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02659 Using energy scenarios to explore alternative energy pathways in California
08 Steam raising (boiler operation~design) presented. Renewable energy sources (RES) supply 14% of the total world energy demand. RES are biomass, hydropower, geothermal, solar, wind and marine energies. The renewables are the primary, domestic and clean or inexhaustible energy resources. The percentage share of biomass was 62.1% of total renewable energy sources in 1995. Experimental results for a large variety of biomass fuels and conditions are presented. Numerical studies are also discussed. Biomass is an attractive renewable fuel in utility boilers. The compositions of biomass among fuel types are variable. Ash composition for the biomass is fundamentally different from ash composition for the coal. Especially inorganic constituents cause to critical problems of toxic emissions, fouling and slagging. Metals in ash, in combination with other fuel elements such as silica and sulfur, and facilitated by the presence of chlorine, are responsible for many undesirable reactions in combustion furnaces and power boilers. Elements including K, Na, S, C1, P, Ca, Mg, Fe; Si are involved in reactions leading to ash fouling and slagging in biomass combustors. Chlorine in the biomass may affect operation by corrosion. Ash deposits reduce heat transfer and may also result in severe corrosion at high temperatures. Other influences of biomass composition are observed for the rates of combustion and pollutant emissions. Biomass combustion systems are non-polluting and offer significant protection of the environment. The reduction of greenhouse gases pollution is the main advantage of utilizing biomass energy.
05•02657 The impact of global change on the hydropower potential of Europe: a model-based analysis Lehner, B. et al. Energy Policy, 2005, 33, (7), 839 855. This study presents a model-based approach for analysing the possible effects of global change on Europe's hydropower potential at a country scale. By comparing current conditions of climate and water use with future scenarios, an overview is provided of today's potential for hydroelectricity generation and its mid- and long-term prospects. The application of the global water model WaterGAP for discharge calculations allows for an integrated assessment, taking both climate and socio-economic changes into account. This study comprises two key parts: First, the 'gross' hydropower potential is analysed, in order to outline the general distribution and trends in hydropower capabilities across Europe. Then, the assessment focuses on the 'developed' hydropower potential of existing hydropower plants, in order to allow for a more realistic picture of present and future electricity production. For the second part, a new data set has been developed which geo-references 5991 European hydropower stations and distinguishes them into run-of-river and reservoir stations. The results of this study present strong indications that, following moderate climate and global change scenario assumptions, severe future alterations in discharge regimes have to be expected, leading to unstable regional trends in hydropower potentials with reductions of 25% and more for southern and southeastern European countries.
05•02655 Renewable energy resources as an alternative to modify the load curve in Northern Cyprus
05•02658 Use of thermodynamic functions for expressing some relevant aspects of sustainability
Ilkan, M. et al. Energy, 2005, 30, (5), 555-572. The average annual increase in electricity consumption and peak demand in Northern Cyprus (N. Cyprus) during the past 20 years have been 7.1 and 5.5%, respectively. In recent years, the demand for electricity has been stretched to its limits in winter. This raised the question of whether renewable energy resources could be utilized to reduce the levei of peak demand. Indeed, Cyprus being a Mediterranean island, enjoys an abundance of solar energy, and preliminary studies showed that a considerable potential of wind energy is also available. Utilization of renewable energy for space heating, water heating, pumping and power generation would increase electrical reserve margins, raise system load factor, improve load following capabilities, and reduce the need for capacity expansion. Currently, solar water heating which leads to a saving of at least 72 GWh energy per annum and a significant reduction in COz emission has been extensively used in N. Cyprus. In N. Cyprus, despite the availability of renewable energy resources constructing renewable base-load, electrical power stations has not been found feasible. However, constructing such systems is recommended for two reasons: firstly, as a supplement to saving fuel and secondly, expanding capacity. In this context, the economic analysis for both solar and wind energy systems, has shown a reasonable internal rate of return (IRR). Although, the I R R is higher for wind energy systems, the availability of wind is limited to a few locations and therefore energy distribution is required.
Bastianoni, S. et al. International Journal of Energy Research, 2005, 29, (1), 53-64. Sustainability is a key concept for our future and the role of thermodynamics in its assessment is fundamental. The use of energy and matter must be considered not only from a microscopic viewpoint (the use of a single fuel or material, or the presence of a single pollutant) but also by means of holistic approaches able to synthesize all the characteristics of a single process. Exergy is a suitable function for this purpose. The exergy concept can also be applied to natural systems and to systems at the interface between natural and artificial ones. In this context, emergy can also express very helpful indications. Four different efficiency indices are here examined to better understand different aspects of the sustainability of processes and systems. An application to two similar agricultural systems (wine production in Italy) shows how these indices work in real case studies.
