage. This operational value of storage was estimated for devices of various sizes, providing different services, and with several sensitivities to fuel price and other factors. Overall, the results followed previous analyses that demonstrate relatively low value for load-leveling but greater value for provision of reserve services. The value was estimated by taking the difference in operational costs between cases with and without energy storage and represents the operational cost savings from deploying storage by a traditional vertically integrated utility. The analysis also estimated the potential revenues derived from a merchant storage plant in a restructured market, based on marginal system prices. Due to suppression of on-/off-peak price differentials and incomplete capture of system benefits (such as the cost of power plant starts), the revenue obtained by storage in a market setting appears to be substantially less than the net benefit provided to the system. This demonstrates some of the additional challenges for storage deployedmore » in restructured energy markets.« less

A multi-agent system architecture for smart grid management and forecasting of energy demand in virtual power plants

Abstract: Recent technological advances in the power generation and information technologies areas are helping to change the modern electricity supply system in order to comply with higher energy efficiency and sustainability standards. Smart grids are an emerging trend that introduce intelligence in the power grid to optimize resource usage. In order for this intelligence to be effective, it is necessary to retrieve enough information about the grid operation together with other context data such as environmental variables, and intelligently modify the behavior of the network elements accordingly. This article presents a multi-agent system model for virtual power plants, a new power plant concept in which generation no longer occurs in big installations, but is the result of the cooperation of smaller and more intelligent elements. The proposed model is not only focused on the management of the different elements, but includes a set of agents embedded with artificial neural networks for collaborative forecasting of disaggregated energy demand of domestic end users, the results of which are also shown in this article.

Enhancing the Dispatchability of Variable Wind Generation by Coordination With Pumped-Storage Hydro Units in Stochastic Power Systems

Abstract: The ever-increasing penetration of variable wind energy in power systems affects the hourly dispatch of thermal power generation in electricity markets. The variability of wind energy, which makes the wind energy non-dispatchable and difficult to control, could bring significant challenges to power system operators. The hourly coordination of wind power generation units with pumped-storage hydro (PS) generation could relieve the variability of wind energy and increase its dispatchability. The wind-PS coordination is based on the application of stochastic security-constrained unit commitment (stochastic SCUC). In this study, the coordinated hourly bus-level scheduling of wind-PS is compared with the coordinated system-level operation strategies in the day-ahead scheduling of power systems.

Intelligent Model-Based Control of a Standalone Photovoltaic/Fuel Cell Power Plant With Supercapacitor Energy Storage

Abstract: A renewable energy hybrid power plant, fed by photovoltaic (PV) and fuel cell (FC) sources with a supercapacitor (SC) storage device and suitable for distributed generation applications, is proposed herein. The PV is used as the primary source; the FC acts as a backup, feeding only the insufficiency power (steady-state) from the PV; and the SC functions as an auxiliary source and a short-term storage system for supplying the deficiency power (transient and steady-state) from the PV and the FC. For high-power applications and optimization in power converters, four-phase parallel converters are implemented for the FC converter, the PV converter, and the SC converter, respectively. A mathematical model (reduced-order model) of the FC, PV, and SC converters is described for the control of the power plant. Using the intelligent fuzzy logic controller based on the flatness property for dc grid voltage regulation, we propose a simple solution to the fast response and stabilization problems in the power system. This is the key innovative contribution of this research paper. The prototype small-scale power plant implemented was composed of a PEMFC system (1.2 kW, 46 A), a PV array (0.8 kW), and an SC module (100 F, 32 V). Experimental results validate the excellent control algorithm during load cycles.

