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00689 Electricity theft: a comparative analysis
06 Electrical power supply and utilization (economics, policy, suppfies, forecasts) diagnose the actual operating condition of the plant components so as to detect its possible malfunction. A simulated example of a 105 MW power plant is presented herein so that thermo-characterization of steam turbines, a condenser, a heat exchanger, and a pump is illustrated. The induced and intrinsic component malfunction effects on the RPS are also presented. Their effects are related to the RPS, thereby opening the possibility to apply methodologies to any internal decay and/or induced malfunctions that could appear in an operating component, in terms of the heat rate impact.
05/00682 Three-dimensional simulation of chemically reacting gas flows in the porous support structure of an integrated-planar solid oxide fuel cell Haberman, B. A. and Young, J. B. International Journal of Heat and Mass Transfer, 2004, 47, (17-18), 3617-3629. The behaviour of an integrated-planar solid oxide fuel cell (IP-SOFC) strongly depends on the reactive diffusive flows within its porous support structure. Fuel is transported through the porous structure to the anodes of the electrochemical cells and the structure may be impregnated with the required catalysts for the steam reforming of methane. It is important to be able to calculate the distribution of gas properties within the porous structure in order to predict the performance of each cell and to determine the amount of internal reforming that takes place. This paper describes a three-dimensional numerical calculation method that has been developed to solve the governing equations in the porous structure. The calculation method includes the interaction between the flow in the porous medium and that in the adjacent fuel supply channel. The results highlight the importance of the kinetics of the reforming reaction and the thermal boundary conditions, both of which have a significant effect on the flow field within the porous structure.
Economics, policy, supplies, forecasts 05/00683 An interactive-dynamic mechanism conceptualizing the cost and benefit of electric power quality Lee, G.-J. and Heydt, G. T. Electric Power Systems Research, 2004, 69, (I), 69-75. With the deregulation of the electric power energy market, providing power quality has become a more important concern of both power suppliers and customers. Customers require better quality with the development of digitally controlled facilities. However, there is not a specific infrastructure to motivate the design of the power system to achieve a specified level of electric power quality. This paper discusses a power quality interactive-dynamic control mechanism to conceptualize the cost and benefit of power quality. The basic objective is to provide an engineering infrastructure and procedure that 'gives the right signals' to the power supplier and the customer to balance power quality and cost. A power quality level index vector is utilized in the proposed infrastructure.
05100684 Carbon management strategies for US electricity generation capacity: A vintage-based approach Dahowski, R. T. and Dooley, J. J. Energy, 2004, 29, (9 10), 1589 1598. Utilities are under increasing pressure to reduce power plant CO2 emissions. If the US and world follow through on their long-term commitment to dramatically reduce emissions, this pressure will become significant over the coming decades. It is in the face of these concerns that the future of US fossil-fired power plants is examined. There are over 1337 operational fossil-fired power generating units of at least 100 MW in capacity that began operating between the early 1940s and today in the continental US. Together these units provide some 453 GW of electric power. Rapidly retiring this still valuable capital stock or undertaking large-scale immediate redevelopment with advanced power cycles as a means of addressing their greenhouse gas emissions will not be a sensible option for all of these units. Considering a conservative 40-year operating life, there are over 667 existing fossil-fired power plants, representing a capacity of over 291 GW, that have at least a decade's worth of productive life remaining. Applying Battelle's specialized analysis tools, relationships between these 667 plants and their technology type, location, emissions, and vintage have been explored. Based on these factors and the proximity of these plants to geologic reservoirs with potential for sequestering large volumes of CO2, the average costs for retrofitting these newer-vintage plants with capture technology and sequestering their CO2 into such reservoirs are presented. A discussion of a set of planned US fossil-fired power projects within the context of a carbonconstrained world is also included.
