Form Energy has closed a $750M Series G, one of the largest funding rounds in grid storage this year.
The Somerville, Massachusetts company builds iron-air batteries that store electricity by oxidizing iron, the same chemistry behind rust, and release it by reversing the process. The design targets multi-day storage at a fraction of the cost of lithium-ion, aimed at keeping grids running through wind and solar lulls.
Form Energy has been scaling manufacturing for its utility-scale systems and expanding deployments with grid operators as renewable buildout accelerates. Its batteries are designed for the gap between daily storage and seasonal needs, giving utilities a way to firm up power when the sun is down and the air is still.
The company was founded in 2017 by a team of scientists and engineers, including former Tesla and MIT figures, and has drawn backing from some of the biggest names in climate investing across earlier rounds.
The raise underscores how climate-hardware startups selling to utilities are drawing mega-rounds even as broader venture funding stays selective. Long-duration storage is widely seen as a prerequisite for a grid that leans heavily on intermittent renewables, and investors are increasingly willing to fund factories rather than just pilots.
Form Energy did not disclose the investors in this round or how the proceeds will be allocated.
