Data Center PUE: A Guide To Energy Efficiency Metrics

What does energy efficiency smell like? Though someone could have come up with a more appealing acronym, power usage effectiveness (PUE) has become the standard metric for managing energy efficiency and understanding data center power consumption.

PUE was developed by the Green Grid industry consortium in 2007 and fine tuned via a white paper published in 2012 (free registration required). An ideal PUE of 1.0 indicates that all the energy going into the data center is being put to productive use in data processing, as opposed to being sucked up for jobs such as cooling, power distribution, and lighting.

The Green Grid defines PUE this way: "PUE measures the relationship between the total facility energy consumed and the IT equipment energy consumed." Think of PUE as indicating how much of the total power load coming into a building goes into doing real computing work. The higher the PUE, the more energy is being wasted.

The organization also warns that PUE isn't intended to compare the efficiency of different data centers but to help with management and optimization of a single data center over time.

So, when you see on their websites that giant data centers run by Google or Facebook are recording impressive PUEs of 1.06, don't get PUE envy. Consider what your PUE is today and what it might be six months from now, after you've installed things like less heat-intensive equipment or natural air cooling.

These selections from the Network Computing archive can help you understand PUE in the real world.

• The Evolving PUE of Containerized Data Centers: The relatively new modular containerized data center -- picture a warehouse full of smart shipping containers -- has PUE directly in its sights, as blogger Jim O'Reilly reports.
• Data Center Efficiency Plateaus: Though a 2013 Uptime Institute survey showed that data center energy efficiency wasn't quite as high a priority as it had been previously, Kurt Marko notes that respondents had already achieved an average PUE of 1.65.
• Dashboard Marries eBay's Data Center and Business Stats: The eBay management dashboard allows executives to track PUE and other performance/efficiency stats in real-time.
• 5 Data Center Trends For 2013: For companies with the flexibility to site their data center in a hospitable environment -- such as Facebook building in Oregon and Google siting in Finland -- lowering the PUE is a nice benefit, as Charles Babcock noted in this 2013 preview.
• Facebook's Data Center: Where Likes Live: Some mega-data centers cut their PUE by locating near rivers and fjords, but Charles Babcock says the cool ambient air of the high desert brought Facebook to Oregon.

Do you know the PUE for your data center? What steps are you taking to improve energy efficiency in your IT operations?