Urban wind energy exploitation systems: Behaviour under multidirectional flow conditions—Opportunities and challenges

Abstract: The growth of the world energy demand, the limited fossil fuel reserves and the increasing greenhouse gas emissions require improvements in energy-generation technologies. Specifically, urban wind energy is a source with great potential that is currently being wasted. The characteristics of urban wind and perspectives and proposals to exploit it have been researched and analysed in the literature. The results show that urban winds have a strong multidirectional component that requires analysing the wind turbine behaviour. To explain the influence of the multidirectional wind on the turbine, a simulation of the air flow around a building section was performed, the sections of various wind turbines were superimposed on the velocity fields, and their aerodynamic behaviour was qualitatively studied. The results show that horizontal-axis wind turbines have better performance in flat-terrain applications, whereas in high-density building environments, the superiority of vertical-axis wind turbines is demonstrated. The main benefits of urban wind power development are: distributed power generation, the use of a renewable energy source, and the technological and economic exploitation of building roofs.

Review of storage schemes for wind energy systems

Abstract: Wind Energy is a fast developing source of energy since 1996. Despite its advantages, this energy could never be a primary source of electric power to be integrated into the grid even in high wind areas, such as Great Plains, due to its intermittent behaviour. This intermittency will generate intermittent power to grid, which leads to instability, unreliability and power quality problem onto the grid system. One of the widely accepted methods to overcome this problem is by coupling the wind turbine with the energy storage system. This paper reviews the ability of four different types of the energy storage system to mitigate the power fluctuated into the grid, especially during low wind speed. This paper also explains the operating principles and the different methods of charging and discharging the energy storage. The ability of permanent magnet synchronous generator (PMSG) in dealing with variable wind speed also will be discussed.

Carbon capture from stationary power generation sources: A review of the current status of the technologies

Abstract: The world will need greatly increased energy supply in the future for sustained economic growth, but the related CO2 emissions and the resulting climate changes are becoming major concerns. CO2 is one of the most important greenhouse gases that is said to be responsible for approximately 60% of the global warming. Along with improvement of energy efficiency and increased use of renewable energy sources, carbon capture and sequestration (CCS) is expected to play a major role in curbing the greenhouse gas emissions on a global scale. This article reviews the various options and technologies for CO2 capture, specifically for stationary power generation sources. Many options exist for carbon dioxide capture from such sources, which vary with power plant types, and include post-combustion capture, pre-combustion capture, oxy fuel combustion capture, and chemical looping combustion capture. Various carbon dioxide separation technologies can be utilized with these options, such as chemical absorption, physical absorption, adsorption, and membrane separation. Most of these capture technologies are still at early stages of development. Recent progress and remaining challenges for the various CO2 capture options and technologies are reviewed in terms of capacity, selectivity, stability, energy requirements, etc. Hybrid and modified systems hold huge future potentials, but significant progress is required in materials synthesis and stability, and implementations of these systems on demonstration plants are needed. Improvements and progress made through applications of process systems engineering concepts and tools are highlighted and current gaps in the knowledge are also mentioned. Finally, some recommendations are made for future research directions.

An overview of renewable energies in Iran

Abstract: Iran as a major oil producing country has increasingly paid attention to the non-fossil energy resources, in particular to renewable energy sources for its longer term energy plans. In this regard, 11 projects pertaining to solar energy are being utilized or carried out by Iran׳s Ministry of Energy. The total photovoltaic power installed in 2004 was 14,020 MW. This rate reached 67 MW by the end of 2010. Further, two geothermal projects are being constructed in Ardabil Province at present. By the end of 2010, the Meshkinshahr geothermal power plant project revealed a progress rate equal to 50%. Similarly, the package construction project in Ardabil revealed a 32% progress. Due to financial hardship in the Fourth Development Program, the completion of these projects was extended to the end of the Fifth Development Program. The nameplate power of biogas power plants in Iran is 1.860 MW the total installed capacity is 1.665 MW. According to Strategy Document of Fuel Cell Technology Development (Approved by the government in 2004), Iran has revealed good progress in fuel cell projects. Private sectors have already signed contracts to build more than 600 MW of biomass systems and 500 MW of new wind energy developments. The nominal power of the wind parks that can be erected in the available sites with remarkable wind potential in Iran is approximately 6500 MW, employing wind turbines of 60,000 MW nominal power. The estimated mean annual capacity factor of these wind parks is 33%.

