Alternative locomotion

You can ride through northern Lower Saxony quietly, comfortably and emission-free. Since last summer, hydrogen-powered trains have been operating the routes between Cuxhaven, Bremerhaven, Bremervörde and Buxtehude. The trains are owned by the Landesnahverkehrsgesellschaft Niedersachsen (LNVG) and operated by Eisenbahnen und Verkehrsbetriebe Elbe-Weser GmbH (evb). The transport association is proud of the new technology: “We own the world’s first hydrogen train fleet,” says Thomas Nawrocki, Head of Vehicle Management at LNVG. By summer 2023, they plan to replace evb’s entire diesel fleet with a total of 14 hydrogen trains.  

And that’s the ultimate goal: diesel trains have got to go. “Around 80 percent of local passenger transport is provided on electrified routes,” explains Nora Dörr, Project Manager for Alternative Drive Systems at VDE. However, thousands of diesel trains are still operating at the moment, and they’re far from climate-friendly. Getting them off the rails requires alternatives, though. It’s not always economical to electrify routes by adding overhead lines. The construction is disproportionately expensive, especially on routes with low passenger numbers. “Drives with overhead lines are the ideal choice in rail transport since they’re the most efficient. But wherever there are gaps in electrification, using hydrogen trains and battery vehicles is a suitable option,” says Rüdiger Wendt, a member of the VDI advisory board on railway technology.  

Pro and contra: HEMU vs. BEMU 

In BEMU (battery-electric multiple unit) vehicles, the contact wire directly powers the drive and simultaneously charges the battery. If no sufficiently long overhead lines are available, charging stations can also be placed along the route. In hydrogen-electric multiple unit (HEMU) trains, hydrogen is converted into electrical energy using atmospheric oxygen. The hydrogen has to be refueled. According to VDE expert Dörr, one technology is not fundamentally better than the other. “Battery vehicles have good energy efficiency and, in the current situation, lower operating costs. But they have to be charged every 120 kilometers, at the latest.” Hydrogen trains have an advantage there: “They can cover long distances without stops.” This past fall, one hydrogen train from LNVG’s fleet – a Coradia iLint series manufactured by Alstom – covered the 1,175 kilometers from Bremervörde to Munich without stopping. 

However, BEMU beats HEMU on one crucial point: “With hydrogen trains, energy efficiency is rather poor,” says Dörr. They require up to three times more power than battery trains. The necessary hydrogen must first be produced – from electricity. The conversion processes reduce efficiency. What’s more, “hydrogen trains are only environmentally friendly and CO2-neutral when they run on green hydrogen.” But that commodity is currently in very short supply. Dörr therefore doesn’t consider hydrogen trains to be the best drive technology for local passenger transport, but it does make sense in certain scenarios: “In places where it’s not possible to operate battery-powered trains because the routes are relatively long, or in areas that will have hydrogen infrastructure in the future anyway – such as in the Ruhr region, which is home to lots of chemical industry operations.” 

Innovation calls for an open mind 

What is technically feasible, economically sensible and ecologically efficient must be assessed for each network: “We always have to individually examine the operating concept, the timetables and other factors,” says Dörr. Baden-Württemberg, for example, fundamentally decided against the use of hydrogen trains. The state’s Ministry of Transport tested HEMU vehicles on multiple routes but found the technology underwhelming. It didn’t recommend using HEMU on any of the routes examined in the study. The Rhein-Main-Verkehrsverbund (RMV), the Frankfurt region’s transport association, decided otherwise. Like evb, it is betting on hydrogen: the first hydrogen trains started testing in the summer of 2022 in the Taunus region. RMV plans to finish building its fleet by spring 2023 – striving to create the “largest hydrogen train fleet in the world”. 

Are transit providers betting on the wrong horse? “Long-term innovation decisions are always a bit like looking into a crystal ball,” says Nora Dörr. LNVG started converting its fleet over ten years ago: “We demanded that industry should provide an alternative to diesel – and nobody could provide that initially. Then Alstom came up with the idea of using hydrogen and fuel cells,” said Nawrocki. 

“At the time, people were generally still very open to tech innovations, not only in rail transport,” says Dörr. “The key is proving the feasibility of new technologies.” Hydrogen trains have passed this test. Only with the experience and data gathered in pilot projects can we now look at the technologies in such a differentiated way. “It’s thanks to the open-mindedness of manufacturers and operators that we have another reliable alternative to coal and oil with fuel cell technology.”  

Beatrice Hüper is a freelance author from Hamburg and an editor of VDE dialog. 

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