280MW solar plant in Arizona can produce power 6 hours after the sun goes down

Treehugger: It's not hard to understand why this kind of storage is important; one of the big problems with renewable energy is that power isn't always available when you need it. This can mitigate the problem, along with other technologies like hydro storage, smart grids that can better match supply and demand, and things like V2G for electric cars (storing renewable energy surplus in batteries, and using it when there's a deficit).

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