Gigantic Form Energy battery to power Google data center in Minnesota
Canary MediaJulian Spector24 Feb 2026all-rights-reservedRead the original
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Xcel Energy plans to install 300 megawatts of Form Energy's iron-air batteries at Pine Island, Minnesota, to serve a Google data centre. The defining feature is duration rather than power rating: the system is designed to discharge continuously for up to 100 hours, far beyond the two- to four-hour range typical of lithium-ion grid storage, and enough to ride through multi-day weather patterns that suppress wind and solar output. Form Energy's iron-air chemistry relies on reversible rusting of iron, using cheap and abundant materials at the cost of lower round-trip efficiency — a trade-off suited to long-duration rather than daily cycling. The company is still building its first commercial installation, also in Minnesota, making this a substantially larger follow-on order in the same state before the initial project is operating.
Quotation
“"The utility Xcel Energy will install 300 megawatts of Form's batteries in Pine Island, Minnesota… What shoots this project into the energy-storage stratosphere is that it will dispatch energy for up to 100 hours straight."”
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The MyGreenSuit briefing
Commentary by MyGreenSuit, not the words of Canary Media.
The number that matters is not 300 megawatts, it is 100 hours. Grid batteries today are two-to-four-hour assets — good for shifting an evening peak, useless against a still, cloudy week. A hundred-hour asset is a different category of thing, and the reason it can exist at all is that iron-air trades round-trip efficiency for materials that cost almost nothing.
The detail worth noticing, and the reason for caution: Form have not finished their first commercial installation yet, also in Minnesota, and this is a substantially larger follow-on ordered before the first one runs. Xcel and Google are buying a chemistry that has not been demonstrated at duration in the field.
That is not a criticism. Somebody has to go first, and the alternative product for firming a data centre is a gas plant with a delivery slot years out. But it does mean the first Minnesota project is now the most consequential storage installation in the country, and almost nobody is watching it.