Google has invested more than $10 million in breakthrough geothermal energy technology called Enhanced Geothermal Systems. This funding also includes next-generation geothermal resource mapping, EGS information tools and a policy agenda for geothermal energy.

Conventional geothermal systems look for naturally occurring pockets of steam and hot water while the EGS process creates it's own "by fracturing hot rock, circulating water through the system, and using the resulting steam to produce electricity in a conventional turbine".

According to one MIT report, just 2% of the heat below the continental US (between 3 and 10 kilometers deep) is more than 2500 times the total annual energy used by the US.

Google's initiatives also focus on solar thermal power, advanced wind along with EGS and other potential breakthrough technologies. The difference between this technology and using solar and wind is that it is available 24/7.

Google's goal is to produce enough renewable energy to power a city the size of San Fransisco, in years, not decades.