05/00685 Co-provision in sustainable energy systems: the case of micro-generation Watson, J. Energy Policy, 2004, 32, (17), 1981-1990. Electricity generation by individual households (known as microgeneration) is attracting an increasing amount of interest within government, industry and the research community. This paper focuses on the potential for micro-generation to contribute to a more active role for household energy consumers in the development and operation of the energy system. The paper applies the concept of energy service co-provision to aid an understanding of this more active role. It considers a number of alternative models for micro-generation investment that imply different kinds of co-provision by consumers and energy companies. The analysis focuses in particular on the economics of these models in the UK, the associated barriers to microgeneration investment, and the scope for overcoming these barriers through changes in fiscal rules. Having conducted this economic analysis, the paper concludes with a brief discussion of the wider implications of these models for consumer behaviour. In particular, it considers the impact of IT and control systems that might be employed to facilitate energy service co-provision that includes micro-generation.
05/00686 Congestion management, transmission pricing and area price hedging in the Nordic region Kristiansen, T. International Journal of Electrical Power & Energy Systems, 2004, 26, (9), 685 695. This paper gives an overview of the current practice for congestion management, transmission pricing, and area price hedging in the Nordic region. Transmission congestion in the Nordic region is managed by using the area price model and counter trade. Whenever there is congestion, two or more area prices are introduced within Norway, two in Denmark, and one each in Sweden and Finland. Transmission congestion risks can be significant for the Nordic market players. Therefore Nord Pool, the Nordic power exchange, introduced contracts for differences that are forward price differential products, on 17 November 2000. The payoff of these products depends on the respective area prices and the system price (the unconstrained price) in the settlement period. This paper describes how contracts for differences work, and how they can be used for hedging and speculation.
05•00687
Electrical energy usage over the business cycle
Thoma, M. Energy Economics, 2004, 26, (3), 463-485. Causality from macroeconomic conditions to electrical usage overall and in the residential, commercial, industrial, and other sectors is examined. The paper shows that changes in macroeconomic conditions cause significant changes in electrical usage in the commercial and industrial sectors, and overall. In addition, the paper shows that causality occurs at business cycle frequencies and that there are asymmetries over the business cycle. An implication is that forecasts used to assess the probability of exceeding capacity constraints should incorporate forecasts of macroeconomic conditions, asymmetries over the cycle, and how the commercial and industrial sectors will respond to such changes.
05/00688 Electricity end-use characteristics of air-cooled chillers in hotels in Hong Kong Yu, F. W. and Chan, K. T. Building and Environment, 2005, 40, (1), 143 151. This paper presents the operating efficiency of air-cooled chillers in three existing hotels and investigates the extent to which the annual electricity consumption can decrease by improving their efficiency. Chillers in these hotels tend to be improperly staged, causing their seasonal efficiency to rise by 0.05-0.12 kW/kW from a full load efficiency of 0.32 kW/kW. When chiller sequencing is restored, their seasonal efficiency could be enhanced to 0.34 kW/kW, which corresponds to an 8.8-22.7% drop in their annual electricity consumption. It is possible to further decrease the annual electricity consumption by 27.0-38.6% when the chillers operate under floating condensing temperature control instead of head pressure control. The implications of improved chiller efficiency for reducing the electricity demand of hotels are discussed.
05•00689
Electricity theft: a comparative analysis
Smith, T. B. Energy Policy, 2004, 32, (18), 2067-2076. Electricity theft can be in the form of fraud (meter tampering), stealing (illegal connections), billing irregularities, and unpaid bills. Estimates of the extent of electricity theft in a sample of 102 countries for 1980 and 2000 are undertaken. The evidence shows that theft is increasing in most regions of the world. The financial impacts of theft are reduced income from the sale of electricity and the necessity to charge more to consumers. Electricity theft is closely related to governance indicators, with higher levels of theft in countries without effective accountability, political instability, low government effectiveness and high levels of corruption. Electricity theft can be reduced by applying technical
Fuel and Energy Abstracts
March 2005 101
06 Electrical power supply and utilization (economics, policy, suppfies, forecasts) solutions such as tamper-proof meters, managerial methods such as inspection and monitoring, and in some cases restructuring power systems ownership and regulation.
