Google was one of the first data center companies to get a PPA. A PPA? Power Purchase Agreement. I am pretty sure Google was first, but it was 2009 when they started and I can't remember if there was possibly someone else. I think back in 2009 people were thinking they need to fund their own renewable energy projects and didn't even know what a PPA was.
I was lucky and spent a bunch of time hanging around OSIsoft friends like Pat Kennedy who were immersed in the workings of power generation and Pat suggested that data centers could benefit from going after lumber decommissioned power plants which have water rights, power and PPAs.
Part of using PPAs is there are now public disclosures and as Amazon, Facebook, Microsoft, Apple, and others follow they are announcing their renewable energy PPAs. Google has summarized their efforts in this nice graphic.
But don't rush to think PPAs solve all your problems for acquiring renewable energy. With Google's experience they have found there is room for improvement as Google's Greg Demasi closes in his blog post.