Compressed-air energy storage, a decades-old but rarely deployed technology that can store massive amounts of energy underground, could soon see a modern rebirth in California’s Central Valley.
On Thursday, the Biden administration offered a $1.76 billion conditional loan guarantee for GEM A-CAES, a wholly owned subsidiary of Canadian startup Hydrostor. That federal backing will help secure financing for the Willow Rock advanced compressed-air energy storage (A-CAES) project planned near the town of Rosamond in California’s eastern Kern County.
To finalize the loan guarantee from the Department of Energy’s Loan Programs Office (LPO), Hydrostor must satisfy technical, legal, environmental, and financial conditions — and retain the support of the incoming Trump administration. The project is also awaiting permitting review by the California Energy Commission.
But even this initial federal support is “a big deal” for what would be Hydrostor’s first North American project at commercial scale, Hydrostor CEO Curt VanWalleghem told Canary Media. The loan guarantee can back up to 80 percent of the estimated $1.5 billion in project construction costs, as well as covering interest during construction and providing a bridge loan for the federal investment tax credits the project will be entitled to when it’s completed.
“What LPO is saying is this is creditworthy technology that is ready for deployment,” VanWalleghem said.
If all goes to plan, Hydrostor would begin construction late this year, with the goal of starting operations in 2030. Much of the construction will happen aboveground, as Hydrostor installs the compressors that will use electricity to pressurize air, the turbines to turn that air back into electricity, and the tanks and reservoirs containing the water that’s vital to the company’s unique approach.
But the heart of the project will be a cavern, roughly the size of a football field in length and width and about 100 yards high, carved by miners out of the bedrock about 2,000 feet below the surface, VanWalleghem said.
Those caverns will be able to store up to 4,000 megawatt-hours of energy in the form of air compressed to high pressures using cheap excess renewable electricity. Hours, days, or weeks later, that air can be expelled to spin power-generating turbines to feed carbon-free power back to California’s grid, at a capacity of up to 500 megawatts for up to eight hours or longer.
Energy analysts and experts believe that long-duration energy storage (LDES) projects like this are crucial to removing fossil fuels from the grid. Today, lithium-ion batteries make up the lion’s share of new grid storage deployments. But power grids making the transition to renewable energy will eventually need longer-duration storage to fill the gaps during days or weeks of low wind and sun.
If built, Willow Rock would be one of the largest real-world examples of an LDES system — and one of the largest energy storage projects in the world, period. It would take the crown for biggest compressed-air energy storage (CAES) system on the planet, too, beating a 1,500 megawatt-hour CAES project that came online in China last year.
LDES technologies range from novel battery chemistries and thermal energy storage systems that can stretch durations into days at a time, to “seasonal” options like producing hydrogen with clean electricity and stashing it in underground caverns for use in generating power months later.
Right now, the most widely deployed LDES technologies are also the oldest. Those include pumped-hydropower reservoirs, which have been around since the 1930s and make up the vast majority of the world’s long-duration storage capacity, and CAES, which has been pursued in various formats, most of them unsuccessful to date.
In fact, beyond the newly built project in China, there are only two operational CAES projects in the world — a 290 MW plant in Huntorf, Germany, built in 1978, and a 110 MW plant in McIntosh, Alabama, built in 1991.
The original article is found here.
Leave a Reply