05•00690 Envisaging feed-in tariffs for solar photovoltaic electricity: European lessons for Canada Rowlands, [. H. Renewable and Sustainable Energy Reviews, 2005, 9, (1), 51-68. While it is widely agreed that support schemes need to be put in place to promote the use of renewable electricity, there is less consensus as to what are the best kinds of strategies to use. What is attracting increasing attention in Canada is a system of renewable portfolio standards. In this, all power suppliers are under an obligation to ensure that a certain percentage of the electricity they generate is from renewable resources. They can either generate that electricity themselves or purchase 'green certificates' from those who have used renewables to generate electricity. Recent experience from Europe, however, suggests that a whole-hearted commitment to this single strategy could be premature and potentially damaging for the development of all kinds of renewable electricity in Canada, solar photovoltaics included. On the other side of the Atlantic Ocean, the use of so-called 'feed-in tariffs' (that is, an obligation for utilities to purchase, at a set price, the electricity generated by any renewable energy resource) is widely credited with accelerating the development of renewable electricity in many countries. The purpose of this article is to reflect upon this European experience with feed-in tariffs, to stimulate discussions regarding what promise they might hold for the development of solar pbotovoltaic electricity in Canada. The article is divided into three main sections. In the first section, policies to promote renewable electricity, presently in place in different parts of Canada, are reviewed. Attention is then focused, more specifically, in the second section of this article, upon 'feed-in tariffs'. After defining and describing this alternative system, experiences in the countries of the European Union are reviewed. The main strengths and weaknesses of feed-in tariffs - in the European experience - are also examined. The focus then moves back to Canada in the third section of the article. In this, a system of feed-in tariffs is proposed for the province of Ontario in order to provide just one example of the kind of support that could be forthcoming.
05100691 Fitness for purpose assessment after an over pressure incident at Arapuni Power Station Firth, D. et al. International Journal of Pressure Vessels" and Piping, 2004, 81, (6), 471-479. In December 2000 the wicket gates of Arapuni Unit G7 closed rapidly when a control arm separated from a shaft and the wickets were free to move. The unit had been operating under normal conditions at the time. The resulting overpressure pulse caused the lower portion of the penstock to become barrel shaped, and a longitudinal riveted joint partially failed. A significant amount of cracking was visible in the cast steel stay vanes and deformation had occurred at the rivets in the scroll case. A program of work was instigated to determine the cause of the failure, and its consequences, i.e. the pressures reached and what work was required to ensure that the unit was fit for reuse. The root cause of the failure was the design and fabrication of a control arm installed when the wicket gate control system had been modified. This control arm had two segments which clamped around a shaft. The clamping bolts used had seen a high residual bending load and cyclic loading. They failed in fatigue. The coating on the inside of the penstock and scroll casing was brittle and an assessment of the degree of craze cracking in the coating on tensile test specimens allowed an accurate method of determining the plastic strain that had occurred in the penstock, and hence the stress and applied pressure that occurred during the incident. The major issue was the condition of the stay vanes and the rivet holes in the scroll casing. The cracking in them was quantified by NDT inspection. Most of the cracks seen in the stay vanes were originaI casting defects that had not propagated during the overpressure. An engineering critical assessment was carried out in accordance with recognized international standards to determine the effects of defects under brittle fracture and overload conditions for a range of pressure conditions. An initial assessment was performed using conservative estimated values for the applied stresses and materials properties. The initial calculation indicated that the units were probably fit for purpose. Mechanical testing on samples taken from the stay vane casting and strain gauging during a proof pressure test was carried out. This allowed the calculations to be refined and the confidence in the result to be increased. A fatigue assessment was then carried out in accordance with the standards. The stay vanes and the scroll in the unit were shown to be fit for purpose without any modification and fatigue was not predicted to be a major problem. The unit was returned to service without any modification to the cracked stay vanes. An inspection procedure and regime was also defined to ensure the unit remains fit for purpose.
