Wind and solar need cheap, long-duration storage to even out its inherent weather-determined intermittency. Deborah Halber, writing for MIT News, describes the development of iron-air batteries. Iron is cheap and available worldwide. Storage duration is multi-day. They are much heavier and take up more space than lithium-ion batteries, but that doesn’t matter for immobile grid storage. The target price tag of $20/kWh (one-tenth the cost of … [Read more...]