Iron air battery backed by Bezos and Gates promises storage at fraction of cost

Form Energy, a Boston-based start-up backed by some of the world’s richest people, has unveiled its new long-duration battery storage technology that it claims will store energy at one-tenth the cost of traditional lithium-ion battery storage systems.

The relatively secretive Form Energy has been working on the science behind its new long-duration battery storage technology for some time now, and last May announced a pilot battery project led by Minnesota-based Great River Energy.

That project – part of Great River Energy’s plans to eliminate coal from its portfolio and build 1,100MW of wind energy by 2023 – promised a 1MW “aqueous air battery” with 150MWh of storage potential that it said was a game changing technology.

Those claims attracted investors Amazon boss Jeff Bezos and Bill Gates’ Breakthrough Energy Ventures, along with Australia’s Macquarie Capital, and more.

After more than a year of secrecy, Form Energy has finally unveiled the chemistry of its multi-day storage battery technology – at the same time that it also announced a $US200 million Series D financing round led by Luxembourg steel giant ArcelorMittal’s XCarb innovation fund.

It describes the technology as a “rechargeable iron-air battery capable of delivering electricity for 100 hours at system costs competitive with conventional power plants and at less than 1/10th the cost of lithium-ion.”

The battery is made from iron – one of the safest, cheapest, and most abundant materials on Earth, meaning that it can be made more cheaply than lithium-ion batteries, which require a number of expensive rare-earth minerals.

Iron is used in combination with water and air and works on the principle of “reversible rusting”.

According to Form Energy, when the battery discharges it “breathes” in oxygen from the air and coverts iron metal to rust, and then when charging, the application of an electric current converts the rust back to iron and the battery breathes out oxygen.

So in addition to providing long-duration storage, the iron-air battery also improves local air quality.

“We conducted a broad review of available technologies and have reinvented the iron-air battery to optimize it for multi-day energy storage for the electric grid,” said Mateo Jaramillo, CEO and Co-founder of Form Energy.

“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.”

Form Energy claims that their iron-air batteries “are the best solution to balance the multi-day variability of renewable energy due to their extremely low cost, safety, durability, and global scalability.”

Both modular and scalable – with each individual battery measuring in at around the same size of a washing machine – the battery modules can be grouped together in modular megawatt-scale power blocks, which comprise thousands of battery modules in an environmentally protected enclosure.

In addition to unveiling the chemistry of their new iron-air battery technology, Form Energy also announced the beginning of a $US200 million Series D financing round led by ArcelorMittal’s XCarb innovation fund, which invested $US25 million.

ArcelorMittal will also work jointly on the development of iron materials which the company will non-exclusively supply for Form Energy’s battery systems.

Form Energy will source the necessary iron domestically and manufacture the battery systems near the location of the promised Great River Energy pilot project.

“Form Energy is at the leading edge of developments in the long-duration, grid-scale battery storage space,” said Greg Ludkovsky, Global Head of Research and Development at ArcelorMittal.

“The multi-day energy storage technology they have developed holds exciting potential to overcome the issue of intermittent supply of renewable energy. They are exactly the kind of ambitious and innovative company we are seeking to invest in through our XCarb innovation fund.”