Who Says a Hydrogen Car Should Be Silent?
In a previous article from December 2024, I laid out my position on electric vehicles (EVs), specifically arguing that fuel-cell-based hydrogen vehicles will ultimately be the final solution for human mobility, and that current battery-based EVs are merely a temporary, intermediate step.
After a few months, the landscape has shifted rapidly as technology in this business segment runs at full speed.
The Hydrogen Status Quo: Fuel Cells
Up until now, the term "hydrogen car" has been synonymous with a fuel-cell-based vehicle. A fuel cell is a device that converts high-pressure hydrogen gas (H₂) and oxygen from the air into electricity, powering an electric motor.
Toyota, the world’s largest car manufacturer by volume of vehicles sold, has been a major investor in this technology since the early 2010s.
The first-generation Toyota Mirai was available to consumers in Japan in 2014 and the US in 2015.
The second-generation Mirai (2021 model) achieved an impressive range of 1,360 km (845 miles).
This approach was also applied to public transit with the Toyota Sora bus.
Toyota Mirai
Toyota Sora Bus
A Roaring New Option: The Liquid Hydrogen Combustion Engine
The biggest news is Toyota's recent announcement of a fundamentally different kind of hydrogen engine: a liquid hydrogen-based combustion engine.
This engine operates much like the tried and true gasoline engine.
Liquid H₂ is converted to gas and then burned in a combustion chamber. This process is the same as a traditional engine: the fuel-air mix is compressed by a piston and ignited by a spark, causing an explosion that pushes the piston back and generates power.
Crucially, the only by-product of this combustion is steam instead of carbon dioxide (CO₂), which is well known to be the main culprit in the world’s current environmental challenges.
So, what are the key advantages of this new combustion option?
| Feature | Hydrogen Combustion Engine | Traditional EV / H₂ Fuel Cell |
|---|---|---|
| Emissions | Environmentally friendly (steam) | Environmentally friendly (zero tailpipe) |
| Battery Needs | Small, non-critical battery | Huge, heavy, costly battery (EV) |
| Refueling Time | Very fast (3-5 minutes) | Slow (30-60 mins minimum, EV) |
| Sound | It roars! (Appeal for sport car lovers) | Silent |
| Power/Range | Same or higher power; higher range | Dependent on battery/tank size |
| Fuel Density | Liquid H₂ is denser (smaller tanks for same range) | High pressure gas H₂ is less dense |
| Infrastructure | Leverages legacy engine manufacturing | Requires new manufacturing lines |
The use of liquid hydrogen introduces further logistical benefits, such as easier long-distance transport via specialized industrial trucks already in use.
The Challenges of Hydrogen Technology
Despite these breakthroughs, both the fuel-cell and combustion hydrogen options share core problems that need to be addressed:
High Production Cost: The current process for hydrogen production, electrolysis, is energy-intensive and often uses electricity generated by fossil fuels. The future depends on moving toward Green Hydrogen, where electricity comes from wind or solar energy, dramatically reducing costs and environmental impact.
Lack of Refueling Infrastructure: Hydrogen refueling stations are still scarce. While progress is being made—Germany already has 100 active stations, and Japan aims to have its infrastructure ready by 2030—deployment is slow. Building a high-capacity H₂ station is costly, ranging from $500,000 to $1,000,000 USD, compared to just $10,000 to $15,000 for an EV charging station.
The liquid hydrogen approach also has a few unique engineering challenges:
Temperature Requirements: Keeping H₂ in liquid form requires extremely low temperatures. We’re talking an insane 20.28 K (−252.87 °C; −423.17 °F)
Durability: Mechanical parts exposed to the liquid hydrogen, such as the pump, experience reduced durability due to these cryogenic working conditions.
Weight: Liquid H₂ is heavier than high-pressure gas, which can increase the overall weight of the vehicle, potentially decreasing mileage as well as potentially posing issues with existing road infrastructure which have been created with the average weight of current vehicles in mind.
The Consumer Cost Gap
While hydrogen vehicles offer superior refueling speed and range, they currently do lose the battle on consumer cost per mile.
Depending on the region and the retail price of hydrogen (which can range from $14 to $36 per kilogram), the fueling cost for a hydrogen car is currently between three and four times higher than a comparable EV, often placing it on par with, or even exceeding, the cost of gasoline. For the hydrogen solution to become truly competitive for private consumers, the cost of Green Hydrogen production must drop drastically, and the retail price must follow suit.
Hydrogen vs. Battery EV: Key Differences in Operation
Some of you might be looking at all of the cons involved in the creation and operation of Hydrogen-based engines that I’ve listed and are confused as to why I still insist that they’re a more feasible option in the future of green transportation.
“EV vehicles are so widespread!” you might be thinking. We have a solid, dependable manufacturing and deployment structure now that has proven successful. Goodness, in 2024 alone, 20% (17 million) of all new cars purchased in the whole world were electric!
That is absolutely true, and a great thing to see. However, the main challenges of the battery-based EV solution—range and recharge time—are where hydrogen truly shines.
| Comparison Point | H₂ Vehicle (Fuel Cell or Combustion) | Battery-Based EV |
|---|---|---|
| Fueling Cost | Currently 3x to 4x higher cost per mile than EV. | Least expensive cost per mile, especially with home charging. |
| Range | A longer range means only a larger, empty tank. Performance is unaffected by tank age or driving conditions. | Range is proportional to battery capacity. Requires a larger/heavier battery for more range. Performance is affected by battery age, traffic, and road conditions. |
| Refuel/Recharge Time | 3-5 minutes at the pump. | 30-60 minutes minimum (supercharging) or much longer (home charging). |
| Battery Replacement | Small, non-critical battery replacement is cheap and infrequent. | Battery replacement (after 6-7 years on average) is a costly, complex operation. |
Furthermore, the H₂ combustion engine can leverage the existing global manufacturing infrastructure, utilizing the core structure of legacy engines (cylinders, pistons, etc.). This could provide a smoother, more cost-effective transition for the automotive industry worldwide.
The Road Ahead: A Pragmatic Revolution
The emergence of the liquid hydrogen combustion engine is not just an engineering footnote; it is a powerful strategic counter-move that validates the notion that global mobility requires diverse solutions. Toyota and others (like Hyundai with its Nexo) are correctly recognizing that there is no single, ideological path to a decarbonized future.
The future of mobility is a flexible, multi-pronged approach:
EVs for urban commuters with stable grids.
Hybrids for transitional markets and areas with weak infrastructure.
Hydrogen for long-haul commercial fleets, public transit, and high-performance vehicles where fast refueling and long range are non-negotiable.
GR Corolla: 1600cc - 3 cylinders / 261 HP
The H₂ combustion engine, in particular, acts as a pivotal disruptor. It marries the emotional appeal of the internal combustion engine (the roar) with a zero-carbon footprint, while simultaneously allowing the global automotive industry to leverage billions of dollars in existing engine manufacturing infrastructure and expertise. This minimizes the industrial pain points of the transition.
Toyota’s new engine is not yet ready for mass production, but it’s moving beyond the prototype phase and it’s being actively road-tested in racing cars like the GR Corolla and GR Yaris.
Ultimately, the battle for sustainable transport will not be won on the factory floor but at the pump. The technology is here, offering unprecedented range, speed, and logistical advantages over heavy battery packs. The true challenge now lies in the rapid deployment of refueling infrastructure and the massive scale-up of Green Hydrogen production. If industry and government can solve the cost and infrastructure equations, the migration from fossil fuels will transform from an expensive inconvenience into a powerful, reliable, and yes—even audible—revolution.