On a gallon of fuel, the fuel cell can silently operate all of the Bradley's electronics for up to four hours, said Henry Cialone, vice president of commercial energy business for Battelle.

"We identified the need for silent watch in a combat vehicle," Cialone said. "If we could put a fuel cell system in a [combat] vehicle, it would give you infinite silent watch."

Additionally, putting a fuel cell in a Bradley would increase the vehicle's fuel efficiency, potentially ease the necessity of carrying additional fuel, and give the vehicle a low heat signature.

The Bradley was originally chosen because Cialone knew the value military officials would place on a fuel cell that could provide extended silent watch for a combat vehicle. Also, it would be easier to work with an existing platform, he said.

"The military was interested and they hooked us up with United Defense," Cialone said.

The Army's Tank Automotive Research Development and Engineering Center (TARDEC) helped fund the technology, developed at Battelle's facilities in Ohio and Washington state. The fuel cell was integrated into the Bradley at United Defense's Ground Systems Division in San Jose, Calif.

United Defense manufactures the Bradley Fighting Vehicle.

"It shows great promise for easing the logistics burden the Army has with transporting fuel," a United Defense spokesman said. "If you could combine a fuel cell with hybrid electric drive technology and higher capacity batteries, it would significantly cut down on the fuel you would need to carry."

The two companies demonstrated their system at last week's Association of the U.S. Army conference in Ft. Lauderdale, Fla. Cialone said General Dynamics [GD] officials expressed interest in fuel cells for the M1A1 Abrams after seeing the Bradley demo, he added.

Battelle and United Defense will continue to partner to examine how to integrate the technology into the Bradley Fighting Vehicle and to look at how many fuel cell systems they could produce in a month, Cialone said.

"The challenge is integrating it into the system," the United Defense spokesman said.

Using Polymer Exchange Membrane (PEM) fuel cells, all of the Bradley's electronics, including sensors and communications equipment could be run without turning on the engine, Cialone said.

The fuel cell technology is scalable and can provide from 2.5 Kwh up to 10 Kwh, Cialone said.

"[The fuel cell is] not intended to drive the unit, but run the auxiliary systems. Things that have nothing to do with moving the vehicle," Cialone said.

But before attendees at AUSA got the chance to see the vehicle, Battelle technicians had to meet a number of challenges. They had only six to seven months to put together a PEM fuel cell that would work in the Bradley. They eventually settled on a commercially available PEM that fit under the Bradley's armor. Cialone said the goal was to incorporate the fuel cell without changing the look of the vehicle.

Additionally, the standard military fuel, JP-8, poses a challenge because of its high sulfur content, Cialone said. The sulfur contaminates the catalyst that produces hydrogen. PEM fuel cells combine pure hydrogen and oxygen into water to produce electricity. For the time being, technicians are using a synthetic diesel that closely resembles JP-8, but without the sulfur.

There are technologies that can remove upwards of 95 percent of the sulfur content in JP-8, Cialone said, but it would still leave a lot of sulfur for the catalytic system to handle.

"We're looking at how to incorporate tolerance for sulfur," he added.

The Bradley demo is going to be at Fort Benning, Ga., this week for demonstrations, Cialone said. He was unsure, however, when the Army might begin testing the vehicle.

"We have to figure out the design and how to harden [the fuel cell] for shock," he said. "You wouldn't want to field test [it] until that is done."

There are also questions about how the system would be distributed in a vehicle, he added. Right now, Battelle is looking at what components in the Bradley could be removed.

Although fuel cells are still expensive, Cialone believes the military will still pursue them because of the missions combat vehicles are put through. Fuel cells also have cost trade offs, he added. Using a fuel cell means there is less wear and tear on the vehicle's engine and batteries.

And the cost of fuel is increasing, Cialone added.

"We have to get a number of units into the field and monitor performance," he said.