Hydrogen motorcycles: MCN's guide to the different types and how they work

Hydrogen is often suggested as an alternative fuel source when the future of motorcycling is discussed. It’s easy to see why, hydrogen is an abundant and clean source of energy and has been on the radar of the automotive industry for decades.

And with governments around the world searching for an alternative to petrol and diesel engines, hydrogen tech is once again in the spotlight.

But what is hydrogen power, how does it work and will it power the next generation of motorcycles? Read on to find out.

Combustion or fuel cell tech?

There is sometimes confusion surrounding hydrogen technology when it comes to motorbikes. Many hail hydrogen as a more palatable alternative to electric, but many hydrogen concepts and prototypes are actually EVs.

This is because, unlike good old-fashioned petrol, there are two ways of using hydrogen to achieve propulsion. Internal combustions engines can be designed or adapted to run it in place of fossil fuels or – more commonly – the gas is used in place of batteries to generate electricity and power a motor.

Hydrogen fuel cell motorbikes

Like a battery, a hydrogen fuel cell has two electrodes – a negative anode and a positive cathode – with an electrolyte membrane between them. But instead of storing energy, like a battery, and hence needing to be recharged, a fuel cell converts fuel, in this case hydrogen, into electricity by reacting with oxygen from the air.

Hydrogen is pumped into the anode, air is blown into the cathode. In the anode, a catalyst splits the hydrogen molecules into electrons and protons. The electrolyte membrane allows the protons straight through to the cathode, but not the electrons, which have to go through the electric circuit to reach the cathode, creating a current.

In the cathode, the oxygen and the hydrogen protons and electrons combine to become the exhaust, which is pure H2O. That’s right, water.

The major drawback with hydrogen is that, as a gas, it requires too much space on board the vehicle to be practical. But fuel cell vehicles use highly pressurised gas molecules of between 5000 and 10,000psi, which demand less space, but make refuelling potentially more difficult.

To get around that problem, car giants Toyota developed cylindrical cartridges that can be swapped once empty and remove part of the problem back in 2022.

The prototype is a cylinder, 40cm tall and 18cm in diameter, weighing in at 5kg when full. When development is complete, a canister is intended to provide 3.3kWh of power. A 3.3kWh li-ion battery would be a similar size but weighs around 25kg more.

Honda announced a partnership with General Motors in February 2023 to build fuel cells for a hydrogen-powered version of the CR-V SUV. The research and development work needed for this four-wheeled application could lead to two-wheeled adaptations down the road, too.

Hydrogen combustion engines

The Big Four Japanese motorcycle brands embarked on a joint hydrogen combustion research project in 2023 to see if they could work around some of the problems with burning hydrogen in engines.

And Kawasaki first unveiled their idea of a hydrogen-based future at the 2022 Eicma trade show in Milan with this variation using the pressurised gas as a replacement for fossil fuels in a supercharged combustion engine based on the Ninja H2.

Ten hydrogen canisters are carried in the prototype’s panniers from where it is directly injected into the cylinders.

And in early 2022, Yamaha have unveiled a V8 hydrogen powered car engine that set the stage for a two-wheeled version in the future, too.

The prototype is based on the 5-litre engine from the Lexus RC F with Yamaha modifying the injectors, cylinder heads, intake manifold and more to create an engine that delivers over 400bhp while firing out little more than water as emissions.

“Hydrogen engines have the potential to be carbon-neutral while keeping our passion for internal combustion alive,” said Yamaha President Hidaka at the time.

Building a hydrogen-powered combustion engine isn’t as simple as injecting hydrogen into a normal petrol design. One of the major changes that must be made is the adoption of direct injection, which involves squirting the fuel straight into the combustion chamber.

As the chamber is pressurised, this is no mean feat with a complex and powerful injection system needed. Kawasaki have already solved that with a petrol direct injection (PDI) version of their H2.

The H2 is well placed to make a hydrogen powered bike, as forced-induction is another important factor. Due to the need for a different fuel/air ratio, hydrogen engines need more air than petrol equivalents – almost three times as much. A supercharged engine achieves this by compressing the air before it’s fed to the cylinders.

Hydrogen filling stations

Another drawback with hydrogen is a lack of refuelling infrastructure, but tech giants Bosch have big plans in place for that issue, too, 4000 filling stations in the works by 2030.

Bosch, which supplies a vast swathe of the motorcycle industry with components – notably electronics and ABS – is already leading the way when it comes to green credentials. The firm became carbon-neutral back in 2020, and already has its own electrolyser to produce green hydrogen at its ‘Industry 4.0’ plant in Homberg, Germany.  

The firm intends to invest nearly 500 million euros into electrolysis by 2030 – by which time it expects the market for electrolyser components to be worth 14 billion euros – and wants to have its hydrogen generation systems on the market by 2025.