Form Energy Unveils Low-Cost, Long Duration Battery that Uses Iron and Air

July 27, 2021
Iron and air are the key ingredients in a long duration battery storage system that Form Energy — the system’s developer — contends can help make emissions-free electricity available for days at a time at a low cost.

Iron and air are the key ingredients in a long duration battery storage system that Form Energy — the system’s developer — contends can help make emissions-free electricity available for days at a time at a low cost.

By TijanaM/

The Form Energy batteries can run for 100 hours without needing to be recharged, making them ideal for storing energy from intermittent wind and solar farms, according to the Somerville, Massachusetts-based startup company.

The batteries are cost competitive with energy from conventional power plants and cost less than a tenth of the price of lithium-ion batteries, Form Energy said July 22. Lithium-ion batteries can typically discharge for four hours before needing to be recharged.

“With this technology, we are tackling the biggest barrier to deep decarbonization: making renewable energy available when and where it’s needed, even during multiple days of extreme weather or grid outages,” said Mateo Jaramillo, Form Energy’s CEO.

Before starting Form Energy four years go, Jaramillo was head of Tesla’s stationary energy storage program. He joined Tesla in 2009 as the electric car company’s director of powertrain business development.

Converts rust

The battery works by reversible rusting, according to Form Energy. While discharging, the battery takes in oxygen and converts iron to rust. When charging, an electric current converts the rust back to iron and the battery releases oxygen.

Each battery is about the size of a washing machine and they are modular, making them easy to site, including in cities, according to the company.

ArcelorMittal’s XCarb innovation fund is leading a $200 million Series D financing round for Form Energy, the company said. The fund invests in companies developing breakthrough technologies that will help the steel industry shift to carbon neutral operations.

A $76 million Series C financing round led by Coatue Management closed in November.

Investors in the company include Capricorn Investment Group, Macquarie Capital and Breakthrough Energy Ventures, a fund set up by Bill Gates and other investors.

Form Energy and ArcelorMittal, a steel and mining company, are developing iron materials that ArcelorMittal will supply for Form’s battery systems.

Form Energy to build first project in Minnesota

Form Energy’s first project is with Minnesota-based cooperative utility Great River Energy. The battery system will be built on a 1-acre site next to a natural gas peaking plant in Cambridge, Minnesota.

Great River expects the 1-MW, grid-connected storage system will be able to deliver its rated power continuously for 150 hours. The utility expects the battery system to be online by the end of 2023.

Other iron-based batteries

Form Energy isn’t alone in developing a battery based on iron. ESS, based in Wilsonville, Oregon, has developed an iron flow battery that will be used in a microgrid in Chile.

Earlier this month, the Department of Energy set a goal of reducing the cost of grid-scale, long-duration energy storage by 90% to $0.05/kWh before 2030.

The California Public Utilities Commission (CPUC) is also trying to spur a market for long-duration storage. In June, the CPUC ordered utilities and power suppliers to contract for 11,500 MW of emissions-free electricity between 2023 and 2026 to replace retiring generation and meet state renewable energy goals. The procurements in 2026 must include 1,000 MW of long-duration storage.

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About the Author

Ethan Howland

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