Standby: Fuel cells as secondary power sources |
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By Karim U. Khan, Contributer
05 Oct 2006 | SearchDataCenter.com |
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This is part two of SearchDataCenter.com's update on fuel cell technology in the data center. Read part one here.
Of course, if you feel good about the electricity you're already getting and merely need a source of standby power in the event of an outage, a 200-kW unit the size of a small shipping container is probably overkill.
In June 2005, APC unveiled a rack-mountable fuel cell UPS compatible with its InfraStruXure power, cooling, management, and services architecture. The 10-kW systems can be stacked three-high for a total of 30 kilowatts of clean, green power.
The InfraStruXure Fuel Cell is seen by the system it plugs into as an ordinary battery. Only you know that outside your building (for safety's sake) are several canisters of hydrogen ready deliver their contents to the fuel cell at a moment's notice. The technology employed is called Proton Exchange Membrane (PEM)—the same technology used in fuel cell vehicles.
Tom Sperrey, managing director at UPS Systems plc, a vendor-neutral UPS reseller based about 70 miles west of London in the UK, is a proponent and user of standby fuel cells.
"We'd been tracking fuel cell systems for about five years, and we made the decision a couple of years ago that it was time for us to get involved," he says, noting that the technology appeared then to make the leap from an expensive toy to a potentially useful solution for customers.
One way a standby system based on a fuel cell can be useful is when other options aren't permitted, like at the small West London financial markets trader where Sperrey's company recently conducted an installation. "They are surrounded by residential premises on all sides—there is certainly nowhere to put a diesel generator," says Sperrey. "For them, a fuel cell was the ideal solution. We are constructing for them a brick-built hydrogen store with a slate roof to look like the rest of the building. The fuel cell is indoors. They would not get planning permission to put a diesel generator in or near the premises."
But why not go with conventional batteries as a backup?
"That was a path they looked at, in fact," Sperrey responds. "Initially they were going to go down the route of four hours worth of batteries. Two things put them off: one was the space it takes up in the computer room. The fuel cell system takes up one cabinet, and the batteries would need three 19-inch rack cabinets. They would have runtime that was limited to four hours, and they would then have a situation where for at least the hour following a four-hour outage, they would have no resilience—if the power were to fail a second time after coming back on, they would have been out of power. With a fuel cell system, they've still got full power." Each canister in the five-foot wide, head-height shed in the yard holds 10 kWh of hydrogen, or about nine hours of backup energy for the firm.
Sperrey has also found that the costs come out well for fuel cells even over a 10-year period. Speaking of an analysis done for a hospital with a mandate to purchase equipment based solely on cost-effectiveness, Sperrey says that "bearing in mind batteries would need to be changed once in 10 years, and taking into account batteries' twice-yearly in-person maintenance checks, it was actually substantially less expensive to put in a fuel cell system than batteries."
Even when considering a diesel generator, which is only two-thirds the cost of an equivalent fuel cell system, Sperrey says the comparison shows fuel cells are competitive: "Diesel engines have filters and oil to be changed, and in a fuel cell all you change are air filters, and you do a yearly calibration of the hydrogen sensor, so maintenance is not time consuming at all."
For a location without a "green mandate," noise and emissions restrictions, or a need for more than "five-nines" of power availability, it's not likely that a fuel cell will be the best option—today. But with cost competitiveness already close and creeping closer as fuel cell efficiency increases and economies of scale make the cells more affordable, it's not likely that the idea of a fuel cell as a viable option for powering and protecting your data center will fizzle out either.
About the author: Karim U. Khan is a freelance journalist based in Highlands, N.J. He is also editor-in-chief of corporate site selection publication, Business Facilities magazine.
Let us know what you think about the story; e-mail: Matt Stansberry, Site Editor
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