LOS ANGELES — The red car humming quietly along this four-lane suburban road looks pretty much like your average four-door sedan.
But take a close look at the latest model of Honda’s FCX Clarity, unveiled at the Los Angeles Auto Show in November, and you’ll spot one key difference: There’s no tailpipe at the back.
This car doesn’t need one. As a hydrogen fuel-cell vehicle, it releases only water vapor from an outlet on its underside, instead of carbon dioxide, carbon monoxide and other unsavory exhaust produced by conventional gasoline-consuming cars.
Honda advertises the latest Clarity model as an exemplar of technological achievement, with more power per unit of weight and considerably higher fuel efficiency than its 2005 predecessor.
Backed by rising calls to stop global warming, top U.S., Japanese and German automakers are competing to develop zero-emission technologies able to withstand a wide range of driving conditions and the test of the marketplace as well.
And despite skepticism from some energy experts, the automakers tout hydrogen fuel-cell cars as key to a sustainable future, with roles also played by other types of hydrogen vehicles and hybrids.
Fuel-cell vehicles are powered by electricity produced by a chemical reaction between hydrogen loaded from a high-pressure tank at a refueling station, and oxygen.
Fuel cells contain a positive electrode, a negative electrode and a membrane separating the two.
Inside the negative electrode, electrons freed from the hydrogen molecules pass through a circuit, creating an electrical current. Over in the positive electrode, the electrons combine with the oxygen and hydrogen ions that have been pulled through the membrane to form a byproduct, water.
That is the vapor that exits from below the car.
Although the principles behind the fuel cell have been understood for more than a century, Honda said great progress has been made in developing the Clarity.
Technicians, for example, have crafted sensors that shut down the flow of hydrogen gas and electricity in the event of a tank leak, spokeswoman Makiko Yoshida said.
Another official said the Clarity has been designed to withstand collisions from multiple angles — and thus prevent explosion, while Honda’s Web site says extensive flood and fire testing has further ensured safety.
To improve driving range, Honda has reduced the weight of the stack of fuel cells stored beneath the passenger area by almost a third and jacked up their horsepower by 16 percent. Maximum speed is 160 kph with a range of 570 km on a full tank.
Perhaps most eye-catching to the environmental crowd, the 2007 Clarity is able to use 60 percent of the energy contained within its fuel — three times that of a conventional gasoline automobile, according to Honda.
But because of the high cost of many of the parts making up a fuel cell — particularly the membrane, which requires platinum to act as a catalyst — car prices are for now out of the range of most consumers.
“It is widely said that one unit would cost ¥100 million or ¥200 million” if the car were to go on sale, said Satoshi Honda, a spokesman at the Japan Automobile Manufacturers Association in Tokyo. The Clarity is not for sale, and Honda would not divulge any estimated sales price.
For those with wallets flush with cash, however, leasing of the 2007 Clarity will begin mid-2008 for about $600 a month, reportedly in California, where most U.S. hydrogen refueling stations are located.
“Californians see themselves as more eco-conscious than people in other states,” said Tetsuo Iwamura, president of American Honda Motor Co. The 2005 model is currently being leased by 21 U.S. municipalities, as well as 17-year-old Hollywood actress Q’Orianka Kilcher and a wealthy businessman and his family, the Spallinos, Fujimoto and other officials said, without providing further information. Leasing will start soon in Japan.
But even as Honda and other automakers race ahead with efforts to promote hydrogen fuel-cell vehicles, some experts are raising fundamental questions over the environmental sustainability of hydrogen fuel cells in autos.
Perhaps the chief detractor is German scientist Ulf Bossel, who has spent two decades working closely with fuel cells and organizes the European Fuel Cell Forum in Lucerne, Switzerland.
Bossel — who also happens to be the great-great-grandson of Christian Friedrich Schonbein, coinventor of the fuel cell — says that though synthetic hydrogen may one day prove useful for stationary energy storage, giant losses of energy during its production make it unsuited for transport.
“The hydrogen economy is a gigantic energy waste,” he said in an interview podcast last year on theWatt, a Web site for energy news.
Hydrogen for fuel is taken from water molecules in a chemical process called electrolysis, then compressed or liquefied for distribution and finally reconverted into electricity to power a fuel-cell vehicle — a system Bossel calls inefficient.
“With the same amount of electricity we have available, you can drive an electric car three times farther than a hydrogen car,” Bossel said in the interview.
“If we want to have mobility in a sustainable future,” he continued, “we have to go for electric cars and not for hydrogen cars because for hydrogen cars, we won’t have the energy to make the hydrogen.”
Bossel sees more potential for fully electric cars powered by lithium-ion batteries that are charged at home than for vehicles relying on hydrogen supplied over an unwieldy new infrastructure of pipelines and stations yet to be built.
Whatever doubts may exist, Honda remains undeterred.
For one, company officials point out that plug-in electric cars generally require hours to charge, compared with the one minute needed to load up the Clarity’s tank with hydrogen.
And so although spokeswoman Yoshida acknowledged great challenges, she expressed confidence that her company’s hydrogen-car technology will ultimately prove successful.
“In the long term,” she said, “Honda’s stance is to further develop (hydrogen) fuel cells by getting over the various hurdles.”