Form Energy raises $450 million to extend battery storage

Form Energy, a Massachusetts-based developer of long duration battery storage using iron, raised $450 million in Series E funding led by TPG Rise.

Why it marters: Long duration storage — a battery that can last for days or even weeks, instead of hours — is key to decarbonizing the electric grid, because it supports inherently intermittent renewables like wind and solar. Particularly at utility scale.

• Other investors include GIC, CPP Investments, ArcelorMittal and Breakthrough Energy Ventures. The company previously raised over $350 million, including in mid-2021 at a $1.2 billion valuation.

The bottom line: Iron is hardly the first material that comes to mind when thinking about energy innovation, but Form believes its iron rusting and de-rusting method will help it avoid the supply bottlenecks and high costs associated with more traditional battery materials like lithium.