EPA's Energy Star for servers and data centers illuminates sustainable paths
New specifications set a much-needed bar for energy efficiency in the products or operations
Over the past couple of years, an increasing number of data center operators and hardware manufacturers have proudly proclaimed that the respective facilities they run or the hardware they produce are oh so greener than the competition's. But such proclamations can leave observers wondering what that really means, given that standards for weighing such claims have been lacking.
That's changed in the past year as the Environmental Protection Agency rolled out not one but two brand-new Energy Star specifications, one for servers and one for data centers, that set a bar for assessing and comparing the energy efficiency of individual machines or entire facilities. While not perfect, these two specs reflect some heavy-duty data gathering and feedback solicitation from stakeholders. More important, these specs mark a couple of critical steps forward for IT sustainability in the United States and beyond.
Energy Star for Servers took well over a year to develop, with the EPA collecting comments from vendors, environmental groups, and other concerned parties. The end result was a standard applicable to machines with between one and four sockets and at least one hard drive. Servers that manage to burn the fewest watts while idling are eligible for the Energy Star designation. Power wasted in idle mode is indeed significant, particularly given that servers are notoriously underutilized. Additionally, compliant servers must be capable of measuring their own real-time power use, processor utilization, and air temperature -- all critical data for helping operators assess the overall efficiency of their facilities.
Devising the first edition of the Energy Star for Data Centers spec entailed gathering and analyzing a wealth of data center measurements, amassed over extended periods of time from an array of facilities. Through careful statistical analysis, and again drawing on feedback from stakeholders, the EPA determined what criteria do and do not account for differences in energy efficiency among data centers. The end result was an Energy Star standard based on PUE (Power Usage Effectiveness), which is the ratio of overall data center power consumption to the power consumption of IT equipment.
Energy Star for Data Centers compares a facility's actual PUE against their predicted PUE, which is effectively what the average PUE would be among similar facilities. Data centers that achieve a PUE well below the predicted level (once verified by the third party) can claim Energy Star status. A finalized version of the spec will be released in Portfolio Manager, the EPA's online benchmarking tool, later this year.
Both sets of specs need fine-tuning. Energy Star for Servers, for example, doesn't consider a server's efficiency when it's doing actual work, nor does it take into account cores per processor. Energy Star for Data Centers is based heavily on PUE, which, though useful, hardly paints a complete picture of power usage. Further, the standard doesn't consider differences that can affect overall PUE, such as tier level or what sort of work a data center is doing. The EPA, however, readily recognizes that these standards (like other Energy Star standards) are a work in progress. The organization is already in the process of developing Version 2.0 of Energy Star for Servers and is seeking feedback from stakeholders.
In the meantime, server vendors and data center operators now have useful maps to guide them down the uncertain path toward sustainability.