As the railroad industry searches for ways to reduce and ultimately eliminate its greenhouse gas emissions, Wabtec sees hydrogen as the locomotive fuel of the future, whether it’s burned in internal combustion engines or used to power fuel cells.
“We think this is going to be an impactful technology. We’re not seeing this as a fringe thing. This is going to be the thing that replaces diesels in the future,” says Philip Moslener, Wabtec’s corporate vice president for advanced technologies.
Hydrogen produces no greenhouse gas emissions when burned as a fuel. “It is not economically viable today,” Moslener says, noting that hydrogen currently costs significantly more than diesel fuel.
But hydrogen production is expected to rise, which should bring the cost down to rival diesel fuel as early as 2030. In the U.S., the Bipartisan Infrastructure Law includes $7 billion in funding to develop six to 10 hydrogen production and storage hubs, while there are similar efforts under way in Canada. Energy companies, meanwhile, are making investments in hydrogen production facilities.
So Wabtec aims to match its hydrogen locomotive research and development efforts to the planned pace of hydrogen production in North America. Wabtec hopes to field its first hydrogen prototype in 2027.
Fuel Cells and Batteries
Hydrogen-powered fuel cells, combined with batteries to store electricity, would be a zero-emissions solution to replace the diesel-electric locomotive, Moslener says.
But fuel cells don’t yet have the energy density required for a line-haul locomotive. A road locomotive would need 3,300 kilowatts of power – or 10 times what’s available from fuel cells that can fit on a locomotive today, Moslener says.
The development of ever more powerful fuel cells is expected to continue, however, much like the way batteries have gained more storage capacity and extended the range of electric vehicles in recent years.
“We will get there,” Moslener says.
If a fuel cell locomotive consist ultimately needs more battery capacity, railroads could always add one of Wabtec’s FLXdrive battery-electric locomotives to the train, he says.
Due to their lower horsepower requirements, fuel cell switching locomotives may become viable sooner than road locomotives.
Road locomotives and switchers will require different energy-management systems because of the different demands of each type of service. Fuel cells prefer producing a consistent amount of power, Moslener says, so switchers would need to draw electricity from batteries rather than tap the fuel cell. Conversely, road locomotives often operate with relatively steady power demands and could tap a combination of the fuel cells and batteries to power their traction motors.
Retrofitting Locomotives to Burn Hydrogen
The other path is burning hydrogen in internal combustion engines. “We also see that as a viable solution, especially one where it’s a transition technology,” Moslener says. “The nice thing about internal combustion engines is it’s engines. We know engines. Customers are comfortable with engines. They know how to maintain them. They know how to operate them.”
Another plus: Wabtec’s Evolution series locomotives can run on hydrogen with little modification. “That’s the nice thing about our EVO family of engines is that they have the capability, the genetics, to be able to be modified to hydrogen,” Moslener says.
The biggest technical hurdle is how to bring hydrogen fuel to the combustion chamber. Like liquified natural gas, hydrogen needs a spark to ignite. The Wabtec LNG-powered locomotives in use on Florida East Coast Railway rely on port injection with diesel fuel used as a pilot. That technology needs to be adapted for hydrogen use, Moslener says.
Hydrogen makes metal brittle over time, which can lead to mechanical failure. To solve this problem, Wabtec is working with the U.S. Department of Energy’s Oak Ridge and Argonne national laboratories. In a project funded by a Department of Energy grant, Argonne is doing computer simulation work, while Oak Ridge is testing a single-cylinder, hydrogen-fueled engine that uses port injection.
Once the combustion characteristics and ideal fuel mixture are worked out using the single-cylinder engine, tests will shift to a multi-cylinder engine. The next research and development stage would be fielding a prototype hydrogen-powered locomotive.
With low pressure direct port injection, a locomotive could burn a 50/50 mix of hydrogen and diesel fuel. More R&D would be needed to push the fuel mix to 70% hydrogen using a low-pressure injection system.
