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March 17, 2026

Holland & Hart Advises Hydrostor on Construction Contract for Willow Rock Energy Storage Center in California

Holland & Hart represented Hydrostor, a leading global long-duration energy storage (LDES) developer and operator, in connection with a construction contract for the Willow Rock Energy Storage Center, as part of Hydrostor's strategic execution partnership and equity agreement with Hatch, announced on February 25, 2026.

Willow Rock is a 500-MW Advanced Compressed Air Energy Storage (A-CAES) facility currently in late-stage development in California, which received final permitting approvals from the California Energy Commission. Designed to deliver 4,000 megawatt hours (MWh) of energy, the facility will be capable of delivering eight hours of clean, reliable energy on a full charge. As the largest A-CAES project in the world, Willow Rock showcases Hydrostor’s scalable technology.

For more information, please see Hydrostor’s press release.

The Holland & Hart transaction team was led by partners Sean Hanlon and Ashley Wald, with subject matter expertise assistance from Lori Blundell, Megan Decker, Adam Cohen, and Melissa Braun, among others.

The firm's Renewable Energy and Storage team has been at the vanguard of the renewable energy industry for decades and serves clients in the ever-changing, complex clean energy market. The team brings specialized experience in renewable energy and storage project finance and development to this dynamic market. We help clients capitalize on existing solar, wind, hydro, geothermal, and other renewable energy technologies in addition to battery storage technologies—as well as innovative new energy opportunities—as part of the global transition to a clean energy economy.

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