Hydrogen fuel cells and
combustion engines

 

Green hydrogen is a potential paradigm shifter that can play a major role alongside battery electrification and other renewable fuels in creating the carbon-neutral societies of tomorrow. Learn about our approach to using green hydrogen in a range of new propulsion systems currently in testing.

Green hydrogen as fuel at Volvo Group

Fuel cell and engine technologies that are practical for use in commercial transport systems and infrastructure are now accelerating, and we anticipate the roll out of hydrogen production and refueling infrastructure to speed up in the coming years. Hydrogen fuel cells and engines used in commercial vehicles and machines will be an essential element for the future of transportation and infrastructure. Hydrogen fuel cells represents a clear focus for us alongside battery electric vehicles and renewable fuels (such as green hydrogen, bigoas and HVO) in the combustion engine. This is what we call our three-pronged approach to decarbonization.

Hydrogen fuel cells

Fuel cell electric vehicles (FCEVs)

Fuel cell electric vehicles (FCEVs) use a hydrogen fuel cell to power an electric motor. Instead of storing energy in a battery, FCEVs store hydrogen gas in tanks and convert the gas into electricity using a fuel cell and a smaller battery for energy recovery and acceleration support. This process is efficient and clean, with water vapor being the only emission. FCEVs can be refueled quickly, much like conventional vehicles, and offer a longer range than most battery electric vehicles (BEVs).

Efficiency of hydrogen fuel cells

Hydrogen fuel cells are an efficient power source for trucks, construction equipment buses and industrial or marine applications, as they benefit from a high energy-to-weight ratio. Unlike batteries, which add weight and require longer recharge times, fuel cells can power heavy loads over longer distances and be refueled quickly. This efficiency is a major advantage for long haul trucking, where minimizing downtime is crucial.

Hydrogen fuel cells and trucks

At Volvo Group we see hydrogen fuel cells as one of the key enablers of fossil-free transportation systems, supporting our transition to net-zero greenhouse gas emissions. Through the use of hydrogen in both fuel cell and combustion applications, we believe that we can offer a competitive long-term balance of power, flexibility, and range, with the benefit of zero emissions.Both hydrogen fuel cell technology and hydrogen powered combustion engines will be needed to decarbonize commerci al transports.

How do hydrogen fuel cells work?

Hydrogen fuel cells generate electricity through a chemical reaction between hydrogen and oxygen. In a fuel cell, hydrogen gas is fed into the anode where a catalyst causes the hydrogen molecules to split into protons and electrons. The protons pass directly through a membrane to form water, which is the only by-product in this process. The electrons create a separate current that can be used before they return to the cathode to be recombined with oxygen and protons.

Off-road, marine and industrial applications

We see hydrogen fuel cells as one vital element in powering construction equipment, like our articulated hauler HX04 prototype and other such applications in the coming years. As with hydrogen fuel cell powered trucks, such applications will also rely on the availability of local or onsite hydrogen generation and refueling infrastructure.

Building fuel cells in our joint venture - cellcentric

cellcentric is a 50:50 joint venture between Volvo Group and Daimler Truck AG. cellcentric takes advantage of the experience gathered over several decades of development work on fuel cells within its owner companies. cellcentric’s ambition is to become a leading global manufacturer of fuel cells, and thus help the world take a major step towards climate-neutral and sustainable transportation by 2050. It will achieve this by developing, producing, and commercializing fuel cell systems for use in heavy-duty trucks, and other applications.

 

Learn more about cellcentric

 

The fuel for tomorrow

Green hydrogen: important as a fuel of the future

Hydrogen is important for the future because it can be a versatile, clean, and abundant energy carrier. It can store surplus renewable energy and release it when needed, easing a shift to more sustainable energy systems. Hydrogen can decarbonize sectors where direct electrification is challenging, like heavy industry and long haul transport, and contribute to energy security.

 

Hydrogen cells now versus tomorrow

Currently, hydrogen cells are used in various niche markets, but their use is expected to grow significantly in the coming years. They will become more cost-effective as production scales up and the technology becomes mature. Future hydrogen cells are expected to be more efficient and affordable.

