Life cycle assessment of geothermal power generation

Abstract

An overview of environmental effects during the life cycle of geothermal power generation including en-hanced geothermal systems (EGS) is presented. Until now, only few studies provide quantitative assess-ments on direct and indirect environmental con-sequences of such deep geothermal systems. Hence, studies based on life cycle assessment (LCA) for the geothermal electricity production are rare. In addition, the few existing studies are country- and/or site-specific with a clear concentration of geothermal systems in California, USA. A global and universal assessment is therefore still challenging mainly caused by the different nature and maturity of the applied geothermal plant technology, the site-specific charac-teristics and uncertainty in long-term productivity of the investigated or planned system. Greenhouse gas emissions (GHG), geological hazards, and water and land use effects are extremely variable and also may change during a life cycle. For conventional geot-hermal energy productions (non-EGS), potential emis-sions of toxic elements such as mercury, boron and arsenic and their environmental consequences are insufficiently studied and should therefore be investigated in future research.