What will we be driving in 2010?
Both Washington and Detroit now believe the car of tomorrow will be powered by hydrogen fuel cells. General Motors caused a stir at this months North American International Auto Show by unveiling a revolutionary prototype that some hailed as the beginning of the end of the internal-combustion engine. This could be the biggest thing in the last 50 years, said David Cole, director of the Center for Automotive Research. GMs Autonomy concept car runs on fuel cells embedded in its 6-inch-thick chassis; the cells power electric motors in the wheels. The Autonomy has no engine, no pedals, and produces no pollution. The chassis is designed to be topped off with a snap-on body that can be easily replaced, allowing motorists to swap a sporty version for a roomier minivan model without buying a new car. DaimlerChrysler, Ford, Honda, Nissan, and Toyota all have fuel-cell cars on the test tracks.
How do fuel cells work?
They mix hydrogen and oxygen to produce a chemical reaction. Two positively charged hydrogen atoms combine with a negatively charged oxygen atom to form H2O, or water. The energy from that reaction is turned into DC (direct current) voltage, about 0.7 volts per fuel cell. Thats not a lot of juice, so many separate cells are joined together in a fuel-cell stack. A stack about the size of a small suitcase can provide enough power to run a car. It can already produce sprightly, if not Porsche-like, acceleration. The only emission is water vapor.
Is the technology new?
Its older than the electric lightbulb. In 1839, a Welsh judge and amateur scientist named Sir William Robert Grove mixed hydrogen and oxygen to produce electricity, although he got such a weak charge that his gas battery wasnt useful. Other scientists kept tinkering, and in 1959 engineer Harry Karl Ihrig unveiled the first fuel cell-powered vehicle, a 20-horsepower tractor. The city of Chicago experimented by putting three fuel cell-powered buses on the roads from 1998 to 2000, and NASA has used the technology to provide electricity onboard spacecraft since the Gemini and Apollo programs. Today the space agencys shuttles use fuel cells to generate aboard electricity, and the water vapor they spit out as exhaust is condensed to quench the thirst of the astronauts.
Why arent fuel-cell cars on the road yet?
There are prototypes zipping along German highways, but a number of obstacles hinder their widespread use. The biggest is that while hydrogen is theoretically a cheap fuel source, its also an unwieldy one. Even in compressed form, hydrogen gas takes up so much space that a cars tank would have to be 3,000 times the size of a standard gasoline tank to store the same amount of energy. Liquefying the hydrogen saves room, but requires a lot of energy, since it has to be kept below minus-422 degrees Fahrenheit. DaimlerChrysler engineers envision cars with Thermos-like fuel tanks. Even then, a service station dispensing liquid hydrogen would require robots to work the pumps, so motorists hands wouldnt be in danger of freezing and breaking off. The oxygen, fortunately, is easier to come byit can be obtained from the air.
Is there a solution to the hydrogen problem?
A device called a reformer can extract hydrogen from other fuels, such as natural gas, propane, and methanol. Adding this step is less efficient than using pure hydrogen, but it has the advantage of using a fuel that is easier to store and distribute. Methanol, for example, would be as easy to use as gasoline. One drawback is that these other fuels would produce some pollution, since they contain gases in addition to hydrogen.
What are the benefits of fuel cells?
Cheerleaders for this technology say it can eliminate our dependence on foreign oil and at the same time clean up our air. Replacing just 20 percent of American cars with fuel-cell vehicles would reduce our annual need for oil by the amount we import from Saudi Arabia, one of our biggest suppliers. Fuel cells that run on pure hydrogen have no emissions, other than distilled water vapor. Even cells that run on methanol or other fuels wont cough out anything nearly as filthy as the pollution spewing from the tailpipes of internal-combustion engines. And fuel cells have no moving parts, so they are likely to be more durable and easier to maintain than traditional engines. GM says its concept car, Autonomy, will last 20 years.
And the drawbacks?
Cost is the principal obstacle. GM says the technology is still several times more expensive than a conventional engine that burns gasoline. For that reason, environmentalists worry that fuel cells will serve as a smoke screen to hide the Bush administrations distaste for fuel efficiency, so that gas-guzzlers can rule the roads for at least another decade.
When will hydrogen-powered cars arrive?
GM and DaimlerChrysler both hope to begin limited production within five years. But most experts say the revolutionary cars wont fill showrooms until sometime after 2010.
The electric car
In the 1970s, with the nation in the grip of an energy crisis, futurists envisioned a day when electric cars would free motorists from the need to line up at the gas pump. Environmentalists and Energy Department planners predicted that by the year 2000 there would be 25 million battery-powered cars whirring along American roads. Upstart automakers began marketing electric vehicles. A Florida company, Sebring-Vanguard, sold 2,200 of the most popular model, the CitiCar. The CitiCar and its main competitor, the Elcar, were underpowered by gasoline-engine standards, reaching top speeds of around 40 mph. They also had to be recharged every 60 miles. When the oil shortage ended, the assembly lines shut down. But the pursuit of fuel efficiency kept the idea of electric cars alive, and in 1993, former vice president Al Gore began championing a federal program to help automakers develop hybrid engines that run on both gasoline and electricity. With $1.5 billion in federal funds, the program came close to its goal of developing a hybrid that gets 80 miles per gallon. The Big Three automakers all plan to roll out hybrid cars over the next several years, and Toyota and Honda are already selling limited numbers of hybrids that get up to 70 miles per gallon. But with gas in the U.S. still cheaper than bottled Perrier, no automaker currently plans to mass-market hybrid cars.