Full environmental life cycle costing analysis of repurposing onshore abandoned oil and gas wells for geothermal power generation

Geothermal energy utilisation is often constrained by high upfront costs. In line with circular economy principles, repurposing onshore abandoned oil and gas wells (AOGWs) for geothermal power generation has emerged as a promising alternative, but its economic sustainability implications remain underexplored. This study presents the first comprehensive environmental life cycle costing (FELCC) analysis of repurposed geothermal systems, incorporating both internal costs and externalities related to environmental degradation and human health. The three evaluated geothermal systems use either two AOGWs (R-GEO double ), one AOGW (R-GEO single ), or semi-AOGWs (i.e. wells still in operation but with high water content, R-GEO semi ). They are compared to a business-as-usual plant (GEO bau ). The total levelised costs of electricity (LCOE) are 12.6, 818.8, 461.7 and 173.3 cents € 2022 /kWh for GEO bau , R-GEO double , R-GEO single , and R-GEO semi , respectively. These high costs arise from low annual power output (125,120 kWh/year) and shorter lifetime (15 years) compared to GEO bau . Break-even analysis indicates that R-GEO semi must achieve 68% system efficiency, if it operates for only 15 years, to match GEO bau’s LCOE, while the remaining repurposed systems face even more challenging conditions. Nevertheless, repurposed systems demonstrate substantially lower environmental externalities, particularly for air pollutants, and offer a pathway to reduce greenhouse gas emissions from legacy fossil infrastructure. This work is the first to monetise environmental and human health burdens in geothermal FELCC, revealing both the limitations and transformative potential of repurposing fossil assets. Strategic policy incentives and system scaling are needed to improve their economic viability and support their integration into decarbonisation strategies. • Repurposed systems' LCOEs are 14–65 times higher than conventional geothermal plants. • System efficiency and operational lifetime are key to economic viability. • Repurposed systems deliver climate value but face economic limits. • Semi-abandoned wells have the most favourable viability among repurposed options. • Costs of externalities are minimal for all geothermal options considered.