Google’s higher calling comes directly from co-founders Sergey Brin and Larry Page, both ardent environmentalists. But it’s made real by the same moxie that has driven Google to create digital editions of 7 million books, with scant concern for copyright issues, and to amass satellite images of almost all of the earth’s nooks and crannies. “We only hire people who really, genuinely believe that big change is possible and the right thing to do,” says Erik Teetzel, a 34-year-old Google engineer who heads a team of researchers looking for ways to produce cheap renewable energy.

Still, now doesn’t seem like an ideal time for Google to be making such an ambitious move. Oil prices are down, eradicating much of the demand for alternatives to fossil fuels. A global economic downturn means many companies now consider green technology a luxury they can’t afford.

Google has never been very successful at diversifying its business; 97 percent of its revenue still comes from online ads.