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Renewable Energy Sources (renewable + energy_source)
Selected AbstractsOptimal Thermal Unit Commitment Integrated with Renewable Energy Sources Using Advanced Particle Swarm OptimizationIEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING, Issue 5 2009Shantanu Chakraborty Student member Abstract This paper presents a methodology for solving generation planning problem for thermal units integrated with wind and solar energy systems. The renewable energy sources are included in this model due to their low electricity cost and positive effect on environment. The generation planning problem also known by unit commitment problem is solved by a genetic algorithm operated improved binary particle swarm optimization (PSO) algorithm. Unlike trivial PSO, this algorithm runs the refinement process through the solutions within multiple populations. Some genetic algorithm operators such as crossover, elitism, and mutation are stochastically applied within the higher potential solutions to generate new solutions for next population. The PSO includes a new variable for updating velocity in accordance with population best along with conventional particle best and global best. The algorithm performs effectively in various sized thermal power system with equivalent solar and wind energy system and is able to produce high quality (minimized production cost) solutions. The solution model is also beneficial for reconstructed deregulated power system. The simulation results show the effectiveness of this algorithm by comparing the outcome with several established methods. Copyright © 2009 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source] Screening co-digestion of food waste water with manure for biogas productionBIOFUELS, BIOPRODUCTS AND BIOREFINING, Issue 1 2009Yan Liu Abstract Anaerobic digestion, an environmental protection technology for treating organic compounds in waste water, produces biogas, resulting in a renewable energy source. A protocol including waste analysis, waste blending, energy potential and energy balance calculations was developed to determine the energy production from blending food and animal wastes. Fruit and vegetable waste water produced from crop commodity processing was characterized in terms of quantity and 5-day biochemical oxygen demand (BOD). Often these wastes have high levels of degradable carbon but lack buffering capacity and adequate nitrogen and other nutrients to meet the minimal C/N ratio needed for optimal digestion. Blending food-processing waste water with high nutrient manure can enhance the biogas production by optimizing nutrient levels and providing buffering capacity. The protocol shows the procedure to determine the optimal blend and theoretical biogas production from the anaerobic digestion of that blend. An energy balance technique that determines the lowest COD concentration required to close the energy balance in the digester during different seasons is illustrated. A case study was conducted to determine the potential energy production from anaerobically digesting blended waste water from the top 14 fruit and vegetable commodities in Michigan. The resulting biogas production supports a substantial amount of the energy consumption needed for the treatment process. This case study in Michigan can be extended to national level since the calculations were based on the mean value of their typical range. © 2008 Society of Chemical Industry and John Wiley & Sons, Ltd [source] The promotion of green electricity in Europe: present and futureENVIRONMENTAL POLICY AND GOVERNANCE, Issue 4 2004Pablo del Río Public support schemes for electricity from renewable energy sources (RES-E) are undergoing a period of change. Two interrelated processes can be discerned at both the EU and member state (MS) levels. On the one hand, the RES-E Directive sets targets for consumption of renewable electricity for the year 2010 and opens the possibility that the European Commission sets a community support framework for RES-E promotion in the future. On the other hand, different types of support scheme have been and are used by countries in order to promote the deployment of renewable electricity. A move from tendering/bidding systems and feed-in tariffs to tradable green certificates can be observed in some MSs. This move may take place in the future in some other MSs while others will certainly continue to rely on their current scheme. This paper provides an overview and assessment of the instruments currently used to promote renewable electricity in Europe and considers some possible trends in the choice of support schemes in the future. Copyright © 2004 John Wiley &,Sons, Ltd and ERP,Environment. [source] Short-term scheduling of a wind generation and hydrogen storage in the electricity marketEUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 5 2010G. Tina Abstract Intermittent renewable energy sources (RES) are promising to be the future of electricity generation. In particular wind generation, owing to its stochastic behaviour, has to be carefully managed. Its lack of sufficient predictability decreases the energy value in the current framework of electrical markets, therefore, beyond a certain threshold; this kind of generation into the electrical system represents a problem for the transmission system operator (TSO) during its despatching service. The coupling of wind energy conversion system (WECS) with a storage medium (i.e. hydrogen) could improve the programmability of such generation plants in electrical markets. In this paper, an economical optimization tool has been developed in order to find the short-term scheduling so as to maximize the economic revenues in the day-ahead electricity market of a storage plant coupled with a wind farm. This tool needs as input the forecasts of both wind generation power and market prices, obtained with the adoption of pre-processing input data algorithm based on different methods that involve both statistical and probabilistic approaches. Copyright © 2009 