 

What needs to be done to make the shift possible.

To shift to hydrogen on a large scale, investments in production, storage, and distribution infrastructure are needed. Developing cost-effective methods for producing green hydrogen from renewable sources is crucial. Additionally, governments and industries must collaborate to create incentives and regulations that encourage the adoption of hydrogen technologies.

Hydrogen fuel cells - Frequently Asked Questions

Hydrogen is used as a fuel for vehicles, in chemical production, and as an energy storage medium. In vehicles, it powers fuel cells for electric trucks, buses, construction equipment and cars. It's also used in industrial processes, such as oil refining and ammonia production, and can store excess energy from renewable sources.

A hydrogen fuel cell works by passing hydrogen through the anode, where it is split into electrons and protons. The electrons flow through an external circuit to produce electricity, while the protons move through a membrane to the cathode. At the cathode, electrons, protons, and oxygen from the air combine to form water.

Hydrogen fuel cells are more efficient than traditional internal combustion engines because they convert chemical energy directly into electrical energy, reducing energy loss from heat. They also emit only water vapor, while traditional engines run on fossil fuels emit greenhouse gases and pollutants.

Hydrogen-powered vehicles can be sustainable, especially when hydrogen is produced from renewable sources. They offer a high-energy, low-emission alternative to fossil fuels. However, sustainability depends on the entire lifecycle of the vehicle, including production, operation, and disposal.

As the use of hydrogen in the transport and infrastructure industry accelerates its availability for use in combustion engines and for fuel cells will become more common. We foresee that many of today’s fuel stations will begin to offer hydrogen and hydrogen production facilities will increase in number to support this. Alternatively, some businesses may invest in on-site hydrogen production and refueling capabilities, especially in fleet operations.

 

Advantages of using hydrogen fuel cells

Hydrogen as an automotive fuel

Hydrogen is a high-energy, zero-emission fuel choice for vehicles. When used in fuel cells, it produces electricity to power an electric motor. It's suitable for larger vehicles where battery weight could be prohibitive. Hydrogen fuel is also appealing because it can be produced from various domestic resources, potentially reducing dependence on imported oil.

Hydrogen versus traditional fuels

Hydrogen offers several advantages over traditional fossil fuels. It can be produced from water, making it almost inexhaustible. Hydrogen combustion is clean, with water being the only byproduct, compared to the CO2 and other harmful emissions from gasoline or diesel. The main challenge for hydrogen is the current lack of infrastructure for distribution and refueling compared to established oil networks.

Environmental
benefits

The primary environmental benefit of using hydrogen fuel cells in trucks is the significant reduction in harmful emissions. Fuel cells emit no pollutants—only water vapor and heat. This can contribute to improved air quality and a reduction in the transportation sector's impact on climate change.

Long haul trucking solutions

For long haul trucking, hydrogen fuel cells offer a solution that could balance range, weight, and refueling time. They can supply a similar range to diesel trucks and can be refueled in a comparable timeframe. This means that trucks can spend more time on the road and less time at charging stations, which is crucial for the economics of freight transportation.

Explore the colors of hydrogen and what they mean

Understanding hydrogen

Hydrogen is an energy carrier with qualities that can help reduce the net sum of greenhouse gas emissions by reducing reliance on fossil fuels, while keeping some of their innate benefits, such as fast-refueling capabilities.

Hydrogen itself is a colorless gas but there are around nine color codes that explain the source, or process used to make it. You can read more about this here.

Hydrogen combustion engines

 

Understanding hydrogen combustion engines

Hydrogen combustion engines work by burning hydrogen in a conventional internal combustion engine, changed to manage the high-speed combustion of hydrogen. They run on similar principles as diesel engines but require specific technologies, such as specialized fuel injectors and ignition systems. These help to manage the distinct characteristics of hydrogen. We believe that hydrogen combustion engines have the potential to offer a competitive total cost of ownership and could prove a great complement to other propulsion technologies.

Hydrogen combustion technology

In July 2023, Volvo Group and Westport Fuel Systems signed a letter of intent to establish a joint venture for high-pressure gas injection fuel systems (HPDI) for long haul and off-road applications. 

