Army Times Magazine Article

Jun. 7/99

Fuel Cells could enhance military capabilities

Though high fuel cost may slow military adaptation

By David Mulholland

U.S. military commanders are watching eagerly as commercial industries, especially automakers, edge closer to producing usable fuel cell technology to replace other energy sources, such as batteries.

The use of fuel cells could result in a wide array of innovations for the military, such as lighter battlefield computers that operate for longer periods before needing to be recharged, smaller more efficient electricity generators; and even an all electric tank.

Mobility improved

In particular, fuel cells could be critical, enabling technology for the U.S. Army's effort to craft smaller, lighter, more mobile forces. For example, one fuel cell the size of a 12-ounce soda can was used during recent Army exercises to generate enough power to operate a light infantry air assault command post for one week, said Gen. John Abrams, commander of Army's Training and Doctrine Command, Fort Monroe, Va.

Abrams spoke earlier this year at a conference of the Association of the United States Army in Orlando, Fla., "Meeting the Challenges: Preparing Industry and the U.S. Army for the Millennium."

The fuel cell itself is a stack of membranes sandwiched between electrodes. Each membrane allows the single proton of a hydrogen atom to pass through, stripping off the atom's single electron and generating a current. The fuel cell stack can be nearly any size.

Not only is the reaction virtually non-polluting, breathing in oxygen and exhaling only water and carbon dioxide, but it produces at least as much power as conventional engines.

As a bonus, fuel cells have almost no moving parts, making them inherently quiet and reliable.

With the U.S. Army changing to rechargeable batteries, for example, fuel cells become attractive for recharging those batteries or even replacing them, said Dick Power, chief of electro-chemistry and energy conversion at the research office of the Army Research office of the Army research Laboratory, Delphi, Md.

"The big draw is reducing the weight soldiers have to carry, now that they are equipped with so much electronic equipment," Power said.

"If you look at the weight diesel [fuel] holds about 100 times the power of a similar weight battery," he said.

"Even when one accounts for the fuel cell and reformer (a device that separates hydrogen from methanol or diesel fuels), they are still about 16 times lighter than disposable batteries and 32 times lighter than rechargeable ones," Power said.

Moreover, he noted that when soldiers have been allowed to experiment with fuel cells, they used them as portable generators to power much more equipment than originally intended. this opens the door to the possibility that a single fuel cell could power all of a soldier's electronic equipment.

Commercial Research 

While interested in these potential benefits, Pentagon officials continue to rely on the commercial sector for the bulk of fuel cell research. 

In particular, Pentagon experts are watching progress in the automotive world.

For example, Daimler-Chrysler AG, Stuttgart, Germany, plans to put a fuel cell-powered car into production by 2004, said Ferdinand Panik, executive vice president and head of the company's fuel cell work, speaking at a conference. "The Road To Fuel Cell Vehicles: A National Forum" in early February. 

But U.S. military-sponsored research is not standing still. Fuel cells appear to be an enabling technology for such concepts as an all-electric tank with an electromagnetic rail gun, according to military experts.

The gun would use a powerful magnetic field to propel a small armor-piercing projectile to hypersonic speeds. Such a vehicle would be fast, quiet and capable of firing flurries of rounds at multiple targets.

The reason fuel cells are being considered for such futuristic uses is their efficiency. Gasoline engines in cars only convert between 15 percent and 20 percent of the fuel's energy into motion, whereas a hydrogen fuel cell running at about 20 percent below peak output converts nearly 70 percent of the fuel's energy into electricity, said Power.

In practice, however, fuel cells in military vehicles probably would achieve only 40 percent to 45 percent efficiency, experts said, because the process of reforming diesel fuel into hydrogen and carbon dioxide requires energy.

But 40 percent to 45 percent is still better than diesel ship generator which are able to convert about 35 percent of the fuel's chemical energy into electricity-- and only when running at the optimum level, said Albert Tucker, director of the Navy's ship science and technology division at the Office of Naval Research, Arlington Va.

He noted that fuel cells are able to work efficiently over a wide range of outputs, which could lead to an eight-fold increase in efficiency over diesel generators. Tucker works on the Sip Service Fuel Cell Program, which uses fuel cells to generate electricity aboard a ship.

The Pentagon's Defense Advanced Research Projects Agency recently turned the program over to the Navy.

Because fuel cells are inherently modular, they could be installed where the power is consumed on a ship, instead of having all power sources concentrating in the engine room, said James Gagorik, ship technology area manager at the Office of Naval research.

This, he explained, would improve a ship's overall survivability by ensuring that one hit would not disable all of a ship's systems.

Considering the cost

But there are drawbacks to fuel cells. Chief among them is that they burn hydrogen, which is difficult and dangerous to store, making it impractical as a military fuel.

While methanol-- both indirectly with a reformer to convert it into hydrogen or directly through some promising new technologies-- would prevent the problems posed by a gaseous fuel like hydrogen, the military is trying to reduce the number of fuels used across its services, said Tucker. Service leaders therefore likely would oppose the introduction of a new fuel, and the costly changes to infrastructure and equipment that would entail.

Another hitch is fuel cells' byproducts, particularly when applied to small electronics.

The cells take in oxygen and vent carbon dioxide and water vapor, while conventional hand-held electronics do not. Electronic devices, such as radios, would require intake and exhaust systems, and would need to be engineered to seal themselves when submerged in water.

Finally, fuel-cell stacks use small amounts of very expensive platinum as a catalyst.

Gerald Halpert, a researcher at NASA's Jet Propulsion Laboratory, Pasadena Calf., who works on direct methanol fuel cells, suggested that for cars the companies could lease the cells to avoid hitting the customer with the full price of the precious metal. The military, on the other hand, would have to bear the cost, he said.

Staff Writer George I. Sellers contributed to this report from Washington