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 these formations 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 10km by 10km resolution to address this gap, using the Sequestration of CO2 Tool (SCO2T) geodatabase and the generalizable GEOthermal techno-economic simulator (genGEO). Our results suggest that when water is used as the heat extraction fluid, the cost of sedimentary basin power is greater than $175/MWh. But the cost of this capacity may decrease to $100/MWh when CO2 is used as the heat extraction fluid. Using CO2 also expands the portion of the sedimentary basin resource base that is amenable to power generation by “unlocking” more marginal quality geologic resources. We also find that there is competition between water-based and CO2-based power systems for the best sedimentary basin resources, thus using the lowest-cost resources for CO2-based power plants will increase the cost of water-based power, or vice-versa. These geologic “sweet spots” that support lower-cost sedimentary basin geothermal power are in California, Louisiana, New Mexico, and South Dakota.