Scientists and engineers around the world are making significant progress in harnessing an energy source that could significantly reduce our dependence on fossil fuels.
That's a little bit of good news at a time when the United States is gearing up for what could be a decades-long war against international terrorism Battles will likely be fought in some of the troubled regions of the globe that now supply oil to fuel the industrial world, and it's not unlikely that supplies will become limited and prices will skyrocket.
That doesn't rank up there with worries about the loss of lives, of course, but the time has never been better for the country to redouble its efforts to reduce its dependence on petroleum.
Inexhaustible, Versatile, Powerful
Now would be a good time for someone to come up with a gadget that could turn out electricity without polluting the air, use an inexhaustible energy source, and be versatile enough to power everything from our cell phones to our automobiles to our factories.
It sounds too good to be true, and it maybe it is, but fuel cells that convert hydrogen — the most abundant element in the universe — directly to electricity with no pollution could fit the bill. Such devices have been around for awhile. Since the 1960s, they have provided the electricity to power the instruments aboard various spacecraft, but they've been too expensive and too weak to do much for the rest of us.
Yet just about every major automobile manufacturer, and numerous companies involved in supplying energy, plus a wide range of research institutions, and the U.S. Defense Department, are betting that's going to change. They are spending billions on research.
Here's why hydrogen is so promising as an energy source: It really packs a wallop, with about three times as much energy by weight as gasoline. When used in a fuel cell to produce electricity, its byproducts are water that is pure enough to drink, and heat that can be used for other purposes.
But here's the down side: Hydrogen is expensive and difficult to isolate. And the atoms in hydrogen gas are so sparse it's difficult to pack enough of them in a small space — like a fuel tank — to do much good, and it can be highly flammable. Plus, if you had a car powered by hydrogen, you couldn't drive into your neighborhood gas station and fill 'er up.
A Non-Hydrogen Cell
So the drive to develop cars that can run on hydrogen has been hindered by a Catch-22 conundrum. Not many folks are likely to put out big bucks to buy a car that runs on a fuel that isn't available. And no one is likely to build the costly supply lines and filling stations until a lot of cars are out there that run on hydrogen.
That has led to a compromise. The main avenue of research these days is directed at using the hydrogen that is already available in commonly used fuels, like gasoline, methanol or diesel, to power fuel cells. But that entails "reforming" the fuel, either under the hood of the car or at the filling station, to extract the hydrogen and feed it to the fuel cell. That has turned out to be expensive and challenging, but industry leaders like DaimlerChrysler and Ford have proved that it can be done.
Meanwhile, some researchers have approached the problem from a different perspective. Instead of reforming standard fuels, they reasoned, why not develop a fuel cell that could run directly on a fuel that is readily available?
That's just what scientists at the University of Pennsylvania have done. They have produced the first fuel cell that runs directly on a liquid that is easy to get: ordinary diesel fuel.
"There used to be a saying that you could run a fuel cell on any fuel as long as it's hydrogen," says Raymond J. Gorte, professor of chemical engineering at Penn and the lead author of a paper reporting the findings in the Journal of the Electrochemical Society.
Gorte and John M. Vohs, chairman of chemical engineering at Penn, figured out how to get around a problem that has stymied so many other researchers. Other attempts to use fuels other than pure hydrogen have worked, but only briefly.
The problem, according to Vohs, is that previous systems used nickel as a catalyst, causing hydrogen and oxygen to combine and freeing up electrons, thus producing electricity.
"But nickel is also an excellent catalyst for making graphite out of hydrocarbons, and that's a problem," Vohs says. The graphite "plugged up the whole fuel cell," he adds, quickly shutting it down.
New Composite Used
The Penn scientists switched to a composite of copper and ceria, which is used in automotive catalytic converters, and the problem was solved.
Of course, running fuel cells on diesel fuel wouldn't eliminate the need for hydrocarbons, but it could reduce it.
"An internal combustion engine is 15 percent efficient in turning the fuel into power, while in a fuel cell you could probably at least double that," Vohs says.
Perhaps more important, fuel cells that could run on standard fuels could help during a transition period. The infrastructure is already in place to support fuel cells that can run on diesel fuel. So for now, you could fill up with diesel, paving the way for the day when hydrogen might be readily available.
It seems likely at this point that we will see a growing use of fuel cells in various applications before they become common in vehicles.
"To be honest with you, transportation is the hardest application in that you have to have a system that's mobile and robust," Vohs says. "You have to be able to hit potholes in the road and have everything survive."
An ideal application, he says, would be to use fuel cells as individual power plants at our homes. It takes a lot of power to run a car — possibly 10 times more than it takes to supply all the electricity needed to run a house — so a small fuel cell down in the basement could do the job. That would cut down on the enormous loss of power through transmission lines, because the juice would be produced where it's needed, thus saving additional energy.
Vohs thinks that application could be available within five years, using natural gas as the fuel.
As for replacing the family bus, a consortium of DaimlerChrysler, Ford and Canada's Ballard Power Systems is on record as expecting to mass produce fuel-cell powered vehicles within about three years. And some industry sources think the four largest automobile makers in Japan might beat them to the punch.
Lee Dye’s column appears weekly on ABCNEWS.com. A former science writer for the Los Angeles Times, he now lives in Juneau, Alaska.