102
Fuel and Energy Abstracts
March 2005
05/00692 Generation capacity adequacy in the competitive electricity market environment Wen, F. S. et al. International Journal of' Electrical Power & Energy Systems, 2004, 26, (5), 365-372. One of the challenges for power industry restructuring is to maintain sufficient generation installed capacity to meet demand in nowadays and in the future, and the electricity market failure in California has brought this subject to the forefront of extensive debates. This paper initiates a review, assessment and discussion on some important issues related to ensuring adequate generation capacity additions under a competitive electricity market environment.
05100693 LCA-LCCA of oil fired steam turbine power plant in Singapore Kannan, R. et al. Energy Conversion and Management, 2004, 45, (1819), 3093-3107. A life cycle assessment (LCA) was conducted to quantify the nonrenewable energy use and global warming potential in electricity generation from a typical oil fired steam turbine plant in Singapore. As the conventional LCA does not include any cost analysis, which is a major criterion in decision-making, the cost of power generation is estimated using a life cycle cost analysis (LCCA) tool. It is estimated that the hidden processes consumed about 9% additional energy on top of the fuel embedded energy, while the hidden GHG emission is about 12%. A correlation is established to estimate the life cycle energy use and GHG emissions directly from the power plant net efficiency. The study methodology, results and the empirical relations are presented, together with a brief overview of the Singapore power sector. It also highlights the need for consideration of the reserves availability in the pricing mechanism and how such cost indices could be developed based on the LCA-LCCA.
05•00694 Modelling and optimization of district heating and industrial energy system - an approach to a locally deregulated heat market Gebremedhin, A. and Moshfegh, B. International Journal of Energy Research, 2004, 28, (5), 411~422. Regions with densely concentration of industries and district heating systems (DHS) could be interesting study object from the light of an integrated heat market on local basis. System analysis with a widened system boundary could be used as an approach to evaluate the benefit of an integrated heat supply system. In this study, an energy system model consisting of totally seven different participants is designed and the optimization results of the system analysis are presented. With applied data and assumptions, the study shows that a significant amount of the heat demand within two sub-systems can be covered by heat supply from the heat market (the entire heat comes from two industries). Shadow prices, which can be used for heat pricing, indicate the advantage of an integrated system. The system cost reduction through integration and the availability of several actors with diverse energy supply system, makes the region under study an interesting area to prove a locally deregulated heat market.
05/00695 Optimization models and solution methods for load management Gustafsson, S. et al. International Journal of Energy Research, 2004, 28, (4), 299-317. The electricity market in Sweden has changed during recent years. Electricity for industrial use can now be purchased from a number of competing electricity suppliers. Hence, the price for each kilowatt-hour is significantly lower than it was just two years ago and interest in electricity conservation measures has declined. However, part of the electricity tariff, i.e. the demand cost expressed in Swedish Kronor (SEK) for each kilowatt, is almost the same as before. Attention has thereby been drawn to load management measures in order to reduce this specific cost. Saving 1 kWh might lead to a monetary saving of between SEK 0.22 and SEK 914; this paper demonstrates how to eliminate only those kWh that actually save a significant amount of money. A load management system has been installed in a small carpentry factory that can turn off equipment based on a pre-set priority and number of minutes each hour. The question now is what level of the electricity load is optimal in a strictly mathematical sense, i.e. how many kW should be set in the load management computer in order to maximize profitability? In this paper, a mathematical model is developed that can be used as a tool both to find the most profitable subscription level and to control the choices to be made. Numerical results from a case study are also presented.
