More than 260 engineers from companies such as Ball Aerospace, Duracell, Eveready, Hewlett-Packard, Palm and Sony attended the conference this past week in Washington D.C., where researchers touted the advantages of fuel cells over conventional batteries and demonstrated working prototypes. The upstart power technology may not be ready for prime time yet, the researchers said, but its day is coming soon.

"You'll see laptops powered by fuel cells no later than next year," promised Charles Call, president and chief executive officer of MesoSystems Technology Inc. (Albuquerque, N.M.). "And once you've scaled the fuel cell for one product, it will be easy to scale it for others."

To prove the viability of the technology, speakers at the conference demonstrated a 15-watt fuel cell source, about the size of a videocassette, that could be used to power a laptop computer. They also showed a hydrogen-powered flashlight that offered 20 hours of continuous use from a fuel cell only slightly larger than six D-sized batteries.

"Fuel cells are definitely a reality today," said Kristopher Gardner, a chemical engineer with the U.S. Army's Communications Electronics Command (Fort Belvoir, Va.). "This is not a technology that's 20 years away."

Engineers at symposium sessions said that hydrogen- and methanol-based fuel cells could fill a looming need for a new power source, particularly as cell phones combine the features of personal digital assistants. Very soon, they said, some cell phones are expected to climb from power draws of between 1 and 3 W to more than 5 W in some cases.

"The power consumption of these devices is ramping up, and batteries can't meet the needs," said Mark Daugherty, chief scientist of DCH Technology Inc. (Valencia, Calif.). "So the manufacturers are looking to fuel cells to grow into those higher-power applications."

Fuel cells could fill the void because they offer theoretical energy densities higher than those of batteries, researchers said. The devices, which work by combining hydrogen and oxygen in water to produce electricity, benefit from the inherently higher energy available from hydrogen. To show the potential of the technology, researchers at the conference cited figures proving that hydrogen offers practical energy densities ranging from 1,000 to 23,000 watt-hours/kilogram, while the best lithium batteries now range from 175 to 300 Wh/kg.

Reality check

They acknowledged, however, that no fuel cell has achieved even the lowest of those practical figures. Early prototypes have typically demonstrated 80 Wh/kg, a figure far below that of the best lithium batteries, Daugherty said.

Some researchers believe that fuel cells could be the key to development of "always on" cell phones. Scientists from Motorola Labs (Schaumburg, Ill.) and Los Alamos National Laboratory said they have developed a fuel cell measuring an inch square and a tenth of an inch thick that could one day allow a cell phone to remain on for more than a month.

Experts said that such fuel cells could eliminate the need for battery chargers and ac adapters because they would just need to be refueled rather than recharged.

Some experts believe that the Motorola-Los Alamos design may ultimately serve as a model for future electronic products because it burns methanol rather than hydrogen. Such direct methanol fuel cells don't need to convert the methanol to hydrogen. Instead, they convert the methanol directly to electricity through a catalyst, typically made from platinum and ruthenium. The catalyst is used to react a dilute mixture of methanol and water to form carbon dioxide, protons and electrons, which provide the electrical current.

Members of the fuel cell community believe that such technologies offer advantages for laptop computers as well as cell phones. "If you're using batteries and you want to run your laptop twice as long, you need two batteries," said DCH's Daugherty. "But with a fuel cell, if you want to run twice as long, you can keep the same fuel cell and double the size of your hydrogen or methanol storage."

Storage tanks typically consist of small aluminum pressure vessels containing a powdery metal alloy, such as a metal hydride. Fuel is generally absorbed into the lattice of the metal alloy, like water in a sponge.

Head-to-head comparison

In a demonstration at the conference, researchers compared a flashlight powered by conventional batteries with one powered by a fuel cell. The conventional unit used about 20 cubic inches of D-cell batteries, while the other employed a 3.7-cubic-inch fuel cell and a 20-cubic-inch hydrogen storage tank. Researchers said that the conventional unit ran for about 14 hours before burning out the batteries, while the fuel- cell-powered system ran for 20 hours.

For small power requirements measured in milliwatts, many experts believe that so-called fuel-cell-on-a-chip approaches, such as those of Motorola-Los Alamos and Manhattan Scientifics Inc. (New York), could hold the key to success. Those systems offer promise because they incorporate circuitry that pumps up the inherent low-voltage output of the fuel cell to a higher voltage that can be used by devices like PDAs, cameras and electronic games.

At larger scales, such as 5 to 150 W, engineers say they are looking more seriously at hydrogen, rather than methanol, as a fuel source. The U.S. Army's Communication Electronics Command is testing hydrogen fuel cells for phones and field generators used by soldiers. Ultimately, engineers say they expect fuel cell technology to offer lower cost than the exotic battery technologies they now use. "We have multiple prototypes in our labs," said Gardner of the U.S. Army. "They work regularly, then we let them sit on a shelf for a while, and they always start back up again."

Cost, safety issues

Issues remain, however, regarding the availability of hydrogen fuels. "The question is, How are we going to find fuel sources that are safe and cost-competitive?" Gardner said. "Hydrogen fuel is not easy to obtain right now."

Engineers said they expect some of the initial fuel cell cost issues to be overshadowed by the fact they may offer lower cost over the life of the device. Fuel cells can be refueled hundreds of thousands of times without degradation, they said, whereas batteries can typically be charged only a few hundred times. "The fuel cell's cost can be amortized over its life," Gardner said. "If you use it for several years, the initial cost is not a big deal."

Proponents of the technology said that it is also more environmentally friendly than some battery technologies. Most fuel cells are made from carbon, plastic, platinum and nontoxic metals and use no mercury or cadmium, which is employed in some batteries. What's more, disposal would be less of an issue because the cells can be refueled almost infinitely.

As a result, they expect fuel cells to enjoy more success in electronic products than they have in automobiles. "Vehicles are not as easy to convert, because you need a very strong fuel infrastructure for fuel cell technology to be cost-effective," Gardner said. In contrast, electronic products won't require a fuel station at every corner, he said.

The fuel cell community believes that the technology will make inroads against traditional batteries in the next five years. "Batteries are a very mature technology manufactured in the billions," Daugherty said. "Fuel cell production is much, much smaller, and there are still a lot of gains to be made."