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02746 New self-excited variable speed constant frequency generator for wind power systems
07
to give an indication of the performance of the system at unknown locations. Results indicate the viability of the radial basis for this kind of problem,
Wind energy 00102745 An adaptive feedback linearization strategy for variable speed wind energy conversion systems Valenciaga, F. Inrerna!ioncrl Journal of Energy Research, 2000. 24, (2) I5 I161. This paper presents a control strategy based on adaptive feedback linearization intended for variable speed grid-connected wind energy conversion systems (WECS). The proposed adaptive control law accomplishes energy capture maximization by tracking the wind speed fluctuations. In addition, it linearizes the system even in the presence of turbine model uncertainties, allowing the closed-loop dynamic behaviour to be determined by a simple tuning of the controller parameters. Particularly, the attention is focused on WECS with slip power recovery, which use a power conversion stage as a rotor-controlled double-output induction generator. However, the concepts behind the proposed control strategy are general and can be easily extended to other WECS configurations. 00102746 New self-excited variable speed constant frequency generator for wind power systems Metwally, H. M. B. Energy Coniers. Manage., 2000, 41, (13), 1405-1417. In this work, the possibility of using a new single-phase commutator machine as a stand-alone self-excited generator is investigated. The performance of this generator is tested under variable speed operation to simulate the practical case of variable wind turbine speed. The generator is self-excited through a resonance capacitor. The effect of varying the capacitance of this capacitor on the generated voltage and its frequency is studied. Load tests under a wide range of operating conditions are conducted to explore the capability of this type of generator. It has been discovered that this machine can operate as a variable speed constant frequency generator simply by varying the capacitance of the excitation capacitor. This important property makes this type of generator suitable for use in wind driven power systems. Finally, a mathematical model for the generator is obtained and a simulation programme is developed to predict the performance of the generator. Close agreement between the simulation and the experimental results is obtained. 00102747 On the regional wind energy potential of Turkey Oztopal, A. Drergy, 2000, 25, (2) 1899200. Continuous uses of fossil fuels are bound to pollute the atmosphere and consequently unwanted green-house and climate change effects will come to dominate every part of the earth. It is, therefore, advised to exploit clean energy resources and for many nations in the world to try to assess their environmentally friendly, clean energy resources such as wind energy. Hence, there is an urgent need to determine the wind energy potential in every country. This paper gives the wind velocity, topography and wind energy variation maps obtained for Turkey with local and regional interpretations. 00/02748 Wind energy development in Tamil Nadu and Andhra Pradesh, India. Institutional dynamics and barriers-a case study Jagadeesh, A. Energy Policy. 2000, 28, (3) 157-168. Tamil Nadu state has the distinction of 719 MW capacity wind farms at the end of September 1998 out of the country’s total figure of 992 MW. Andhra Pradesh has 58 MW installed windfarms in the state. 1995-96 saw a boom when 282 MW wind farms were set up in Tamil Nadu and capacity in Andhra Pradesh increased by 39 MW. Subsequently there was a steady decline in the wind farm development in both the states. This case study attempted in detail to trace the reasons for the boom and the factors that contributed to the slump in wind farm activity in the states. The role of institutions in determining the effectiveness of national and regional publicsector initiatives to promote and disseminate wind energy in the two states is discussed in the paper. The study has also looked into the financial, technical, transaction and institutional barriers which inhibit the diffusion of wind energy in the states. Creation of Wind Fund, establishment of cooperative wind farms, setting up of wind estates, linking generation to incentives for optimum production, promotion of reliable water pumping windmills and wind battery chargers for small-scale applications suggested in the paper for rapid growth of wind energy in Tamil Nadu and Andhra Pradesh. The results of the case study may be used to improve public policy intervention in disseminating wind energy in the country. It may also be relevant to multilateral and bilateral aid agencies in their projects and/or programmes to promote cost-effective wind energy technology dissemination in developing countries. 00102749 Wind power: gaining momentum Moore, T. GPR~Journul. 1999. 24, (4), 8-17. In the past two decades, wind power has emerged as one of the most economically competitive and promising renewable energy technologies, giving rise to a thriving commercial industry with substantial global reach.
