Form Energy, a long-duration energy storage startup, raised USD 200 million in a Series D funding round led by the XCarb innovation fund, an initiative of ArcelorMittal (a Luxembourg-based multinational steel manufacturer). The funds are expected to accelerate the commercialization of the company’s battery technology. 

Form Energy has also signed an agreement with ArcelorMittal to jointly develop iron materials for its batteries. 

Following the round, Form Energy unveiled its first long-duration energy storage solution to be commercialized. The product is a rechargeable iron-air battery with a storage duration of around 100 hours. The company claims its new battery would cost 1/10th of the cost of conventional lithium-ion batteries.

Founded in 2017, Form Energy develops long-duration utility-scale energy storage solutions to bridge renewable energy supply gaps. The company’s solution, known as “reversible rusting,” uses oxygen from the air to convert iron metal to rust while discharging, and while charging, the electrical current converts the rust back to iron. Since May 2020, Form Energy has been in partnership with Great River Energy, the second-largest electricity company in Minnesota, to roll out the first commercial deployment of its long-duration battery technology. 

Analyst Quicktake: Form Energy’s new battery is claimed to be a breakthrough development in long-duration energy storage. Current long-duration batteries generally last around 2-4 hours compared to Form Energy’s 100-hour battery.