TechHermit has been vocal on Google's PUE #'s.
Google's Urs Hoelze posted a comment that many of you may not see.
Tech Hermit –
I wanted to address some of the questions in your post regarding Google’s data center efficiency.
First, to the question “how can the use of water economized facilities alone get you there?” To clarify, we do not claim that cooling towers alone will achieve these results. Rather, they are just one of the many techniques needed to achieve a PUE of 1.21. There’s no silver bullet in data center design and one needs a well-integrated set of techniques of which cooling towers are just one element.
You also make note of our reference to “caveats”. Please let us know what specifically you believe we omitted in the technical description of how we interpret and measure PUE. To the best of our knowledge, we have documented everything in detail and do follow the PUE definition as it is intended.
How can we claim to have the world’s most efficient data centers? We did carefully look for other published PUEs, and did not find any lower values. One of the reasons we took pains to describe our measurement methodology and measurement accuracy in detail is that we hope to encourage other data center operators to publish their results in this kind of detail as well. As you and others have rightly pointed out, claims without detail have already entered the realm of marketing. That said, I think you’ll agree that the industry certainly can benefit from PUE disclosures which include details about how they were measured, what the measurement accuracy is, and show a full year of measurements. That is the standard we set for ourselves.
Will there be someone better down the road? I certainly hope so, because I believe that data center technology will evolve quickly in the next few years. Until then, I believe that we have sufficiently documented and published the lowest PUE values of any large production data center.
Urs Hoelzle, SVP Operations, Google
I am waiting for the PUE auditors to address the confusion. It is funny to think someone would specialize in certifying a PUE, but once you make a statement of performance, you open yourself to compliance.