Battery startup Form Energy said on Wednesday that it has raised $750 million to expand its manufacturing capacity in West Virginia, the latest sign that the AI data center building boom is fueling investment in energy storage.

The U.S. installed 9.7 gigawatt-hours of energy storage in the first three months of this year, up 32% from 2025. Most of those batteries can discharge for a few hours at most, but Form Energy’s iron-air batteries can deliver power for up to 100 hours. Long-duration energy storage is particularly desirable because it can help bridge the power supply gap in renewable power generation, which is expected to account for more than 90% of new generating capacity in the U.S. this year.

Form’s unique battery chemistry helps it store massive amounts of electricity for less by relying on iron instead of pricier minerals like lithium, cobalt, and nickel. Inside a Form battery, iron is oxidized and reduced as it is discharged and charged — that is, the battery turns iron into rust when it discharges and reverses the process when it charges, turning rust back into iron. 

The approach has helped Form land some big customers. Google is building a new data center in Minnesota that will be partially powered by a massive, 30-gigawatt-hour Form battery that cost the tech company about $1 billion. Crusoe said in March that it would buy 12 gigawatt-hours of batteries from Form. Utility Xcel Energy is also a customer, as is FuturEnergy Ireland.

Some 80% of Form’s materials come from the U.S., while the balance comes from Europe and Asia — notably not China. Chinese companies dominate both the battery supply chain and battery manufacturing, and both the Biden and Trump administrations have sought to decrease U.S. reliance on China for batteries.

The company’s domestic-focused supply chain has helped it land big new customers as U.S. electricity demand rises for the first time in decades. Data centers are largely responsible for the uptick; they are expected to quadruple their electricity use in the U.S. by 2035, consuming about 20% of all electricity generated in the country.

The startup currently has a backlog of commercial projects worth about 80 gigawatt-hours of energy storage, the Wall Street Journal reported, up fourfold from earlier this year.

The Series G round was led by T. Rowe Price with participation from Sequoia Capital, Janus Henderson, Franklin Templeton, PEAK6 Investments, Prelude Ventures, Engine Ventures, TPG Rise Climate, Capricorn’s Technology Impact Funds, Breakthrough Energy Ventures, Dustin Moskovitz and Cari Tuna, Gigascale Capital, Coatue, Energy Impact Partners, NGP, GE Vernova, Blindspot Ventures, and M&G Catalyst Fund.

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