A Hybrid System of Li-Ion Capacitors and Flow Battery for Dynamic Wind Energy Support

Abstract: Wind farm output power fluctuations create adverse effects on the voltage, frequency, and transient stability of the utility grid. Short-term wind farm power variations with high ramp rates can cause voltage instabilities, particularly if the farm is located in weak-grid areas. The integration of wind energy with energy storage devices to support the short-term shortcomings of wind energy is discussed in this paper. A turbine level hybrid configuration of an energy storage system is used to limit the power ramp rates and apply power smoothing. The proposed energy storage devices are the zinc bromide flow battery and lithium-ion capacitors. The actual models for the battery and capacitors used in this study are derived from laboratory tests. The wind farm power is also modeled using measured wind speed data. A new concept has been introduced to evaluate the effectiveness of energy storage system for wind energy support. The analysis shows that significant improvements can be made to shape the output power of the farm using energy storage systems.

A review on the development of wind turbine generators across the world

Abstract: Wind power as a source of green and abundant energy is proposed as one of the main new world power sources and has acquired a great momentum across the world. In the last few decades, wind turbines with different generators have been developed to increase the maximum power capture, minimize the cost, and expand the use of the wind turbines in both onshore and offshore applications. This paper reviews the development of different types of wind turbine generator technologies and discusses advantages and disadvantages of each type. In addition, a comparison of different generator designs based on the technical data and market trends is provided. To better understand the development of generator concepts on the market, the market trends of current large generators with a capacity of 2.5 MW and above across the world are evaluated.

Power System Security in a Meshed North Sea HVDC Grid

Abstract: There are very ambitious plans in Europe for changing the energy infrastructure in order to reduce greenhouse gas emissions. This involves scenarios where renewable energy sources by 2050 will meet almost 100% of the electric power demand. This has spurred offshore wind farm development activities in the North Sea due to the vast wind energy potential in this region and the potential lack of suitable onshore sites in the future. Large-scale wind farms in the North Sea pose grid integration challenges such as the need for long-distance subsea power transmission and tackling the impact of wind power variation on alternating current (ac) grids. These challenges can be properly managed by the use of meshed high-voltage direct current (HVDC) grids. Three of the regional groups (RGs) in the European Network of Transmission System Operators for Electricity (ENTSO-E), namely Regional Group Great Britain (RG-GB), Regional Group Nordic (RG-N), and Regional Group Continental Europe (RG-CE), surround the North Sea area. A meshed North Sea HVDC interconnection between offshore wind farms and these three asynchronous ac grids can also enable market integration of the otherwise separate regions. This, in turn, results in better utilization of generation and transmission infrastructures, improved security of power supply, and maximized utilization of renewable energy resources. In this paper, a test scenario of a meshed North Sea HVDC grid is studied to demonstrate the potential of such a system for enhancing power supply security of the ac grids. Simulation studies of the test case show that with proper control techniques, a meshed North Sea HVDC grid can mitigate the effect of wind power variation by facilitating exchange of primary and secondary reserves between asynchronous ac grids.

