US, Europe, Japan agree on data center efficiency metric

IDG News Service - Industry groups and government agencies from the U.S., Europe and Japan have reached a basic agreement on how to measure the energy efficiency of data centers, they are expected to say on Monday.

The agreement is seen as significant because it establishes a common metric that different types of data centers, in different parts of the world, can use to report their level of energy efficiency. That could provide a yardstick for companies to assess the efficiency of their own data centers, and also to gauge the effectiveness of energy-saving techniques employed by other facilities.

The agreement is unusual for its level of international cooperation. Orchestrated by the Green Grid, an industry consortium in the U.S., the agreement is backed by the U.S. Department of Energy, the U.S. Environmental Protection Agency, the European Union Code of Conduct and the Japan Ministry of Economy, according to a statement from the Green Grid.

"The Green Grid is working with organizations around the world to develop a clear and well-defined language for the way we communicate about energy efficiency metrics, which will give us a common measuring stick for all data centers regardless of their location," said Tom Brey, an IBM employee who is secretary of The Green Grid, in a statement. "With that type of consistency, we can start driving behavioral changes in the industry."

The participants have agreed to adopt Power Usage Effectiveness, or PUE, as their "preferred energy efficiency metric," the statement says. PUE, which was developed by the Green Grid, divides the total energy consumed by a data center by the amount of energy used to power the IT equipment. The result shows how much energy is being lost to mechanical and electrical systems.

The choice of PUE is no surprise. It has emerged as the most popular metric for measuring data center efficiency, and some large companies, notably Microsoft and Google, have been publishing PUE numbers as a way to show off the efficiency of their newest facilities.

But there is no standard method for calculating PUE, and the groups participating in the agreement still have some work to do, in defining how the total energy consumed by a data center should be measured, for example. They are also expected to develop and define further efficiency metrics.

"A global task force with representatives from each of the above mentioned organizations will continue to move this initiative forward and reconvene later this year to evaluate progress," the Green Grid says in the statement.

The agreement follows several meetings of stakeholders and interested parties. In January representatives from the EPA met with several data center industry groups from the U.S., including 7x24 Exchange and ASHRAE (The American Society of Heating, Refrigerating and Air-Conditioning Engineers). The EPA then took the input from those groups to a meeting of international representatives on Feb. 2. A copy of the Feb. 2 agreement (PDF) was quietly posted on the Green Grid Web site this week.