Hydrostor’s Willow Rock Energy Storage Center Secures 60 MW Offtake Agreement with Clean Energy Alliance
Hydrostor, a global developer and operator of long-duration energy storage (LDES) projects, has reached a significant commercial milestone for its flagship U.S. project after securing a 60-megawatt (MW) offtake agreement with Clean Energy Alliance (CEA), a community choice aggregator serving customers across San Diego County, California. The agreement strengthens the commercial foundation of the Willow Rock Energy Storage Center while reinforcing California’s broader efforts to expand reliable, zero-emission electricity resources capable of supporting an increasingly renewable-powered grid.
The long-term agreement comes as construction-related activity begins at the Willow Rock project site, marking the transition from development and permitting into the next stage of project execution. The partnership will provide CEA with access to long-duration energy storage capacity designed to improve grid reliability, better utilize renewable energy resources, and help meet California’s ambitious clean energy and reliability objectives.
The Willow Rock Energy Storage Center represents Hydrostor’s first utility-scale energy storage project under construction in the United States and serves as an important milestone in the company’s international growth strategy. The project also reflects the increasing role of long-duration energy storage technologies in addressing the operational challenges associated with higher levels of renewable electricity generation.
Commercial milestone for Willow Rock
The newly signed agreement provides Clean Energy Alliance with 60 MW of energy storage capacity from the Willow Rock facility. As California continues to experience rapid growth in solar and wind generation, utilities and community choice aggregators are increasingly seeking energy storage solutions capable of storing electricity for extended periods and delivering it when renewable generation declines or electricity demand reaches its highest levels.
Unlike shorter-duration battery systems that are primarily designed for daily balancing, long-duration storage technologies are intended to provide electricity over longer discharge periods, improving grid flexibility while helping reduce dependence on conventional fossil fuel generation during periods of peak demand.
Hydrostor believes the agreement demonstrates growing confidence among electricity providers in long-duration storage as an essential component of future energy infrastructure.
Jordan Cole, Chief Commercial Officer at Hydrostor, described the agreement as an important milestone for both the Willow Rock project and the company’s broader U.S. expansion strategy.
He noted that construction activity has now begun at the project site and emphasized that the partnership with Clean Energy Alliance will support the delivery of reliable and cost-effective energy storage services as electricity demand continues to increase across California.
Cole also highlighted the broader value of the project, stating that the facility is expected to contribute to a more resilient electricity grid while supporting California’s long-term clean energy transition.
Supporting California’s clean energy goals
For Clean Energy Alliance, the agreement aligns with its strategy of expanding access to reliable, carbon-free electricity for the communities it serves.
Community choice aggregators have become increasingly important participants in California’s electricity market, allowing local governments to procure cleaner electricity supplies while supporting state climate objectives.
Greg Wade, Chief Executive Officer of Clean Energy Alliance, said the partnership with Hydrostor represents another important step in advancing the organization’s commitment to delivering dependable, zero-emission electricity to customers.
According to Wade, long-duration energy storage offers the ability to capture surplus solar electricity generated during periods of high renewable production and store that energy until regional electricity demand increases later in the day or during other periods of reduced renewable generation.
He explained that this capability helps reduce reliance on fossil fuel power plants while improving overall grid stability.
Wade further emphasized that the Willow Rock facility will play an important role in helping Clean Energy Alliance satisfy California’s reliability requirements while providing customers with dependable clean energy capacity capable of supporting future electricity demand growth.
Construction activities underway
Hydrostor confirmed that on-site work officially commenced at the Willow Rock Energy Storage Center in July 2026, representing a major step forward after several years of project development, environmental review, and regulatory approvals.
Located in California’s Antelope Valley, the project has successfully completed several important permitting milestones over the past two years.
In December 2025, the California Energy Commission granted approval for the project, providing one of the final regulatory authorizations required before construction could proceed.
During the same month, the Kern County Board of Supervisors approved the project’s franchise agreement, enabling additional progress toward implementation.
Earlier in April 2025, the Kern County Board of Supervisors had also issued a conditional letter of support, demonstrating local government backing for the development.
Together, these approvals created the regulatory pathway necessary for Hydrostor to begin physical work at the project location.
Long-duration storage becoming increasingly important
California has become one of the world’s largest markets for energy storage as renewable electricity continues to account for a growing share of total power generation.
The state regularly experiences periods when solar generation exceeds electricity demand during daylight hours, creating the need for technologies capable of storing surplus renewable electricity for use later in the evening.
Long-duration energy storage systems are increasingly viewed as a critical solution to this challenge because they can provide electricity over extended discharge periods while supporting renewable integration, grid reliability, and emergency resilience.
These technologies also help reduce renewable energy curtailment by capturing electricity that might otherwise be wasted during periods of oversupply.
As electrification expands across transportation, buildings, and industrial sectors, electricity demand is expected to continue rising, further increasing the need for flexible storage resources capable of balancing variable renewable generation.
Projects such as Willow Rock are therefore expected to become increasingly valuable components of California’s evolving electricity system.
Hydrostor expands U.S. presence
The Willow Rock Energy Storage Center marks an important milestone in Hydrostor’s expansion into the United States.
Although the company has already demonstrated its technology through an operational project in Ontario, Canada, Willow Rock represents its first utility-scale facility currently being developed in the U.S. market.
The project also highlights Hydrostor’s broader international growth ambitions.
The company reports a global development pipeline totaling approximately 7 gigawatts (GW) of long-duration energy storage projects spanning multiple regions, including the United States, Canada, Australia, and the United Kingdom.
These projects are intended to support electric utilities, independent power producers, and other electricity providers seeking reliable storage solutions capable of integrating increasing amounts of renewable generation.
As governments and electricity markets continue pursuing decarbonization strategies, Hydrostor expects long-duration energy storage to play an increasingly central role in supporting reliable electricity delivery while reducing greenhouse gas emissions.
Source Link: https://www.businesswire.com/
