CO2 plume geothermal (CPG) and the earth battery - Innovative, dispatchable geothermal power production and geologic energy storage using non-water working fluids

CO2 Plume Geothermal (CPG) and Earth Battery technologies constitute a continuum of renewable power and geologic energy storage systems that are innovative in their use of non-water, and combinations of water and non-water, fluids as the working media to harness geothermal heat and store energy in permeable subsurface formations. These non-water fluids - primarily CO2, but also nitrogen and air - are expected to allow a dramatic expansion of the areas worldwide where geothermal power and bulk aquifer energy storage can be technically and economically deployed (e.g., Randolph and Saar (2011); Buscheck et al. (2016)). Ultimately, our approach will use CO2 as a below-ground working fluid, with each system using MMtonnes of CO2, helping to turn CO2 from a liability into a renewable power resource. Here, we discuss non-water geo-energy technologies in the context of existing power generation and energy storage systems. We discuss the current state of academic research and make note of next steps in the planned commercial deployment of these new geo-energy technologies.