form energy

The Cambridge Energy Storage Project in Cambridge, Minnesota will be the first commercial deployment of iron-air battery technology. Developed by startup company Form Energy, the battery system will provide 1.5 MW and 150 MWh of multi-day energy storage.

Iron-air batteries are based on the principle of reversible rusting. When discharging, the battery releases energy by breathing in oxygen from the air and converting iron metal to rust. When charging, the battery takes up electrical current that converts rust back into iron and breathes out oxygen.

An individual iron-air battery module is about the size of a washer/dryer set and contains about 50 individual cells filled with a water-based, non-flammable electrolyte. For a utility-scale system like that being built in Cambridge, modules are grouped together in enclosures and hundreds of enclosures grouped together in megawatt-scale power blocks. A one-megawatt low-density system would take up about half an acre of land. High-density systems would be capable of producing more than 3 MW per acre.

The technology has lower costs compared to lithium-ion battery technology but may be best suited as complementary with it since lithium-ion is primarily used for short-duration energy storage while air-iron can store energy for several days.

The system is expected to be operational by late 2025. Great River Energy, the operator of the system, plans to conduct a multi-year study to evaluate the system’s performance and potential for broader development.

**********

Web Links

Minnesota co-op breaks ground on multi-day energy storage project

Photo courtesy of Form Energy.

Earth Wise is a production of WAMC Northeast Public Radio

Lithium-ion batteries are the standard energy source for electric vehicles, and they are also the dominant technology for storing energy in the electric grid. However, they are not the only game in town. There are other battery technologies that have various potential advantages over lithium-ion and some of them are getting the chance to show what they can do.

One is the iron-air battery. Unlike lithium-ion batteries that require expensive and strategically challenging materials like lithium, cobalt, nickel, and graphite, iron-air batteries make use of one of the most common elements in the earth’s crust.

Iron-air batteries operate on a principle known as “reversible rusting”. When discharging, the battery takes in oxygen from the air and converts iron into rust. While charging, electrical current converts rust back into iron and the battery releases oxygen. Batteries consist of a slab of iron, a water-based electrolyte, and a membrane that feeds a controlled stream of air into the battery.

A Massachusetts-based company called Form Energy is building a $760 million iron-air battery storage facility in the city of Weirton in West Virginia. Investment financing along with a $290 million government incentive package is paying for the facility.

The facility is designed to address the need for long-duration energy storage and will be capable of storing electricity for 100 hours at competitive prices. The battery modules will be about the size of a side-by-side washer/dryer and will contain a stack of 50 3-foot-tall cells. Such batteries are too big and heavy for use in cars but will be cheaper and higher-capacity than equivalent lithium-ion battery systems.

**********

Web Links

Form Energy selects West Virginia for its first iron-air battery plant

Photo credit: Form Energy

Earth Wise is a production of WAMC Northeast Public Radio

Energy storage with iron-air batteries

The Cambridge Energy Storage Project in Cambridge, Minnesota will be the first commercial deployment of iron-air battery technology. Developed by startup company Form Energy, the battery system will provide 1.5 MW and 150 MWh of multi-day energy storage.

Web Links

An Iron-Air Battery Plant | Earth Wise

Web Links