TOPICS > Science

Hydrogen Power

October 20, 2003 at 12:00 AM EDT


TOM BEARDEN: This little stack of plastic, silicon and copper is the prototype of a miniature hydrogen fuel cell created by Neah Power Systems in Seattle. If development goes as planned, the company’s fuel cells could provide up to eight hours of power for a laptop computer within the next three years. Products like this are likely to be the first exposure consumers have to hydrogen fuel technology. But scientists believe more powerful fuel cells could someday power most vehicles, generate most of the world’s electricity, and ultimately replace all use of fossil fuels.

What has a lot of people excited is that fuel cells don’t burn anything. The devices combine hydrogen with oxygen, and the resulting electrochemical reaction produces electricity, heat, and water. That means the only thing that would come out of a fuel cell car’s tailpipe would be water vapor; there’d be no pollution.

At Rice University, Nobel Prize-winning physicist Richard Smalley thinks it’s essential that a new source of energy be found.

RICHARD SMALLEY: I believe it is the single most important problem facing humanity today: Energy. How are we going to get prosperous when oil and gas and coal are no longer enough?

EXHIBITOR: So, this is our show car.

TOM BEARDEN: These Denver-area students got a preview of the potential hydrogen future at a recent traveling exhibition of Ford Motor Company prototype cars and related technologies.

EXHIBITOR: As the fuel cells become more reliable and we can use them in volume transportation, we replace the internal combustion engine and the transmission with a fuel cell and an electric motor to turn the wheels.

MAN: That’s tight.

EXHIBITOR: Yeah. And it’s coming, too.

TOM BEARDEN: The question is, how fast are fuel cells coming? In his state of the union message, President Bush committed $1.2 billion over five years for basic scientific research into hydrogen power.

PRESIDENT GEORGE W. BUSH: With a new national commitment, our scientists and engineers will overcome obstacles to taking these cars from laboratory to showroom, so that the first car driven by a child born today could be powered by hydrogen, and pollution-free.

TOM BEARDEN: But there are enormous scientific challenges that must be surmounted before fuel cells will be practical for transportation. The first problem is getting enough pure hydrogen. Current technologies would require the construction of vast factories like this one. Even though hydrogen is the third most abundant element on earth, it takes a lot of energy to extract it because it exists in combination with other elements in the air, in water and in natural gas. And fuels cells will have to get a lot cheaper, more efficient, and produce a lot more electricity to be commercially viable.

The short-term prospects are promising. Laptops, for example, don’t require huge amounts of power. Neah power’s chief technology officer, Leroy Ohlsen, says the key is to make a fuel cell small enough to fit in the same volume as an existing battery.

LEROY OHLSEN, Neah Power Systems: It’s the volume, getting all these systems into a tight small volume. And the trick to doing that is you need to get as much power as you possibly can off of your electrode, because the more power you can get, the smaller this thing can be, and then of course, the more efficient it is.

TOM BEARDEN: The prototype that Neah is developing and testing in the laboratory uses methanol as a source of hydrogen. Unlike batteries, fuel cells never have to be recharged. They’re simply refueled.

LEROY OHLSEN: Basically we have these ports, little tubes. And then what we do is, we flow methanol into the tube, it flows into the surface, goes through the pores, and out the middle chamber, which you can’t see, and that would come out one of these tubes, essentially. And then on the other side, we flow in our oxidant. And then there will be a little pump that will pump the liquids through the tubes to the engine, and when you’re ready for recharge … in fact, you don’t recharge at all, you just pull the cartridge off, you can either dispose it or recycle it, and then pop in a new cartridge, and you’re ready to rock ‘n’ roll.

TOM BEARDEN: But it’s a long way from laptops to cars. Early hydrogen cars are operating now, but they’re costly. This prototype cost half a million dollars. And they don’t have the range to compete with a gasoline-powered car. A fuel-cell vehicle has to carry more hydrogen to go the same distance as a tank of gasoline, because hydrogen is a less concentrated source of energy. But current storage methods would require the fuel tank to be impractically large.

