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Compressed-air energy proposal in east Kern comes up for state review

State review is officially underway on a major energy-storage project near Rosamond that would use compressed air, thermal engineering and hydrostatic force to even out delivery of renewable power and make the state's electrical grid more resilient.

At a cost estimated at $975 million, the 500-megawatt, 4,000-megawatt-hour proposal would take electrons from renewable energy sources nearby to power air compression and underwater injection.

When energy is needed later, air would be released upward to run a turbine generator. Heat would be removed early then returned later in the process.

Named the Gem Energy Storage Center, the Canadian-led project would be one of the largest of its kind on the planet, a new-generation infrastructure investment to help meet California's huge need for large-scale energy storage.

"Gem’s quick-starting, flexible and dispatchable long-duration energy supply will have the ability to ramp-up and down through a wide range of electrical output," Toronto-based Hydrostor said in a Dec. 1 news release announcing its local subsidiary had filed an application for certification from the California Energy Commission.

Added CEO Curtis VanWalleghem: "We look forward to working closely with the citizens of Kern County to earn their trust and support on our way to becoming a valued member of the community."

Besides widening Kern's already diverse energy portfolio, Hydrostor said, the project would create 30 to 40 good-paying, full-time jobs, plus 700 construction jobs, all without emissions.

Gem is slated to open in early 2026 after a four-year construction period, and thereafter generate property tax revenues and $500 million in regional economic benefits over its 50-year lifespan.

The project has a little longer discharge capacity than a similar energy-storage proposal in San Luis Obispo that Hydrostor recently brought before the energy commission.

The energy commission will act as lead agency for both projects' environmental review and permitting. County government and various state and federal agencies are expected to participate in the commission's review.

A CEC spokesman said the commission does have financial support to offer "emerging long duration energy storage projects" like Gem, but the project's large commercial scale rules it out for state grants.

"Projects like this have been proposed before at this level (greater than 300MWs) for compressed air technologies," spokesman Michael Ward said by email. "So far, we are not aware of any of those system being approved for funding in California."

State government has called for development by 2030 of at least 1,000 megawatts of energy storage lasting at least eight hours at a time. By 2045, there's supposed to be three to four times that much.

"To date, no project of this scale has been approved, but they could be approved in the future," Ward added.

Two other large-scale, long-duration energy-storage facilities have been proposed in Kern but neither is as far along as Hydrostor's projects. Both would use pumps and hydroelectric generators and cost more than $1 billion.

Gem would interconnect with electrical transmission systems, either at an existing substation for delivery to the state grid or a planned switching station for delivery to the Los Angeles Department of Water and Power.

Hydrostor said it chose to site the Rosamond area in order to operate it in connection with existing and future renewable energy projects in the high desert.