2,803 Kilometres on a Single Tank of Hydrogen Where Will the Next Technological Advances Take Us?

Stadler’s hydrogen trains have covered a record-breaking 2,803 kilometres on a single tank, yet the biggest obstacle to their wider adoption remains something other than the technology itself. Johannes Wilhelmer and Stefan Bernsdorf from Stadler explain why the vehicle itself is the easier part of the equation, where they see the real limits of hydrogen rail transport, and which hydrogen technologies they believe have the greatest potential.

Why did you start developing hydrogen powered trains?

We started developing hydrogen powered trains to meet our customers‘ demands. For example, a full day of autonomy for areas where no catenary exists and battery recharging is not feasible. Our first project was delivered to the San Bernardino County Transportation Authority (SBTCA) in California. We decided to work with a well known technical gas, where generation, logistics, storage and safety had established solutions and suppliers. Then we adapted it for rail.

What evolution of hydrogen do you see in railway applications?

After a hype phase in early 2020 and having the first projects in the field, we achieved a learning stage that focused on developing ecosystems together with the involved stakeholders. There are follow up orders for California with 10 trains for public transportation that are being built, and the first trains for our Italian customers have been presented to the public. The tailor made vehicles for Italy serve several regions, where renewable energy and hydrogen generation are being developed in parallel to the trains. Three References: ARST, FdC, FCE.

What do you currently see as the biggest technical and economic challenge for hydrogen rail?

Technical gas is well known, but ecosystems that exist for industry and the development of transport and railway specific ecosystems involve many stakeholders. We support our customers in this with partners for systems not in our scope- with generation, logistics or refueling.

We started implementing hydrogen systems into our trains in 2019. The challenges on the vehicle side are manageable and our vehicle is in commercial operation. The bottle neck is still in the hydrogen availability and price. This is where train operators need additional stakeholders for the energy infrastructure. Individual elements like electrolysers, logistics, refueling stations or systems for trains exist, however harmonising the timeframes of the stakeholders for the new fleet is where we see a lot of friction and uncertainties. Also, the bureaucracy regarding approvals is reflecting the silos, which hinders agile project development for all involved stakeholders. It is a multi-stakeholder management topic, as the energy system is changing.

The record-breaking range of 2,803 km without refuelling is an extraordinary achievement. How did you achieve it?

Two factors are key: sufficient capacity and an energy efficient traction chain – from the fuel cell to the wheel. Energy management was adapted to the parallel hybrid traction chain with batteries and fuel cells, based on the existing hybrid know-how that Stadler has built over the century. The record was a relevant type test to validate the systems together with the software in the original configuration. Therefore,there was no adaptation specific to the test and the real performance could be proven.

What were the most significant technological improvements and lessons learned from operating the FLIRT H2 in Colorado?

The time we spent at the test ring was valuable for the validation of the system in various operating scenarios. Furthermore, we could optimise the software and create evidence for the homologation of the train with a focus on safety, optimisation and reliability. We see the innovation in the integration of the various systems in the train. For Stadler, it is not about marketing values at a component level, but about creating a train where both the passenger and the customer get performance and comfort in a seamless way. How you engineer and build the train is what makes or breaks the technology applied.

Fuel cells are among the most critical and sensitive components of a hydrogen propulsion system. What operating lifetimes do modern systems achieve today in terms of hours or kilometres, and what are the main factors affecting their degradation?

Purity of the hydrogen is relevant for the reliability of the fuel cell. This is not self-evident yet and needs to be ensured at the point of refueling.

The load cycle plays a significant role for the degradation of the fuel cell. This is a general learning area in the railway industry, as fuel cells are implemented in a limited number of fleets for less than a decade. The design of the parallel hybrid was specifically tailored to the fuel cell capabilities and the performance the vehicle needs to fulfill the time tables our customer requested.

The system design on train level influences the availability of the train and the maintenance cost. With a clever redundancy and hybrid system we can optimise both lifetime and availability. Lifetime and maintenance schedules are contract specific and not public. They are incorporated in the already established balanced maintenance schemes, where a split into preventive, condition based and corrective maintenance tasks ensure availability of the vehicle and plannable cost over the lifetime of the train.

Where is Stadler currently looking for the next technological breakthrough? Which innovations in zero-emission rail transport do you believe will reshape the market in the coming years, even if they are not yet widely available to customers?

We see the applicability of hydrogen combustion engines, as we showcase with our RS Zero train-design. The application of combustion engines are well known and established with existing spare parts and supply chain and maintenance management capabilities. Combustion engines can tolerate impurities in hydrogen and therefore use whatever hydrogen is available to avoid downtime of the fleet in case of hydrogen supply chain disruptions Flexibility in how an ecosystem is built – with local electrolysers, pipelines or other sources, as well as with different refueling station designs are key and we work with partners to achieve this.