WIND - Scientists calculate the energy required to store wind and solar power on the grid

Renewable energy holds the promise of reducing carbon dioxide emissions. But there are times when solar and wind farms generate more electricity than is needed by consumers. Storing that surplus energy in batteries for later use seems like an obvious solution. But a new study finds that when you factor in the energetic costs, grid-scale batteries make sense for storing surplus solar energy, but not for wind ...

http://www.sciencedaily.com/releases/2013/09/130909105253.ht