We’re using more renewable power than ever. But what happens when the sun sets or the wind stops or the sun does not shine? Grid operators need a way to store electricity for those periods and they need to do it cheaply.

New iron-based batteries that may be the solution. They’re made using abundant materials and could be cheaper and more practical than other types of grid storage batteries.

Iron is one of the most abundant materials on the planet and using it could eventually be cheaper than other grid storage candidates, like lithium-ion and vanadium flow batteries. This batteries cost just $20 per kilowatt-hour, being lower than even optimistic projections for lithium-ion batteries in the future. There are still challenges to address because iron batteries typically have low efficiency, meaning that a large fraction of the energy put into them can’t be recovered. Another problem is that iron batteries also degrade faster over time, which leads to lower charge cycles before being replaced.

However, if iron-based batteries can be deployed at a low enough cost, we could power more of the world with renewable energy and reduce the need for fosil fuels.

Buiding large-scale iron battery grids could power might be the solution to power the world but irt also need a multi-country infrastructure to be built as power needs to flow between countries and regions that don't have large capacity of producing wind, solar or hydro electricity.