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Researchers Offer Shortcut for Hydrogen Cars: Gasoline

May 6 ? Suppose you could build a car in your backyard that runs on pure hydrogen, freeing you forever from the need to burn those polluting and increasingly scarce fossil fuels. This baby would run so cleanly the only waste product would be water so clear you could drink it.

That would be great until you tried to fill up your fuel tank.

It took decades and trillions of dollars to create coast to coast gas stations and pipelines and refineries that make up the infrastructure that powers a nation on the move. And it will take decades and even more money to build a hydrogen infrastructure, so what are you going to do in the meantime?

Most likely you'll have to use what's there. You'll still need to pull into the local gas station and fill up your tank and somehow use that fossil fuel to produce hydrogen to run your car. Sounds a bit clumsy, but that's where we are in the move toward what is being called the "hydrogen future."

Even if we knew how to do it, there isn't any way to jump from the present to the future. We are going to rely on fossil fuels for decades to come, despite growing evidence that they will be in short supply as rapidly developing countries demand a larger share of a shrinking pie.

In the short term, at least, hydrogen power may turn out to be too good to be true. An inexhaustible source of clean-burning fuel would be great, but the hurdles are enormous.

Brick of Fuel?

At this point hundreds of millions of dollars are being pumped into efforts to solve problems that on the surface seem quite simple. Hydrogen is the smallest of all atoms, so you ought to be able to store a bunch of them in a small space. But a bunch isn't even close to what you're going to need.

One reason fossil fuels have hung around so long is it doesn't take much to pack a real punch. You get more bang for your buck with a gallon of gasoline than you could from a tank full of hydrogen. In fact, it would take so much hydrogen to power your backyard buggy on a 300 mile trip that researchers have given up on the idea of compressing gaseous hydrogen enough to provide an adequate fuel supply.

Thus storage has emerged as the No. 1 issue on the road to a hydrogen future. How do you store enough of the stuff to get you where you want to go?

The most likely answer, many experts contend, is you store it as a solid, not a gas. Scientists are looking at various chemical compounds that can hold hydrogen within their chemical lattice in a way that it can be both released and replenished.

But here's the figure that puts the difficulty of this problem into perspective. The goal is to create a solid compound composed of at least 7 percent hydrogen. Put another way, 93 percent of the mass of the storage system would be material that serves no purpose but storing hydrogen.

That's sort of like using a brick to hold a speck of gold.

"It's a real challenge," says one expert involved in the research.

On-Board Conversion

That problem is going to take a long time to solve, but there's a way to get around it, at least for awhile. Gasoline can be converted to hydrogen, thus paving the way for a gradual transition. Three different ways of producing hydrogen from gasoline are being studied, and a significant milestone has been reached.

Researchers at the U.S. Department of Energy's Pacific Northwest National Laboratory have managed to strip hydrogen atoms from water and hydrocarbon molecules (both gasoline and diesel fuel) to produce hydrogen gas. And they can do it quickly, thus leaping a hurdle that could make hydrogen power far more appealing.

"We've shown the feasibility of this approach," says Larry Pederson, project leader at the lab.

On-board conversion of fossil fuels to hydrogen is seen as the best way to bridge the gap, but up until now there has been a real obstacle. All of the possible techniques require time for the conversion to begin, because all depend on the production of heat to start the process.

So if you actually built your backyard dream machine, you might have to sit in it for about 15 minutes before it warmed up enough to begin producing hydrogen. That could be a showstopper.

But Pederson and his team have developed a new gadget, called a "steam reformer," that launches the conversion process within 12 seconds. So by the time you get your seatbelt on, and your radio tuned to the right station, you're ready to roll.

"The target [set by the Department of Energy] had been 60 seconds," Pederson says. Exceeding that goal by a considerable margin is a technological triumph, but no one is claiming victory yet. Before they can do that, they have to scale it up to provide enough hydrogen to power a 50 kilowatt fuel cell.

"That would run a small compact car," Pederson says. For your SUV, he adds, it's "probably going to be double that."

Fossil Fuel Dependant

What all of this shows, however, is that even in our effort to break away from fossil fuels, we still rely on fossil fuels.

"We're using something like 12 million barrels [of oil] a day for transportation needs," Pederson says, and he doesn't see us breaking away from that anytime soon. Some modes of transportation will probably depend on fossil fuels for many decades.

"I don't think anybody's going to be flying a plane real soon" powered by a hydrogen fuel cell, Pederson says.

But he sees hydrogen making inroads in the not too distant future, especially as auxiliary power units. Our cars are demanding more and more electricity to run our gizmos, and using an alternator to generate that electricity is a very inefficient process, he argues.

Converting part of the vehicle's fuel to hydrogen to power a small fuel cell could produce large amounts of electricity and greater fuel economy, he adds. Diesel trucks that now idle all night to keep their refrigerators running could use fuel cells instead, thus reducing the waste considerably.

So there are many ways that hydrogen is likely to play an increasingly important role in the years ahead. But it will take a few miracles to reach the goal set by President Bush in his State of the Union address last year.

He said "the first car driven by a child born today could be powered by hydrogen, and pollution free." That's if all this can be moved from the laboratory to the showroom within the next two decades.

Posted by thinkum at May 6, 2004 01:43 PM