

Unconventional grid storage is a market especially rife with questionable claims and vaporware.
There’s no shortage of people trying to dethrone King Lithium-Ion and corner the market for storing wind and solar power for hours and days. But sometimes, startups actually follow through on what they promise.
When I first wrote about Hydrostor in 2017, the Canadian company was already talking about building storage plants at the massive scale of hundreds of megawatts. At the time, nobody was building grid batteries anywhere close to that size, and certainly not with long-duration capabilities.
Hydrostor fell into the bucket of “go build a commercial project and let’s talk again in a couple of years.” But the company actually pulled it off. After operating its compressed-air storage technology in Ontario’s wholesale markets for multiple years, it is now developing a project in the 300- to 500-megawatt range, with up to 12 hours of duration, Canary Media reported.
To be clear, this project does not exist yet, and it likely wouldn’t be constructed until 2025. But Hydrostor was convincing enough about its prospects to win a 4 million Canadian dollar ($3.2 million) grant from the Canadian government to start the design and engineering work. This puts the company in the running to become a leading supplier of long-duration grid storage, not to mention a leader among the technologies vying to improve upon the dominant lithium-ion battery for storing clean power.
The speed to market comes from Hydrostor’s use of existing industrial machinery to excavate caverns and pump compressed air into them, which emerges to spin conventional 100-megawatt turbines. It’s a different path to market than, say, flow batteries, which have been fine-tuned in laboratories for literal decades and still haven’t made a dent in the marketplace.
The long-duration storage market is shaping up to be a showdown between people inventing exotic breakthrough hardware and others who engineer around established industrial supply chains. We’ll see who wins the race to market.
And if you’re wondering what kind of money is on the line here, investors have made big bets on unconventional storage companies in recent months, including:
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Photo courtesy of Hydrostor.
Julian Spector is senior reporter at Canary Media.