Hydrostor has signed a 60 megawatt (MW) offtake agreement for its Willow Rock Energy Storage Center with the Clean Energy Alliance (CEA), a San Diego County-based community choice aggregator. This deal secures capacity for CEA’s 255,000 customers, marking a significant commercial milestone for Hydrostor’s first utility-scale project currently under construction within the United States.
CEA Offtake Agreement and Willow Rock Capacity
The agreement establishes a commercial framework for the Willow Rock Energy Storage Center to provide 60 MW of capacity to CEA. This partnership aims to utilize long-duration energy storage (LDES) to capture excess solar energy during peak production periods and discharge it during high-demand intervals. By doing so, the facility is positioned to displace fossil fuel generation and strengthen regional grid stability. For CEA, the project serves as a strategic tool to meet California's state reliability mandates and address the growing energy requirements of its customer base through dependable, zero-emissions power.
Project Permitting and Kern County Development
Located in California’s Antelope Valley, the Willow Rock project has reached critical execution milestones. Following a conditional letter of support from the Kern County Board of Supervisors in April 2025, the project secured both its franchise agreement and its California Energy Commission permit in December 2025. On-site construction activity officially commenced in July 2026. While Hydrostor maintains an extensive 7 GW global project pipeline across Australia, Canada, and the UK, Willow Rock represents the company's inaugural utility-scale deployment in the U.S. market, building upon its existing operational experience in Ontario, Canada.
Key Takeaways
- Hydrostor signed a 60 MW offtake agreement with the Clean Energy Alliance (CEA).
- The Willow Rock Energy Storage Center is located in California's Antelope Valley, Kern County.
- On-site work for the project officially began in July 2026.
EnergyInsyte's Take
In our view, this offtake agreement validates the commercial viability of long-duration energy storage (LDES) for community choice aggregators. By securing a 60 MW commitment, Hydrostor demonstrates that LDES can move from theoretical pipeline to actionable grid assets. This signals a shift toward localized, large-scale storage solutions designed to manage solar intermittency. For developers, the successful navigation of Kern County permitting and the transition to on-site work provide a blueprint for U.S. utility-scale execution.
Questions & Answers
How does the Willow Rock project support California's grid reliability?
The facility uses long-duration energy storage to capture excess solar energy during peak production and discharge it when regional demand is highest, helping to displace fossil fuel generation.
What is the scale of the Clean Energy Alliance's customer base?
The CEA serves more than 255,000 customers located in San Diego County.
What is Hydrostor's current global project standing?
Hydrostor maintains a 7 GW project pipeline globally, with active interests in the U.S., Australia, Canada, and the UK.
What regulatory milestones were achieved for the Willow Rock site?
The project received a conditional letter of support in April 2025, followed by a franchise agreement and a California Energy Commission permit in December 2025.
Source: BUSINESSWIRE
