Techno-Economic Optimization of a CO2-based Advanced Geothermal System (AGS)

Advanced Geothermal Systems (AGS) are power systems that harness energy by circulating a working fluid through a closed-loop circuit, extracting thermal energy from deep geologic reservoirs via conductive heat transfer across an impermeable wellbore wall. AGS benefit from using carbon dioxide (CO2) as the working fluid within the wellbores, at least for electricity generation and possibly also for direct heat usage. Here, we investigate a range of configurations for combined electricity and heat production. These designs aim to enhance flexibility and efficiency in AGS while reducing system costs. Central to this research is formulating an optimal AGS pilot plant design, complemented by a comprehensive techno-economic feasibility study. Compared to the design benchmarks of previous work on AGS for electricity generation only, this optimization yields an improvement in the Specific Capital Cost (SpCC) by approximately 215%. Furthermore, by incorporating heat co-generation with electricity, the SpCC is considerably further reduced.