Willow Rock Energy Storage Center

The Willow Rock Energy Storage Center (WRESC) is proposed by Gem A-CAES LLC, a wholly owned subsidiary of Hydrostor, Inc. The project would be located at 8684 Sweetser Road in Rosamond, Kern County, California.

WRESC would be a nominal 500-megawatt (MW), 4,000 MW-hour (MWh), advanced compressed air energy storage (A-CAES) facility capable of charging and discharging daily. WRESC would compress air into a purpose-built underground cavern, using electricity from the grid, most likely off-peak, excess, or surplus electricity. The heat from the air compression process would be captured and stored in an aboveground thermal storage system. The compressed air would then be stored in the cavern under the pressure of a hydrostatic head created by an onsite, aboveground water reservoir. When electricity is needed by the grid, the compressed air would be released using the hydrostatic head pressure, re-heated using the stored thermal energy, and directed through aboveground turbine-generators to produce electricity.

WRESC’s major equipment would consist of five all-electric air compressor trains, five 100-MW air-driven power turbine generators, heat exchangers, thermal heat storage, an underground compressed air storage cavern, an aboveground water reservoir, miscellaneous aboveground support facilities, and a 10.9-mile interconnection to the existing Southern California Edison (SCE) Whirlwind Substation.