Getting rail emissions to zero

Rail is already the least emissions-intensive mode of transport, but the European goal is to get to net zero by 2050. How can railways get to this goal?

The overall final energy mix of rail worldwide is currently split roughly equal between diesel and electricity, with diesel consumption slightly higher overall in 2021 than electricity, according to an International Energy Agency (IEA) report from 2022. Diesel specifically plays a more prominent role in freight rail, accounting for around two-thirds of its total energy consumption worldwide in 2021. Electric trains emit the least CO2, but even with diesel as part of the mix, rail freight is calculated to produce over 6 times less CO2 than transport by road trucks.

To get on track with the EU goal of net zero emissions by 2050, emissions will need to decline by about 6 per cent annually, according to the IEA. This goal requires the electrification of diesel operations wherever viable, as well as blending biodiesel and implementing a wide range of other efficiency measures, the Agency says.

Electrification rate increasing, but not always viable

To lower transport emissions as a whole, a shift from road to rail is important, but to reach net zero emissions, diesel in rail has to disappear. Electrifying railway tracks is one of the options, and several countries are making progress with that, such as Belgium and Lithuania. Belgium is already among the European top in rail electrification rate, and continues the process. Belgian infrastructure manager Infrabel opened the newly electrified freight line Genk Goederen – Bilzen last year, for example, and currently just around 4 per cent of the network is not electrified.

Lithuania is after Ireland the country with the lowest electrification rate of the EU with just 8 percent in 2020. It is however making great strides. Railway manager LTG Infra is in the process of electrifying 731 kilometres of tracks, after which the rate of electrified railway tracks in Lithuania will have risen to 35 per cent.

In Europe, the only country with a 100 percent electrified railway network is Switzerland, and of the EU countries, Luxembourg has the highest rate of electrified tracks with just 31 kilometres of non-electrified tracks on the primary network, out of 630 kilometres. There are no technical obstacles to further electrification, but the cost for upgrading and electrifying the existing rail infrastructure and the expected carbon reduction need to be considered on a case by case basis, states the EU report ‘Electrification of the Transport Network’.

The most heavily used railway lines are already electrified, and for smaller regional lines, this is not always deemed viable. Therefore in Belgium for example, where after electrification works only 5 lines in Flanders will remain unelectrified with current plans, the diesel trains will be replaced with battery trains at some point, said Mobility Minister Georges Gilkinet. After studies, battery trains were found the best option compared to for example hydrogen. Partial electrification will be necessary to deploy these trains, a spokesperson of railway operator NMBS told RailTech.be.

Existing diesel trains

To decarbonise diesel operations, also hydrogen projects are on the rise, further cementing this fuel as a key pillar in the broader energy transition, sees the International Energy Agency. Germany last year started operating 14 Alstom-built hydrogen trains to serve passenger transit over a 100 kilometre track in the state of lower Saxony. But also outside of Europe, countries like Japan, India and China are developing hydrogen trains.

Generally, existing trains and locomotives which still have a decent amount of service life left will usually not be replaced by brand new trains. To still make use of the trains, retrofitting them with for example hydrogen propulsion systems is an option. But also replacing diesel fuel by non-fossil fuels with a lower carbon footprint, such as Hydrotrated Vegetable Oil (HVO) or B100 fuel can reduce emissions on the shorter term.

German operator Deutsche Bahn is increasingly filling the tanks of their diesel trains with HVO fuel, and reached their 2025 target two years earlier. DB’s Diesel Exit programme, launched last year, was started to reduce current emissions for existing diesel trains. “As DB forwarded its climate neutrality goal from 2050 to 2040, this means it’s only 18 years left, which in terms of railway innovation cycles is a very short time”, Sittipan Reinold, programme lead said in a RailTech webinar.

Want to hear more about shifting from diesel to sustainable rolling stock and continue the discussion? Join the Rail Infra Forum on March 15 in Rotterdam or online, which makes the link between rolling stock such as hydrogen, battery and biofuel operations and the infrastructure needed for this. Speakers from Deutsche Bahn, TU Delft, TÜV SÜD Rail, ProRail, Hydrogen Center Austria, TUC Rail, Plasser & Theurer and more are on the programme.