 

HPDI enables the world's trucking and off-road equipment manufacturers to address the challenges of meeting the regulatory requirements of Euro 7 and the US EPA while offering end users affordable options that are powered by carbon neutral fuels like biogas, zero carbon fuels like green hydrogen and other renewable fuels. The HPDI fuel system consists of a fully integrated "tank to injector" solution, based on diesel technology.

 

At the heart of the engine is a revolutionary patented injector with a dual concentric needle design. A small amount of pilot fuel (which can be HVO, or diesel fuel) is injected into the cylinder prior to the gas, to initiate the ignition resulting in a reduction of almost 97% of CO2 emissions, and only a small amount of NOx and particles, in-line with the existing Euro 6 and proposed Euro 7 emission regulations.

 

We see hydrogen combustion engines as eminently suitable for long haul applications where there is limited access to, or time for, recharging, and refueling options are limited.

 

Hydrogen combustion technology is a key element in the ongoing transition to net zero emissions that will support our customers' journey and investments in reducing their carbon footprint. 

Hydrogen dual engine from Volvo Penta

As with both transport and construction, hydrogen as a fuel for industrial and marine applications makes perfect sense. In this case we are talking about a dual-fuel solution which increases flexibility and helps to make today’s combustion engines hydrogen-ready in advance of the rollout of hydrogen production and refueling facilities. This same technique of using hydrogen as a combustion engine fuel will offer further options as the transition to fossil-free fuels continues.

 

The benefits of hydrogen combustion engines

Hydrogen combustion versus fuel cell technology

While both technologies use hydrogen, they do so differently. Hydrogen combustion engines burn hydrogen, producing power through combustion, like conventional engines. Fuel cells, on the other hand, use a chemical process to convert hydrogen into electricity.

How hydrogen combustion engines work

In a hydrogen combustion engine, hydrogen is mixed with air and a pilot fuel (biodiesel for example) and ignited in the combustion chamber, causing an explosion that drives the pistons. These engines must manage the quick flame speeds and high temperatures of hydrogen combustion, which are achieved through advanced engine design, fuel injection technology and hydrogen-friendly materials.

 

Emissions and efficiency

If the pilot fuel used to ignite the hydrogen is CO2-neutral, hydrogen combustion engines produce no CO2 emissions, as there's no carbon in hydrogen. The primary emission is water vapor, with some NOx emissions due to high combustion temperatures. These engines can be more efficient than gasoline engines but less so than hydrogen fuel cells. However, they can use much of the current engine technology and refueling infrastructure, making them an attractive choice.

Together, we can shape the world we want to live in

Explore our broad circle of partners and collaborations, aimed at driving decarbonization across the transportation, infrastruture, mobility industry and beyond.

Commercializing green hydrogen:
the challenges and opportunities

Clearer energy policies and cross-sector collaboration

Many countries around the world now have ambitious hydrogen strategies and hydrogen plays an essential role in the EU Green Deal. There is a great willingness to engage in cross-sector hydrogen usage and the industries are actively looking for potential synergies with, for example, trucks and construction equipment hydrogen usage.

However, there is a need for a certificate of origin system for hydrogen. This to be able to trace that climate friendly hydrogen has been used and thereby resulting in fulfillment of low emission. This can be used as a basis for the level of taxation. Volvo Group would encourage a CO2 declaration on hydrogen rather than talking about colors.

Development of infrastructure to support the transition

National and local governments, the industry, and investors will need to band together to develop the necessary infrastructure to support the energy transition to Green hydrogen and make it commercially viable. There are several hurdles we need to cross, for example the lack of infrastructure and hydrogen prices for end-users.

The biggest problem today is that new offtakes (users) are not yet present. There is a huge willingness to invest, but not without the assurance of customers. Trucks are seen as a practical level to practice upon before going really big scale, such as the cement industry.

Governments and industries need to work together

Governments and industries need to work together to ensure that both existing and new regulations won’t impede investment in Green hydrogen. The trade of hydrogen will benefit from a common international standard for both transporting and storing large quantities, and for tracking the environmental impacts different hydrogen supplies might have.

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