Energy Storage: Not Just Lithium Anymore

January 12, 2022

Hydrostor is a scrappy start up with a dead-simple energy storage idea that seems to have overcome the most serious barriers to CAES – Compressed Air Energy Storage – technologies.

Working on a shoestring budget of a few million dollars, the company has managed to build convincing enough demonstrations to convince serious investors to jump in. Goldman Sachs just tossed in 250 Million.

There are so many more options coming along for energy storage in different locations, different environments, and for different time frames – it seems this fits the definition of paradigm shift.

Canary Media:

An iconoclastic Canadian startup just raised a landmark investment from Goldman Sachs to build massive storage for clean energy.

Hydrostor stores surplus electricity by compressing air into underground caverns. It updates a long-standing technology that never took off for electrical storage. Hydrostor thinks the tweaks it has made will allow underground storage to work in more places — just as grids increasingly need help turning wind and solar production into reliable 24/7 electricity.

Goldman Sachs agreed and invested $250 million from its private equity division. That’s unusual for the long-duration energy storage sector, which typically draws riskier venture-capital investment.

“It is growth capital; it’s not ​‘prove the technology’ venture capital,” Hydrostor CEOCurtis VanWalleghem told Canary Media on Monday. ​“We were able to show them how compelling the technology is and how advanced our development projects are.”

This investment exceeds the $240 million that Form Energy raised last year to commercialize its novel iron-air battery technology. That makes Hydrostor’s raise one of the largest corporate investments ever made in a long-duration storage company.

This portends palpable acceleration for a startup that came a long way while spending relatively little money. 

Hydrostor made strategic use of Canadian government grants to develop its early demonstrations. The company got an early commercial project running in Ontario’s wholesale power market in 2019. That one is small, just 2 megawatts/​10 megawatt-hours, but generates around $1 million in annual revenue. Having a megawatt-scale project making money in a power market is a basic achievement that still continues to elude many long-duration storage startups.

Hydrostor put around $5 million into development efforts elsewhere. That work produced three late-stage projects that, if built, would require $2.5 billion of construction capital and generate at least $5 billion of contracted revenue, VanWalleghem said.

Two of those projects are undergoing environmental permitting review in California. One is proposed for the Central Coast, to help cope with the loss of baseload carbon-free power from Diablo Canyon, the nuclear plant slated to close by 2025. The second would go into the Central Valley, near a hot spot for large-scale solar development. The third project is planned for Australia

To build these projects, Hydrostor excavates an 8-foot-diameter shaft that goes 2,000 feet deep. Workers descend to hollow out a cavity, which the company then floods. When it’s time to ​“charge,” the aboveground facility compresses air and shoots it below the water barrier. To discharge, it releases the compressed air, which spins a turbine and produces electricity.

These projects are designed for eight hours of discharge at full power capacity. But the technology can provide longer storage durations with a bigger cavern to hold more air.

That kind of duration, at the scale of hundreds of megawatts, puts Hydrostor into contention with a conventional pumped hydro plant, which is by far the leading source of grid-scale energy storage. But pumped hydro requires a site with significant changes in elevation and copious supplies of water. Hydrostor’s concept boasts a dramatically smaller footprint and relatively negligible water needs, making it more geographically versatile.

“All we need is reasonably competent bedrock,” VanWalleghem said.

With the influx of cash, Hydrostor aims to double its roughly 25-person staff this year, VanWalleghem said. Crucially, it will also expand development activities to new markets, including Europe and the rest of the U.S. And it will have resources to pursue new developments while bringing its current efforts fully to fruition, which is expected to take four years. 

Hydrostor will also hone 24/7 clean energy offerings for large corporate customers that want to step up their sustainability commitments. Combining wind and solar contracts with a Hydrostor facility could achieve the round-the-clock clean energy goal.

“We have a mousetrap that we truly believe is better than other people’s mousetraps,” VanWalleghem said. ​“Where we choose to play and put our money, we expect to win.”

The roster of competitors is increasingly well funded, but leadership of this nascent market is still very much up for grabs.

