Brine displacement by CO₂, energy extraction rates, and lifespan of a CO₂-limited CO₂-Plume Geothermal (CPG) system with a horizontal production well

Several studies suggest that CO₂-based geothermal energy systems may be operated economically when added to ongoing geologic CO₂ sequestration. Alternatively, we demonstrate here that CO₂-Plume Geothermal (CPG) systems may be operated long-term with a finite amount of CO₂. We analyze the performance of such CO₂-limited CPG systems as a function of various geologic and operational parameters. We find that the amount of CO₂ required increases with reservoir depth, permeability, and well spacing and decreases with larger geothermal gradients. Furthermore, the onset of reservoir heat depletion decreases for increasing geothermal gradients and for both particularly shallow and deep reservoirs.