They'd put their geothermal as well.

NPR: Al Gore's Very, Very Good Year

Before you rush out and order a geothermal system, remember that furnace and air-conditioning technology has advanced as well, with new units 20% more efficient than a decade ago.

FORBES: Fort Knox's Buried Treasure

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?