The U.S. Department of Energy has announced it will offer a loan guarantee of $1.76 billion to Hydrostor for its planned 500 MW/4,000 MWh Willow Rock energy storage facility located in Southern California. This technology utilizes advanced compressed-air energy storage (A-CAES), which will provide up to eight hours of energy during peak times. The aim is to lower energy costs, enhance grid reliability, and promote the use of renewable energy in California.
Scott Bolton, Hydrostor’s executive vice president, stated that the company is nearing the final stages of obtaining necessary permits from local and state authorities. Construction of the facility is expected to commence by the end of 2025, with plans to have the facility operational by 2030.
There is some uncertainty regarding whether the loan guarantee will be finalized by the time President-elect Donald Trump takes office on January 20. The incoming Republican administration has shown a potential interest in altering or abolishing the Loan Programs Office, which could impact the project.
Despite these uncertainties, Bolton emphasizes the substantial benefits the Willow Rock project offers to the local community and its alignment with both current and upcoming energy policy goals. The project is positioned to benefit from federal tax credits thanks to the Inflation Reduction Act, which will further support its development.
To meet its energy reliability goals, California may require up to 37 GW of long-duration energy storage systems by 2045, especially if it plans to phase out all gas-fired power plants. In August, the California Public Utilities Commission announced plans to procure up to 2 GW of long-duration energy resources, indicating an increasing focus on sustainable energy solutions.
Hydrostor’s A-CAES technology stands out by using underground caverns to store compressed air more efficiently than traditional systems. Its unique thermal storage approach makes it possible to recover energy without needing fuel combustion. This innovation could expand the reach of energy storage, as A-CAES technology is suitable for a majority of the U.S. subsurface landscape.