Superconductivity and the environment: a Roadmap

Abstract: There is universal agreement between the United Nations and governments from the richest to the poorest nations that humanity faces unprecedented global challenges relating to sustainable energy, clean water, low-emission transportation, coping with climate change and natural disasters, and reclaiming use of land. We have invited researchers from a range of eclectic research areas to provide a Roadmap of how superconducting technologies could address these major challenges confronting humanity.Superconductivity has, over the century since its discovery by Kamerlingh Onnes in 1911, promised to provide solutions to many challenges. So far, most superconducting technologies are esoteric systems that are used in laboratories and hospitals. Large science projects have long appreciated the ability of superconductivity to efficiently create high magnetic fields that are otherwise very costly to achieve with ordinary materials. The most successful applications outside of large science are high-field magnets for magnetic resonance imaging, laboratory magnetometers for mineral and materials characterization, filters for mobile communications, and magnetoencephalography for understanding the human brain.The stage is now set for superconductivity to make more general contributions. Humanity uses practically unthinkable amounts of energy to drive our modern way of life. Overall, global power usage has been predicted to almost double from 16.5 to 30?TW in the next four decades (2011 Equinox Summit: Energy 2030 http://wgsi.org/publications-resources).The economy with which electrons carry energy compels the continued quest for efficient superconducting power generation, energy storage, and power transmission. The growing global population requires new arable land and treatment of water, especially in remote areas, and superconductivity offers unique solutions to these problems. Exquisite detectors give warning of changes that are otherwise invisible. Prediction of climate and disasters will be helped by future supercomputer technologies that support huge amounts of data and sophisticated modeling, and with the aid of superconductivity these systems might not require the energy of a large city.We present different sections on applications that could address (or are addressing) a range of environmental issues. The Roadmap covers water purification, power distribution and storage, low-environmental impact transport, environmental sensing (particularly for the removal of unexploded munitions), monitoring the Earth?s magnetic fields for earthquakes and major solar activity, and, finally, developing a petaflop supercomputer that only requires 3% of the current supercomputer power provision while being 50 times faster.Access to fresh water. With only 2.5% of the water on Earth being fresh and climate change modeling forecasting that many areas will become drier, the ability to recycle water and achieve compact water recycling systems for sewage or ground water treatment is critical. The first section (by Nishijima) points to the potential of superconducting magnetic separation to enable water recycling and reuse.Energy. The Equinox Summit held in Waterloo Canada 2011?(2011 Equinox Summit: Energy 2030 http://wgsi.org/publications-resources) identified electricity use as humanity?s largest contributor to greenhouse gas emissions. Our appetite for electricity is growing faster than for any other form of energy. The communiqu? from the summit said ?Transforming the ways we generate, distribute and store electricity is among the most pressing challenges facing society today?. If we want to stabilize CO2 levels in our atmosphere at 550 parts per million, all of that growth needs to be met by non-carbon forms of energy? (2011 Equinox Summit: Energy 2030 http://wgsi.org/publications-resources). Superconducting technologies can provide the energy efficiencies to achieve, in the European Union alone, 33?65% of the required reduction in greenhouse gas emissions according to the Kyoto Protocol (Hartikainen et?al 2003 Supercond. Sci. Technol. 16 963). New technologies would include superconducting energy storage systems to effectively store power generation from renewable sources as well as high-temperature superconducting systems used in generators, transformers and synchronous motors in power stations and heavy-industry facilities. However, to be effective, these systems must be superior to conventional systems and, in reality, market penetration will occur as existing electrical machinery is written off. At current write-off rates, to achieve a 50% transfer to superconducting systems will take 20?years (Hartikainen et?al 2003 Supercond. Sci. Technol. 16 963).The Roadmap next considers dc transmission of green power with a section by Eckroad and Marian who provide an update on the development of superconducting power transmission lines in view of recent sustainability studies. The potential of magnetic energy storage is then presented by Coi and Kim, who argue that a successful transition to wind and solar power generation must be harmonized with the conventional electrical network, which requires a storage technology with a fast response and long backup times.Transport. Superconducting Maglev trains and motors for international shipping have the potential to considerably reduce the emissions that contribute to greenhouse gases while improving their economic viability by reducing losses and improving efficiencies. International shipping, alone, contributes 3% of the greenhouse gas emissions. Three sections of the Roadmap identify how high-speed rail can be a major solution to providing fast, low energy, environmentally-friendly transport enabling reduction in automobile and aircraft travel by offering an alternative that is very competitive. With maritime international environmental regulations tightening, HTS motors with the characteristics of high torque and compactness will become important devices for high-performance and low-emission electric ship propulsion systems. A section on the development of a megawatt-class superconducting motor for ship propulsion is presented by Umemoto.Monitoring in manufacturing for waste reduction. Environmental impact from the waste created by the manufacturing sector and the need to make manufacturing efficient can be addressed by terahertz imaging. This technology has great potential in non-destructive testing, industrial process monitoring and control to greatly improve the industry process efficiency and reliability by reducing waste materials and toxic by-products. The section by Du shows how terahertz imaging can provide process and property information such as rust levels under paint that can assist with the reduction of waste in manufacturing and maintenance.Monitoring for naturally occurring disturbances. The environmental and social impact of natural disasters is mounting. Febvre provides the Roadmap for the use of ultra-sensitive magnetometry to understand geomagnetic phenomena and Earth?ionosphere couplings through the study of very small variations of the magnetic field. This magnetic monitoring has many implications for understanding our environment and providing new tools for early warning of natural hazards, either on Earth or in space which will enable us to be better prepared for natural disasters.Restoring environments after military use. Throughout the world, there are many areas confirmed or suspected of being contaminated by unexploded munitions known as unexploded ordnance (UXO). Its presence is the result of wars and training of military forces. Areas affected by UXO contamination are hazardous to the public and have a major influence on the nature of land use. UXO has impact in developed as well as developing nations. For example, the USA has UXO dating back to the American Civil War and countries such as Cambodia are living with landmines as a daily issue due to more recent wars. Underwater UXO has caused severe impacts such as the explosion in 1969 in the waters of Kent in the UK that caused a reading of 4.5 on the Richter scale for earthquake monitors. Another example was a land-based detonation of a 500?kg World War II bomb in Germany killing three people in 2010. There is countless UXO from recent conflicts worldwide. Detection and accurate location with 100% reliability is required to return land to safe civilian use. Keenan provides details of a prototype magnetic gradiometer developed for this purpose.Reducing power needs for high-end IT. Supercomputers are so large that they are close to requiring their own small power plant to support the energy needed to run the computer. For example, in 2011 Facebook data centers and operations used 532 million kW hours of energy. Mukhanov explores the potential of reducing the power dissipation for future supercomputers from more than 500?MW for Exascale systems to 0.2?MW by using superconducting-ferromagnetic Josephson junctions for magnetic memory and programmable logic.Clearly superconductivity is an ultimate energy-saving technology, and its practical implementation will contribute to the reduction of CO2 emissions, improved water purification, reduction of waste and timely preparedness for natural disasters or significant events. This Roadmap shows how the application of superconducting technologies will have a significant impact when they are adopted.

