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Transient stability analysis of commercial scale open cycle disk MHD generator connected to power system
06 Electrical power supply and ufihzation (economics, policy, supplies, forecasts) transient response of the system (fuel cell and compressor) is investigated in order to optimize the start-up running through a model of a fuel cell stack and a compressor simulation. The model and its results are proposed as a work procedure to solve the problem, by varying external conditions: in fact, to perform the system start-up under stable conditions, the air relative humidity and temperature must be maintained in a proper range of values. The approach here presented has been utilized for the definition of the characteristics of the power module and layout of a middle-size hybrid city bus in the framework of a project promoted by the European Union.
only manipulates the inverter control angle. Its control
sequence has two steps. At first, the control angle is reduced toward 90” just after the fault occurs. Next, it is linearly increased to its rated value with constant increasing rate per cycle after the removed line is reconnected. It is made clear through the simulations that the proposed control scheme of the inverter is very effective to improve the transient stability of the generator. The reduction of the inverter control angle is effective to stabilize the MHD generator, but the operating state shifts from its normal operation. The increase of the control angle can stably return the generator to its normal operation.
03/01208 The direct carbonate fuel cell technolo y: advances In multi-fuel processing and internal re! ormlng Katikaneni, S. et ul. Cota~vsis Today, 2002, 77, (l-2). 99-106. Carbonate fuel cells are new generation of power plants that provide electricity at very high efficiency and low environmental emissions. The direct carbonate fuel cell (DFCTM) technology is fast approaching its commercial entry. DFC cell operates on a variety of hydrocarbon fuels such as natural gas, biogas, coal gas, diesel and LPG. Conventionally, an external reformer is used to supply hydrogen-rich gas to fuel cell. FuelCell energy’s DFCTM technology has adopted an internal reforming approach that eliminates the need for an external reformer, resulting in increased efficiency, compactness, better thermal management and lower cost. Fuel processing operation in DFCTM technology varies based on the nature of fuel. However, the fuel thus supplied to the fuel cell has a two-step refinement approach involving impurities (sulfur) removal followed by pre-reforming desulfurized fuel to knock out higher hydrocarbons. Methane-rich gas obtained from prereformer is thus fed into fuel cell for internal reforming to produce hydrogen in DFC stacks, thereby producing DC power. At each stage of this operation, catalysts are used to facilitate production of desirable fuel cell fuel. FCE has developed stable catalyst system at each one of these steps. FCE’s experience with internal reforming (indirect internal reforming and direct internal reforming catalysts) and fuel processing catalysts is discussed here.
03/01209 The Italian Green Certificates market between uncertainty and opportunltles Lorenzoni, A. Energy Policy, 2003, 31, (l), 33-42. With the overall reform of the electricity industry in 1999, Italy has started the implementation of a new support mechanism for renewable energy sources that is based upon a Green Certificates market. Such certificates will be delivered for 8 years for electricity production to renewable power plants commissioned after 31 March 1999. All the electricity production based on non-renewable energy sources and import have an obligation to cover 2% of its total with Green Certificates. This support mechanism is open to foreign production, but only from countries with reciprocal opportunities for Italian production. The new market has formally started on January 2002, even if some important rules have not yet been defined. This paper describes the new support mechanism, investigates the critical aspects for its activation and shows some possible trends for the quantity of the supplied certificates and their prices in the coming years.
03/01210 Three-dlmenslonal computational analysis of gas and heat transport henomena in ducts relevant for anodesupported solfd ox Pde fuel cells Yuan, J. cf al. Inrernarional Journal of Heat and Mass Transjer, 2003, 46. (5), 809-821. Various transport phenomena occurring in an anode duct of medium temperature solid oxide fuel cell (SOFC) have been simulated and analysed by a fully three-dimensional calculation method. The considered composite duct consists of a thick porous layer, the gas flow duct and solid current interconnector. Unique fuel cell boundary and interfacial conditions, such as the combined thermal boundary conditions on solid walls, mass transfer associated with the electrochemical reaction and gas permeation across the interface, were applied in the analysis. Based on three characteristic ratios proposed in this study, gas flow and heat transfer were investigated and presented in terms of friction factors and Nusselt numbers. It was revealed that, among various parameters, the duct configuration and properties of the porous anode layer have significant effects on both gas flow and heat transfer of anode-supported SOFC ducts. The results from this study can be applied in fuel cell overall modelling methods, such as those considering unit/stack level modelling.
