Hydrostor applies for license for 4GWh California compressed air storage project

December 2, 2021
LinkedIn
Twitter
Reddit
Facebook
Email
Ribbon-cutting at Hydrostor’s first A-CAES plant in Ontario, Canada in 2019. Image: Hydrostor

Advanced compressed air energy storage (A-CAES) company Hydrostor has made its second application to license a gigawatt-hour scale project as a power plant with the California Energy Commission (CEC).  

The Canada-headquartered company has filed an Application for Certification (AfC) to the CEC for the development of its proposed 500MW / 4,000MWh A-CAES plant in Kern County, California. Only a few days ago Hydrostor had made a similar filing for another, the Pecho Energy Storage Center 400MW / 3,200MWh project in San Luis Obispo County.

Hydrostor has developed a proprietary A-CAES technology solution and built a commercial demonstration project in Ontario. The company has previously said that it had modelled the potential for California to host 15GWh of A-CAES plants, which store energy in compressed air in underground salt caverns. 

The project in Kern County, Gem Energy Storage Center, could achieve a commercial operation date in 2026, Hydrostor claimed. Gem Energy Storage Center would require around US$975 million capital investment, providing up to 700 employment opportunities during construction and up to 40 full-time jobs once in operation. 

This article requires Premium SubscriptionBasic (FREE) Subscription

Try Premium for just $1

  • Full premium access for the first month at only $1
  • Converts to an annual rate after 30 days unless cancelled
  • Cancel anytime during the trial period

Premium Benefits

  • Expert industry analysis and interviews
  • Digital access to PV Tech Power journal
  • Exclusive event discounts

Or get the full Premium subscription right away

Or continue reading this article for free

It would connect to the CAISO transmission system via the existing Whirlwind Substation near the City of Rosamund, enhancing utilisation of renewable energy resources in the area. 

“Today’s filing marks the second of many important milestones in the implementation of Hydrostor’s commitment to helping California meet its recognised long-duration energy storage needs,” Hydrostor CEO Curtis VanWalleghem said.

“Our A-CAES facilities are designed to operate safely and efficiently for over 50 years with zero degradation.”

California looks set to be one of the first parts of the world to host multiple large-scale, long-duration energy storage projects (defined as technologies with eight hours storage and discharge capability or more).

A 1,000MW solicitation is planned by grid and wholesale power market operator CAISO, while last week Energy-Storage.news reported that Central Coast Community Energy (CCCE), an energy supplier, is going ahead with three vanadium redox flow battery (VRFB) projects totalling 226MWh

Read Next

Premium
April 8, 2026
A panel at the 2026 US Energy Storage Summit in Dallas, Texas, discussed the “creative, innovative structures” developers are having to embrace to secure long-term revenues for energy storage projects.
April 7, 2026
China’s biggest energy storage companies were out in force at a recent trade expo in Beijing, with integrated offerings, bigger battery cells, data centre solutions and sodium-ion products among the new products and tech on show.
Premium
April 2, 2026
The Reno Planning Commission, in Nevada, US, recommended approval for a conditional-use permit for the 200MW Trego Grid energy storage project on 4 March.
March 31, 2026
Form Energy, Noon Energy and Ore Energy are all commercialising proprietary 100-hour battery technologies for LDES applications, but how do they compare on metrics like cost, energy density and round-trip efficiency? We look at what they have revealed, as well as what they haven’t.
Premium
March 25, 2026
Ex-Fluence alumnus Marek Kubik sat down with Energy-Storage.news at last month’s Energy Storage Summit 2026 in London to talk big picture BESS technology trends, including energy density, LDES and sodium-ion.