Summary:

* Form Energy, with funding from Breakthrough Energy Ventures (backed by Bezos and Gates)

* Iron/air chemistry

* Siting in Bangor, Maine

* 85 MW/8500 MWh

* Can discharge for ~100 hours

One key number missed out is:

> its round-trip efficiency is under 50%, in contrast to lithium-ion's 85%

edit: the comments on the article suggests under 50 means 35% in this specific case.

So if you have both on a grid you want to fill the lithium batteries first and drain them first.

> At full production, the modules will produce electricity for one-tenth the cost of any technology available today for grid storage.

So depending on your local grid clean energy and curtailment metrics, this is likely a superior short term option until further lithium and sodium BESS cost declines, continued rapid phase out of fossil generation systems, and deployment of renewables towards overbuild scenarios to approach/reach net zero.

It's funny that they say "can keep on supplying the grid for up to 100 hours" like that's a good thing.

The slower you go, the more hours you last. 100 hours at max speed is a severe bottleneck.