Form Energy makes iron-air batteries that store electricity for up to 100 hours — roughly 20× the duration of standard lithium-ion systems. The technology works by reversibly oxidizing iron powder with atmospheric oxygen in a water-based electrolyte ("reversible rusting"), enabling very large energy storage at low material cost. Customers are electric utilities and large power consumers — AI data center operators in particular — who need reliable backup power during multi-day renewable generation gaps. The company built Form Factory 1, a 550,000-sq-ft plant on the site of a former steel mill in Weirton, West Virginia, which started commercial production in 2025. Its first commercial system shipped to Minnesota utility Great River Energy in Q4 2025. A landmark 300 MW / 30 GWh project with Xcel Energy to power a Google data center in Minnesota is under agreement, as is a 12 GWh supply deal with AI infrastructure firm Crusoe. Form has also announced its first international deployment in Ireland. The company self-describes as an American manufacturing and energy technology company.