Form Energy raises $750m Series G at a lower valuation

Form Energy closed a $750 million Series G financing led by T. Rowe Price, the long-duration storage company announced from Weirton, West Virginia on 12 August 2026. The Form Energy Series G takes the company’s total equity raised past $2 billion and funds both its manufacturing scale-up in Weirton and commercial deployments of its 100-hour iron-air battery. Morgan Stanley acted as sole and exclusive placement agent.

T. Rowe Price also led Form’s Series F. Sequoia Capital, Janus Henderson, Franklin Templeton and PEAK6 Investments joined as new investors. Returning backers include 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 the M&G Catalyst Fund.

The Form Energy Series G was raised at a lower price than the last round

Form Energy did not publish a valuation. Axios Pro reported on the day of the announcement that the round was raised at a $1.75 billion pre-money valuation, down from about $3 billion pre-money in October 2024, and headlined the story “Form Energy cuts valuation in latest raise”. Form has not confirmed the figure. Axios attributes both numbers to its own reporting rather than to the company.

The valuation moved in the opposite direction to the order book. Form states that “earlier this year, the company increased its backlog from approximately 20 gigawatt-hours to 80 gigawatt-hours”, without dating either endpoint. Two intermediate company figures give a rough shape to that growth: Form cited more than 65GWh on 17 March 2026, and a Crusoe release a week later put it above 75GWh.

What the backlog is made of

Three named agreements account for most of the disclosed order book. The largest is with Xcel Energy, which in February 2026 said it would install 300MW/30GWh of Form’s batteries to serve a Google data centre at Pine Island, Minnesota, as part of a wider package adding 1,400MW of wind and 200MW of solar. Xcel described it as the largest battery project by energy capacity announced anywhere to date. The electric service agreement was submitted to the Minnesota Public Utilities Commission for approval and had not been approved at the time of that announcement.

Sources: Form Energy project announcements, February to March 2026; Energy-Storage.News, 26 February 2026.

The Crusoe deal, announced at CERAWeek in Houston on 24 March 2026, reserves 12GWh of volume with agreed pricing and delivery terms rather than committing to a built site. The Irish project, with FuturEnergy Ireland, a 2021 joint venture between the state utility ESB and the forestry company Coillte, is Form’s first announced international deployment. RJ Johnson, Form’s chief commercial officer, said at the time: “This project with FuturEnergy Ireland marks Form Energy’s first international deployment – and the first, we hope, of many more to come.”

Form’s press release for the Series G carries no direct quotes from the company or from T. Rowe Price.

How the iron-air battery works, and the efficiency question

Form’s cells store energy through what the company calls reversible rusting. On discharge the battery takes in oxygen from the air and converts iron metal to rust; on charge, an electrical current converts the rust back to iron and the battery releases oxygen. The inputs are iron, water and air, with a water-based non-flammable electrolyte and no lithium, cobalt or nickel. Form states the system can store and discharge energy for up to 100 hours and claims it is “capable of storing energy at less than 1/10th the cost of lithium-ion battery technology”. That cost claim is the company’s own and has not been independently audited.

The trade-off is round-trip efficiency, and Form does not publish a figure. Third-party estimates cluster well below lithium-ion. A January 2026 report from Energy Solution Intelligence put iron-air round-trip efficiency at approximately 40 to 50 per cent against 85 to 90 per cent for lithium-ion, while Energy-Storage.News has written that Form “might contend” its figure sits in the 50 to 60 per cent range. The storage consultant Jim McDowall told the same outlet that 40 per cent was “more like the real number, from what I’ve heard”. Xcel Energy, asked about the gap, said round-trip efficiency was “extremely important when evaluating energy storage technologies” but that Form’s scaled-up manufacturing “has helped make it a viable option when it comes to the capital cost as compared to alternatives”.

That is the core commercial argument for the chemistry: multi-day duration bought cheaply enough that the energy lost in the cycle matters less than the cost per kilowatt-hour of capacity. The trade-off is set out in more detail in our explainer on whether iron-air batteries can deliver long-duration storage.

Only one commercial system is confirmed operating. Form said it shipped, installed and operated its first commercial iron-air system in the fourth quarter of 2025 at a pilot site in Cambridge, Minnesota with Great River Energy, and that “under sub-zero winter conditions, essential iron-air battery functionality was successfully demonstrated”. The full 1.5MW/150MWh project is expected online during 2026. Earlier grid-connected test systems ran in the Sacramento Valley in 2023 and the California Bay Area in 2024.

Form Factory 1 and two new executives

Production runs at Form Factory 1 on the site of the former Weirton Steel mill in West Virginia. The plant covers 550,000 square feet, employs nearly 400 people and started commercial production in 2025 after construction began in 2023. Form plans to expand it to around 850,000 square feet and more than 750 employees by 2028, reaching production capacity of at least 500MW a year. The company originally announced the site in December 2022 with a stated investment of $760 million, 750 jobs and up to $290 million in West Virginia performance financing. Company-wide headcount is nearly 1,000 across West Virginia, Massachusetts and California.

The Series G release also named two executives. Navneet Govil joins as chief financial officer after serving as executive managing partner, chief financial officer and investment committee member at SoftBank Investment Advisers, where he oversaw finance and investment operations across the SoftBank Vision Funds. Wes Sloan joins as chief operating officer from Panasonic Energy North America, where he was executive vice president responsible for production in Nevada, and previously held senior roles at Rolls-Royce. Form’s own leadership page, last updated on 17 August 2026, still lists co-founder Ted Wiley as president and chief operating officer and does not yet list Sloan; neither the company nor the release describes any departure.

The round lands in an active market for storage capital. Antora Energy raised $550 million for its thermal battery earlier this year, and climate tech venture funding reached $26.1bn in the first half of 2026, with low-carbon data centre technology taking 34 per cent of the total. Global deployment is running at record levels: the IEA reported that battery storage additions hit 108GW in 2025.

About Form Energy

Form Energy was founded in 2017 by five energy storage specialists: Mateo Jaramillo, Ted Wiley, Billy Woodford, Yet-Ming Chiang and Marco Ferrara. Seed funding and early lab space came from MIT’s The Engine. Jaramillo, the chief executive, previously started and ran Tesla’s stationary storage products and programmes business, joining the company in 2009, and was earlier chief operating officer and a founding team member at Gaia Power Technologies. Woodford is chief technology officer, Chiang chief science officer and Ferrara chief digital officer. The company is headquartered in Somerville, Massachusetts, with an engineering site in Berkeley, California opened in 2020 and its factory and corporate address at 26 Iron Way in Weirton, West Virginia. It raised successive rounds from 2018 onward, reaching more than $1.2 billion in total funds by the 2024 Series F, and secured public support including a US Department of Energy battery materials award of up to $150 million in September 2024. The Series G is the first round in which an outside report has put Form’s valuation below its previous mark, even as the company reports a fourfold increase in its order backlog.

Sources: Form Energy; Axios Pro; TechCrunch; Energy-Storage.News; Energy-Storage.News; Form Energy

Featured image: photo by Petr Ganaj on Pexels (free Pexels license).

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Figen Sekin

I specialize in sustainability education, curriculum co-creation, and early-stage project strategy. At WINSS, I craft articles on sustainability, transformative AI, and related topics. When I’m not writing, you’ll find me chasing the perfect sushi roll, exploring cities around the globe, or unwinding with my dog Puffy — the world’s most loyal sidekick.