R9UIC-CA5-FY25-1: Willow Rock Energy Storage Center, Rosamond, CA

Operator Name: GEM A-CAES LLC (Hydrostor) 
Facility Name: Willow Rock Energy Storage Center 
Facility Address: 34.909676 north latitude/118.155717 west longitude in Kern County, California

UIC Class V Authorization by Rule (ABR) issued September 8, 2026, to Hydrostor for two Class V underground injection wells at the proposed Willow Rock Energy Storage facility in Kern County, California. The ABR includes conditions for well construction, testing, monitoring, reporting, and financial assurance.

• UIC Class V Authorization by Rule (ABR) No. R9UIC-CA5-FY25-1: Willow Rock Energy Storage Center, Rosamond, CA (pdf) (1.06 MB, September 8, 2026)
  UIC Class V Authorization by Rule (ABR) issued to GEM A-CAES LLC (Hydrostor) for two injection wells at the proposed Willow Rock Energy Storage facility in Kern County, California. The ABR includes conditions for well construction, testing, monitoring, reporting, and financial assurance.