05•02656 The economic and institutional rationale of PV subsidies Sanddn, B. A. Solar Energy, 2005, 78, (2), 137-146. In terms of cost and performance, infant technologies, such as solar photovoltaics (PV), are normally inferior to entrenched technologies. It is a Catch-22 situation since the diffusion on larger markets that would be needed to reduce cost is hindered by the high cost. Therefore it would make sense to subsidize PV to increase sales, which would increase experience and induce investments in larger factories, which in turn would drive down costs and the subsidies needed. The total costs of such a scheme does not have to be prohibitive if cost reductions with increased volumes are large enough. Over the last 20 years the cost of PV modules was reduced by 18-23% per doubling of cumulative production (a progress ratio of 0.77-0.82). For a progress ratio of 0.80 and an annual growth rate of 30%, the modelled annual subsidy peaks at US$14 billion, which corresponds to an additional electricity tax of no more than 0.1 US cents/kW h in OECD countries. A market support programme also creates institutional learning and increases the political power of the proponents of PV. The current federal German support programme is a product of learning and network formation in earlier market stimulation and research, development and demonstration (RDD) programmes of smaller scale. Hence, the current support programme is now likely to create not only economic virtuous circles that reduce costs, but also institutional virtuous circles that work for the survival and expansion of the programme itself. As the PV industry grows, care should be taken to maintain variety to reduce the risk of a premature lock-in of an inferior design. To maintain variety in the market place may prove costly when the market grows but variety creation at the level of R D D investments is fairly cheap. To increase the world expenditure on RDD of renewable energy technology by a factor of 10 would not cost more than US$1/ton C or 0.02 cents/kW h of electricity.
388
Fuel and Energy Abstracts
November 2005
05/02659 Using energy scenarios to explore alternative energy pathways in California Ghanadan, R. and Koomey, J. G. Energy Policy, 2005, 33, (9), l117I142. This paper develops and analyses four energy scenarios for California that are both exploratory and quantitative. The business-as-usual scenario represents a pathway guided by outcomes and expectations emerging from California's energy crisis. Three alternative scenarios represent contexts where clean energy plays a greater role in California's energy system: Split Public is driven by local and individual activities; Golden State gives importance to integrated state planning; Patriotic Energy represents a national drive to increase energy independence. Future energy consumption, composition of electricity generation, energy diversity, and greenhouse gas emissions are analysed for each scenario through 2035. Energy savings, renewable energy, and transportation activities are identified as promising opportunities for achieving alternative energy pathways in California. A combined approach that brings together individual and community activities with state and national policies leads to the largest energy savings, increases in energy diversity, and reductions in greenhouse gas emissions. Critical challenges in California's energy pathway over the next decades identified by the scenario analysis include dominance of the transportation sector, dependence on fossil fuels, emissions of greenhouse gases, accounting for electricity imports, and diversity of the electricity sector. The paper concludes with a set of policy lessons revealed from the California energy scenarios.
08
STEAM RAISING Boiler operation/design
05/02660 Control concepts for direct steam generation in parabolic troughs Valenzuela, L. et al. Solar Energy, 2005, 78, (2), 301-311.
05•02657 The impact of global change on the hydropower potential of Europe: a model-based analysis Lehner, B. et al. Energy Policy, 2005, 33, (7), 839 855. This study presents a model-based approach for analysing the possible effects of global change on Europe's hydropower potential at a country scale. By comparing current conditions of climate and water use with future scenarios, an overview is provided of today's potential for hydroelectricity generation and its mid- and long-term prospects. The application of the global water model WaterGAP for discharge calculations allows for an integrated assessment, taking both climate and socio-economic changes into account. This study comprises two key parts: First, the 'gross' hydropower potential is analysed, in order to outline the general distribution and trends in hydropower capabilities across Europe. Then, the assessment focuses on the 'developed' hydropower potential of existing hydropower plants, in order to allow for a more realistic picture of present and future electricity production. For the second part, a new data set has been developed which geo-references 5991 European hydropower stations and distinguishes them into run-of-river and reservoir stations. The results of this study present strong indications that, following moderate climate and global change scenario assumptions, severe future alterations in discharge regimes have to be expected, leading to unstable regional trends in hydropower potentials with reductions of 25% and more for southern and southeastern European countries.
