Previous clean energy investments by Google include eSolar Inc, which builds Concentrating Solar Power (CSP) plants, as well as AltaRock Energy and Potter Drilling, which use various techniques to optimize and develop geothermal energy sources.

FORBES: Is Google Becoming A Utility Company?

Large power companies such as NRG Energy Inc. and Mid American Energy Holdings Co. have been buying solar projects because the low prices of panels are improving the return on investment of such projects.

WSJ: California Solar Deal Hits a Snag