Google's bold "cheaper than coal" renewable energy initiative has a lot of the blogosphere fitting the company for an even bigger green halo. But by its admission, Google's own infrastructure may have given them enough reason to jump in.

The Atlanta Journal Constitution is kind enough to put a dollar amount on that motivation:

But by some estimates, the company spends more than $2 million per month on electricity to power its network of an estimated 450,000 computer servers.

Seems plausible and falls around other estimates I've heard about the size of their server farms. And Google is still growing, let's not forget. Ultimately, though, it may have been a smart investment opportunity that pushed Google into action:

Page said the company expects to see returns "on a reasonable time scale" from its energy investments, either in the form of higher stock prices of the companies it invests in, in savings from producing its own power, or from the sale or licensing of solar and other technologies it develops.

Google, of course, isn't the only company that sees greenbacks in going green.

Atlanta media mogul Ted Turner, who has made big investments in solar energy lately, recently called the solar business "the greatest business opportunity in the history of humanity."

Hey, where is it written that you have to lose your shirt by going green? Guiltless capitalism, if you ask me.