We’re going to need a lot more grid storage. New iron batteries could help.

Batteries don’t have that limitation. However, most grid-scale batteries operating today are lithium-ion batteries. Relatively expensive, they also deteriorate within a few years and are made from difficult-to-recycle materials that can burst into flames or explode. Worse, if you want to double the storage capacity of your battery array, you have to buy twice as many batteries. That makes it too expensive to store energy for longer than a few hours, says Scott Litzelman, who manages a program that focuses on long-term energy storage at ARPA-E, the US agency that funds research and development of advanced energy technologies. Flow batteries, like the one ESS developed, store energy in tanks of liquid electrolytes—chemically active solutions that are pumped through the battery’s electrochemical cell to extract electrons. To increase a flow battery’s storage capacity, you…

Read more…