Transient stabthty analysis of commercial scale open cycle disk MHD generator connected to power system
03/01211
et al. Energy Conversion and Management, 2003,44, (5), 7333 743. The authors propose and investigate a new improvement method for transient stability under power line fault condition for commercial scale open cycle subsonic inflow disk MHD generators connected to the power system through time dependent numerical simulations of a total interconnecting system. The method needs no additional device and Inoue, I.
Economics, policy, supplies, forecasts 03/01212 Exlstln electrlclty eneration capacity using solid fuels within tR e enlarged 1 U: market size and renovatlon options Kakaras, E. et al. VGB PowerTech. 2002, 82, (4). 81-87. A review of solid fuel power plants in the EU. The studies examined the main technical and environmental parameters as well as the foreseeable life span of the power plants, and evaluated the needs for renovation activities. Total efficiency values can be >24-27% for nonEU coal-fired units, while they may exceed 42% in the EU-units of advanced technical design. Most of the EU coal-fired power plants apply denitrification and desulfurization measures, while only 25% of the installed capacity in the non-EU area have desulfurization equipment. Little control is exercised over NO, emissions in East European countries. Lifetime extension measures are an economically attractive alternative for the exploitation of the remaining coal reserves and the technology improvement of the existing coal-fired plants, as well as for CO2 reduction purposes.
03/01213 A North American definition for ‘green electricity’: lmpllcatlons for sustalnablllty Rowlands, I. H. and Patterson, M. J. Inr. J. Environment and Sustainable Development, 2002, 1, (3), 249-264. This paper investigates the potential implications, for sustainability, of a North American standard for ‘green electricity’ (that is, electricity generated by environmentally-friendlier means). More specifically, four conceivable approaches to a North American standard are identified: namely, a continental standard with no local variation, a continental standard with ‘objective’ local variations, a continental standard with local interpretations and a set of continental norms with local priorities. For the first and last of these four approaches, potential sustainability impacts are highlighted and discussed. The paper concludes by arguing that further investigation is warranted: the particular approach taken at the continental level has the potential to be a powerful force, either positively or negatively, with respect to the sustainability of the North American electricity system.
03/01214 A preliminary study on potential for very largescale photovottalc power neratlon (VLWV) system In the Gobi desert from econom 8” c and envlronmentat vlewpolnts Ito, M. et al. Solar Energy Materials and Solar Cells. 2003, 7.5. (3-4), 507-517. A 100 MW very large-scale photovoltaic power generation (VLS-PV) system is designed assuming that it will be installed in the Gobi desert, which is one of the major deserts in the world. Array arrangement, array support, foundation, wiring, and so on are designed in detail. Then energy payback time (EPT), life-cycle CO2 emission rate and generation cost of the system are estimated based on the methodology of life-cycle analysis. As a result of the estimation, 1.7 year of EPT and 12 g C/kWh of CO2 emission rate are obtained. These show that VLSPV in the Gobi desert would be very promising for the global energy and environmental issues. The generation cost is calculated at 8.6 cent/ kWh assuming that PV module price is one US $/W and system lifetime is 30 years.
