Google is a search engine, an advertising company and now a cellphone maker. But a green energy company? That too, said Bill Weihl, Google’s so-called green energy czar, in an interview with Jeffrey Marlow of The Times on the Green Inc. blog. He said:

Some people might look at that and say, ‘I don’t see any relationship between that and Google’s business.’ And then maybe five years later they’ll say, ‘Whoa, it’s a good thing you guys thought about that.’

Google is interested in making renewable energy less expensive than coal in part because Google, with its massive servers, uses so much energy itself, and because the founders and many of the employees simply care about environmental issues, Mr. Weihl said.

Google has invested $45 million in alternative energy since 2007, including in solar companies eSolar and BrightSource Energy, though the primary goal is not to make money, Mr. Weihl said:

We’d be delighted if some of this stuff actually made money, obviously; it is not our goal to not make money. All else being equal, we’d like to make as much money as we can, but the principal goal is to have a big impact for good.

In the interview, Mr. Weihl also discusses Google’s problem with coal, the technologies it thinks will solve that problem — concentrated solar thermal, enhanced geothermal and high-altitude wind — and what he thinks Google can do to address climate change that other companies can’t. He says:

I believe that the problems we’re facing are solvable, but they’re not going to solve themselves. And solving them is either going to require spending a lot more money on energy than we’re spending today, which I think is probably a non-starter, or it’s going to require major technological innovation. That’s where I think Google can help.