American energy storage technology newcomer Form Energy says it has received funding to deploy a groundbreaking 85 MW/8.5 GWh iron-air multi-day battery, which will be capable of up to 100 hours of storage and will be the world’s biggest battery once built.

The US Department of Energy last week announced $US389 million ($A579 million) in funding for the Power Up New England project which seeks to unlock up to 4.8GW of additional offshore wind and innovative battery energy storage systems in the local grids to boost resilience and optimise the delivery of renewable energy.

Part of the Power Up New England project, and easily the most exciting, is the 85 MW/8,500 MWh iron-air battery system to be built on the site of a former paper mill in rural Maine.

Form Energy will receive $US147 million ($A218 million, converted) to build the battery, using its novel iron-air battery technology which is based on the principle of “reversible rusting.”

Tthe battery charges by the application of an electrical current which converts rust back to iron, in turn breathing out oxygen. To discharge, the battery breathes in oxygen from the air and converts the iron metal to rust.

At about the size of a side-by-side washer/dryer set and contains a stack of approximately 50 one-meter-tall cells, each individual battery module includes the iron and air electrodes that enable the electrochemical reactions to store and discharge electricity.

These modules are then grouped together, allowing for modular and scalable megawatt-scale power blocks.

Form Energy says its iron-air battery systems can be deployed anywhere to meet utility-scale energy needs, and while they are able to complement the function of traditional lithium-ion batteries, they also store energy at less than 1/10^th the cost of lithium-ion battery technology.

The batteries are also particularly safe, with no risk of thermal runaway. They also don’t use any heavy metals, making them highly recyclable.

All told, Form Energy claims that its iron-air battery technology will deliver the multi-day storage duration necessary to make renewable energy sources reliable anywhere in the world.

“We are pleased to be selected by the U.S. Department of Energy for the Power Up New England initiative to deploy an 85 MW/8500 MWh multi-day battery system – which marks a significant milestone on multiple fronts,” said Mateo Jaramillo, CEO and co-founder of Form Energy.

“Located at the site of a former paper mill in rural Maine, this iron-air battery system will have the most energy capacity of any battery system announced yet in the world.

“The project will ensure a more reliable, clean, and affordable grid in New England by reducing transmission congestion and making valuable wind energy resources available when and where they are needed.”