US startup Form Energy has raised $450m in growth funding (Series E) to build its first serious factory. The first instance of Form's water-based iron-air battery will come on stream not - as announced below - in 2023 but a year later, CEO Mateo Jaramillo tells Canary Media. Below is the original post on Form Energy from 20 May 2020. Source Form Energy by Thijs ten Brinck - 05 Oct 2022

Again relevant: 22 July 2021 | Originally published: 20 May 2020

The monkey is out of the bag. Form Energy's mysterious new battery technology involves rusting iron. The startup revealed this in promotion of a new funding round.

An iron-air battery is nothing new and what Form does differently from previous attempts remains unsaid.

So it is still a mystery how (and if) Form Energy will force a breakthrough in energy storage with this concept.

Steel producer and iron specialist ArcelorMittal at least had enough confidence in the startup to step in for $25 mln. Below is the original post on Form from 20 May 2020.

Secretive battery delivers full power continuously for over 6 days

Energy company Great River Energy has ordered a battery with a storage capacity of 150 megawatt hours (MWh) from US startup Form Energy, for installation in Cambridge Minnesota. The battery should be in operation by 2023.

Particularly low power

The striking feature of the deal between Great River Energy and Form Energy is the ratio between the storage capacity to be delivered (150 MWh) and the maximum power of just 1 megawatt (MW).

In the case of large lithium-ion batteries such as the well-known Big Batteryin South Australia, power and capacity are much closer together.

Tesla's Big Battery has an output of 100 MW and a capacity of 129 MWh, which means it is empty after 1 hour and 17 minutes at full power. Form Energy's battery lasts no less than 6 days and 6 hours at full power.

Competitive on power, bargain on storage capacity

With lithium batteries, it is also possible to run on low power for a long time. Technically, Tesla's Big Battery is capable of delivering 1 MW for 129 consecutive hours. Economically, however, this cannot be done.

Lithium batteries have to rely on relatively short sprints at full power when electricity prices are high.

Form Energy is on a different track.

Water and air

The startup describes its technology as an aqueous air battery system. What that means is still a mystery to me, but cheap it must be.

Mateo Jaramillo, CEO of Form Energy, tells Greentech Media he expects to be able to compete on a "dollar per kilowatt basis" with the now also quite affordable lithium battery technology.

That's quite a claim. At the stated power to storage capacity ratio, it would then be extremely cheap.

On the other hand, most likely it takes even longer to charge the battery than the 6 days it takes to drain it.

Cycles of 2 weeks make 150 MWh of this storage, so much less usable than 150 MWh of lithium batteries anyway.

We'll see, battle to 2023

Because so little is still known about the startup, too good to be true is on the tip of my tongue.

On the other hand, CEO Jaramillo (7 years of Tesla, including 2 years as Tesla Energy boss), MIT pro and co-founder Yet-Ming Chiang and the other founders are prominent figures in the world of energy storage, who have a reputation to lose.

Moreover, this team has already convinced investors such as Macquarie, Breakthrough, Enel and Saudi Aramco to buy tens of millions.