“Obviously we want to push it towards 100% hydrogen,” Moslener says. That would require a leap to high-pressure direct injection, which could enable a 90/10 mix of hydrogen and diesel fuel.
Some diesel is required in order to ignite the hydrogen, so an internal combustion engine would always produce at least some carbon dioxide. “If we want to go to zero emission, we have to go to fuel cell,” Moslener says.
A drawback to burning hydrogen in a traditional internal combustion engine is that nitrous oxide emissions are not reduced because they’re created during the combustion event, Moslener says. Particulate emissions, however, would fall in line with the reduction in diesel in the fuel mix.
Modifying locomotives would enable railroads to begin reducing their carbon footprint right away by blending hydrogen and diesel, Moslener says.
Hydrogen-powered locomotives would have to be paired with fuel tenders in order to have a range comparable to today’s diesel-electrics. Like FEC’s LNG locomotives, a hydrogen consist would have two locomotives sandwiching a tender. Wabtec dubs these locomotive-tender-locomotive consists “triplets.”
Transition Challenges
Even when hydrogen production scales up, it won’t be available immediately across all 140,000 miles of the rail network. And that will initially create interoperability problems within railroads as well as with interchange service.
The use of internal combustion engines that can be powered by hydrogen or diesel is one way to attack the interoperability problem. An ES44AC or ET44AC with a hydrogen port injection system could run on 100% diesel fuel. Although less efficient, Moslener says this fuel flexibility would help ease the transition from diesel to hydrogen.
The other transition solution is to create hydrogen corridors between terminals that have hydrogen storage and fueling systems. “Customers hate to think about dedicated corridors — but I think we’re going to have to,” Moslener says.
Another mindset change: Thinking about the interaction between triplets, trailing tonnage, and topography rather than just locomotive power.
“We have to start changing that mentality and talk about trains,” Moslener explains, noting that a hydrogen triplet and a battery electric locomotive, combined with energy the locomotives can capture from the train during dynamic braking along particular routes, all will have to be factored into the equation.
One advantage of burning hydrogen directly in internal combustion engines as a bridge to fuel cells is that it will give railroads experience with refueling, safety, training, and hydrogen production, storage, and distribution infrastructure, Moslener says.
Pieces of the Puzzle
A shift to hydrogen power will be complicated. It’s a bit like trying to put together a puzzle without fully knowing what the pieces look like because multiple problems need to be solved along the way.
First, there are five potential hydrogen fuel forms. They include compressing the gas at one of three different pressures; cryo-compression; and liquid hydrogen. Each form requires a different type of storage tank.
Wabtec believes liquid hydrogen is the most logical choice for railroads because it has twice the energy density of compressed hydrogen, Moslener says.
Refueling times also give liquid hydrogen an edge. It would take five or six hours to fill a liquid hydrogen tender today, Moslener says, compared to up to 30 hours for compressed hydrogen. NASA has significantly faster flow rates, he says, and further research and development likely could make liquid hydrogen fueling as fast as refueling a diesel.
“We are thinking the industry needs to go to liquid in the long term, so that’s where we’re putting our R&D efforts,” Moslener says.
But Wabtec can’t go it alone, and investment from railroads and governments will be required.
“There’s a lot of stuff that we need to figure out. Wabtec can’t do it on its own,” Moslener says. “If the industry believes hydrogen is the fuel of the future, then we need to put investments in this to figure out a multitude of issues before it can be a safe, usable fuel.”
ProgressRail, Chevron, and BNSF Railway announced in December 2021 that they are partners in a hydrogen locomotive project. ProgressRail will build a high-horsepower fuel-cell locomotive, Chevron will develop the fueling infrastructure, and BNSF will operate the locomotive as part of a test program.
The supporting infrastructure will be installed next year, with a planned delivery of the unit in 2025, BNSF says. ProgressRail and Chevron did not respond to emails seeking additional details.
Wabtec is closely following Canadian Pacific Kansas City’s hydrogen fuel cell locomotive project. The hydrogen community is small, particularly in rail, and all of its players encourage and support each other, Moslener says.