05•02655 Renewable energy resources as an alternative to modify the load curve in Northern Cyprus
05•02658 Use of thermodynamic functions for expressing some relevant aspects of sustainability
Ilkan, M. et al. Energy, 2005, 30, (5), 555-572. The average annual increase in electricity consumption and peak demand in Northern Cyprus (N. Cyprus) during the past 20 years have been 7.1 and 5.5%, respectively. In recent years, the demand for electricity has been stretched to its limits in winter. This raised the question of whether renewable energy resources could be utilized to reduce the levei of peak demand. Indeed, Cyprus being a Mediterranean island, enjoys an abundance of solar energy, and preliminary studies showed that a considerable potential of wind energy is also available. Utilization of renewable energy for space heating, water heating, pumping and power generation would increase electrical reserve margins, raise system load factor, improve load following capabilities, and reduce the need for capacity expansion. Currently, solar water heating which leads to a saving of at least 72 GWh energy per annum and a significant reduction in COz emission has been extensively used in N. Cyprus. In N. Cyprus, despite the availability of renewable energy resources constructing renewable base-load, electrical power stations has not been found feasible. However, constructing such systems is recommended for two reasons: firstly, as a supplement to saving fuel and secondly, expanding capacity. In this context, the economic analysis for both solar and wind energy systems, has shown a reasonable internal rate of return (IRR). Although, the I R R is higher for wind energy systems, the availability of wind is limited to a few locations and therefore energy distribution is required.
Bastianoni, S. et al. International Journal of Energy Research, 2005, 29, (1), 53-64. Sustainability is a key concept for our future and the role of thermodynamics in its assessment is fundamental. The use of energy and matter must be considered not only from a microscopic viewpoint (the use of a single fuel or material, or the presence of a single pollutant) but also by means of holistic approaches able to synthesize all the characteristics of a single process. Exergy is a suitable function for this purpose. The exergy concept can also be applied to natural systems and to systems at the interface between natural and artificial ones. In this context, emergy can also express very helpful indications. Four different efficiency indices are here examined to better understand different aspects of the sustainability of processes and systems. An application to two similar agricultural systems (wine production in Italy) shows how these indices work in real case studies.
05•02656 The economic and institutional rationale of PV subsidies Sanddn, B. A. Solar Energy, 2005, 78, (2), 137-146. In terms of cost and performance, infant technologies, such as solar photovoltaics (PV), are normally inferior to entrenched technologies. It is a Catch-22 situation since the diffusion on larger markets that would be needed to reduce cost is hindered by the high cost. Therefore it would make sense to subsidize PV to increase sales, which would increase experience and induce investments in larger factories, which in turn would drive down costs and the subsidies needed. The total costs of such a scheme does not have to be prohibitive if cost reductions with increased volumes are large enough. Over the last 20 years the cost of PV modules was reduced by 18-23% per doubling of cumulative production (a progress ratio of 0.77-0.82). For a progress ratio of 0.80 and an annual growth rate of 30%, the modelled annual subsidy peaks at US$14 billion, which corresponds to an additional electricity tax of no more than 0.1 US cents/kW h in OECD countries. A market support programme also creates institutional learning and increases the political power of the proponents of PV. The current federal German support programme is a product of learning and network formation in earlier market stimulation and research, development and demonstration (RDD) programmes of smaller scale. Hence, the current support programme is now likely to create not only economic virtuous circles that reduce costs, but also institutional virtuous circles that work for the survival and expansion of the programme itself. As the PV industry grows, care should be taken to maintain variety to reduce the risk of a premature lock-in of an inferior design. To maintain variety in the market place may prove costly when the market grows but variety creation at the level of R D D investments is fairly cheap. To increase the world expenditure on RDD of renewable energy technology by a factor of 10 would not cost more than US$1/ton C or 0.02 cents/kW h of electricity.
388
Fuel and Energy Abstracts
November 2005
05/02659 Using energy scenarios to explore alternative energy pathways in California Ghanadan, R. and Koomey, J. G. Energy Policy, 2005, 33, (9), l117I142. This paper develops and analyses four energy scenarios for California that are both exploratory and quantitative. The business-as-usual scenario represents a pathway guided by outcomes and expectations emerging from California's energy crisis. Three alternative scenarios represent contexts where clean energy plays a greater role in California's energy system: Split Public is driven by local and individual activities; Golden State gives importance to integrated state planning; Patriotic Energy represents a national drive to increase energy independence. Future energy consumption, composition of electricity generation, energy diversity, and greenhouse gas emissions are analysed for each scenario through 2035. Energy savings, renewable energy, and transportation activities are identified as promising opportunities for achieving alternative energy pathways in California. A combined approach that brings together individual and community activities with state and national policies leads to the largest energy savings, increases in energy diversity, and reductions in greenhouse gas emissions. Critical challenges in California's energy pathway over the next decades identified by the scenario analysis include dominance of the transportation sector, dependence on fossil fuels, emissions of greenhouse gases, accounting for electricity imports, and diversity of the electricity sector. The paper concludes with a set of policy lessons revealed from the California energy scenarios.
08
STEAM RAISING Boiler operation/design
05/02660 Control concepts for direct steam generation in parabolic troughs Valenzuela, L. et al. Solar Energy, 2005, 78, (2), 301-311.