Alternative
energy sources (others, including development,
economics)
Policymakers and energy planners around the world expect wind to supply an increasing share of electricity generation, thereby helping to limit atmospheric emissions of carbon dioxide. The cost of electricity from wind has declined dramatically with the maturing of the technology through several generations of turbines. But further cost reduction and technology breakthroughs are essential to the development of wind power’s enormous potential and its integration into a competitive generation market.
Others,
including
development,
economics
00102750 A Geographic Information System-based modeling system for evaluating the cost of delivered energy crop feedstock Graham, R. L. Biomass and Bioenergy, 2000, 18, (4), 309-329. The use of Geographic Information Systems (GIS) for understanding the geographic context of bioenergy supplies is discussed-and a regional-scale, GIS-based modelling system for estimating potential biomass supplies from energy crops is described. While GIS models can capture geographic variation that may influence biomass costs and supplies, GIS models are not likely to handle uncertainty well and are often limited by the lack of spatially explicit data. The presented modelling system estimates the costs and environmental implications of supplying specified amounts of energy crop feedstock across a state. The system considers where energy crops could be grown, the spatial variability in their yield and transportation costs associated with acquiring feedstock for an energy facility. The modelling system was used to estimate potential switchgrass costs and supplies in 11 US states. Transportation costs increased with increased facility demand and were lowest in Iowa, North Dakota and South Dakota and highest in South Carolina, Missouri, Georgia and Alabama. Farmgate feedstock costs were lowest in Alabama, North Dakota and South Dakota and highest in Iowa and Nebraska. Across the 11 states, delivered feedstock costs ranged from $33 to $55/dry tonne to supply a facility requiring 100 000 tonne/year. Delivered feedstock costs for a 630 000 tonne/year facility ranged from $36 to $58/dry tonne. 00102751 Biofuel production using slow pyrolysis of the straw and stalk of the rapeseed plant Karaosmanoglu, F. er ol. Fuel Process. Techno/.. 1999, 59, (I). l-12. Biomass, perhaps more so than the renewable alternative energy sources, has a large potential for commercial usage. Pyrolysis is the most important among the thermal conversion processes. In this study, slow pyrolysis of the straw and stalk of the rape-seed plant was investigated within a tubular reactor under the conditions of static atmosphere, varying temperatures of 350”, 450”, 550” and 650°C and at heating rates of 10 and 30 K/min. The maximum liquid yield was observed to be evolving at ‘650°C pyrolysis temperature and at a heating rate of 30 Wmin. The various characteristics of pyrolytic oil obtained under these conditions were identified. Following the chemical characterization, a biofuel candidate is presented in the form of the pyrolytic oil originated from the straw and stalk of the rape-seed plant. 00/02752 Biomass and bioenergy applications of the POLYSYS modeling framework De La Torre Ugarte, D. G. and Ray, D. E. Bmmcrss and BiomergJ, 2000, 18, (4),
291-308.
The Policy Analysis System (POLYSYS) is a national simulation model of the US agriculture sector which can incorporate agricultural supply and demand and related modules to estimate agricultural production response, impacts of projected resource use, price, income and environmental changes from an agricultural baseline. The framework recursively incorporates linear programming, econometric and process models to estimate an impact path resulting from changes imposed on a baseline scenario and its underlying assumptions. POLYSYS estimates prop production and supply at a disaggregated regional level, whereby the 48 contiguous states are subdivided into 305 geographic regions with relatively homogeneous production characteristics. POLYSYS is capable of estimating a wide range of policy alternatives and economic and environmental conditions and simulations may be tailored to a variety of specific analytical needs. This paper presents a broad overview of the structure and approach of the POLYSYS model with emphasis on biomass and bioenergy related applications of the model. 00/02753 Can a high-quality alternative fuel be manufactured from wastes? Heilmann, A. and Wagner, S. Beifr. A&//wirrsch, 1999, 9, 89-99 (In German) This paper explains the interactions between separated material recovery and the manufacture of alternative fuel. Also dtscussed are the conditions for the qualitative high-value alternative fuel production from wastes. The residual waste (after material recovery) contains consumer goods with a high content of pollutants compared to the packing materials. The manufacture of alternative fuels is carried out by different aggregate configurations to varying qualities. The process involves homogenization and drying and the homogenization and separation of high calorific value and low-pollutant containing fuel components.
