Green Grid Provides PUE Measurement Guidance

On Thursday the Green Grid released consolidated recommendations for measuring and reporting the Power Usage Effectiveness (PUE) metric in dedicated data center facilities.  "Driving industry alignment of PUE through consistent measurement and reporting processes represents a significant step in improving data center energy efficiency," said Dan Azevedo, Symantec representative and board member of The Green Grid.

A group of leading U.S. organizations released a task force report titled Recommendations for Measuring and Reporting Overall Data Center Efficiency - Version 1 - Measuring PUE at Dedicated Data Centers. The recommendations for measuring and reporting PUE put forth by the group are aimed at use of multiple energy sources (electric, natural gas, water, etc.).

The report affirms the PUE metric as the industry's preferred data center infrastructure efficiency metric by The Green Grid in collaboration with 7x24 Exchange, ASHRAE, Silicon Valley Leadership Group, U.S. Department of Energy Save Energy Now Program, U.S. Enviornmental Protection Agency's ENERGY STAR Program, United States Green Building Council, and the Uptime Institute.

The task force report provides guidance on assigning a weighted factor to various source energy types, representing the total amount of raw fuel that is required to operate the building. The weighted energy for each energy type is calculated by taking the annual energy use and multiplying it by the source energy weighting factor.

The report covers reusing waste energy as an effort to improve energy efficiency and states that renewable energy sources should be included in the total energy and assigned the same source factor as grid electricity.

The task force also addresses operators that do not have the consumption measurement capability to use demand based power readings when calculating PUE.  They recommend four measurement categories for PUE within a data center: PUE Category 0 through Category 3, based on definitions of IT energy, total energy and IT energy measurement location.

To address the issue of proper reporting of PUE in the industry, the task force report covers proper publishing formats and related resources to map standards. The report concludes with a note about inclusion of mixed use buildings in the next version of the report and an example calculation of PUE using the new recommendations.