Panel 3A: Geological Thermal Energy Storage (GeoTES) in Sedimentary Reservoirs: Technology and Market Assessment

As renewable energy becomes a mainstream resource for the United States' electricity and other energy sectors, including the electric load and the heat & cooling load, there is an attendant need for reliable and sustainable long duration energy storage (LDES) to counteract the intrinsic variabilities. Geological Thermal Energy Storage (GeoTES) is an emerging technology that addresses this need. As a reliable LDES technology, it takes advantage of the vast volumes of subsurface pore space in sedimentary formations with minimal storage media degradation over the project lifecycle. It also cuts across several temporal scales between diurnal and seasonal operations. Suitable storage media include brackish and saline aquifers and depleted hydrocarbon reservoirs across multiple reservoir depths. Two main thermal energy sources have been considered: (1) renewable heat production from concentrating solar thermal systems and (2) excess or curtailed renewable energy via Carnot battery systems. Other sources of thermal energy could be industrial and nuclear waste heat. In this session, we will discuss the state of the art in GeoTES technologies, current efforts to evaluate and improve system performance, and an assessment of GeoTES market readiness. We will also examine potential challenges and deliberate on possible solutions based on oil and gas experience with thermal recovery and past projects on aquifer based thermal storage for heating and cooling applications.