"It's really in an experimental stage," said Steven Carlini, director of product management at APC.

APC's fuel cell technology, which can support up to 30 kilowatts of electricity -- about the amount some large blade servers use -- gets about 10 minutes from each tank of hydrogen, which are typically the size of a welder's tank. The fuel cell will continue to supply power as long as it doesn't run out of hydrogen fuel.

That's where Powell's concern about size comes in. He houses a 25,000-square-foot mainframe data center and a separate 5,500-square-foot facility for Unix and Windows machines, which together use about one megawatt of energy a month. He envisions the need for a separate building just to house a fuel cell's power supply.

Brian Cihak, a network and data center engineer at Bridgestone Firestone Retail and Commercial Operations LLC in Bloomingdale, Ill., said he doesn't know if fuel cell technology has "quite reached the maturity that's needed yet, but it's certainly well on its way," he said.

With fuel cell use still somewhere down the road, other technologies are getting attention. Less exotic are flywheel technologies from companies such as Pentadyne Power Corp. in Dallas, and Emmerson Network Power's Liebert Corp. in Columbus -- which are working together on that technology -- and Active Power Inc. in Austin, Texas. In the event of a power interruption, the spinning flywheels can provide power in lieu of batteries until the data center generators kick mon. A flywheel may provide power up to 30 seconds, but that is typically enough time for a switch to generator power to occur.