compete with one another for location or for a particular sedimentary basin resource. Our supply curves suggest that the order of least-cost sedimentary basins was different for brownfield CO 2 -based power plants than for water-based power plants (Figure ). Because sedimentary basins are massive, it is possible that this order would be much different when higher spatial resolution geologic data are used. As a result, it is possible that developing sedimentary basins for geothermal power generation using heat extraction fluids of both water and CO 2 could proceed in parallel. Or if there are insufficient amounts of geologic CO 2 storage, this finding suggests that developing water-based power plants in the short term may not eliminate options for CO 2 -based plants in the long term while waiting for enough CO 2 to be geologically stored.