Why? The potential money saved from upgrading to more energy-efficient equipment would all but ensure that the chief information officer or the IT executive in charge design the most energy-efficient data centers possible, Nelson reasoned.

"When the CIO is paying the power bill, [he or she] really understands the impact of the decisions being made," he told an audience of data center managers at the Uptime Institute 2010, being held this week in New York. "You're self-funding the activities [you wish to pursue] by becoming more and more efficient," he said.

As proof, Nelson pointed to eBay's newest data center, a US$287 million facility that just opened in Salt Lake City last month. EBay lumps the facility bills in with the IT budget, and as a result, the company has aggressively looked for ways to cut power consumption.

And the payoff is the new data center. According to Nelson, the facility was "paid for by the cost savings we've achieved within the last two years."

Until the past few years, eBay's growth was closely followed by its operational costs, Nelson explained. The company sought to break this correlation by looking for ways to support growth of the business while keeping the IT budget flat.