The railway industry is certainly not the biggest polluter in the world – especially when compared to road transport or shipping – but with the threat of climate change rising, it could still play a big part in the global effort to decarbonise.

In the UK, urgent action is particularly required in light of the government’s recent pledge to eliminate diesel-only trains from the network by 2040.

However, fresh research from the Institution of Mechanical Engineers (IMechE) suggests that with less than 50% of the national network currently electrified, this target risks never being achieved.

As a result, IMechE has studied the impact of hydrogen-powered trains and how they can be used on non-electrified lines, and is now campaigning for their introduction on the UK network.

In a report titled “The future for hydrogen trains in the UK”, researchers from IMechE have also advised the Department for Transport (DfT) to embark on more innovative and long-term electrification programmes, and called for the construction of a more sustainable and comprehensive infrastructure.

Dr Jenifer Baxter, head of engineering at IMechE, explains the report and considers what the next steps should be for the government and policymakers.

Adele Berti: What are the main findings of your report?

Jenifer Baxter: The report is about the potential for hydrogen trains in the UK in the future. Within it, the main finding is that the best thing that we can do to decarbonise the rail sector is to electrify more of the line.

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Where possible, electric trains should be introduced as they are the most efficient way of moving large numbers of people and freight around the UK.

That is primarily what the UK Government and the DfT need to do, to look at the cancellation of some of the electrification projects and take a deep look at whether or not that’s the most appropriate thing to do considering their own policy of removing diesel trains by 2040.

As part of that, one of our recommendations is, in a longer-term approach, to roll out an electrification programme. So, rather than creating ad hoc and short-term projects, the programmes should be ongoing, so that we keep electrifying lines all over the UK.

This means that the supply chain skills and the career opportunities of people working in that sector are much more likely to be sustainable. This is because when you have projects that come and go, each time you do a project and then you leave a long gap, you lose all of your skills and the supply chain, which makes the project much more expensive.

The second area we’ve looked into is about making sure that when we’ll be thinking about hydrogen trains in the future, we only put them into places where the refuelling system is straightforward and can be done easily.

AB: Where would they work specifically?

JB: When considering using hydrogen trains, you need to make sure that you will only use them in areas where it’s completely impossible either to electrify a line or it is economically unviable.

[This would be the case of] train lines that have good connections to industrial clusters where you can create more hydrogen, and that hydrogen can be used not just for the transport sector and trains, but also for vessels and HGVs, so you have an industrial hub for refuelling for a number of large types of vehicles.

So, there may be areas where running an electrification would be a real challenge and expensive and it wouldn’t be really worth it because you would only be running few trains up and down that line.

For example, the DfT has been looking at regions like Cumbria and Northumbria, where there are train lines that don’t run a lot of trains on them. In those sorts of areas, there is a big possibility that you could run hydrogen trains, particularly as they’ve got connections into the larger cities like Liverpool, Manchester and Middlesbrough.

AB: What benefits does electrifying the network bring compared to introducing hydrogen trains?

JB: Electricity generation is much more direct. So, if you are able to generate a lot of electricity using renewable sources or nuclear power, low-carbon electricity, that electricity goes straight into the fixed electric network of the rail and trains can use it directly.

On the other hand, hydrogen in itself doesn’t exist as a fuel, so you have to extract it from something and you need a large amount of electricity to do so.

The electricity network is also really well established, whereas, with hydrogen, we would have to develop that network and make sure that there is a refuelling system in the critical places where trains will need it.

Another important thing is that an electric train is easy to understand; we know how the technology works and how an electric train will behave on different parts of the rail network. With hydrogen trains we don’t know what happens if, for example, they have an accident inside a tunnel.

AB: What should the next steps be for the DfT?

JB: It’s an interesting time at the moment because a lot of money that’s being spent by the government is being spent on trying to understand what to do when we leave the European Union, so making major commitments to the rail network may not be a priority for them right now.

They have already stated that they’re interested in running hydrogen trains on some of the lines in Cumbria and it’s really good to have areas where we can demonstrate exactly what happens with these new technologies, how they work and explore and investigate all the different possibilities that could come up with them before they’re used elsewhere on the rail network.

It will be interesting to see how they connect it up with some industrial clusters to enable hydrogen to be used in things like HGVs, buses and other vehicles that don’t do so well being battery-powered.

AB: How urgently do we need to act?

JB: [According to an article previously published by IMechE], around 2021, it’s likely that we’ll see this type of demonstration implemented. I think it’s really critical that we build the capabilities for developing hydrogen in a green way.

We don’t want to end up with a situation where hydrogen is produced from natural gas, so then when all of the carbon dioxide is taken out, it’s just released into the atmosphere. If that’s the case, you might just burn natural gas in your train, so we need to be sure that we’re building the capabilities in industrial areas that produce hydrogen that is green.

We have to start this correctly; if we start to build an infrastructure that is still dirty, it will remain so. Before we set out on demonstration projects we have to make sure that we’ve got them right and that we are clean.

If we want to see the same type of activity we’ve seen with wind power, and how it has changed over the last 20 years thanks to the amount of subsidies being put by the government during that time, with hydrogen, then an equal commitment has to be made to it.

It’s unlikely though, because of the various investment risks and not knowing exactly which direction things are going to go in and whether the private sector will spontaneously invest in the area.

If you want to see hydrogen as a much more widely used fuel for the decarbonisation, then there will have to be government investments and commitments in the same way that we’ve seen for other sectors.