John Wiley & Sons, Ltd. [source] Dimensioning of secondary and tertiary control reserve by probabilistic methodsEUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 4 2009Christoph Maurer Abstract Given the rising share of intermittent generation out of renewable energy sources on the one hand and the increased regulatory efforts to lower transmission costs and tariffs on the other hand, the optimal dimensioning of necessary control reserve has gained additional importance during the last years. Grid codes like the UCTE Operation Handbook do not provide definitive and unambiguous methods for dimensioning of secondary and tertiary control reserves. This paper therefore presents a method which calculates the necessary control reserve considering all important drivers for power imbalances like power plant outages, load variations and forecast error. For dimensioning, a probabilistic criterion, the accepted probability of insufficient control reserve, is used. Probability density functions of control area imbalances are calculated using a convolution algorithm. This paper provides analyses for a stylised example system to demonstrate the capabilities of the method. In a sensitivity analysis the impact of drivers like plant failures and forecast errors of load and generation is shown. The presented method is used by transmission system operators and regulatory authorities to determine and substantiate the necessary amount of control reserve. Copyright © 2009 John Wiley & Sons, Ltd. [source] Hydrogen for the Mobility of the Future Results of GM/Opel's Well-to-Wheel Studies in North America and EuropeFUEL CELLS, Issue 3 2003U. Winter Abstract General Motors conducted two well-to-wheel studies for fundamental clarification on the question of which is the cleanest and most environmentally sustainable source of energy for the mobility of the future. In both studies the complete energy chains were analyzed from fuel production using primary energy to the actual consumption of the fuel in the car, i.e. from the well up to the wheels of the vehicle (well to wheel). The aim of the studies was to evaluate total energy consumption on the one hand and, on the other, the total greenhouse gas emissions arising between the production of a fuel and its final use to power an automobile. The results of the studies clearly show that fuel cell vehicles can greatly reduce greenhouse gas emissions from passenger cars or, if they run on hydrogen from renewable energy sources, they can eliminate them entirely. Regenerative fuels, however, will be more expensive than current products. With the fuel cell, because of its superior efficiency (35 , 45% less energy consumption well to wheel), it will be possible to keep individual mobility affordable in the future. [source] Solar-Energy Production and Energy-Efficient Lighting: Photovoltaic Devices and White-Light-Emitting Diodes Using Poly(2,7-fluorene), Poly(2,7-carbazole), and Poly(2,7-dibenzosilole) DerivativesADVANCED MATERIALS, Issue 8 2010Serge Beaupré Abstract World energy needs grow each year. To address global warming and climate changes the search for renewable energy sources with limited greenhouse gas emissions and the development of energy-efficient lighting devices are underway. This Review reports recent progress made in the synthesis and characterization of conjugated polymers based on bridged phenylenes, namely, poly(2,7-fluorene)s, poly(2,7-carbazole)s, and poly(2,7-dibenzosilole)s, for applications in solar cells and white-light-emitting diodes. The main strategies and remaining challenges in the development of reliable and low-cost renewable sources of energy and energy-saving lighting devices are discussed. [source] Analysis of the current methods used to size a wind/hydrogen/fuel cell-integrated system: A new perspectiveINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 12 2010H. G. Geovanni Abstract As an alternative to the production and storage of intermittent renewable energy sources, it has been suggested that one can combine several renewable energy technologies in one system, known as integrated or hybrid system, that integrate wind technology with hydrogen production unit and fuel cells. This work assesses the various methods used in sizing such systems. Most of the published papers relate the use of simulation tools such as HOMER, HYBRID2 and TRNSYS, to simulate the operation of different configurations for a given application in order to select the best economic option. But, with these methods one may not accurately determine certain characteristics of the energy resources available on a particular site, the profiles of estimated consumption and the demand for hydrogen, among other factors, which will be the optimal parameters of each subsystem. For example, velocity design, power required for the wind turbine, power required for the fuel cell and electrolyzer and the storage capacity needed for the system. Moreover, usually one makes excessive use of bi-parametric Weibull distribution function to approximate the histogram of the observed wind to the theoretical, which is not appropriate when there are bimodal frequency distributions of wind, as is the case in several places in the world. A new perspective is addressed in this paper, based on general system theory, modeling and simulation with a systematic approach and the use of exergoeconomic analysis. There are some general ideas on the advantages offered in this method, which is meant for the implementation of wind/hydrogen/fuel cell-integrated systems and in-situ clean hydrogen production. Copyright © 2009 John Wiley & Sons, Ltd. [source] The role of policy instruments for promoting combined heat and power production with low CO2 emissions in district heating systemsINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 6 2005Å. Marbe Abstract Policy instruments clearly influence the choice of production technologies and fuels in large energy systems, including district heating networks. Current Swedish policy instruments aim at promoting the use of biofuel in district