Ireland’s national railway operator Iarnród Éireann (Irish Rail) has announced that it will trial the retrofit of a locomotive diesel engine to a hydrogen internal combustion engine, a still nascent technology that is less efficient than fuel cells, but has been argued to present fewer upfront costs.

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The plan comes after China’s state-owned train manufacturer CRRC converted a diesel-engine locomotive to run purely on hydrogen-powered fuel cells in a world-first in June this year.

The locomotive overhaul will also mark the first time in Europe that a an existing diesel locomotive has been retrofitted to run on hydrogen.

The engine will be made and installed in a CIE 071 Class freight locomotive — weighing nearly 100 tonnes — by Latvian technology firm DIGAS, with the first static tests of power and emissions output to take place next year. The converted locomotive will not enter actual service until 2025.

Overall, the trial will cost €1.5m ($1.6m), funded by Iarnród Éireann, DIGAS, and the EU’s European Institute of Innovation and Technology, although the exact split has not been disclosed.

Similarly, while Iarnród Éireann has agreed to manage the supply of hydrogen for the project, it is as yet unclear which partners the railway operator will bring in to deliver this H2, or at what cost.

The railway operator currently has 18 CIE 071 Class diesel locomotives in operation, 12 of which are used for freight.

“If the conversion tests are successful, these locomotives can be converted to greener and more efficient alternatives,” said Jim Meade, CEO of Iarnród Éireann.

Hydrogen Insight has reached out to confirm when these locomotives are expected to reach the end of life, and which other technologies have been considered to replace diesel fuel.

While freight trains are generally considered a less emissions-intense mode of transporting goods than heavy-duty vehicles, both are considered difficult to electrify.

For freight, this is generally due to the cost of constructing overhead lines or electrified lines.

Some operators, such as Varamis in the UK, are using repurposed electric passenger trains along routes with this infrastructure already in place.

Similarly, Wabtec in the US had in 2019 unveiled a battery-electric version of its existing freight locomotives, with the first units set to enter service this year.

And Engie and Alstom last year agreed to co-develop a hydrogen fuel-cell system to power electric locomotives on non-electrified sections of railway, with Nestlé agreeing to use the technology from 2025 to transport mineral water from its facility in the Vosges to distribution centres throughout France.

However, even if the infrastructure is in place, some rail operators with electric locomotives have switched back to diesel due to exposure to high electricity costs.

DB Cargo’s UK subsidiary this July permanently discharged twenty-four electric Class 90 locomotives, citing overly high operating costs due to the skyrocketing price of electricity — with the grounded trains substituted with Class 66 freight trains running on biodiesel.

Hydrogen Insight has reached out to DIGAS to confirm the economics of running a hydrogen internal combustion engine compared to an electric or fuel cell locomotive.