American Power Conversion Corp. (APC) Monday unveiled a backup power system for data centers that uses fuel cell technology to keep the centers running during a power failure.

The InfraStruXure with Integrated Fuel Cells system, which fits within a single 42U rack, provides up to 30 kilowatts of power using bottled hydrogen gas as fuel. Bill Hunt, product line manager at the West Kingston, R.I., vendor of backup power systems, said the system sells for between US$50,000 and $100,000 and is aimed at data centers where generators are impractical -- such as in high-rise buildings -- and that require longer runtimes than universal power supplies alone can deliver.

The Integrated Fuel Cells system, which APC showed off at its headquarters, includes up to three 10-kilowatt fuel cell "stacks" built by APC, a DC-to-DC power converter that steps down power to the requirements of individual devices, and a management console accessible via a Web browser. From the front, each fuel cell module appears as a sealed black metal box. At the rear of the rack, power cables were visible, as was a clear drainage tube, about 1 in. in diameter, that emptied waste water into a small container on the floor.

Fuel cell systems generate water vapor as a byproduct, so data centers will need a drain or container to trap that, said Hunt, although APC plans to add a system that automatically captures waste water and removes it from the room.

Because the fuel cell modules require up to 20 seconds to come up to full power, the system also includes a backup UPS that bridges the power gap in the initial moments of an outage. Fuel cells also don"t respond well to fluctuating power demands, so the backup batteries also "work like a shock absorber between high and low steps," Hunt said. The fuel cell system also continuously charges the batteries when running.

A single 10-kilowatt fuel cell module generates a total of 13 kilowatts of usable power, with 3 kilowatts used to recharge the batteries and the rest available to power IT equipment.

The InfraStruXure system consumes fuel from standard hydrogen gas "T cylinders." The cylinders, which are 60 in. high by 9 in. in diameter, must be stored outside of the building and connected to the data center with stainless steel tubing. One cylinder can run a 10-kilowatt fuel cell pack for 79 minutes, APC said, with runtimes extended by adding more tanks.

A minimum of three cylinders is required to achieve N+1 redundancy, Hunt said, adding that for a 30-kilowatt system, he expects users to connect between nine and 10 cylinders. While fuel cell technology is expensive, cylinders are not. T cylinders typically cost around $30, he said.

The system is available now and sells for $25,000 per 10-kilowatt module, plus an installation and setup charge. That will typically run about $25,000, meaning a 30-kilowatt system costs about $100,000, Hunt said.

The system also requires a chilled water supply to cool the fuel cell system, and an air handling system to exhaust air from the rack outside of the data center. The air handling system is designed to ensure that any water vapor or hydrogen byproducts from the fuel cell process are ventilated outside of the data center. Water cooling is required in part because fuel cells are only about 50 percent efficient, Hunt says.

While APC demonstrated a working model in its labs, it does not currently have any early adopters using or testing the system. "We have units on order, [but] we don"t have any named accounts we"re sharing yet," Hunt says.