What is PUE?

PUE or Power Usage Effectiveness is a commonly used data center measurement that demonstrates how efficiently data center power is used. The measurement was created by the Green Grid, and acts as a great catalyst for industry benchmarking. PUE is a measurement of the total amount of power consumed by a facility, compared to the total power actually used by the facility (PUE=Total Facility Power/IT Equipment Power). An ideal PUE is 1.0 and many of today's high powered data centers have been able to approach this mark in recent years.

Ian Bitterlin, CTO of Ark Continuity Discuses "The Pursuit of an Ultra Low PUE in Context" at GDCON London, 2012

The session will review what it means to be 'green' in data centre terms (including the three classic steps to sustainability). Data centre expert Dr. Ian Bitterlin will demonstrate that PUE is just one small part of the sustainability pie whilst a concentration on achieving a low PUE can actually decrease the overall sustainability of the data centre. In. Within this PUE discussion focus areas will be the ICT load, the facility itself, the sourcing of renewable energy and, finally, recycling the hardware and facility.

Metronode Uses Free Cooling Option TO Lower Data Center PUE

Metronode is looking to build a small empire of energy-efficient, green data centers across the world with extremely low PUE through the implementation of use free cooling. According to The Australian based Metronode, implementation of this new cooling technique has allowed them to significantly reduce the new facility's PUE, dropping it from the traditional average of 2-3 down to 1.5. That translates to some pretty drastic savings, says Juniper. "Assuming an electricity price of twelve cents per kilowatt hour and an IT load of 1 megawatt, we say that a data center with a PUE of between 1.15 and 1.2 can save about $8.5 million in 10 years when compared with a facility that has a PUE of around 2."

The Benefit of PUE

PUE (Power Usage Effectiveness) has become a commonly used phrase to describe the efficiency of data centers worldwide. As the enterprise demand for data centers continues to rise and designers continue to search for new ways of "Greening", the common PUE designation helps data center owners and operators benchmark their efficiency effort and compare themselves to their competitors. The demand for IT infrastructure and data centers is still on the rise, and the efficiency at which they operate will continue to be a top priority for designers, managers and the general IT community. Creating a competitive environment by setting up the PUE measurement is a creative and positive move for the expanding industry, and provides a much needed push towards technological environmental sustainability.

Using PUE to Benchmark the Efficiency Effort

With IT equipment accounting for 2% of the worlds carbon emissions, common metrics and measurements need to be defined in order to establish an industry efficiency standard. PUE or Power Usage Effectiveness has emerged as the accepted metric and has become widely used throughout the data center community. It is crucial to look at all aspects of data center efficiency including power, cooling, network and storage. Having set standards for efficiency gives facility owners and operators the common designations needed to benchmark their efforts.