05•00696 market
Pricing of contracts for difference in the Nordic
Kristiansen, T. Energy Policy, 2004, 32, (9), 1075 1085. The purpose of this paper is to give an introduction to, and a pricing analysis of a new forward locational price differential product, contracts for difference (CfD), introduced on 17 November 2000 at Nord Pool - the Nordic electricity exchange. To the best of the authors'
05/00682 Three-dimensional simulation of chemically reacting gas flows in the porous support structure of an integrated-planar solid oxide fuel cell Haberman, B. A. and Young, J. B. International Journal of Heat and Mass Transfer, 2004, 47, (17-18), 3617-3629. The behaviour of an integrated-planar solid oxide fuel cell (IP-SOFC) strongly depends on the reactive diffusive flows within its porous support structure. Fuel is transported through the porous structure to the anodes of the electrochemical cells and the structure may be impregnated with the required catalysts for the steam reforming of methane. It is important to be able to calculate the distribution of gas properties within the porous structure in order to predict the performance of each cell and to determine the amount of internal reforming that takes place. This paper describes a three-dimensional numerical calculation method that has been developed to solve the governing equations in the porous structure. The calculation method includes the interaction between the flow in the porous medium and that in the adjacent fuel supply channel. The results highlight the importance of the kinetics of the reforming reaction and the thermal boundary conditions, both of which have a significant effect on the flow field within the porous structure.
Economics, policy, supplies, forecasts 05/00683 An interactive-dynamic mechanism conceptualizing the cost and benefit of electric power quality Lee, G.-J. and Heydt, G. T. Electric Power Systems Research, 2004, 69, (I), 69-75. With the deregulation of the electric power energy market, providing power quality has become a more important concern of both power suppliers and customers. Customers require better quality with the development of digitally controlled facilities. However, there is not a specific infrastructure to motivate the design of the power system to achieve a specified level of electric power quality. This paper discusses a power quality interactive-dynamic control mechanism to conceptualize the cost and benefit of power quality. The basic objective is to provide an engineering infrastructure and procedure that 'gives the right signals' to the power supplier and the customer to balance power quality and cost. A power quality level index vector is utilized in the proposed infrastructure.
05100684 Carbon management strategies for US electricity generation capacity: A vintage-based approach Dahowski, R. T. and Dooley, J. J. Energy, 2004, 29, (9 10), 1589 1598. Utilities are under increasing pressure to reduce power plant CO2 emissions. If the US and world follow through on their long-term commitment to dramatically reduce emissions, this pressure will become significant over the coming decades. It is in the face of these concerns that the future of US fossil-fired power plants is examined. There are over 1337 operational fossil-fired power generating units of at least 100 MW in capacity that began operating between the early 1940s and today in the continental US. Together these units provide some 453 GW of electric power. Rapidly retiring this still valuable capital stock or undertaking large-scale immediate redevelopment with advanced power cycles as a means of addressing their greenhouse gas emissions will not be a sensible option for all of these units. Considering a conservative 40-year operating life, there are over 667 existing fossil-fired power plants, representing a capacity of over 291 GW, that have at least a decade's worth of productive life remaining. Applying Battelle's specialized analysis tools, relationships between these 667 plants and their technology type, location, emissions, and vintage have been explored. Based on these factors and the proximity of these plants to geologic reservoirs with potential for sequestering large volumes of CO2, the average costs for retrofitting these newer-vintage plants with capture technology and sequestering their CO2 into such reservoirs are presented. A discussion of a set of planned US fossil-fired power projects within the context of a carbonconstrained world is also included.