Railroads also will have to follow developments and cooperate with other industries. “Rail is a small industry,” Moslener says. “We’re not going to be leading where hydrogen is going. Other industries will be driving the large investments.”
The trucking industry already has some hydrogen fuel cell rigs in revenue service. J.B. Hunt, for example, in July announced the purchase of 13 zero-emissions Class 8 trucks from Nikola, three of which are powered by hydrogen-fuel cells. Nikola’s hydrogen subsidiary, HYLA, is providing the hydrogen and fueling infrastructure. The fuel cell trucks have a 500-mile range.
Hydrogen also will have to overcome a reputation that it’s unsafe. Images of the 1937 Hindenburg airship disaster are still seared into the public consciousness. But hydrogen is safely used in industrial processes across North America today, Moslener notes, and is transported by highway every day without incident.
The railroad industry will, however, have to develop standards around hydrogen production, storage, and fueling, as well as how to detect and handle leaks. If there is a leak, Moslener notes, hydrogen rises and quickly dissipates.
Thanks to a federal grant, Wabtec is working with the Sandia National Laboratory on the development of potential hydrogen standards and regulations for the rail industry.
The Federal Railroad Administration has issued a Net Zero Greenhouse Gas Emissions by 2050 Challenge to the rail industry. Although the agency doesn’t officially back any specific technology to reach zero emissions, the FRA is directly involved in a few industry hydrogen efforts.
FRA is a member of the Association of American Railroads’ Alternative Fuel Tender Technical Advisory Group and participated in Sandia National Lab research on safety and design requirements for a hydrogen tender.
The agency also is involved in the American Public Transportation Association’s efforts to develop a white paper on hydrogen and battery energy storage systems. That paper may lead to a standard and the development of FRA regulations over the long term.
The Hydrogen Rainbow
Hydrogen is the most common element in the universe but is rarely found as a gas on Earth. So it’s produced from compounds that contain hydrogen. Most hydrogen is produced through steam methane reforming, which removes hydrogen from natural gas. It’s also produced through electrolysis, which splits water molecules into two hydrogen atoms and one oxygen atom.
Green hydrogen is produced through electrolysis using power that comes from renewable sources like hydro, wind, and solar power. An offshoot is pink hydrogen, which is produced using nuclear power.
Nearly all of the hydrogen produced in North America today is what’s known as gray hydrogen that comes from steam methane reforming or coal gasification. This hydrogen is considered “dirty” because it’s produced from fossil fuel while also using fossil fuel as an energy source in the production process.
A variation is blue hydrogen, which captures and stores the carbon produced through steam methane reforming or coal gasification.
Why does all this matter? Because the true carbon footprint of any fuel needs to be measured from well to wheel — in other words, the entire production cycle from its source, refining, and distribution to its use as a fuel in a locomotive.
“Our mindset is that we don’t need to wait for green hydrogen to arrive,” Moslener says. “We can start now and benefit from the natural greening of hydrogen as time goes on.”
This progression, he says, would be much like what has happened to battery electric vehicles in recent years. As the electrical grid has become greener as coal-fired generation has declined and wind and solar power have increased, the overall environmental footprint of battery electric cars has improved.
Modal Shift
Moslener says that if you want to decarbonize rail, reduce and ultimately eliminate emissions from locomotives. If you really want to decarbonize transportation, move truckloads to rail. “The real decarbonization play after alternative fuels is modal shift,” he says. “That’s how we’re going to decarbonize North America.”
The transition away from the diesel-electric is likely to cost in the hundreds of millions of dollars when the required infrastructure is included. “It’s going to be very expensive,” Moslener says.
“We’ve got a global crisis on our hands now. To me it’s not about cost,” Moslener says, noting that the first generation to feel the impact of climate change is the last generation that can do something about it.
“We have a moral obligation to invest in this space now. It will be too late tomorrow. Yes, it will be costly, but we have to bite the bullet and do it now,” Moslener says.
