Powerful Experiments

Solar arrays, gas turbines and fuel cells are among the innovative options for powering data centers.

Data center power usage is soaring -- the U.S. Environmental Protection Agency estimates that data center energy requirementsdouble in the next five years. To address that surge in energy use, some companies are turning to alternative sources of energy, including solar arrays, natural gas turbines, wind power, fuel cells and hydro power. But one big question is whether these power sources will deliver a return on investment in the near future.

Ted Ritter, an analyst at Nemertes Research Group, says many companies are having a hard time justifying an investment in alternative power sources right now -- especially if it means completely replacing the reliable AC power already coming into their buildings, as opposed to merely supplementing it.

But some users are forging ahead with alternative energy projects anyway, figuring on a payoff within 15 years.

For the North County Transit District (NCTD) in San Diego, solar was the most obvious choice for alternative power. The organization's data center is relatively small, but it's big enough to enable the agency to handle ticketing for 12 million public transportation users annually and process video from security cameras in transit stations.

Angela Miller, the transit agency's CIO, says her group felt a need to be a better environmental citizen. As part of a data center redesign, the agency spent about $600,000 on a 30-panel solar array, invested in virtualization technology for server and storage systems, and bought new pods that pull hot air out and help cool equipment inside the racks.

The NCTD sells solar-generated power back to the local utility to earn credits on AC power usage (which is allowed under California law), meaning the solar initiative has become a profit center. The solar panels don't generate power for the building directly.

It works like this: The local utility sells AC power to the NCTD, then the agency sells the utility the solar energy for a 100% credit. The agency has a five-year plan in place to offset all AC power in its data center. The NCTD generates up to 450 kilowatt-hours of electricity, and it plans to reach 1 megawatt-hour in five years.

"Solar is what has made the [data center redesign] project even have an ROI," says Miller.

Bob Mobach, a consultant at systems integrator Logicalis Group, helped the NCTD redesign its data center. He says a key to realizing an ROI with alternative power is embracing virtualization. The agency's data center is about 80% virtualized, and that's a primary reason why the solar arrays are such a successful power source.

"Virtualization was critical for so many reasons," says Miller, noting that the new setup is "way more efficient," makes better use of hardware, gives the data center a smaller footprint and is easier to manage with fewer people. "My actual physical footprint went from not having any more slots in the racks available to having only half of the racks occupied, and yet we've increased our applications this year," she says.

Analysts laud efforts like the NCTD's but warn that solar power isn't right for every data center. "The level of efficiency you can get out of solar energy is dictated by the location of the data center," says Forrester Research analyst Doug Washburn. "If you are in an area where the sun shines more frequently, you can take advantage of a solar investment."

One reason why solar may not be the best data center power source is the fact that data centers use 10 to 100 times more energy per square foot than a typical office complex, Washburn says. Moreover, resiliency and uptime are so crucial to a data center's operation that "it's a critical risk, and maybe even foolhardy to think you could power the majority of your data center from solar," he adds.

Washburn agrees that virtualization

an article that appeared earlier on Computerworld.com.

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