This is how hydrogen trains could transform transport

The United States has launched its first zero-emission passenger train, in what could prove to be a significant milestone in global efforts to decarbonize public transport.

The Zero Emission Multiple Unit (ZEMU) made its debut in San Bernardino, California. The train carries 108 passengers and is scheduled to go into full service in early 2025. The ZEMU offers a real-world test of the potential of hydrogen technology in everyday public transport.

While the US is just starting its hydrogen train journey, other countries have already made significant progress.

Germany launched the world's first hydrogen-powered train in 2018, setting a precedent for others. The United Kingdom is currently testing hydrogen trains as part of its ambitious plan to phase out diesel trains by 2040. France has ordered hydrogen trains for several regional lines and plans to start operations in 2025. These global initiatives underscore the growing recognition of hydrogen's potential to revolutionize rail transport.

It’s just over 200 years since the world’s first railway line opened in 1825, with coal-fired steam engines connecting two towns in the north of England. Two centuries on, the rail industry has largely moved away from coal, with modern trains hauled by diesel and electric locomotives.

With sustainability now at the forefront of development, we’ll likely see more focus on electricity and hydrogen as the power source for railway engines. So, what are the relative merits of each?

The starting point for this debate is that both electric and hydrogen trains are considered to be emissions-free at the point of use. However, electric trains rely on power generated from external sources, and if that energy is not generated from renewables, these trains are adding to overall carbon emissions. A Canadian study also points out that electric trains require expensive and complex infrastructure, including overhead gantries to carry power cables and substations to provide the power.

The development of battery-powered electric trains could do away with thousands of kilometres of cables, but they would create the need for fast-charging infrastructure or facilities to swap drained batteries for newly charged ones.

The same study finds hydrogen has multiple benefits as a power source for the next generation of trains. These include a much higher level of energy embedded in hydrogen, the ability to burn it in combustion engines or transform it in fuel cells to create electricity, and a much lower level of up-front infrastructure investment compared to electric railways.

One of the main advantages of electric railways is that infrastructure and safety measures to supply and manage huge power loads are already in place. The implementation of hydrogen as a rail fuel would require infrastructure development on a large scale to transport, store and deploy it safely. Hydrogen is a volatile and highly explosive chemical, so strict safety measures at every point in the supply chain would be required.

Storing large quantities of hydrogen on a fast-moving train is potentially hazardous. The UK’s Rail Safety and Standards Board has published a report that addresses questions of safety, technical standards and regulation required to facilitate the safe introduction of hydrogen trains into regular service. It identifies fire as the main concern and explores several ways to mitigate the risks, including the location of hydrogen tanks on rolling stock and the maintenance requirements to ensure safe operation.

The success of hydrogen trains will depend on parallel developments in green hydrogen production and supporting infrastructure. As technology advances and economies of scale come into play, we can expect to see more hydrogen-powered trains rolling out across the globe, contributing significantly to the journey towards a net-zero future.

The choice between hydrogen and electric trains will likely depend on specific route requirements, existing infrastructure, local energy production methods, and long-term cost projections.

In many cases, a combination of both technologies might prove to be the most effective approach to achieving a fully decarbonized rail network.

The World Economic Forum’s Advanced Energy Solutions community aims to rapidly accelerate the industrial-scale deployment of advanced technologies – such as clean fuels, hydrogen, advanced nuclear, energy storage, and carbon removal – reducing timelines from decades to years by engaging leaders in key energy sectors driving the transition.