Geothermal energy may be the most prolific renewable fuel source that most people have never heard of. Although the supply is virtually limitless, the massive upfront costs required to extract it have long rendered geothermal a novelty. But that’s changing fast as this industry buzzes with activity after decades of stagnation: Billionaire Warren E. Buffett has invested big. Internet giant Google Inc. is bankrolling advanced research. Entrepreneurs are paying record prices for drilling leases in places like Nevada. (Read more at the L.A. Times) Thanks to Sun Star for sending the link!