It sounds like science fiction — a car that runs on hydrogen gas, spits nothing but water vapor out the tailpipe, and can take you from Washington to New York City on a single tank.

But after a long and bumpy road from futuristic concept car to real-world production vehicle, the first mass-produced hydrogen-powered cars will hit dealerships this spring in the United States, and they are on display this week at the Washington Auto Show.

How soon you’ll see them on the roads in our region remains to be seen, as auto manufacturers, fueling companies and policymakers look for ways to tackle serious challenges that now stand in the way — not the least of which is where do you refuel with hydrogen.

“It’s coming, this is the next wave, and from what some of the manufacturers are saying, it’s an even better bet than some of the alternatives already on the market,” said Kevin Reilly, owner of Alexandria Hyundai and chairman of the Washington Auto Show. “Now all we need is the infrastructure to make it a viable option for drivers.”

What are the advantages?

Manufacturers such as Toyota, Honda and Hyundai — the latter of which will soon begin selling its first hydrogen-powered vehicle in parts of California where fueling stations already exist — say this new propulsion system tackles the age-old pollution problems of standard gasoline engines without many of the limitations that have held back the market for battery-powered and other alternative fuel vehicles.

On board the vehicles, hydrogen and oxygen are combined in a fuel cell, causing a chemical reaction that yields electricity to power the car. The only other byproduct is water, which comes out the tailpipe as steam — so, no greenhouse gases, just like the plug-in hybrids and electric cars already on the road today.

And while some processes used to extract hydrogen for fuel usage do emit greenhouse gases, research has shown that the overall “well-to-wheel” carbon footprint is lower for hydrogen-powered cars than for electric plug-ins and other alternative fuel vehicles.

Meanwhile, filling up at a hydrogen pump takes a few minutes, compared to several hours for even the fastest of electric charging stations. And fuel cells can be scaled to power trucks and sport utility vehicles, whereas experts say it is currently difficult to stack enough batteries to power cars much larger than a sedan.

Most importantly, though, hydrogen-powered cars can travel upwards of 300 miles on one tank, giving consumers the same range they have grown accustomed to with gas engines. Conversely, the market for plug-ins continues to be limited by the fact that all but the most expensive models can travel no more than 100 miles on a full charge.

Indeed, as the area’s network of electric charging stations has become more dense, electric vehicle sales in the Washington region have ticked up from around 150 last year to more than 600 in the past 11 months, according to data from the Washington Area New Auto Dealers Association. Still, that represents less than half of 1 percent of all cars sold in the region during that period.

“Drivers want larger cars, especially here in the United States, and they want to be able to drive further without refueling,” Mike O’Brien, Hyundai’s vice president of corporate and product planning, said in an interview. “So while we think there will always be a place for battery-powered electrics in our fleet, they’ll always be supplemental vehicles, not ones that can displace combustion engines.”

How did we get here?

With so many advantages to hydrogen, why are we so much further down the road on an electric charging network than we are on hydrogen fueling stations? It comes down to federal funding and the current administration’s evolving stance on hydrogen.

A test version of Toyota's fuel cell concept was on display at the 2014 Consumer Electronics Show. The car uses hydrogen for fuel and emits only water vapor as exhaust. (Zoeann Murphy/The Washington Post)

During his first few years in office, then- Energy Secretary Steven Chu openly questioned the viability of hydrogen fuel cell vehicles, at one point stating that it would require several “miracles” to make that dream a reality, including better ways to produce and store hydrogen and more affordable fuel cells. Under his watch, the Energy Department cut by more than half its funding for fuel cell research, while at the same time pouring additional resources into cultivating an infrastructure of electric charging stations for plug-in vehicles.

Not long afterward, Shell closed the only commercial hydrogen station in the District, located on Benning Road, along with another three pilots it had been built in New York. On the East Coast, it looked like the end of the road for hydrogen cars.

Only three years later, though, Chu acknowledged that he had changed his mind about hydrogen, pointing to new techniques developed to extract hydrogen from natural gas as well as improvements and cost reductions in automotive technology. Toyota executives, for instance, say they have reduced the cost of hydrogen vehicles by 95 percent in the past decade, mostly by bringing down the size of the fuel cells and by finding new, less expensive materials with which to build the tanks.

At that point, though, the United States had already fallen behind the likes of Japan, Germany, Sweden, South Korea and the United Kingdom, all of which have made considerable government investments in hydrogen infrastructure and already have dense refueling networks.

Now in catch-up mode, and now under the watch of Obama’s second-term Energy Secretary Ernest Moniz, the United States has started to invest more money back into hydrogen. In May, the agency launched H2USA, a public-private collaboration between fuel suppliers, automakers, government agencies and clean technology groups to coordinate research and map out a plan for a hydrogen infrastructure.

