Google today disclosed details of its data center energy usage, confirming that it operates some of the most efficient facilities in the world. Google said it is averaging a Power Usage Effectiveness (PUE) rating of 1.21 across its six company-built data centers, and one of its facilities is operating with a PUE of 1.13, the lowest ever published and just above the "perfect" efficiency score of 1.0.
"Today we are operating what we believe to be the world's most efficient data centers," Google says. "Through these efficiency efforts we save hundreds of millions of kWhs (kilowatt hours) of electricity, cut our operating expenses by tens of millions of dollars, avert the emission of tens of thousands of tons of CO2, and save hundreds of millions of gallons of water."
The typical enterprise data center is estimated to have a PUE of 2.0 or higher, and the lowest claim in our travels here at DCK is a PUE of 1.28 for Sun's data center in Santa Clara, Calif. Compare that to this chart tracking the PUE at the six Google-designed data centers that have been in operations for six months or longer. The PUE number is on the left axis:
"We reduced the energy-weighted average overhead across all Google-built data centers to 21% versus the average of 96% reported by the EPA," Google says in a new section of its web site dedicated to data center efficiency. "In other words, compared to standard data centers we've reduced the overhead by more than fourfold. To our knowledge, no other large-scale production data center has ever operated as efficiently. In fact, one of our data centers is running at an even lower overhead of only 15%, a sixfold improvement in efficiency."
The company also adds an interesting metric. "In the time it takes to do a Google search, your own personal computer will use more energy than we will use to answer your query."
Google has become known for its secrecy about its data center operations. The company's disclosure of its PUE data comes at a time of increased information sharing about energy efficiency within the industry. Digital Realty Trust (DLR) has begun publishing the PUE information for its facilities, and more than 200 data centers are now participating in a data-sharing project with the U.S. Environmental Protection Agency. Google's chief rival, Microsoft, has also been actively sharing information about its use of the PUE metric.
PUE is an emerging standard promoted by The Green Grid and others in the data center industry to provide a consistent way to measure the ratio of power delivered to IT equipment versus the total amount of power used by the facility. PUE allows data center managers to calculate how much power is driving the actual IT equipment versus non-IT elements such as cooling and lighting.