The blue bus — one of just over 60 hydrogen-powered buses in use by public agencies in the United States — is powered by a chemical process that transforms hydrogen and oxygen into electrons and water. (Fredrick Kunkle/The Washington Post)

As the bus rolls into D.C. traffic, the ride inside is so quiet that all a passenger can hear is the creaking and squeaking of the vehicle’s frame.

Now and then comes a faint, high-pitched whistling of its motor, but the whoosh of the wind outside and the air-conditioning unit is much louder.

But perhaps the only thing better than the lack of noise is the lack of emissions from the bus’s hydrogen-fueled engine.

The blue bus — one of just more than 60 in use by public transit agencies in the United States — is powered by a chemical process that transforms hydrogen and oxygen into electrons and water. The electrons power the bus engine. The water trickles out the tailpipe.

Kirt Conrad, chief executive of the Stark Area Regional Transit Authority (SARTA), brought the hydrogen-powered bus to Washington to promote the vehicles as an alternative to louder, dirtier diesel buses that most cities and suburbs use to move people around.

“The funny thing is that passengers get used to the diesel noise,” Conrad said. “The first time you ride one of these, everybody whispers.”

The roadshow — funded in part by the federal government and the Toyota Mobility Foundation — was intended to build a market for vehicles powered by hydrogen fuel cells, especially for public transit. Conrad and representatives from the bus and fuel cell manufacturers met with officials from Metro, Alexandria DASH, the Fairfax Connector and other regional transportation officials. DASH took the vivid blue bus for a spin over a few routes.

“It handles pretty good compared to what I drive now,” said Joseph Fletcher, a DASH operator who drove the bus into Washington for a demonstration Thursday at the U.S. Transportation Department. Come early next week, the blue SARTA bus will be headed back to Ohio the way it came — on a flatbed.


Joseph Fletcher, a bus driver with Alexandria DASH, maneuvers a hydrogen-powered bus through the streets of Washington as part of a promotional demonstration of the cutting-edge technology. (Fredrick Kunkle /The Washington Post)

Hydrogen fuel cell technology has long been seen as prohibitively expensive and exotic but has been working its way toward the market since Honda, Hyundai and Toyota announced plans in 2013 to begin rolling out passenger vehicles. The U.S. Energy Department, in a 2016 report on the growing use of hydrogen fuel cells, says California has led the way, with a few hundred vehicles on the road and about 20 refueling stations open to the public.

Sunline Transit Agency, headquartered in Thousand Palms in California’s Coachella Valley, operates 23 hydrogen-powered buses, as does AC Transit in the Oakland area, according to Sydney Krueger, a sales consultant with BusStuf 2.0.

Supporters tout the fact that the hydrogen-powered fuel cells go farther than battery-powered vehicles. But the technology has its downside, too, and some believe its prospects have been overhyped. While hydrogen can be produced from water through electrolysis, the process consumes a significant amount of electricity. A more common method at the moment produces the gas from methane, which is a fossil fuel. Building a network of hydrogen refueling stations is costly and lags far behind recharging stations, while a big chunk of the market has already voted in favor of batteries and plug-in electric cars.

Yet hydrogen power has its believers, including Japan. NPR reported last month that the nation is eager to become the first “hydrogen society.”

Conrad’s proud to say that his corner of Ohio has the third-largest fleet in the country. Just don’t ask him about the risks of using a highly flammable gas such as hydrogen. And if you do, don’t mention the Hindenburg, the German airship that exploded at a landing site in New Jersey in 1937 when static electricity ignited a leak.

“Around work, I kind of kid around say, ‘We don’t mention the word “Hindenburg,” and if you do, we’re going to write you up,” Conrad said. He said the zeppelin’s outer lining was more to blame for the fatal catastrophe than the gas.

Conrad said handling hydrogen requires the same precautions one would use for natural gas. If anything, because it’s the lightest element on the planet, hydrogen dissipates rapidly in the event of a punctured tank. And no fuel comes without risk, including the gasoline and diesel that’s sloshing around inside millions of vehicles.

But he also hopes his demonstration tour will help educate people. The bus, wrapped in a blue bubble, cost about $1.2 million, or just about twice what a diesel bus would cost, Conrad said. But it also gets about twice the mileage.

SARTA pays about $4.60 per kilogram of compressed hydrogen gas, which produces about the equivalent amount of energy as a gallon of diesel fuel. (AAA says diesel costs about $3.06 a gallon at the moment.) As the idea of using hydrogen fuel cells catches on, the pricing should become even more competitive, he said.

SARTA, which received more than $4 million from the Federal Transit Administration in 2016, will have 18 buses on the road by the end of the year, including the first hydrogen-powered paratransit buses, Conrad said. The fleet serves the area around Canton and operates in partnership with Ohio State University on the school’s campus. Conrad said his passengers, drivers and even mechanics who have become accustomed to using compressed natural gas don’t notice much difference with the hydrogen-powered buses, except for the quiet ride.