Circularity and Environmental Sustainability of Geothermal Energy

This chapter examines the effectiveness of the adoption of circular economy (CE) framework into geothermal power generation to boost life cycle environmental sustainability. With geothermal energy expected to grow by 251% by the year 2030, tapping into this consistent energy source is crucial for the 2050 net-zero target. Nevertheless, challenges such as limited natural hydrothermal reservoirs and high exploration costs persist. The chapter evaluates the ‘repurpose’ strategy of CE, focusing on converting abandoned oil and gas wells (AOGWs) for geothermal power generation. Three systems, repurposed two completely AOGWs (R-GEOdouble, a single completely AOGW (R-GEOsingle), and semi-AOGWs (R-GEOsemi), are analysed against a business-as-usual geothermal plant, GEObau. Results indicate that these systems can decrease their climate change potential by 15%, 23%, and 34% respectively. Compared to GEObau, R-GEOsemi emerges as the most promising, though its advantage over GEObau is slight due to limited electricity generation. The effectiveness of repurposed systems largely depends on the choice of AOGWs, especially those with high water content. While R-GEOdouble and R-GEOsingle offer climate change mitigation benefits, their overall environmental sustainability still necessitates systematic optimisation. This chapter illuminates the potential for transitioning the fossil fuel sector to renewable energy through the use of AOGWs.