Form Energy is trying to solve the hardest problem in clean energy: what happens when the sun does not shine and the wind does not blow for three days straight? Their answer: batteries made of rust. Iron-air batteries store energy for 100 hours — 25x longer than lithium-ion — using iron, air, and water. The raw material is literally the most abundant metal on earth. Bill Gates invested through Breakthrough Energy. ArcelorMittal (the world's largest steelmaker) invested because they make iron. If this works, it eliminates the last excuse for burning fossil fuels to keep the lights on. If it does not work, it is another clean energy technology that was brilliant in the lab and impossible at scale. The factory in West Virginia will be the answer.
Founded
2017
HQ
Somerville, Massachusetts
Total Raised
$925 million
Founder
Mateo Jaramillo, Yet-Ming Chiang, Ted Wiley, Marco Ferrara, William Woodford
Status
Private (valued at $1.2B+ as of 2022)
Website
formenergy.comTHE ORIGIN STORY
Mateo Jaramillo (former head of Tesla's energy storage division) and Yet-Ming Chiang (MIT professor and serial battery entrepreneur who co-founded A123 Systems and 24M Technologies) co-founded Form Energy in 2017. They identified the "multi-day storage" gap: solar and wind are cheap for 4-hour storage windows, but what about a cloudy, windless week in January?
Lithium-ion cannot economically cover multi-day storage. Form developed iron-air chemistry — essentially, the battery breathes oxygen and rusts iron plates to store energy.
Breakthrough Energy Ventures (Bill Gates's climate fund) was an early backer.
WHAT THEY ACTUALLY DO
Form Energy is developing iron-air batteries for grid-scale energy storage. Unlike lithium-ion batteries (which store energy for 4 hours), Form's iron-air batteries can store energy for 100 hours — enough to keep the grid running through multi-day weather events when solar and wind are not producing.
The battery technology is based on reversible rusting: iron rusts (oxidizes) to discharge, and the process is reversed to charge. Iron is cheap, abundant, and domestically sourced.
Revenue will come from selling battery systems to electric utilities.
THE PRODUCTS
Iron-Air Battery System (100-hour grid-scale energy storage), Form Factory (commercial manufacturing facility in Weirton, WV)
HOW THEY GREW
Deploy iron-air batteries with major electric utilities across the US. Form has announced pilot projects with Great River Energy (Minnesota), Xcel Energy, and Georgia Power.
The first commercial-scale factory in West Virginia will produce enough batteries for major grid installations. The strategy: prove the technology works at scale, then sign contracts with every utility that wants to decarbonize.
THE HARD PART
Scaling from lab to commercial deployment. The iron-air technology works in the lab but has never been deployed at utility scale.
Manufacturing batteries at the size and cost needed to compete with natural gas peaker plants is an enormous engineering and logistics challenge. Form is building its first commercial-scale factory in Weirton, West Virginia.
MONEY TRAIL
Series A
2018 · Led by
$9M raised
Series D
2021 · Led by
$240M raised
Series E
2022 · Led by
$450M raised
WHO BACKED THEM
Breakthrough Energy Ventures (Bill Gates), ArcelorMittal, TPG Rise Climate, GIC, MIT The Engine
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