heating systems, and at promoting electric power generation from renewable energy sources. However, there is increasing pressure to harmonize energy policy instruments within the EU. In addition, natural gas based combined cycle technology has emerged as the technology of choice in the power generation sector in the EU. This study aims at exploring the role of policy instruments for promoting the use of low CO2 emissions fuels in high performance combined heat and power systems in the district heating sector. The paper presents the results of a case study for a Swedish district heating network where new large size natural gas combined cycle (NGCC) combined heat and power (CHP) is being built. Given the aim of current Swedish energy policy, it is assumed that it could be of interest in the future to integrate a biofuel gasifier to the CHP plant and co-fire the gasified biofuel in the gas turbine unit, thereby reducing usage of fossil fuel. The goals of the study are to evaluate which policy instruments promote construction of the planned NGCC CHP unit, the technical performance of an integrated biofuelled pressurized gasifier with or without dryer on plant site, and which combination of policy instruments promote integration of a biofuel gasifier to the planned CHP unit. The power plant simulation program GateCycle was used for plant performance evaluation. The results show that current Swedish energy policy instruments favour investing in the NGCC CHP unit. The corresponding cost of electricity (COE) from the NGCC CHP unit is estimated at 253 SEK MWh,1, which is lower than the reference power price of 284 SEK MWh,1. Investing in the NGCC CHP unit is also shown to be attractive if a CO2 trading system is implemented. If the value of tradable emission permits (TEP) in such as system is 250 SEK tonne,1, COE is 353 SEK MWh,1 compared to the reference power price of 384 SEK MWh,1. It is possible to integrate a pressurized biofuel gasifier to the NGCC CHP plant without any major re-design of the combined cycle provided that the maximum degree of co-firing is limited to 27,38% (energy basis) product gas, depending on the design of the gasifier system. There are many parameters that affect the economic performance of an integrated biofuel gasifier for product gas co-firing of a NGCC CHP plant. The premium value of the co-generated renewable electricity and the value of TEPs are very important parameters. Assuming a future CO2 trading system with a TEP value of 250 SEK tonne,1 and a premium value of renewable electricity of 200 SEK MWh,1 COE from a CHP plant with an integrated biofuelled gasifier could be 336 SEK MWh,1, which is lower than both the reference market electric power price and COE for the plant operating on natural gas alone. Copyright © 2005 John Wiley & Sons, Ltd. [source] The lignite electricity-generating sector in Greece: Current status and future prospectsINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 9 2004N. Koukouzas Abstract Lignite plays an important role in Greece's energy sector as it satisfies over 70% of country's needs in electric power. The extraction of lignite takes place mainly in three regions of Greece, namely Ptolemais-Amyndeon, Megalopolis and Florina. The annual production of lignite is around 60 million tons, out of which 48 million tons derive from the coal fields of northern Greece (Ptolemais-Amyndeon and Florina). Almost the entire lignite production is consumed for electricity generation, while small amounts of lignite are used for briquettes and other applications. The Greek coal-fired power plants, which are about 4500 MW, use conventional technology and they are old (an average of 30 years). In the coming years new coal fields will be exploited in Florina,another 2.5 million tons of coal,in order to satisfy the currently under construction 365 MW plant located at Meliti, Florina, Northern Greece. Even though the lignite reserves are widespread in Greece and other areas such as Elassona and Drama could possibly host power plants, it is expected that the Florina power plant will be the last coal-fired plant to be build in the country. Lignite has to compete with natural gas,the construction of the main gas pipeline network has been completed,imported oil and renewable energy sources. The new EU regulations on power plant emissions raise obstacles for the firing of lignite, although it is low in sulphur. It must be shown that lignite produces low cost electricity in a environmentally friendly manner. The utilization of fly ash and land reclamation can improve the situation in lignite mining. In particular, specific attention was paid to further research and potential use of fly ash in road construction, the production of bricks and concrete, and the production of zeolites from lignitic fly ash. The use of clean coal technologies in power plants can solve many emission problems. Specific measures to increase the efficiency of lignite-fired power units might include: identification of the loss sources of every unit, improvement of the cold end of the steam turbines, optimization of the beater wheel mills operation, and the combination of natural gas-fired turbines with the existing boilers. The liberalization of the electricity market needs to be considered seriously from the lignite industry, since the potential electricity producers can freely choose from all kinds of fuels, such as imported coal, oil, gas and renewables. However, Greek lignite meets the requirements for the security of supply, as indicated in the EU's Green Paper. It needs only to be competitive in the new energy sector by improving mining and combustion conditions. Further research on these topics, through the European Commission's ECSC and Framework Programmes, as well as the national programmes, is required. Copyright © 2004 John Wiley & Sons, Ltd. [source] Economic theory and nuclear energyOPEC ENERGY REVIEW, Issue 2 2000Ferdinand E. Banks The economics literature dealing with nuclear energy and uranium is inadequate, and several extremely important topics deserve a more