The Green Grid, in conjunction with a number of other data center industry groups and US government agencies, has released the first version of a document that recommends a specific process for measuring a data center’s Power Usage Effectiveness.

One of the major sources of criticism of the PUE metric, which compares a facility’s total energy use to energy used by the IT equipment, has been the argument that there are different ways to make these measurements, opening the final ratio to being "gamed."

"Driving industry alignment of PUE through consistent measurement and reporting processes represents a significant step in improving data center energy efficiency," said in a statement Dan Azevedo, one of The Green Grid board members. "The guidance specific to calculating PUE for data centers that use multiple energy sources (electric, natural gas, water, etc.) is substantial to ensuring PUE is measured and reported equitably."

The report, titled "Recommendations for Measuring and Reporting Overall Data Center Efficiency – Version 1 – Measuring PUE at Dedicated Data Centers," was a collaboration among The Green Grid, 7x24 Exchange, ASHRAE, Silicon Valley Leadership Group, US Department of Energy’s Save Energy Now program, the US Environmental Protection Agency’s Energy Star program, US Green Building Council and Uptime Institute.

The document provides guidance for calculating PUE from weighted energy types, based on source energy, outlines four measurement categories as subsets of The Green Grid’s measurement methods as well as guidance for renewable energy sources, combined heat and power plants and energy reuse.

The report can be downloaded from The Green Grid’s Web site.