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Titill:
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Efficiency in geothermal utilization processesEfficiency in geothermal utilization processes |
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Höfundur:
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Ingimar Guðni Haraldsson 1975
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LaGeo
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Jarðhitaskóli Háskóla Sameinuðu þjóðanna
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United Nations University
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United Nations University, Geothermal Training Programme
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URI:
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http://hdl.handle.net/10802/16580
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Útgefandi:
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United Nations University
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Útgáfa:
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2016 |
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Ritröð:
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United Nations University., UNU Geothermal Training Programme, Iceland. Short Course ; SC-22 |
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Efnisorð:
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Jarðhiti; Jarðhitanýting; Umhverfismat; Sjálfbærni; Endurnýjanleg orka
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ISSN:
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1670-794x |
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Tungumál:
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Enska
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Tengd vefsíðuslóð:
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https://orkustofnun.is/gogn/unu-gtp-sc/UNU-GTP-SC-22-12.pdf
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Tegund:
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Bók |
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Gegnir ID:
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991010157109706886
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Athugasemdir:
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Presented at “SDG Short Course I on Sustainability and Environmental Management of Geothermal Resource Utilization and the Role of Geothermal in Combating Climate Change”, organized by UNU-GTP and LaGeo, in Santa Tecla, El Salvador, September 4-10, 2016.
Improvements in energy efficiency have been advocated by many acclaimed world bodies. One of the targets of UN Sustainable Development Goal 7 is to double the global rate of improvements in energy efficiency by 2030. In this paper, efficiency in geothermal utilization processes is examined – in electricity generation and direct utilization. An overview is given of these two main types of processes and how geothermal fluid is suitable for different purposes at different temperatures. Carnot efficiency, exergy and the work potential of geothermal fluid are addressed. First and second law efficiencies of geothermal power plants are reported – many obtained from the literature, but some values estimated by the author. Comparisons are made between different types of geothermal processes (steam cycles and binary cycles) and between geothermal power plants on one hand and fossil fuel fired and nuclear power plants on the other. While geothermal power plants do not compare well to the other types of thermal power plants on first law basis, they compare well on second law basis and in particular outperform fossil fuel fired power plants on carbon emissions parity basis. Different forms of efficiency equations (simple, functional and conditional) are presented on the basis of primary energy (first law efficiencies) and exergy (second law efficiencies) for both types of processes (electricity generation and direct use). The equations are used to calculate efficiencies for five Icelandic power plants. Efficiencies are dynamic metrics that, through effort, can improve with time. Improvements in energy efficiency benefit the environment and have the potential to conserve resources compared to a business-as-usual scenario. |