methodical treatment. This survey provides: an alternative derivation for the optimal mix of generating capacity; a systematic but essentially non-technical approach to the nuclear fuel cycle; some comments on alternative technologies; and a stock-flow analysis of the market for uranium. It is also argued: that existing nuclear facilities in countries like Sweden can compete with all fossil fuels in the generation of electricity; and that claims that unconventional or renewable energy sources are economic at the present time are misleading, and might serve to accelerate the introduction of a plutonium-based energy economy. [source] THE SOCIAL EFFICIENCY OF INSTRUMENTS FOR THE PROMOTION OF RENEWABLE ENERGIES IN THE LIBERALISED POWER INDUSTRYANNALS OF PUBLIC AND COOPERATIVE ECONOMICS, Issue 3 2006Dominique Finon ABSTRACT,:,This paper compares the social efficiency of the two main regulatory instruments used to promote renewable energy sources in electricity generation (RES-E), taking into consideration their role in promoting the preservation of the climate. They are based on a purchase obligation and act either by price (feed-in tariffs) or by quantity (RES-E quotas). In their reference design, the instruments show different performances in several dimensions: market incentives intensity, control of the cost for consumers, safeguards of RES-E investments, and conformity with the new market regime of the electricity industry. The comparison shows that neither instrument offers an optimal solution in each of these dimensions. In particular, the intrinsic qualities of the quotas instrument that are put forward to mandate its adoption by the EU members are overestimated. A government will thus select an instrument in accordance with the relative importance of its objectives: environmental policy versus cost control by market pressure. [source] Hydrogen Economy Options for AustraliaASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 5-6 2004B. Mclellan Global concerns over the effects of current carbon dioxide (CO2) emissions have lead to extensive research on the use of hydrogen as a potential energy carrier for a lower emissions society. Hydrogen can be produced from both fossil and renewable energy sources. The hydrogen economy, in which hydrogen will be a carrier of energy from renewable sources, is a long-term development and any increasing demand for hydrogen will probably be covered initially from fossil sources. Technologies for hydrogen generation from renewable energies are being explored, whereas technologies for hydrogen production from fossil fuels have to a certain extent reached maturity. This paper addresses the major hydrogen generation processes and utilisation technology (fuel cells) currently available for the move from a fossil fuelsbased economy to a hydrogen economy. In particular, it illustrates the applicability of different hydrogen sources using Australia as an example. [source] Determinants of price mark-up tolerance for green electricity , lessons for environmental marketing strategies from a study of residential electricity customers in GermanyBUSINESS STRATEGY AND THE ENVIRONMENT, Issue 5 2010Torsten J. Gerpott Abstract This paper develops hypotheses on the effects of various attitudinal and perceptual variables as well as socio-demographic characteristics of residential electricity customers on an individual's willingness to pay a mark-up for electricity generated from renewable energy sources compared with the price due for electricity from conventional sources. The hypotheses are tested with data from a standardized telephone survey of 238 household electricity consumers in Germany. 53.4% of the participants are willing to pay a mark-up for green electricity. 26.1% report a price tolerance equal to a 5,10% increase in their current electricity bill. Binary logistic and ordinal regression analyses indicate that price tolerance for green electricity is particularly influenced by attitudes (1) towards environmental issues and (2) towards one's current power supplier, (3) perceptions of the evaluation of green energy by an individual's social reference groups, (4) household size and (5) current electricity bill level. The findings are used to derive suggestions for energy related informational activities of public institutions, green marketing strategies of energy companies and future consumer research regarding demand for pro-environmental goods. Copyright © 2009 John Wiley & Sons, Ltd and ERP Environment. [source] Driving on liquid sunshine , the Brazilian biofuel experience: a policy driven analysisBUSINESS STRATEGY AND THE ENVIRONMENT, Issue 8 2009Clovis Zapata Abstract This paper analyses Brazil's experience with biofuels, focusing on the central role of the federal government as the main force driving the implementation of alternative locally produced ethanol (ethyl alcohol) and biodiesel. The pioneering, large scale ethanol programme that started over 30 years ago can be considered the most successful experience with the use of biofuels to date, as the government was able to rapidly implement the use of ethanol (ethyl alcohol) as a substitute for petrol in the 1970s and 1980s. The work contributes to the general discussion of sustainable and renewable energy sources and sets out the key policy mechanisms used. The paper also innovatively looks at the second large governmental intervention in the renewable fuels market , the biodiesel programme. In addition to the contribution to the debate surrounding command-and-control measures and economic incentive instruments, the paper analyses how lessons learned from the ethanol experiment were taken into consideration in the design and implementation of the biodiesel mandate, including social and environmental facets. It emphasizes the uniqueness of producing sugarcane ethanol in the Brazilian context and how attempts to carry out similar fast growing biofuels programmes may not be possible in other parts of the world. Copyright © 2008 John Wiley & Sons, Ltd and ERP Environment. [source] | |||||||||||||||||||