Life cycle sustainability assessment and circularity of geothermal power plants

Geothermal power generation is expected to increase fivefold worldwide by 2040 compared to 2018. The up-coming growth of geothermal power plants (GPPs) requires assessments of its role in tackling climate change and other impacts within complex environmental, economic and social systems. This study presents the first lit-erature review of GPPs, including comparisons among different GPP technologies, based on life cycle sustainabil-ity and circular economy perspectives. A total of 76 core literature studies on geothermal-related topics are reviewed, including technology choices, and critically discussed in terms of their environmental, economic, social and circular economy aspects. Firstly, seven life cycle environmental impact indicators (global warming, acidifi-cation, eutrophication, human toxicity, ozone depletion, photochemical oxidation, and cumulative energy de-mand) are compared both within GPP technologies and to other conventional electricity generation technologies (such as coal and hydro). Secondly, economic sustainability is considered via life cycle costing, and the results show that geothermal could be economically competitive when compared to solar photovoltaic (PV), hydro, and even wind energy sources. Thirdly, social aspects are discussed considering 15 articles that eval-uated concerns such as public acceptance, technology safety and local employment rate, although none rigor-ously considered a life cycle approach. Lastly, a total of 12 articles were found linking the circular economy with GPPs and elaborating on some of the'9Rs' framework. To improve the effectiveness of future research, stud-ies should focus on fulfilling major data gaps in literature such as the lack of detailed documentation for specific materials and background process choices in life cycle assessment databases. The development of GPPs can be an important alternative in efforts to decrease climate change impacts and pursue cleaner energy sources in coun-tries where geothermal energy is more easily available.(c) 2022 The Authors. Published by Elsevier Ltd on behalf of Institution of Chemical Engineers. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).