Globe Newswire:

San Francisco, Dec. 01, 2021 (GLOBE NEWSWIRE) — Gem A-CAES LLC, a subsidiary of Hydrostor, today filed its Application for Certification (“AFC”) with the California Energy Commission (“CEC”) for development of a 500 MW, 4,000 MW-hour (“MWh”) energy storage facility located outside of the City of Rosamond, Kern County, California. The Gem AFC filing follows Hydrostor’s recent announcement and AFC filing of the Pecho Energy Storage Center, a 400 MW x 8-hour A-CAES project located in San Luis Obispo County.

The Gem Energy Storage Center (“Gem” or the “Project”) will deploy Hydrostor’s proprietary Advanced Compressed Air Energy Storage (“A-CAES”) solution. The state-of-the-art project will provide large-scale, long-duration energy storage for the region with no fossil fuel consumption and no greenhouse gas emissions. With a commercial operation date (“COD”) as early as 2026, Gem will play a vital role in helping meet the region’s future energy supply and reliability needs, allowing California’s growing solar and wind resources to be directly converted into reliable, on-demand peak capacity for the High Desert, the greater Los Angeles region and the broader California grid.

Gem’s ability to flexibly deliver 500 MW of stored energy for eight hours without relying on fossil fuels or other polluting resources would make it one of California’s largest single new energy storage facilities. Gem would surpass all existing battery energy storage projects in California in terms of both megawatts delivered and duration of generation, with an expected capital investment of $975 million.

Long-duration energy storage is one of the cornerstone solutions to a carbon-free renewable energy future. Gem’s ability to deliver 500 megawatts of carbon-free electricity for 8 hours will be comparable in size and resiliency to some of California’s largest fossil-fueled powerplants. 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. This flexibility over long durations is vital in facilitating the integration of onshore and offshore renewable energy and will play a critical role in helping achieve California’s climate change objectives.


5 Responses to “Energy Storage: Not Just Lithium Anymore”

  1. redskylite Says:

    Paradigm shift indeed, we still need plenty of developments to finally wean ourselves off using hydrocarbons (and keep ourselves in the manner accustomed).


    “People have said that range anxiety is one of the big things. But no, no, charge time is the new range anxiety. People think, OK, I can live with an electric car but I don’t want to be stopping for 30-45 minutes to charge if I’m on a road trip.”


    “We were astounded with the performance of these new batteries. There is great potential to develop these further and to produce larger scaled devices with the technology.”

    • rhymeswithgoalie Says:

      Hey, if only people who truly needed long range bought ICE vehicles we’d be way ahead of the game. Not having a bunch of commuters and errand-runners with ICEs idling in traffic or at stoplights would save a lot of wasted combustion. Even then, people could still rent ICE vehicles for road trips.

      People hesitating about buying BEVs have a lot of unwarranted range anxiety, considering what small percentage of people drive more than 50 miles on any given day. The people who have no place to charge at home have a real practical issue that needs resolving.

  2. John Oneill Says:

    ‘One is proposed for the Central Coast, to help cope with the loss of baseload carbon-free power from Diablo Canyon, the nuclear plant slated to close by 2025.’
    500 MW for eight hours, then hope there’s surplus wind for a recharge. Diablo Canyon does 2250 MW for eighteen months straight. Closing it forty years earlier than some of its peers is environmental vandalism.

  3. mboli Says:

    This is a bit reminiscent of the several ocean-floor pumped-water storage companies.

    The water at the bottom of the ocean is naturally under high pressure.

    You put a tank at the bottom of the ocean, or under the ocean floor. The ocean pressure forcing water into the tank (through a turbine) mimics water falling from a high place. Pumping out against the pressure mimics pushing the water back up to a high place. It is pumped-water storage. Except that it doesn’t need an elevated large piece of ground for a reservoir.

    I was reminded of this because one start-up company received a lot of press in the past few days for a product called Ocean Battery. (Not to be confused with more conventional battery with the same name.) An older company is called Stored Energy at Sea.

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