Form Energy, the US developer of iron-air battery technology for long-duration energy storage, has closed a $750 million Series G financing round led by global investment manager T. Rowe Price. The funding represents one of the largest single investments in long-duration storage to date and signals deepening institutional confidence in multi-day storage solutions as essential infrastructure for a decarbonizing grid. With this capital, Form Energy plans to scale manufacturing at its West Virginia factory and accelerate deployments with utility customers including Georgia Power and Xcel Energy.
The iron-air chemistry at the heart of Form Energy’s system offers a compelling economic case for durations of 100 hours or more — far beyond the four-to-six-hour sweet spot of lithium-ion. By using abundant, low-cost materials like iron, water, and air, the technology targets a levelized cost of storage that could undercut gas peakers and enable deep renewable penetration without reliability trade-offs. That cost curve has been the missing link in many grid decarbonization models, and Form Energy’s progress toward commercial validation has drawn intense scrutiny from utilities and system planners alike.
T. Rowe Price’s leadership of this round carries particular weight. The firm’s participation alongside existing strategic investors — including ArcelorMittal, Breakthrough Energy Ventures, and major utilities — suggests that long-duration storage is crossing the threshold from venture bet to infrastructure asset class. For a capital-intensive hardware company building a new factory in Weirton, West Virginia, the involvement of a traditional asset manager signals that the risk-return profile is maturing toward project-finance readiness.
Deployment timelines are now the critical metric. Form Energy’s first commercial installation, a 150-megawatt, 100-hour system for Georgia Power, is slated for 2026. A second project with Xcel Energy in Minnesota follows a similar schedule. Meeting those dates will require flawless execution on the manufacturing ramp — a challenge that has tripped up many hard-tech climate ventures. The Series G proceeds are explicitly earmarked for that ramp, as well as for expanding the company’s engineering and project development teams.
The broader implication extends beyond a single company’s balance sheet. As the Inflation Reduction Act’s production tax credits for advanced manufacturing and standalone storage take effect, the economics of domestic long-duration storage improve markedly. Form Energy’s financing milestone suggests private capital is beginning to price in those policy tailwinds. If iron-air proves scalable, it could reshape resource adequacy planning across North American grids, giving system operators a dispatchable, carbon-free asset that fills the multi-day gaps left by weather-dependent renewables.
Read the full report at Energy Storage News.