It is important to note that there are currently a number of energy and performance metrics for data centers in addition to PUE™. Many go beyond the facility power and cooling systems and judge the efficacy of the IT systems. Some of these are being used by the industry, while others are still under development. The information presented here focuses on PUE, since it is used worldwide as a standard to measure data center efficiency and is not meant to minimize the importance of the other standards.
32.2 Origin and Application of PUE as a Metric
In 2007, the US Environmental Protection Agency (EPA) report to Congress on server and data center energy efficiency stated: “The federal government and industry should work together to develop an objective, credible energy performance rating system for data centers, initially addressing the infrastructure portion but extending, when possible, to include a companion metric for the productivity and work output of IT equipment.” This was a clear directive to the industry to develop a uniform metric. Just a few years later, the metric Power Usage Effectiveness (PUE), developed and proliferated by the Green Grid to determine the energy efficiency of data centers, was being used worldwide in the technology industry and had become a mainstream approach to determine data center energy use efficiency. While the definition of PUE is ...