The Promising Future of Hydrogen Combustion Engines

Transportation still largely relies on gasoline and diesel engines. Burning fossil fuels releases carbon dioxide and other greenhouse gases, slowing the world’s progress toward carbon neutrality.

However, fleet transformation is a costly and complex project, which can deter transportation and logistics providers from taking the plunge.

A practical bridge is the hydrogen internal combustion engine, or H2ICE for short. These propulsion systems follow the same mechanical blueprint as their predecessors, meaning less retraining for mechanics and operators.

By swapping fossil fuels for hydrogen, the switch slashes nearly all tailpipe carbon and most nitrogen oxide (NOx) emissions.

Transport industry leaders have already proven the concept. In March 2025, Cummins validated a 6.7-liter hydrogen ICE (a sister-engine to its 15-liter model) that cuts carbon by more than 99 percent compared to its diesel counterparts.

Cummins’ breakthroughs are just some of many showing that hydrogen ICEs can clean up today’s fleets without wholesale vehicle replacement.

What Is a Hydrogen Internal Combustion Engine?

Internal combustion engines work by burning fuel inside cylinders, propelling the pistons up and down. The pistons, in turn, power a crankshaft that converts the energy generated into forward motion.

A hydrogen combustion engine looks, functions, and performs like the gasoline or diesel models technicians already service. The biggest difference is the fuel: cylinders burn gaseous hydrogen instead of liquid fossil fuels.

What stays the same

• H2ICEs can support the same block, pistons, crankshaft, and mounting points—exemplified by Cummins’ new line
• Refueling takes minutes, comparable to gas, diesel, and fast-fill CNG.
• Familiar service tools and maintenance routines

What changes

• A pressurized tank replaces liquid fuel storage
• Reinforced valves to handle the hotter, drier burn
• Specialized seals, sensors, and ventilation to prevent and clear hydrogen leakage

Swapping fuel instead of hardware lets fleets decarbonize quickly without retraining every mechanic or redesigning every chassis.

Today, you’ll already find heavy-duty hydrogen ICE trucks cruising the highways and delivering goods. These vehicles are driving broader interest in H2ICE as a clean and efficient alternative.

3 Benefits of Hydrogen Internal Combustion Engines

H2ICEs are gaining traction because they hold considerable promise. There are several benefits of switching from standard ICE vehicles to H2ICE-powered ones.

1. Lower Emissions (Decarbonization)

Perhaps most importantly, H2ICEs emit far fewer emissions than the standard ICE. Fossil fuel emissions include:

• Carbon dioxide (CO2)
• Carbon monoxide (CO)
• Methane (CH4)
• Fluorinated gases

While H2ICE vehicles produce some emissions (notably trace amounts of nitrogen oxides, or NOx), they don’t release any of the above gases. Burned hydrogen mainly emits water vapor. As a result, H2ICEs are far cleaner.

Hydrogen fuel has other benefits, too. Because it can be produced domestically, switching to H2ICE means less reliance on the heavy-emission process of oil and gas welling, refining, and shipping.

2. Familiarity

H2ICE's familiar technology makes it broadly accessible. The close mechanical similarities all but eliminate the learning curve for maintenance personnel. This similarity offers a cost-effective middle ground without the retraining costs of switching to hydrogen fuel cells.

3. Fuel Efficiency

Modern hydrogen engines deliver diesel-like torque, performance, and range. These features are critical for logistics providers operating under tight cost and time constraints. Early tests clock thermal efficiency above 45 percent, matching elite diesel engines while delivering far cleaner exhaust.

What Are the Challenges of Hydrogen Engines?

Although hydrogen combustion engines have undeniable advantages over standard ICEs, they’ve yet to be fully embraced by regulators, the automotive industry, and the public. Here’s why:

Cost

As always, money is a driving factor. Hydrogen fuel remains relatively expensive when compared to:

• Gasoline
• Diesel
• Natural gas

Though this trend varies regionally based on local variability, California reports prices of $12–$15 per kilogram, about three times diesel’s energy-equivalent cost.

The U.S. Department of Energy established goals to close that gap to $2/kg by 2026 and $1/kg by 2031—but those targets depend on larger plants, cheaper renewables, and streamlined delivery networks. Until hydrogen becomes economically competitive with the existing options, fleets are unlikely to adopt it as their main fuel source.

Luckily, cost reductions are coming. The hydrogen economy is still in the early stages of its development, yet major hydrogen projects are in progress around the world. As these projects come to fruition, greater availability and industry competition will drop hydrogen prices faster than ever.

Public Perception

Most drivers and policymakers still confuse hydrogen with exotic rockets or fuel cells, unaware that a hydrogen combustion engine is a viable option. Because many people haven’t seen it in action, this unfamiliarity remains a hurdle. Unfamiliarity can even breed fear, even though hydrogen safety is well understood.

Demonstrations and public awareness campaigns can close this information gap and speed adoption.

Promising Developments in Hydrogen Engine Design

As mentioned, H2ICEs are already on the road, specifically heavy-duty vehicles that are difficult to electrify. These trucks run on early versions of H2ICE technology. One exciting development is the recent use of hydrogen in an opposed-piston engine. These engines are simple yet powerful, making them an ideal replacement for traditional ICEs.

Notably, fueling access remains thin compared with diesel. A 2025 survey counted roughly 1,160 public hydrogen stations worldwide—most in Asia and Europe—with only 89 operating in the United States, and most of those clustered in California.

Until more clean fuel corridors open, long-haul fleets must plan around these hubs or establish their own supply lines.

FASTECH: Powering Hydrogen ICEs

As more developments become clear, H2ICE vehicles are on track to become a serious asset for heavy-duty and public transport.

That’s why we’re building renewable energy resilience, expanding hydrogen infrastructure one project at a time.

Get in touch with our EPC+M experts to learn more.