A review of International green power markets: recent experience, trends, and market drlvers
03/01215
Bird, L. et al. Renewable and Sustainable Energy Rc~iew~s, 2002. 6, (6). 513-536. Green power marketing - the act of differentially selling electricity generated wholly or in part from renewable sources - has emerged in more than a dozen countries around the world. Almost two million customers worldwide buy green power today. This paper reviews green power marketing activity in Australia, Canada, Japan, the US, and in a number of countries in Europe to gain an understanding of consumer demand for electricity generated from renewable sources. It also examines key factors that influence market penetration of green power products, such as product designs, pricing, incentives, marketing strategies, policies, and product certification. Fuel and Energy Abstracts
July 2003
227
only manipulates the inverter control angle. Its control
sequence has two steps. At first, the control angle is reduced toward 90” just after the fault occurs. Next, it is linearly increased to its rated value with constant increasing rate per cycle after the removed line is reconnected. It is made clear through the simulations that the proposed control scheme of the inverter is very effective to improve the transient stability of the generator. The reduction of the inverter control angle is effective to stabilize the MHD generator, but the operating state shifts from its normal operation. The increase of the control angle can stably return the generator to its normal operation.
03/01208 The direct carbonate fuel cell technolo y: advances In multi-fuel processing and internal re! ormlng Katikaneni, S. et ul. Cota~vsis Today, 2002, 77, (l-2). 99-106. Carbonate fuel cells are new generation of power plants that provide electricity at very high efficiency and low environmental emissions. The direct carbonate fuel cell (DFCTM) technology is fast approaching its commercial entry. DFC cell operates on a variety of hydrocarbon fuels such as natural gas, biogas, coal gas, diesel and LPG. Conventionally, an external reformer is used to supply hydrogen-rich gas to fuel cell. FuelCell energy’s DFCTM technology has adopted an internal reforming approach that eliminates the need for an external reformer, resulting in increased efficiency, compactness, better thermal management and lower cost. Fuel processing operation in DFCTM technology varies based on the nature of fuel. However, the fuel thus supplied to the fuel cell has a two-step refinement approach involving impurities (sulfur) removal followed by pre-reforming desulfurized fuel to knock out higher hydrocarbons. Methane-rich gas obtained from prereformer is thus fed into fuel cell for internal reforming to produce hydrogen in DFC stacks, thereby producing DC power. At each stage of this operation, catalysts are used to facilitate production of desirable fuel cell fuel. FCE has developed stable catalyst system at each one of these steps. FCE’s experience with internal reforming (indirect internal reforming and direct internal reforming catalysts) and fuel processing catalysts is discussed here.
03/01209 The Italian Green Certificates market between uncertainty and opportunltles Lorenzoni, A. Energy Policy, 2003, 31, (l), 33-42. With the overall reform of the electricity industry in 1999, Italy has started the implementation of a new support mechanism for renewable energy sources that is based upon a Green Certificates market. Such certificates will be delivered for 8 years for electricity production to renewable power plants commissioned after 31 March 1999. All the electricity production based on non-renewable energy sources and import have an obligation to cover 2% of its total with Green Certificates. This support mechanism is open to foreign production, but only from countries with reciprocal opportunities for Italian production. The new market has formally started on January 2002, even if some important rules have not yet been defined. This paper describes the new support mechanism, investigates the critical aspects for its activation and shows some possible trends for the quantity of the supplied certificates and their prices in the coming years.
03/01210 Three-dlmenslonal computational analysis of gas and heat transport henomena in ducts relevant for anodesupported solfd ox Pde fuel cells Yuan, J. cf al. Inrernarional Journal of Heat and Mass Transjer, 2003, 46. (5), 809-821. Various transport phenomena occurring in an anode duct of medium temperature solid oxide fuel cell (SOFC) have been simulated and analysed by a fully three-dimensional calculation method. The considered composite duct consists of a thick porous layer, the gas flow duct and solid current interconnector. Unique fuel cell boundary and interfacial conditions, such as the combined thermal boundary conditions on solid walls, mass transfer associated with the electrochemical reaction and gas permeation across the interface, were applied in the analysis. Based on three characteristic ratios proposed in this study, gas flow and heat transfer were investigated and presented in terms of friction factors and Nusselt numbers. It was revealed that, among various parameters, the duct configuration and properties of the porous anode layer have significant effects on both gas flow and heat transfer of anode-supported SOFC ducts. The results from this study can be applied in fuel cell overall modelling methods, such as those considering unit/stack level modelling.
