Guidelines for applying PUE metric completed

The latest recommendations for energy efficiency measurement and reporting completes the guidelines for applying the Power Usage Effectiveness (PUE) metric.


The Green Grid Association, together with The Data Center Metrics Coordination Taskforce, has announced its latest recommendations for energy efficiency measurement and reporting.

The new report, Recommendations for Measuring and Reporting Overall Data Center Efficiency: Version 2 – Measuring PUE at Data Centers, completes the guidelines for applying the Power Usage Effectiveness (PUE) metric, created and promoted by The Green Grid. The new information includes specific recommendations for how to measure and calculate PUE in mixed-use data center facilities and introduces a condenser water source energy weighting factor.

Alignment on these methodologies across the industry will lead to consistent and repeatable measurement strategies that allow data center operators to monitor and improve the energy efficiency when operating their existing data centers, or when designing new facilities. The task force’s latest report represents the combined decision-making from the 7x24 Exchange, ASHRAE, The Green Grid, Silicon Valley Leadership Group, U.S. Department of Energy’s Save Energy Now and Federal Energy Management Programs, U.S. Environmental Protection Agency’s ENERGY STAR Program, U.S. Green Building Council, and Uptime Institute.

The following principles were reportedly agreed to:

  • PUE, using source energy consumption, is the preferred energy efficiency metric for data centers.
  • When calculating PUE, IT energy consumption should, at a minimum, be measured at the output of the uninterruptible power supply (UPS). However, the industry will continue to improve measurement capabilities so that measurement of IT energy consumption directly at the IT load (e.g., servers, storage, network, etc.) becomes the common practice.
  • For a dedicated data center, the total energy in the PUE equation will include all energy sources at the point of utility handoff to the data center owner or operator. For mixed-use data centers, the total energy will be all energy required to operate the data center, similar to a dedicated data center, and should include cooling, lighting, and support infrastructure for the data center operations.

- Edited by Amanda McLeman, Consulting-Specifying Engineer,

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