Nationwide Assessment of Sedimentary Basin Geothermal Power

Abstract

We estimate the cost and capacity of sedimentary basin geothermal power plants across the contiguous United States. Sedimentary basins are ubiquitous, naturally porous and permeable, and the geothermal heat in these basins can be extracted with in-situ water or geologically - stored CO₂ and used to generate electricity. Despite this, the potential that sedimentary basins may have for generating electricity has been understudied. Here, we estimate the cost and capacity of sedimentary basin power plants across the contiguous United States on a 10 km by 10 km resolution using the Sequestration of CO₂ Tool (SCO₂T^PRO) geodatabase and the generalizable GEOthermal techno-economic simulator (genGEO). We find that the cost of sedimentary basin power is generally high (>$250/MWh) across the entire country and using CO₂ as the heat extraction fluid reduces the cost compared to using water. Depending on the financing assumptions and possibility of using wells drilled previously for CO₂ sequestration, the cost of electricity generation when CO₂ is used can decrease to ~$100/MWh, including in states not typically considered for geothermal power: Mississippi, Louisiana, and South Dakota. Overall, using CO₂ as the heat extraction fluid effectively doubles the portion of the sedimentary basin resource base that is amenable to power generation by “unlocking” resources that are either too thin, too cold, or that have insufficient reservoir transmissivity to support power generation with water.