In large, multimegawatt data centers, where annual power bills can easily exceed US$1 million, more-efficient designs can significantly cut costs. In many data centers, electricity now represents as much as half of operating expenses, says Peter Gross, CEO of EYP Mission Critical Facilities Inc., a New York-based data center designer. Increased efficiency has another benefit: In new designs, more-efficient equipment reduces capital costs by allowing the data center to lower its investment in cooling capacity.

Pain points

Trinity's data center isn't enormous, but Roberts is already feeling the pain. His data center houses an IBM z900 mainframe, 75 Unix and Linux systems, 850 x86-class rack-mounted servers, two blade-server farms with hundreds of processors, and a complement of storage-area networks and network switches. Simply getting enough power where it's needed has been a challenge. The original design included two 300-kilowatt uninterruptible power supplies.

"We thought that would be plenty," he says, but Trinity had to install two more units in January. "We're running out of duplicative power," he says, noting that newer equipment is dual-corded and that power density in some areas of the data center has surpassed 250 watts per square foot.

At Industrial Light & Magic's brand-new 13,500-square-foot data center in San Francisco, senior systems engineer Eric Bermender's problem has been getting enough power to ILM's 28 racks of blade servers. The state-of-the-art data center has two-foot raised floors, 21 air handlers with more than 600 tons of cooling power and the ability to support up to 200 watts per square foot.