In fact, the Department of Energy is now poring over applications for research grants to investigate that problem. The agency believes the storage challenge is so critical that it will award $150 million for basic scientific research.

DR. SMALLEY: The hydrogen storage problem, challenge, is huge. We’re looking for an experience in our cars that’s like our current experience. So we can’t have a huge volume. We can’t take up the whole back of the car just to store the hydrogen. We need to have the hydrogen molecules closer to each other. Well, even if we made it liquid hydrogen, about as close as they can get, it’s still going to be substantially larger volume than a gasoline tank.

TOM BEARDEN: Dr. Smalley thinks the solution lies in the black gunk in this jar. An electron microscope reveals that the gunk is really atomic-scale structures of carbon atoms linked together like chicken wire, and rolled into tubes. Smalley calls these “bucky tubes.” They’re an elongated version of “bucky balls,” which he shared a Nobel Prize for discovering. He named them after Buckminster Fuller’s geodesic domes. They’re also called carbon nanotubes, “nano” because they’re only one nanometer, one billionth of a meter, wide. One of the potentially useful properties of bucky tubes: they can attract molecules of hydrogen.

DR. SMALLEY: So what we’re looking for is something that the hydrogen molecules will love to sidle up against at near-liquid densities, but something that we can go into the gas station, connect up, and three minutes later we’ve got, you know, the equivalent of 20 gallons of gas.

TOM BEARDEN: Smalley thinks it might be possible to make a fuel tank full of bucky tubes. They would concentrate the hydrogen and provide more storage in much less volume. The National Renewable Energy Laboratory in Golden, Colo., is also working with bucky tubes, and has applied for a DOE grant.

Mike Heben says one of the biggest problems is how to get the hydrogen on and off the carbon. To be practical, the bond must be strong enough to hold the hydrogen, but not so strong that it would take high temperatures and pressures to release it when needed.

MICHAEL HEBEN: We hope to be able to find a middle ground where we can have hydrogen stored with just the right energy that we want, so adding and subtracting hydrogen from that host material will not be very energy-intensive.

TOM BEARDEN: It sounds like you’re talking about finding the most efficient sponge for hydrogen.

MICHAEL HEBEN: That’s exactly right. And the challenge is to discover if a sponge can be used, and what would that sponge look like, what are the properties of that sponge.

TOM BEARDEN: And even if bucky tubes prove workable, scientists will still have to learn how to cheaply mass produce them. Today the National Renewable Energy Lab makes them by blasting a carbon target with a laser beam. The high temperatures create small batches of the material, which collect in cobweb-like strings. Bucky tubes produced by this process currently cost thousands of dollars a pound. Smalley is confident that one day they will be turned out as easily as petroleum products in a refinery.

RICHARD SMALLEY: Here in Houston, Texas, we’ve got a huge chemical enterprise that manipulates carbon and puts them in perfect molecules and sells them. Well, I’ve got a perfect new molecule for them to make: bucky tubes. If we can make them … and I’m confident we will, in time, find a way of making them very low-cost with great perfection.

TOM BEARDEN: Carbon is just one material whose properties will be investigated through the energy department grants. DOE hopes the money will allow some of the key questions to be answered in the very near term.

TOM BEARDEN: It almost seems as if the government is trying to order up a breakthrough.

MICHAEL HEBEN: No, I agree. They are trying to order up a breakthrough, and I agree that that’s a difficult thing to do. But if the bar is not set high, I think scientists, like me, would perhaps not be challenged so strongly.

RICHARD SMALLEY: Scientists and engineers, I mean, God love them (laughs). They get a particular idea in their mind, and they want to solve it and they want to … leave them alone, they want to play. So it’s like herding cats. And to get a big thing like this done, out of the garden of physical sciences and engineering, you’ve got to set a bold goal and get serious people thinking about it, and then there’s a good chance we can do it.

TOM BEARDEN: While some optimists see thousands of hydrogen fuel cell cars on the nation’s highways within ten years, the Department of Energy’s goal is more modest: to gather enough data in the next three years to know where the most promising avenues are for further investigation.