Globally, interest in hydrogen as a low-carbon fuel option has been steadily growing. Hydrogen — the most abundant element in the universe — can be produced from readily available domestic resources, such as water electrolysis and biomass. Electrolysis is the process of using an electric current to break down chemical compounds and isolate individual elements. Biomass is any recently living material used for energy production. Hydrogen has a higher energy density per unit weight than any other natural element. 

These qualities — combined with its ability to store energy for extended periods — make hydrogen a promising candidate as a future fuel for passenger cars. Hydrogen fuel cell electric vehicles (FCEV) use compressed hydrogen gas as fuel and produce zero carbon emissions from their exhaust. 

In essence, hydrogen-fueled vehicles are classified as zero-emission vehicles because the conversion of hydrogen to electricity in fuel cells produces only water as a byproduct. This makes them a promising solution for lowering carbon use in the transportation sector, which currently relies on fossil fuels for 90 per cent of its energy needs worldwide. However, despite these advantages, hydrogen-fueled cars remain a rarity in today’s automotive market. 

A 2021 population census revealed that over 80 per cent of Canadians relied on their personal vehicles for their daily commute, while only 14 per cent used sustainable transportation. By the end of 2019, just 7,500 hydrogen cars had been sold globally, compared to over five million battery electric vehicles (BEVs) sold by the end of 2018. This highlights that the shift toward greener transportation has been largely dominated by electric vehicles, with hydrogen-powered vehicles struggling to gain widespread adoption. 

Exploring the drawbacks of hydrogen as a fuel source 

While both BEVs and FCEVs are considered zero-emission vehicles and are powered by electric motors rather than gas engines, they operate fundamentally differently. BEVs use rechargeable batteries to store and supply energy, whereas FCEVs generate electricity by combining hydrogen fuel with oxygen in a fuel cell. 

Although hydrogen, as a molecule, has the potential to leak into the atmosphere and pose flammability concerns, safety is not the primary reason for the limited presence of hydrogen-powered vehicles on the roads. FCEVs are generally considered safe, equipped with advanced leak detection systems and subjected to rigorous testing to prevent mishaps. The main challenge lies in efficiency, as FCEVs are significantly less efficient than BEVs, from power generation to pushing a car forward.

In a BEV, charging and discharging the lithium-ion battery consumes 10 per cent of the battery energy. An additional five per cent is lost in powering the motor, and another five per cent is lost during the transmission of electricity from the source to the recharging station. This results in an overall efficiency of 80 per cent for the BEV. 

However, with a hydrogen fuel cell, the overall efficiency drops to 38 per cent. About 25 per cent of the energy is lost to electrolysis. Another 10 per cent is lost during the transporting of compressed and chilled hydrogen, and an additional five per cent is lost while running the electric motor, similar to BEVs. Finally, the process of converting hydrogen back into electricity is only 60 per cent efficient. For a kilowatt of energy, BEVs can use up to 800 watts, whereas FCEVs can only utilize 380 watts — significantly less than BEVs.

Moreover, the production of 95 per cent of hydrogen currently relies on fossil fuels, making FCEVs an inferior environmental choice. While hydrogen is abundant, it is typically found bound to other elements, such as oxygen to form water. Extracting hydrogen gas for fuel is an energy-intensive process that depends on fossil fuels. 

In the US, most hydrogen is obtained from methane and water in natural gas through steam methane reforming, a process that catalyzes the formation of hydrogen gas from methane. This method can result in significant carbon emissions unless the carbon is captured or if methane leaks into the environment.

The efficiency of the FCEV energy supply chain will likely improve with ongoing research and the increasing shift from fossil fuels to renewable energy sources for hydrogen fuel production. However, given the limited existing infrastructure for generating hydrogen fuel compared to the rapidly expanding infrastructure for BEVs, it remains challenging for FCEVs to catch up to the popularity of their battery-powered counterparts.

The potential of hydrogen as a fuel source

Nevertheless, hydrogen-powered vehicles still have their advantages. While BEVs are more efficient, they face limitations in battery life and longer recharging times. These issues can be mitigated with larger batteries, but for vehicles requiring continuous use and long-distance travel, such as trains or commercial trucks, the batteries’ weight becomes impractical. 

For example, with the rise of online shopping, home deliveries, and freight transportation — especially commercial trucks travelling long distances, which account for a 53 per cent increase in energy use in Canada — hydrogen-fueled trucks offer an advantage over BEV trucks, which are less practical.

Hydrogen fuel can be refilled much faster than BEVs, often requiring long charging periods. Additionally, FCEVs offer a range of 560 to 640 kilometres on a single tank of fuel and can refuel in just three to five minutes, similar to conventional diesel vehicles. In comparison, electric buses typically range from 190 to 210 kilometres. As a result, interest in hydrogen-fueled buses is growing, with companies like Nikola Motor, a zero-emission truck manufacturer, developing hydrogen semi-trailer trucks, and hydrogen double-decker buses now in service in London, UK.

The future of sustainable transportation

While hydrogen-fueled vehicles show promise in certain applications, they have yet to gain widespread popularity compared to their battery-powered counterparts. Efficiency, infrastructure support, and sourcing hydrogen from renewable resources are key factors that will determine the future success of hydrogen in the transportation sector. 

Nonetheless, efforts to improve the sustainability of hydrogen fuel, such as the Inflation Reduction Act of 2022 in the US, which allocates $1.55 billion USD to fund methane reduction programs like the Waste Reduction Incentive Program, demonstrate that hydrogen still holds promise for the future of sustainable transportation. The goal is that if the electricity used in hydrogen production comes from renewable sources or carbon capture and storage technologies are more effectively applied, hydrogen can be produced with minimal to no carbon emissions. 

As technology advances and the world moves toward decarbonization, further research into green hydrogen fuel may help hydrogen-fueled vehicles find their place alongside battery electric vehicles, contributing to a more sustainable future for the automotive industry.