Fuel and Energy Abstracts
September
2000
305
to give an indication of the performance of the system at unknown locations. Results indicate the viability of the radial basis for this kind of problem,
Wind energy 00102745 An adaptive feedback linearization strategy for variable speed wind energy conversion systems Valenciaga, F. Inrerna!ioncrl Journal of Energy Research, 2000. 24, (2) I5 I161. This paper presents a control strategy based on adaptive feedback linearization intended for variable speed grid-connected wind energy conversion systems (WECS). The proposed adaptive control law accomplishes energy capture maximization by tracking the wind speed fluctuations. In addition, it linearizes the system even in the presence of turbine model uncertainties, allowing the closed-loop dynamic behaviour to be determined by a simple tuning of the controller parameters. Particularly, the attention is focused on WECS with slip power recovery, which use a power conversion stage as a rotor-controlled double-output induction generator. However, the concepts behind the proposed control strategy are general and can be easily extended to other WECS configurations. 00102746 New self-excited variable speed constant frequency generator for wind power systems Metwally, H. M. B. Energy Coniers. Manage., 2000, 41, (13), 1405-1417. In this work, the possibility of using a new single-phase commutator machine as a stand-alone self-excited generator is investigated. The performance of this generator is tested under variable speed operation to simulate the practical case of variable wind turbine speed. The generator is self-excited through a resonance capacitor. The effect of varying the capacitance of this capacitor on the generated voltage and its frequency is studied. Load tests under a wide range of operating conditions are conducted to explore the capability of this type of generator. It has been discovered that this machine can operate as a variable speed constant frequency generator simply by varying the capacitance of the excitation capacitor. This important property makes this type of generator suitable for use in wind driven power systems. Finally, a mathematical model for the generator is obtained and a simulation programme is developed to predict the performance of the generator. Close agreement between the simulation and the experimental results is obtained. 00102747 On the regional wind energy potential of Turkey Oztopal, A. Drergy, 2000, 25, (2) 1899200. Continuous uses of fossil fuels are bound to pollute the atmosphere and consequently unwanted green-house and climate change effects will come to dominate every part of the earth. It is, therefore, advised to exploit clean energy resources and for many nations in the world to try to assess their environmentally friendly, clean energy resources such as wind energy. Hence, there is an urgent need to determine the wind energy potential in every country. This paper gives the wind velocity, topography and wind energy variation maps obtained for Turkey with local and regional interpretations. 00/02748 Wind energy development in Tamil Nadu and Andhra Pradesh, India. Institutional dynamics and barriers-a case study Jagadeesh, A. Energy Policy. 2000, 28, (3) 157-168. Tamil Nadu state has the distinction of 719 MW capacity wind farms at the end of September 1998 out of the country’s total figure of 992 MW. Andhra Pradesh has 58 MW installed windfarms in the state. 1995-96 saw a boom when 282 MW wind farms were set up in Tamil Nadu and capacity in Andhra Pradesh increased by 39 MW. Subsequently there was a steady decline in the wind farm development in both the states. This case study attempted in detail to trace the reasons for the boom and the factors that contributed to the slump in wind farm activity in the states. The role of institutions in determining the effectiveness of national and regional publicsector initiatives to promote and disseminate wind energy in the two states is discussed in the paper. The study has also looked into the financial, technical, transaction and institutional barriers which inhibit the diffusion of wind energy in the states. Creation of Wind Fund, establishment of cooperative wind farms, setting up of wind estates, linking generation to incentives for optimum production, promotion of reliable water pumping windmills and wind battery chargers for small-scale applications suggested in the paper for rapid growth of wind energy in Tamil Nadu and Andhra Pradesh. The results of the case study may be used to improve public policy intervention in disseminating wind energy in the country. It may also be relevant to multilateral and bilateral aid agencies in their projects and/or programmes to promote cost-effective wind energy technology dissemination in developing countries. 00102749 Wind power: gaining momentum Moore, T. GPR~Journul. 1999. 24, (4), 8-17. In the past two decades, wind power has emerged as one of the most economically competitive and promising renewable energy technologies, giving rise to a thriving commercial industry with substantial global reach.
