For decades, hydrogen fuel cell cars have been the automotive technology of tomorrow: the big idea, for someday far in the future.

No longer. At auto shows in Los Angeles and Tokyo this week, Toyota Motor Corp., Honda Motor Co. and Hyundai Motor Co. will introduce hydrogen-powered cars. Hyundai's will reach U.S. showrooms next year, while the other models will begin selling a year later.

It amounts to "a coming out party for hydrogen," said John Krafcik, chief executive of Hyundai Motor America.

Toyota's car, being unveiled at the Tokyo Motor Show, "has the same potential as the first Prius," said Bill Fay, general manager of Toyota's U.S. sales arm. Fuel cell offerings from the two other automakers will debut at the L.A. Autos Show.

In a little more than a decade, the Prius has become America's favorite hybrid and California's bestselling vehicle.

The global automakers believe cars powered by fuel cells represent the best path to building the zero-emission vehicles now demanded by regulators in California and many other states and, increasingly, by consumers. Using hydrogen to create electricity, fuel cells combine the best of electric and gasoline cars without the downsides, the automakers say. They drive like electric cars — quietly, with tons of off-the-line power — but can be refueled just like gasoline-powered cars.

"Hydrogen vehicles allow you to be lean and green with the same range as an internal combustion engine," said Thilo Koslowski, an analyst at Gartner Inc.

The challenge: Producing them cheaply enough to entice consumers and building enough hydrogen fueling stations to keep them on the road. Initially, the cars are expected to cost more than comparable gasoline-powered and electric vehicles, though they probably will qualify for government incentives to buyers. The sticker prices are expected to come down if automakers can sell the cars in volume.

None of the automakers have revealed prices yet. The cars are likely to be offered first as three-year leases.

Even before these fuel cell cars hit dealer lots, they are causing a schism in the green car community, as advocates of electric and hydrogen vehicles compete for limited government funds for fueling stations and incentives needed to jump-start sales, Koslowski said.

Elon Musk, a technology tycoon and Tesla Motors' chief executive, disparaged fuel cell cars, calling them a marketing ploy by the mainstream auto companies.

"Hydrogen is quite a dangerous gas," said Musk, who also runs SpaceX, the rocket company formally known as Space Exploration Technologies Corp. "It's suitable for the upper stage of rockets, but not for cars."

Not true, says Matt McClory, one of the principal engineers of the Toyota fuel cell vehicle. And he has a bullet to prove it. In safety tests, Toyota's engineers shot rifle bullets at its high-pressure hydrogen tanks to see if they would explode or catch fire.

"The smaller-caliber bullets would just bounce off the tank," McClory said. "It took a 50-caliber armor-piercing bullet to penetrate the tank, and it then just left a hole and the gas leaked out."

Hyundai has set its entire car ablaze without triggering an explosion. When the temperatures rise high enough, the hydrogen vents in a flair pattern through a pressure valve but burns off quickly.

Gasoline cars can be fully engulfed in flames when their tanks break, the automakers noted, and in the last few months three Tesla vehicles have burned when in severe accidents.

Still, this "Hindenburg" perception — referring to the 1937 disaster that consumed a German airship in a hydrogen fireball — is something automakers will have to tackle, said Mike O'Brien, Hyundai's vice president of product and corporate planning.

"The car meets the same crash standards of any other car we sell," O'Brien said. "But only miles on the road, and people in the seats of these vehicles, will overcome those perceptions."

The cars are likely to get those miles because of California's stringent environmental regulations, which require 15% of the new cars sold in the state by 2025 to be zero-emission vehicles. An additional nine states have adopted the same sales goals, with a target of having 3.3 million zero-emission vehicles on the road by 2025. That's what's behind the automakers' efforts to bring hydrogen autos to the U.S. market now.

All three of the vehicles to be introduced this week will have a range of 300 miles or more, compared with about 75 miles for most battery-using electric cars and more than 200 for the high-end Tesla Model S, which starts at $71,070. The fuel cell cars drive like normal vehicles and have about the same amount of interior space as vehicles of similar size. They take three to five minutes to fuel up. The fuel nozzle locks into the car to prevent hydrogen leaks but is otherwise similar to a gasoline pump.