Official Google Blog: Saving electricity one data center at a time

"The graph below [follow link] shows what we've achieved: our data centers use considerably less energy for the servers themselves, and much less energy for cooling, than a typical data center. We achieved this milestone by significantly reducing the amount of energy needed for the data center facility overhead. Specifically, Google-designed data centers use nearly five times less energy than conventional facilities to feed and cool the computers inside. Our engineers worked hard to optimize every element in the data center, from the chip to the cooling tower."