Hydrogen Fuels in UK Transport: Comparing Fuel Cells and Combustion Engines
Hydrogen Fuel Cells (HFCs)
Hydrogen fuel cells convert the chemical energy of hydrogen directly into electrical energy through an electrochemical reaction. This process is similar to how a battery works, but it doesn’t need recharging. HFCs mix pressurized hydrogen gas with oxygen to generate electricity, which powers an electric drivetrain. The only byproducts are heat and pure water vapor.
Benefits of HFCs for UK Transport:
- High Efficiency: HFC vehicles achieve impressive energy efficiency, typically between 40-60%. This is notably higher than H2-ICEs (20-30%) and traditional internal combustion engines (30-40%). This makes HFCs especially suitable for larger vehicles needing high fuel efficiency for long distances and heavy loads, like HGVs, buses, and marine applications.
- Zero Tailpipe Emissions: HFC vehicles are virtually emission-free during operation, releasing only water vapor. This makes them more environmentally friendly than H2-ICEs, which can emit nitrogen oxides—a greenhouse gas—during combustion.
- Fast Refueling: HFC vehicles can be refueled quickly, similar to conventional petrol or diesel vehicles, typically taking 10-15 minutes. This is a major advantage for long-haul trucking and high-utilization fleets, where minimizing downtime is essential.
- Long Range: HFC vehicles offer considerable driving ranges. Some fuel cell trucks are expected to reach 600 to 1,000 miles per tank, matching or exceeding the range of traditional diesel trucks.
- High Energy-to-Weight Ratio: Fuel cells provide a high energy-to-weight ratio compared to batteries, which add significant weight and require longer recharge times. This makes HFCs ideal for heavy loads over long distances.
Challenges of HFCs for UK Transport:
- Infrastructure: The growth of HFC vehicles has been slowed by a lack of public refueling stations in the UK. Currently, there are only about 15 hydrogen refueling stations, which complicates operations for fleets without their own facilities.
- Cost: Raw hydrogen gas and the HFC vehicles themselves can be pricey. However, costs are expected to drop with more investments and larger-scale production.
- Efficiency vs. BEVs: While HFCs are more efficient than combustion engines, they fall short of lithium-ion battery electric vehicles (BEVs), which can achieve nearly 80% efficiency.
Hydrogen Internal Combustion Engines (H2-ICEs)
Hydrogen internal combustion engines are modified conventional engines that burn hydrogen fuel like gasoline is used in traditional engines. They are very similar to spark-ignition engines but use hydrogen instead of fossil fuels.
Benefits of H2-ICEs for UK Transport:
- Familiar Technology: H2-ICEs use existing internal combustion engine technology. This might allow a quicker transition to hydrogen for fleets since they are more familiar and less disruptive than completely new HFC systems.
- Power and Torque: H2-ICE trucks can provide diesel-like power and torque while producing near-zero emissions.
- Complementary Use Cases: H2-ICEs tend to be most efficient under high load conditions. Many believe both HFC and H2-ICE technologies will be necessary to reduce carbon emissions in commercial transport, offering a strong balance of power, flexibility, and range.
Challenges of H2-ICEs for UK Transport:
- Lower Efficiency: H2-ICEs are much less efficient than HFCs, typically achieving only 20-30% efficiency. This leads to higher fuel costs because of their lower overall efficiency.
- Emissions: Even though they use a zero-carbon fuel, H2-ICEs can still produce emissions like nitrogen oxides (NOx) due to combustion, making them less eco-friendly than HFCs in terms of tailpipe emissions.
- Limited Investment: Due to their lower efficiency and potential emissions, investment and research are mainly focused on HFC technology rather than H2-ICE technology for future hydrogen vehicles.
The Future of Hydrogen Fuels in UK Transport
There is a general agreement that hydrogen fuel cell technology is likely to receive more investment and broader use for future hydrogen vehicles in the UK, mainly because of its higher efficiency and lack of harmful emissions. For heavy-duty applications, like long-haul trucking and buses, HFCs are seen as a key component for creating fossil-free transportation systems because of their high energy-to-weight ratio, long range, and quick refueling.
However, some experts think that H2-ICEs could act as a complementary or transitional technology, especially for certain commercial transport applications, as regulations on greenhouse gas emissions get stricter worldwide. Ultimately, both technologies work towards the goal of achieving net-zero greenhouse gas emissions in the transport sector.
For more information on UK government hydrogen initiatives, see the official government announcement on hydrogen transport and learn about hydrogen technology from the Institution of Gas Engineers and Managers.
Hydrogen Energy Case Studies & Resources
Explore these real-world applications and strategic documents about hydrogen technology:
Hydrogen Refuelling Case Studies
Fuel Cell Systems showcases practical implementations of hydrogen refuelling solutions across various industries.
Source: Fuel Cell Systems UKTees Valley Hydrogen Transport Project
A case study on hydrogen-powered transport initiatives in the Tees Valley region of the UK.
Source: CenexHydrogen-Powered HGV Innovation
Case study about an innovative hydrogen-powered heavy goods vehicle developed in Glasgow.
Source: Glasgow City of Science & InnovationUK Hydrogen Strategy
The official UK government publication outlining the national strategy for hydrogen energy development.
Source: UK GovernmentNote: These links are external resources and will take you to third-party websites.