Hydrogen cars, Mutolo said, have an advantage over battery-powered electric cars because drivers don't have to worry about running out of electricity and having to wait hours for recharging. "It's very similar to the kind of behavior that drivers have come to expect from their gasoline cars," he said.

Hydrogen fuel cells use a complex chemical process to separate electrons and protons in hydrogen gas molecules. The electrons move toward a positive pole, and the movement creates electricity. That powers a car's electric motor, which turns the wheels.

Since the hydrogen isn't burned, there's no pollution. Instead, oxygen also is pumped into the system, and when it meets the hydrogen ions and electrons, that creates water and heat. The only byproduct is water. A fuel cell produces only about one volt of electricity, so many are stacked to generate enough juice.

Hydrogen costs as little as $3 for an amount needed to power a car the same distance as a gallon of gasoline, Mutolo said.

Manufacturers likely will lose money on hydrogen cars at first, but costs will decrease as precious metals are reduced in the fuel cells, Mutolo said.

Toyota said its new fuel cell vehicle will go on sale in Japan in 2015 and within a year later in Europe and U.S.

Toyota's fuel cell car is a "concept" model called FCV that looks similar to the Prius gas-electric hybrid.

Honda, which has leased about two-dozen fuel cell cars since 2005, took the wraps off a futuristic-looking FCEV concept vehicle in Los Angeles. It shows the style of a 300-mile range fuel cell car that will be marketed in the U.S. and Japan in 2015.

Stephen Ellis, manager of fuel cell marketing for Honda, also wouldn't say where vehicle will be marketed in the U.S. But he expects hydrogen fueling stations to be abundant first in California, and then Northeast states. He predicts it will take five years for the stations to reach significant numbers outside California, and up to 25 years to go nationwide.

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