Use the Web? Congrats, you’re an environmentalist.

Google, Yahoo, and Microsoft are part of a growing number of tech and other major companies that are entering into long-term "power purchase" agreements (PPAs) with wind farms to ensure a steady stream of power, at a fixed cost, over a period as long as several decades. What these deals have in common is that they involve purchasing clean energy in close proximity to the power hungry data centers that these companies operate -- data centers that in turn drive, searches, apps like Gmail, and much more.