Another method—Power Usage Effectiveness (PUE)—was developed by The Green Grid, a group of technology companies collaborating to improve energy efficiency in data centers.

The PUE is calculated by dividing the total utility load (the power coming into your facility) by the total IT equipment load (the power consumed by switches, routers, servers and related gear). In this instance, the lower the PUE, the better.

Forrester's Washburn warns that while these methods can be effective, the measurements required to calculate the benchmarks can be challenging to obtain. "Because most organizations do not pay for their energy-related IT expenditures, many are not measuring energy consumption—especially on a granular level—which is required to actually calculate your data center energy efficiency metrics," he says.

Your ROI May Vary

Although the emergence of industry-accepted benchmarks means you can be more certain you're measuring the right things, Washburn also notes it's usually larger businesses that benefit from benchmarking. The bigger the data center, the more energy it consumes and the more likely it will be that you'll have an incentive to reduce consumption. "For smaller businesses, the financial impact may not be as significant, and you can direct your time elsewhere."

What's more, there isn't enough publicly available data yet for companies to benchmark against each other, so it's hard to know how efficient you can really get. If you try to compare your energy consumption with another company, peers in your industry might be a good start, says Washburn. But a more relevant comparison would be an organization with a similar-sized data center and similar server, storage and network needs.

Christian Belady, principle power and cooling architect for Microsoft Global Foundation Services and Microsoft's representative to The Green Grid, agrees that there are limits to these metrics, specifically for smaller businesses. But he thinks even small organizations can still benefit by benchmarking on a smaller scale. Belady says that once CIOs decide to benchmark their energy usage, they should consider benchmarks such as The Green Grid's PUE or any other metrics that may make sense for driving the right behavior for their business. "The industry is moving so fast that you can't wait for everyone to have the perfect definition of these metrics," he says.

One key to UPS's benchmarking success, Parrino and Swanson believe, is the support and trust from their CIO, David Barnes, to make these decisions. "You need to constantly strive to challenge yourself and be constructively dissatisfied with your own operation," Swanson says.