05/00685 Co-provision in sustainable energy systems: the case of micro-generation Watson, J. Energy Policy, 2004, 32, (17), 1981-1990. Electricity generation by individual households (known as microgeneration) is attracting an increasing amount of interest within government, industry and the research community. This paper focuses on the potential for micro-generation to contribute to a more active role for household energy consumers in the development and operation of the energy system. The paper applies the concept of energy service co-provision to aid an understanding of this more active role. It considers a number of alternative models for micro-generation investment that imply different kinds of co-provision by consumers and energy companies. The analysis focuses in particular on the economics of these models in the UK, the associated barriers to microgeneration investment, and the scope for overcoming these barriers through changes in fiscal rules. Having conducted this economic analysis, the paper concludes with a brief discussion of the wider implications of these models for consumer behaviour. In particular, it considers the impact of IT and control systems that might be employed to facilitate energy service co-provision that includes micro-generation.
05/00686 Congestion management, transmission pricing and area price hedging in the Nordic region Kristiansen, T. International Journal of Electrical Power & Energy Systems, 2004, 26, (9), 685 695. This paper gives an overview of the current practice for congestion management, transmission pricing, and area price hedging in the Nordic region. Transmission congestion in the Nordic region is managed by using the area price model and counter trade. Whenever there is congestion, two or more area prices are introduced within Norway, two in Denmark, and one each in Sweden and Finland. Transmission congestion risks can be significant for the Nordic market players. Therefore Nord Pool, the Nordic power exchange, introduced contracts for differences that are forward price differential products, on 17 November 2000. The payoff of these products depends on the respective area prices and the system price (the unconstrained price) in the settlement period. This paper describes how contracts for differences work, and how they can be used for hedging and speculation.
05•00687
Electrical energy usage over the business cycle
Thoma, M. Energy Economics, 2004, 26, (3), 463-485. Causality from macroeconomic conditions to electrical usage overall and in the residential, commercial, industrial, and other sectors is examined. The paper shows that changes in macroeconomic conditions cause significant changes in electrical usage in the commercial and industrial sectors, and overall. In addition, the paper shows that causality occurs at business cycle frequencies and that there are asymmetries over the business cycle. An implication is that forecasts used to assess the probability of exceeding capacity constraints should incorporate forecasts of macroeconomic conditions, asymmetries over the cycle, and how the commercial and industrial sectors will respond to such changes.
05/00688 Electricity end-use characteristics of air-cooled chillers in hotels in Hong Kong Yu, F. W. and Chan, K. T. Building and Environment, 2005, 40, (1), 143 151. This paper presents the operating efficiency of air-cooled chillers in three existing hotels and investigates the extent to which the annual electricity consumption can decrease by improving their efficiency. Chillers in these hotels tend to be improperly staged, causing their seasonal efficiency to rise by 0.05-0.12 kW/kW from a full load efficiency of 0.32 kW/kW. When chiller sequencing is restored, their seasonal efficiency could be enhanced to 0.34 kW/kW, which corresponds to an 8.8-22.7% drop in their annual electricity consumption. It is possible to further decrease the annual electricity consumption by 27.0-38.6% when the chillers operate under floating condensing temperature control instead of head pressure control. The implications of improved chiller efficiency for reducing the electricity demand of hotels are discussed.
05•00689
Electricity theft: a comparative analysis
Smith, T. B. Energy Policy, 2004, 32, (18), 2067-2076. Electricity theft can be in the form of fraud (meter tampering), stealing (illegal connections), billing irregularities, and unpaid bills. Estimates of the extent of electricity theft in a sample of 102 countries for 1980 and 2000 are undertaken. The evidence shows that theft is increasing in most regions of the world. The financial impacts of theft are reduced income from the sale of electricity and the necessity to charge more to consumers. Electricity theft is closely related to governance indicators, with higher levels of theft in countries without effective accountability, political instability, low government effectiveness and high levels of corruption. Electricity theft can be reduced by applying technical
Fuel and Energy Abstracts
March 2005 101
06 Electrical power supply and utilization (economics, policy, suppfies, forecasts) solutions such as tamper-proof meters, managerial methods such as inspection and monitoring, and in some cases restructuring power systems ownership and regulation.
