Pumped-Storage Hydropower using Abandoned Underground Mines as an Innovative Energy Storage Technology for Fossil-Integrated Systems

Despite exponential growth in utility-scale battery storage in recent years to approximately 1 gigawatt operating capacity, pumped-storage hydropower (PSH) still accounts for around 95% of all utility-scale storage in the U.S. and globally. PSH is a proven, cost-effective technology that is poised for massive expansion throughout the U.S. if the “ΔH challenge” can be solved. The ΔH challenge refers to achieving a suitable difference in hydraulic head height between the upper and lower reservoirs in a PSH system to enable hundreds of megawatts of electricity generation power by turbines located at the lower reservoir. To date, PSH deployment has been constrained to locations throughout the U.S. for which natural topography provides suitable elevation relief between the upper and lower reservoirs. We propose to solve the ΔH challenge and facilitate the commercialization of a game-changing energy storage technology termed PSH-AUM—Pumped-Storage Hydropower using Abandoned Underground Mines. Phase I research will advance the initial work that our team has accomplished in engineering de- sign, pre-feasibility technical assessment and techno-economic analysis of the PSH-AUM concept. The proposed research will address DOE’s goal of developing low-cost storage technologies for fossil-integrated systems by resolving key knowledge gaps in the PSH-AUM concept, including 1) subsurface reservoir performance, 2) integrated system design, operation, performance and cost metrics, and 3) optimal siting via detailed geospatial and technical screening analysis covering the lower 48 state region of the U.S. The Phase II effort will leverage our long-standing relations with key energy industry partners in the power utility and mining sectors along with other key stake- holders to advance the commercialization of the nation’s first PSH-AUM technology as a fossil- integrated energy storage system.