​Jesse traveled to a factory in Oregon, that’s building a new type of battery.

Sitting in a row outside of the factory, these giant batteries are the size of freight containers. Powered by vats of iron and saltwater, they’re called iron flow batteries. And they’re part of a wave of cleantech inventions designed to store energy from the sun and the wind, and solve a problem that has stumped the energy world for more than 150 years.

Grist