Hydrogen internal combustion engines look like diesel engines, run like diesel engines, take only minutes to refuel and have markedly lower emissions, Engine Technology Forum presenters said Wednesday in a webinar.
"We find ourselves in the midst of an energy transition," says Allen Schaeffer, executive director of the forum, which also released a white paper along with the webinar, Opportunities for Hydrogen-Fueled Internal Combustion Engines H2-ICE.
That's not news to anyone. What may be news is that hydrogen engines aren't all that new and ones that can run the trucks of tomorrow sustainably aren't that far away. One of the earliest engines designed, way back in 1807, ran on hydrogen, the report says. Jim Nebergall, executive director, EBU market strategy at Cummins, says the company may have scaled production as early as 2028.
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In addition to hydrogen internal combustion engines (ICE), Cummins is also working toward battery electric and fuel cell electric vehicles. That's because each powertrain has its own applications.
"It will not be one single solution," Nebergall stressed.
Dimitri Konson, vice president of engineering for Tenneco Clean Air, broke it down.
Battery-electric vehicles are good for moderate power and range, especially in an urban environment, and for applications that allow the truck to stop for long periods to charge. Fuel cell electric vehicles are preferred for long-distance vehicles with medium power requirements, such as coaches. Hydrogen ICE works well in high-power applications, including off-road vehicles and long-haul trucking.
H2-ICE Similar to Diesel
Nebergall says Cummins views each powertrain solution as complimentary. But for long-haul, heavy-duty commercial vehicles, internal combustion hydrogen is an attractive choice. He says it's carbon-zero from well to wheel, and end users like it because it's most like the diesel engines they know. It's also easy to service, with very little training and no special tools needed.
"We know how to make engines run on this fuel," Nebergall says. Plus, Konson says, it's reliable and, most importantly, clean.
Hydrogen internal combustion engines meet the 2027 emissions regulations in the U.S. and, in Europe, could even receive a zero-emission vehicle certification. Like diesel trucks, much depends on the aftertreatment.
Aftertreatment on a H2-ICE truck would work similar to a diesel truck with a notable difference. There's no carbon in hydrogen fuel, meaning there are no hydrocarbons, no carbon dioxide and no soot particulate emissions. There's also lower nitric oxide (NOx) than in diesel exhaust. This means, the report concludes, aftertreatment systems can be more simple than those in diesel trucks.
"Hydrogen itself does not have any nitrogen to produce NOx," Konson says. "The only nitrogen that appears in the exhaust is from the air that is part of the production process."
Louise Arnold, product line director for Johnson Matthey, a specialty chemicals company, says the similarities to diesel aftertreatment could mean a boost in total cost of ownership for H2-ICE trucks because the systems to build, run and service these systems already exist.
"We will have an aftertreatment system similar to many of the systems that are on the road today," she says.
Fueling Challenge
While Nebergall says Cummins H2-ICE tech could be produced at scale globally as early as 2028, there is a significant challenge in the lack of fueling infrastructure.
"It seems the biggest challenge is to make that fuel available," Schaeffer says.
There is investment in the pipeline to fix that problem, the white paper says. More than $300 billion has been invested in low-emission hydrogen production, including renewable forms of fuel. Ivan Tate, head of the techincal centre at FPT Industrial, says his company envisions a future where farmers can produce their own renewable hydrogen for their equipment.
There are different types of hydrogen fuels, named by color:
- Green hydrogen is produced through electrolysis by renewable energy or other processes that involve no net greenhouse gas emissions. It is the most expensive way to produce hydrogen.
- Yellow hydrogen is produced from grid electricity through electrolysis.
- Blue hydrogen is produced by using a stream-reforming process to pull hydrogen from natural gas with carbon dioxide captured and sequestered. It can be a low or even zero-carbon process. This is one of the most common production methods.
- Gray hydrogen is similar to blue hydrogen, but without capturing and sequestering the carbon.
- Pink hydrogen is produced from nuclear energy through electrolysis.
- Turquoise hydrogen is produced by methane electrolysis, a process which also creates solid carbon.
- Brown or black hydrogen is produced from gassified coal through a steam reforming process. It's the least expensive way to make hydrogen, but also the least environmentally friendly.
Unlike hydrogen fuel cells, Wednesday's panelists say H2-ICEs aren't as sensitive to the impurities in the fuel.
"Because it's combustion, it's inherently more tolerant," Nebergall says.
On the truck, fuel tanks would look similar to a natural gas truck, he says, adding that he hopes the extra weight would qualify for Department of Transportation allowances similar to modifications for other alternative fuels, meaning that even with the extra weight, the truck can carry the same cargo.
Ultimately, things such as fueling infrastructures are so large that it can only be funded by government choices, Arnold says, no matter where you live.
"We've got to talk to our leadership and actually have that conversation," she says. "There's going to be a need for a portfolio of solutions."