Solar power when the sun has set

http://i.cdn.turner.com/cnn/.element/apps/cvp/3.0/swf/cnn_416x234_embed.swf?context=embed&contentId=tech/2012/11/16/orig-ideas-future-battery.cnn CNN) — What if we could use solar energy when the sun has set, or wind energy when the air is calm? Donald Sadoway is working on a way […]