Rust? Trains? Why clean energy is turning to exotic ideas to fix its storage problem

Traces of rust on iron have been a sign of decay for thousands of years. But now this chemical process — the oxidation of iron into iron oxide — forms the basis of a battery that Jaramillo said could offer a way to store energy on power grids for more than 100 hours, but at about one-tenth of the cost of an equivalent facility powered by lithium-ion batteries, the leading battery technology…

“Cost-effective, durable and reliable energy storage opens up whole new areas of possibility for grid decarbonization,” said Costa Samaras, an associate professor of environmental engineering at Carnegie Mellon University in Pittsburgh who studies efforts to create a power grid with effectively no carbon emissions. “It reduces the stress on the grid during peak times, and it stores renewable energy in the times where you have a lot of it to the times where you don’t.”