U.S. Department of Energy,
Keywords: CCS, energy storage
Summary:It is challenging to construct a business case for Carbon Capture and Storage (CCS) without a supportive revenue model or adequate policy. Most CCS projects that attained financing at least in Y2015 relied on CO2 utilization revenues through Enhanced Oil Recovery (EOR) markets; but EOR is deemed insufficient for growing CCS projects numerically and geographically (H. Herzog, “Lessons Learned from CCS Demonstration and Large Pilot Projects”, May 2016, MITEI working paper). In addition to a plurality of promising CO2 utilization pathways under consideration, energy storage is beginning to receive attention as a potential approach for utilizing CO2 and thus for supporting a CCS business case. Much like Compressed Air Energy Storage (CAES), CO2 can be used as an energy storage system and one version of this approach has been elegantly conceptualized as "Earth Battery" that is based on an integration with geothermal sources (it received recognition as a semi-finalist in Carbon XPRIZE at the time of writing this abstract). Unlike CAES, the highly exothermic gas compression step does not dissipate energy to the surroundings or need thermal storage solutions – the heat generated during CO2 compression is recovered effectively within the CCS plant. Approaches to compressed CO2 energy storage systems could provide other services such as cooling. This presentation will describe the potential of compressed CO2 energy storage and identify the innovation needs that could lead to economically feasible demonstrations.