05•00690 Envisaging feed-in tariffs for solar photovoltaic electricity: European lessons for Canada Rowlands, [. H. Renewable and Sustainable Energy Reviews, 2005, 9, (1), 51-68. While it is widely agreed that support schemes need to be put in place to promote the use of renewable electricity, there is less consensus as to what are the best kinds of strategies to use. What is attracting increasing attention in Canada is a system of renewable portfolio standards. In this, all power suppliers are under an obligation to ensure that a certain percentage of the electricity they generate is from renewable resources. They can either generate that electricity themselves or purchase 'green certificates' from those who have used renewables to generate electricity. Recent experience from Europe, however, suggests that a whole-hearted commitment to this single strategy could be premature and potentially damaging for the development of all kinds of renewable electricity in Canada, solar photovoltaics included. On the other side of the Atlantic Ocean, the use of so-called 'feed-in tariffs' (that is, an obligation for utilities to purchase, at a set price, the electricity generated by any renewable energy resource) is widely credited with accelerating the development of renewable electricity in many countries. The purpose of this article is to reflect upon this European experience with feed-in tariffs, to stimulate discussions regarding what promise they might hold for the development of solar pbotovoltaic electricity in Canada. The article is divided into three main sections. In the first section, policies to promote renewable electricity, presently in place in different parts of Canada, are reviewed. Attention is then focused, more specifically, in the second section of this article, upon 'feed-in tariffs'. After defining and describing this alternative system, experiences in the countries of the European Union are reviewed. The main strengths and weaknesses of feed-in tariffs - in the European experience - are also examined. The focus then moves back to Canada in the third section of the article. In this, a system of feed-in tariffs is proposed for the province of Ontario in order to provide just one example of the kind of support that could be forthcoming.
05100691 Fitness for purpose assessment after an over pressure incident at Arapuni Power Station Firth, D. et al. International Journal of Pressure Vessels" and Piping, 2004, 81, (6), 471-479. In December 2000 the wicket gates of Arapuni Unit G7 closed rapidly when a control arm separated from a shaft and the wickets were free to move. The unit had been operating under normal conditions at the time. The resulting overpressure pulse caused the lower portion of the penstock to become barrel shaped, and a longitudinal riveted joint partially failed. A significant amount of cracking was visible in the cast steel stay vanes and deformation had occurred at the rivets in the scroll case. A program of work was instigated to determine the cause of the failure, and its consequences, i.e. the pressures reached and what work was required to ensure that the unit was fit for reuse. The root cause of the failure was the design and fabrication of a control arm installed when the wicket gate control system had been modified. This control arm had two segments which clamped around a shaft. The clamping bolts used had seen a high residual bending load and cyclic loading. They failed in fatigue. The coating on the inside of the penstock and scroll casing was brittle and an assessment of the degree of craze cracking in the coating on tensile test specimens allowed an accurate method of determining the plastic strain that had occurred in the penstock, and hence the stress and applied pressure that occurred during the incident. The major issue was the condition of the stay vanes and the rivet holes in the scroll casing. The cracking in them was quantified by NDT inspection. Most of the cracks seen in the stay vanes were originaI casting defects that had not propagated during the overpressure. An engineering critical assessment was carried out in accordance with recognized international standards to determine the effects of defects under brittle fracture and overload conditions for a range of pressure conditions. An initial assessment was performed using conservative estimated values for the applied stresses and materials properties. The initial calculation indicated that the units were probably fit for purpose. Mechanical testing on samples taken from the stay vane casting and strain gauging during a proof pressure test was carried out. This allowed the calculations to be refined and the confidence in the result to be increased. A fatigue assessment was then carried out in accordance with the standards. The stay vanes and the scroll in the unit were shown to be fit for purpose without any modification and fatigue was not predicted to be a major problem. The unit was returned to service without any modification to the cracked stay vanes. An inspection procedure and regime was also defined to ensure the unit remains fit for purpose.