Transient stabthty analysis of commercial scale open cycle disk MHD generator connected to power system
03/01211
et al. Energy Conversion and Management, 2003,44, (5), 7333 743. The authors propose and investigate a new improvement method for transient stability under power line fault condition for commercial scale open cycle subsonic inflow disk MHD generators connected to the power system through time dependent numerical simulations of a total interconnecting system. The method needs no additional device and Inoue, I.
Economics, policy, supplies, forecasts 03/01212 Exlstln electrlclty eneration capacity using solid fuels within tR e enlarged 1 U: market size and renovatlon options Kakaras, E. et al. VGB PowerTech. 2002, 82, (4). 81-87. A review of solid fuel power plants in the EU. The studies examined the main technical and environmental parameters as well as the foreseeable life span of the power plants, and evaluated the needs for renovation activities. Total efficiency values can be >24-27% for nonEU coal-fired units, while they may exceed 42% in the EU-units of advanced technical design. Most of the EU coal-fired power plants apply denitrification and desulfurization measures, while only 25% of the installed capacity in the non-EU area have desulfurization equipment. Little control is exercised over NO, emissions in East European countries. Lifetime extension measures are an economically attractive alternative for the exploitation of the remaining coal reserves and the technology improvement of the existing coal-fired plants, as well as for CO2 reduction purposes.
03/01213 A North American definition for ‘green electricity’: lmpllcatlons for sustalnablllty Rowlands, I. H. and Patterson, M. J. Inr. J. Environment and Sustainable Development, 2002, 1, (3), 249-264. This paper investigates the potential implications, for sustainability, of a North American standard for ‘green electricity’ (that is, electricity generated by environmentally-friendlier means). More specifically, four conceivable approaches to a North American standard are identified: namely, a continental standard with no local variation, a continental standard with ‘objective’ local variations, a continental standard with local interpretations and a set of continental norms with local priorities. For the first and last of these four approaches, potential sustainability impacts are highlighted and discussed. The paper concludes by arguing that further investigation is warranted: the particular approach taken at the continental level has the potential to be a powerful force, either positively or negatively, with respect to the sustainability of the North American electricity system.
03/01214 A preliminary study on potential for very largescale photovottalc power neratlon (VLWV) system In the Gobi desert from econom 8” c and envlronmentat vlewpolnts Ito, M. et al. Solar Energy Materials and Solar Cells. 2003, 7.5. (3-4), 507-517. A 100 MW very large-scale photovoltaic power generation (VLS-PV) system is designed assuming that it will be installed in the Gobi desert, which is one of the major deserts in the world. Array arrangement, array support, foundation, wiring, and so on are designed in detail. Then energy payback time (EPT), life-cycle CO2 emission rate and generation cost of the system are estimated based on the methodology of life-cycle analysis. As a result of the estimation, 1.7 year of EPT and 12 g C/kWh of CO2 emission rate are obtained. These show that VLSPV in the Gobi desert would be very promising for the global energy and environmental issues. The generation cost is calculated at 8.6 cent/ kWh assuming that PV module price is one US $/W and system lifetime is 30 years.
A review of International green power markets: recent experience, trends, and market drlvers
03/01215
Bird, L. et al. Renewable and Sustainable Energy Rc~iew~s, 2002. 6, (6). 513-536. Green power marketing - the act of differentially selling electricity generated wholly or in part from renewable sources - has emerged in more than a dozen countries around the world. Almost two million customers worldwide buy green power today. This paper reviews green power marketing activity in Australia, Canada, Japan, the US, and in a number of countries in Europe to gain an understanding of consumer demand for electricity generated from renewable sources. It also examines key factors that influence market penetration of green power products, such as product designs, pricing, incentives, marketing strategies, policies, and product certification. Fuel and Energy Abstracts
July 2003
227