POTENTIAL IN THE CONTIGUOUS UNITED STATES FOR CARBON CAPTURE AND STORAGE COMBINED WITH GEOTHERMAL HEAT EXTRACTION UTILIZING SUPERCRITICAL CO2 AS THE CIRCULATING FLUID

Recent research has advanced the possibility of utilizing supercritical CO₂ as the circulating fluid in geothermal energy production (Brown, 2000, and Pruess, 2007). The proposed process has many potential benefits, including the long term geological sequestration of CO₂. As such, development of this power generation method presents the opportunity to partner with ongoing and future Carbon Capture and Storage (CCS) projects to capture CO₂from stationary sources while producing electricity from geothermal energy, reducing the costs associated with CCS.

As part of the Department of Energy funded project “Geothermal Energy Production Coupled with Carbon Capture and Storage: Heat Recovery Using an Innovative High-Efficiency Supercritical CO₂ Turboexpansion Cycle”, (Freifeld, et al., 2012) the University of Texas, Austin, Bureau of Economic Geology (BEG) has identified sedimentary basins in the contiguous United States possessing potential for both CCS and geothermal heat extraction utilizing supercritical CO₂ as the circulating fluid. Stationary CO₂ sources capable of providing CO₂ to projects within each basin were then identified and used to provide a preliminary estimate of power generation capacity in large sedimentary basins.

In the present study, power generation capacity was developed for identified basins in the United States using a 30-year power plant build-out and operations scenario assuming all CO₂ in the area is utilized for power generation. The proposed build-out scenario was developed to optimize power generation and Levelized Cost of Electricity through economic modeling completed by the Bureau of Economic Geology (BEG) and reservoir modeling completed by Echogen Power Systems and Lawrence Berkley National Laboratories. Preliminary estimates show a power generation capacity of 7.3 GW if the process is fully deployed in identified large sedimentary basins of the contiguous U.S. This would also result in the capture of 1.8 billion metric tonnes of stationary source CO₂ emissions per year.

Within the South Central Region, the Texas and Louisiana Gulf Coast is one of the most promising basins in the U.S., with a power generation capacity of 2.0 GW and the ability to capture 465 million metric tonnes of stationary source CO₂ emissions per year.