Techno-economic assessment and multi-objective optimization of CO2 hydrogenation via geothermal energy storage using synthetic natural gas, refrigeration, and freshwater production

Abstract This study addresses the challenge of sustainable, multi-generational energy production by introducing an innovative geothermal-powered system for simultaneous methane, electricity, cooling, and freshwater generation. The configuration integrates a flash-binary geothermal power setup with an Organic Rankine Cycle, dual-effect absorption cooling, multi-stage flash desalination, and a solid oxide electrolyzer cell (SOEC) linked to a Sabatier reactor for CO2 hydrogenation. Financial analysis reveals annual revenue of $63.6 million, with operating expenses of $54.8 million and labor costs of $5.81 million, leading to a 7.3-year return on investment period. Optimized SOEC operation, including higher working temperatures, reduces voltage losses, improving energy efficiency.