102
Fuel and Energy Abstracts
March 2005
05/00692 Generation capacity adequacy in the competitive electricity market environment Wen, F. S. et al. International Journal of' Electrical Power & Energy Systems, 2004, 26, (5), 365-372. One of the challenges for power industry restructuring is to maintain sufficient generation installed capacity to meet demand in nowadays and in the future, and the electricity market failure in California has brought this subject to the forefront of extensive debates. This paper initiates a review, assessment and discussion on some important issues related to ensuring adequate generation capacity additions under a competitive electricity market environment.
05100693 LCA-LCCA of oil fired steam turbine power plant in Singapore Kannan, R. et al. Energy Conversion and Management, 2004, 45, (1819), 3093-3107. A life cycle assessment (LCA) was conducted to quantify the nonrenewable energy use and global warming potential in electricity generation from a typical oil fired steam turbine plant in Singapore. As the conventional LCA does not include any cost analysis, which is a major criterion in decision-making, the cost of power generation is estimated using a life cycle cost analysis (LCCA) tool. It is estimated that the hidden processes consumed about 9% additional energy on top of the fuel embedded energy, while the hidden GHG emission is about 12%. A correlation is established to estimate the life cycle energy use and GHG emissions directly from the power plant net efficiency. The study methodology, results and the empirical relations are presented, together with a brief overview of the Singapore power sector. It also highlights the need for consideration of the reserves availability in the pricing mechanism and how such cost indices could be developed based on the LCA-LCCA.
05•00694 Modelling and optimization of district heating and industrial energy system - an approach to a locally deregulated heat market Gebremedhin, A. and Moshfegh, B. International Journal of Energy Research, 2004, 28, (5), 411~422. Regions with densely concentration of industries and district heating systems (DHS) could be interesting study object from the light of an integrated heat market on local basis. System analysis with a widened system boundary could be used as an approach to evaluate the benefit of an integrated heat supply system. In this study, an energy system model consisting of totally seven different participants is designed and the optimization results of the system analysis are presented. With applied data and assumptions, the study shows that a significant amount of the heat demand within two sub-systems can be covered by heat supply from the heat market (the entire heat comes from two industries). Shadow prices, which can be used for heat pricing, indicate the advantage of an integrated system. The system cost reduction through integration and the availability of several actors with diverse energy supply system, makes the region under study an interesting area to prove a locally deregulated heat market.
05/00695 Optimization models and solution methods for load management Gustafsson, S. et al. International Journal of Energy Research, 2004, 28, (4), 299-317. The electricity market in Sweden has changed during recent years. Electricity for industrial use can now be purchased from a number of competing electricity suppliers. Hence, the price for each kilowatt-hour is significantly lower than it was just two years ago and interest in electricity conservation measures has declined. However, part of the electricity tariff, i.e. the demand cost expressed in Swedish Kronor (SEK) for each kilowatt, is almost the same as before. Attention has thereby been drawn to load management measures in order to reduce this specific cost. Saving 1 kWh might lead to a monetary saving of between SEK 0.22 and SEK 914; this paper demonstrates how to eliminate only those kWh that actually save a significant amount of money. A load management system has been installed in a small carpentry factory that can turn off equipment based on a pre-set priority and number of minutes each hour. The question now is what level of the electricity load is optimal in a strictly mathematical sense, i.e. how many kW should be set in the load management computer in order to maximize profitability? In this paper, a mathematical model is developed that can be used as a tool both to find the most profitable subscription level and to control the choices to be made. Numerical results from a case study are also presented.
05•00696 market
Pricing of contracts for difference in the Nordic
Kristiansen, T. Energy Policy, 2004, 32, (9), 1075 1085. The purpose of this paper is to give an introduction to, and a pricing analysis of a new forward locational price differential product, contracts for difference (CfD), introduced on 17 November 2000 at Nord Pool - the Nordic electricity exchange. To the best of the authors'