Nationwide cost and capacity estimates for sedimentary basin geothermal power and implications for geologic CO2 storage.

Introduction: Sedimentary basins are naturally porous and permeable subsurface formations that underlie approximately half of the United States. In addition to being targets for geologic CO₂ storage, these resources could supply geothermal power: sedimentary basin geothermal heat can be extracted with water or CO₂ and used to generate electricity. The geothermal power potential of these basins and the accompanying implication for geologic CO₂ storage are, however, understudied. Methods: Here, we use the Sequestration of CO₂ Tool (SCO2T^PRO) and the generalizable GEOthermal techno-economic simulator (genGEO) to address this gap by a) estimating the cost and capacity of sedimentary basin geothermal power plants across the United States and b) comparing those results to nationwide CO₂ sequestration cost and storage potential estimates. Results and discussion: We find that across the United States, using CO₂ as a geothermal heat extraction fluid reduces the cost of sedimentary basin power compared to using water, and some of the lowest cost capacity occurs in locations not typically considered for their geothermal resources (e.g., Louisiana, South Dakota). Additionally, using CO₂ effectively doubles the sedimentary basin geothermal resource base, equating to hundreds of gigawatts of new capacity, by enabling electricity generation in geologies that are otherwise (with water) too impermeable, too thin, too cold, or not deep enough. We find there is competition for the best sedimentary basin resources between water- and CO₂-based power, but no overlap between the lowest-cost resources for CO₂ storage and CO₂-based power. In this way, our results suggest that deploying CO₂-based power may increase the cost of water based systems (by using the best resources) and the cost of CO2 storage (by storing CO2 in locations that otherwise may not be targeted). As such, our findings demonstrate that determining the best role for sedimentary basins within the energy transition may require balancing tradeoffs between competing priorities. [ABSTRACT FROM AUTHOR]