The Green Grid has introduced a free online tool for data center operators to report Power Usage Effectiveness (PUE) scores, saying it hoped to "establish global consistency" in reporting the split between energy flowing to IT equipment and facility operations. The results will be compiled in an online database, and categorized according to the methodology used in each report.
The effort comes amid calls for standardization in reporting of PUE, the leading metric for data center energy efficiency, as a growing number of providers are touting low ratings in marketing material. Critics say too many reports are citing low scores while offering limited information about how those efficiency ratings are compiled and achieved.
In launching a central reporting database, The Green Grid has established four classes of PUE reports, based on the amount of data being shared and whether it is validated:
The PUE metric (PDF) compares a facility’s total power usage to the amount of power used by the IT equipment, revealing how much is lost in distribution and conversion. An average PUE of 2.0 indicates that the IT equipment uses about 50 percent of the power to the building.
“The Green Grid’s PUE metric is now widely adopted as the standard for measuring data center efficiency, and we’ve taken necessary steps to refine it so that it becomes even more impactful,” said John Tuccillo, a board member of The Green Grid. “We expect that the user-driven database will be an invaluable tool for data center managers to determine the relative energy efficiency of their operations by comparing to others across industries, or even inside their own company.”
The Green Grid has previously outlined three levels of PUE measurement. The Basic, Intermediate and Advanced PUE ratings are defined by where the IT equipment power and total facility power measurements are taken, and how often the data is collected. Here's an overview:
To receive a PUE or DCiE registration number from The Green Grid, organizations need to:
- Follow The Green Grid’s measurement guidelines in the most recent revision of “DCiE Detailed Analysis”
- Report the process through which the data was collected (L1, L2, L3) using the nomenclature in the most recent revision of “Usage and Public Reporting Guidelines for The Green Grid’s Infrastructure Metrics”
- Report your measurement data and input the required information into the Green Grid’s Metrics Data Collection Database
- Agree to The Green Grid’s metrics public reporting consent form
To be considered for a "Registered" or "Certified" award, all PUE and DCiE measurement reports should include:
- The accuracy level of the measurement
- The timeframe of the measurement (yearly, monthly, weekly, daily)
- The granularity of the measurement
The Green Grid said that on-site energy generation and the re-use of waste heat will not be considered in PUE submissions. Both strategies could contribute to a lower PUE score.