University of Twente Student Theses


A life cycle assessment based comparison of large & small scale geo-thermal electricity production systems

Yu, Tianqi (2017) A life cycle assessment based comparison of large & small scale geo-thermal electricity production systems.

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Abstract:Greenhouse gas(GHG)emissions from fossil fuel electricity production cause a big problem on global warming. Using renewable energy, such as wind, solar and geothermal energy, is a more sustainable solutionto produce electricity. During the operating phase of a geothermal energy power plant, there are muchless GHG emissions compared to conventional power plants. But how sustainable are geothermal electricity production systems considering the whole life cycle, from construction, operation to closure of the power plant. Most researchon the life cycle assessment (LCA) ofgeothermal energy (GTE) systems is conducted on large-scale geothermal power plants (installed capacity > 5MW)to assess theirenvironmental performance. Little is known on the LCA of small-scale GTE systems. The main aim of this research was therefore to compare the environmental impacts of a large-scale GTE flash system (the installed capacity is 110MW) and a small-scale binary GTE system(the installedcapacity is 500KW)using LCA, for the construction and operation stages. The results shows that marine aquatic eco-toxicity caused by deep well drilling is the most significant environmental impact in a life cycle aspect for a large-scale flash system, followed by human toxicity and abiotic depletion (fossil fuel). A small-scale binary system is more sustainable related to deep well drilling. Considering the process of power plant machinery and pipeline production, a large-scale flash system is more sustainable than a small-scale binary as overall less materials are required to produce the same amount of electricity. A small-scale binary system performs better in the power plant building phase. The same can be said for the operation phase as there are zero gas emissions from a small-scale binary systemwhile a large-scale flash system has a large impact on marine aquatic toxicity and to a lesser extent on global warming and human toxicity.
Item Type:Essay (Master)
Faculty:ITC: Faculty of Geo-information Science and Earth Observation
Programme:Geoinformation Science and Earth Observation MSc (75014)
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