Alternative
energy sources (others, including development,
economics)
Policymakers and energy planners around the world expect wind to supply an increasing share of electricity generation, thereby helping to limit atmospheric emissions of carbon dioxide. The cost of electricity from wind has declined dramatically with the maturing of the technology through several generations of turbines. But further cost reduction and technology breakthroughs are essential to the development of wind power’s enormous potential and its integration into a competitive generation market.
Others,
including
development,
economics
00102750 A Geographic Information System-based modeling system for evaluating the cost of delivered energy crop feedstock Graham, R. L. Biomass and Bioenergy, 2000, 18, (4), 309-329. The use of Geographic Information Systems (GIS) for understanding the geographic context of bioenergy supplies is discussed-and a regional-scale, GIS-based modelling system for estimating potential biomass supplies from energy crops is described. While GIS models can capture geographic variation that may influence biomass costs and supplies, GIS models are not likely to handle uncertainty well and are often limited by the lack of spatially explicit data. The presented modelling system estimates the costs and environmental implications of supplying specified amounts of energy crop feedstock across a state. The system considers where energy crops could be grown, the spatial variability in their yield and transportation costs associated with acquiring feedstock for an energy facility. The modelling system was used to estimate potential switchgrass costs and supplies in 11 US states. Transportation costs increased with increased facility demand and were lowest in Iowa, North Dakota and South Dakota and highest in South Carolina, Missouri, Georgia and Alabama. Farmgate feedstock costs were lowest in Alabama, North Dakota and South Dakota and highest in Iowa and Nebraska. Across the 11 states, delivered feedstock costs ranged from $33 to $55/dry tonne to supply a facility requiring 100 000 tonne/year. Delivered feedstock costs for a 630 000 tonne/year facility ranged from $36 to $58/dry tonne. 00102751 Biofuel production using slow pyrolysis of the straw and stalk of the rapeseed plant Karaosmanoglu, F. er ol. Fuel Process. Techno/.. 1999, 59, (I). l-12. Biomass, perhaps more so than the renewable alternative energy sources, has a large potential for commercial usage. Pyrolysis is the most important among the thermal conversion processes. In this study, slow pyrolysis of the straw and stalk of the rape-seed plant was investigated within a tubular reactor under the conditions of static atmosphere, varying temperatures of 350”, 450”, 550” and 650°C and at heating rates of 10 and 30 K/min. The maximum liquid yield was observed to be evolving at ‘650°C pyrolysis temperature and at a heating rate of 30 Wmin. The various characteristics of pyrolytic oil obtained under these conditions were identified. Following the chemical characterization, a biofuel candidate is presented in the form of the pyrolytic oil originated from the straw and stalk of the rape-seed plant. 00/02752 Biomass and bioenergy applications of the POLYSYS modeling framework De La Torre Ugarte, D. G. and Ray, D. E. Bmmcrss and BiomergJ, 2000, 18, (4),
291-308.
The Policy Analysis System (POLYSYS) is a national simulation model of the US agriculture sector which can incorporate agricultural supply and demand and related modules to estimate agricultural production response, impacts of projected resource use, price, income and environmental changes from an agricultural baseline. The framework recursively incorporates linear programming, econometric and process models to estimate an impact path resulting from changes imposed on a baseline scenario and its underlying assumptions. POLYSYS estimates prop production and supply at a disaggregated regional level, whereby the 48 contiguous states are subdivided into 305 geographic regions with relatively homogeneous production characteristics. POLYSYS is capable of estimating a wide range of policy alternatives and economic and environmental conditions and simulations may be tailored to a variety of specific analytical needs. This paper presents a broad overview of the structure and approach of the POLYSYS model with emphasis on biomass and bioenergy related applications of the model. 00/02753 Can a high-quality alternative fuel be manufactured from wastes? Heilmann, A. and Wagner, S. Beifr. A&//wirrsch, 1999, 9, 89-99 (In German) This paper explains the interactions between separated material recovery and the manufacture of alternative fuel. Also dtscussed are the conditions for the qualitative high-value alternative fuel production from wastes. The residual waste (after material recovery) contains consumer goods with a high content of pollutants compared to the packing materials. The manufacture of alternative fuels is carried out by different aggregate configurations to varying qualities. The process involves homogenization and drying and the homogenization and separation of high calorific value and low-pollutant containing fuel components.
Fuel and Energy Abstracts
September
2000
305