“It’s not the kind of problem the federal government is going to solve on its own, or that state governments or the industry are going to solve on their own; it really needs a team effort,” David Danielson, head of the department’s Office of Energy Efficiency and Renewable Energy, said at the auto show last week. He added that H2USA members will put forth several recommendations for the agency and other stakeholders in the next few months.

Moniz, who also spoke at the show, said the department is taking a close look at steps that have been taken at the state level in California, where, sparked by public investments under former Gov. Arnold Schwarzenegger (R) and accelerated by legislation signed by Gov. Jerry Brown (D), a cluster of nine hydrogen stations have sprouted around Los Angeles.

Over the next decade, the state will invest an additional $200 million to reach 100 stations by 2024. Money for the program comes from vehicle registration fees, meaning drivers are footing much of the bill for the infrastructure.

Some private stakeholders, such as Toyota, which is planning on bringing its first hydrogen-powered car to the United States starting next year, have taken steps to speed up the process. The company partnered with the University of California, Irvine to fund research to determine how far apart to build hydrogen stations to make refueling practical for the largest number of potential buyers.

If they want to sell the cars on the East Coast, some say carmakers will need to make those same investments here.

“The first companies to sell a hydrogen fuel cell car are going to have to do some work like Nissan did with the Leaf,” said Joe Taylor, training director at Darcars Automotive Group, a privately owned collection of more than 20 local dealerships. “That was the first mass-produced all-electric car, and before they did it, they worked with other groups to help build the start of an infrastructure and put charging stations in some of their dealerships.”

While automakers say they are willing to invest in research, they are unlikely to dive much further into the fuel production and gas station business, even if it means waiting longer for the infrastructure they need to start selling hydrogen cars in new markets.

Who would have to step up?

Instead, the onus will likely fall on existing hydrogen producers, technology firms and other investors. A small Connecticut-based company called SunHydro, for example, has started planting the first seeds in the Northeast, building its first hydrogen fueling station in central Connecticut in 2010 and recently starting construction on another just outside of Boston.

Hydrogen is generated on site at both stations using energy from solar panels on the roof to electrolyze water. Purchased a few years ago by Tom Sullivan, who made his fortune with Toano, Va.-based hardwood flooring company Lumber Liquidators, SunHydro initially planned to build a chain of stations that would allow hydrogen cars to travel from Maine to Miami.

However, Sullivan said he later realized that building a central hub of stations was a more practical path for hydrogen cars, and he hopes to start with a dense network around Boston. Once in place, if hydrogen cars start selling in the Northeast, the network would likely sprout satellite stations that he thinks would spread quickly to New York, and then down to Washington.

In order for hydrogen cars to be a real option in this area, though, Sullivan estimates we would need at least a dozen stations in the region. And without cars to fill up at his existing pumps up north, he says there is little incentive to move forward, as each station costs a couple million dollars to build and needs roughly 100 vehicles locally to make it economically viable.

“We need more cars to make it worthwhile, that’s the bottom line,” he said. Meanwhile, Hyundai, Toyota and Honda representatives all say they are eager to bring their cars to market on this side of the country — just as soon as they see hydrogen stations sprout on the East Coast.

It leaves both sides at a stalemate, waiting for the other to jump first. Some are hoping that’s where the H2USA partnership will step in with funding or other incentives to get the early stages of a fueling network off the ground.

“In California, they provided a walking bridge across the river for investors during this period where there are not yet enough hydrogen cars on the road,” O’Brien said. “It would be great to see that model expanded or duplicated at the state or federal level.”

When will this all happen?

With a little more push from elected officials, carmakers and fuel producers say they could have hydrogen-powered vehicles rolling out of dealerships in this region in as little as three or four years.

“It’s not going to happen overnight, but it will happen,” Sullivan said. “I think, realistically, we are a few years away from seeing hydrogen-powered cars in this region.”

Others think it will take significantly longer, some pointing out that it took about a decade to build an adequate recharging infrastructure here to support battery-powered electrics — a far less expensive undertaking than building hydrogen stations.

“It could happen, but it’s going to take a long time and a large investment,” Eric Wachsman, director of the Energy Research Center at the University of Maryland, said in an interview. He added that hydrogen vehicles may prove more practical down the road for public buses and shipping fleets, which always return to the same location.

However, “having hydrogen replace gas pumps at every corner station, that’s a long way out,” he added.

Some local dealers were equally skeptical. Alex Perdikis, general manager of Koons Ford Lincoln Mazda in Silver Spring, said, “We don’t hear a lot of people asking or talking about hydrogen fuel.”

Then again, that’s precisely why they are on display at the show, Reilly said.

“In part, they’re shown because [automakers] want consumers here to get excited about these cars,” the auto show chairman said. “And second, they want lawmakers and agency officials walking around to see that this is no longer something automakers are thinking about doing, it’s here and it’s ready to roll out.”

Ultimately, he said, the idea “is to get them to see what’s happening in California and get them thinking: ‘Alright, what do we need to do to get these vehicles on the road here and across the country?’”

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