Bill Weihl, Google's green-energy czar, has been worrying about the environment for much of his IT career, including 10 years teaching computer science at the Massachusetts Institute of Technology and five more as a research scientist at the famed DEC Systems Research Center in Palo Alto, Calif. In 2004, he left Akamai, a content-delivery company where he was chief technology officer, to figure out how he could use his skills to help fight climate change.