Water constraints on European power supply under climate change: impacts on electricity prices

Abstract: Recent warm, dry summers showed the vulnerability of the European power sector to low water availability and high river temperatures. Climate change is likely to impact electricity supply, in terms of both water availability for hydropower generation and cooling water usage for thermoelectric power production. Here, we show the impacts of climate change and changes in water availability and water temperature on European electricity production and prices. Using simulations of daily river flows and water temperatures under future climate (2031‐2060) in power production models, we show declines in both thermoelectric and hydropower generating potential for most parts of Europe, except for the most northern countries. Based on changes in power production potentials, we assess the cost-optimal use of power plants for each European country by taking electricity import and export constraints into account. Higher wholesale prices are projected on a mean annual basis for most European countries (except for Sweden and Norway), with strongest increases for Slovenia (12‐15%), Bulgaria (21‐23%) and Romania (31‐32% for 2031‐2060), where limitations in water availability mainly affect power plants with low production costs. Considering the long design life of power plant infrastructures, short-term adaptation strategies are highly recommended to prevent undesired distributional and allocative effects.

Design of a Least-Cost Battery-Supercapacitor Energy Storage System for Realizing Dispatchable Wind Power

Abstract: A statistical approach is used in the design of a battery-supercapacitor energy storage system for a wind farm. The design exploits the technical merits of the two energy storage mediums, in terms of the differences in their specific power and energy densities, and their ability to accommodate different rates of change in the charging/discharging powers. By treating the input wind power as random and using a proposed coordinated power flows control strategy for the battery and the supercapacitor, the approach evaluates the energy storage capacities, the corresponding expected life cycle cost/year of the storage mediums, and the expected cost/year of unmet power dispatch. A computational procedure is then developed for the design of a least-cost/year hybrid energy storage system to realize wind power dispatch at a specified confidence level.