Demand for “untethered” electric trains will increase rapidly over the coming years, with sales to grow four-fold year-on-year to reach over 100 deliveries this year, according to a report by market research and business intelligence company IDTechEx.

The ‘Battery Electric & Hydrogen Fuel Cell Trains 2023-2043’ report attributes this growth to rail original-equipment manufacturers (OEMs) and operators seeking to reduce high diesel costs of diesel locomotives, as well as self-made climate targets set to align with broader goals such as the Paris Agreement and Fit for 55 in Europe.

Currently, rail networks largely consist of electric trains “tethered” to electric overhead and live rail systems; however, this is not feasible everywhere owing to high infrastructure costs per kilometre, remote geographic locations and the practicality of building through tunnels and over bridges.

For these stretches of track, rail rolling stock manufacturers and operators currently rely on diesel fuel – which is their second largest cost.

The IDTechEx report sets out granular 20-year forecasts including train deliveries, battery demand, fuel cell demand and market value across locomotive, multiple unit and shunter trains.

The cost evolution of railroad batteries, fuel cells and green hydrogen is also explored to assess long-term feasibility.

Industry momentum is also building through the rapid advancement of lithium-ion battery technology, with systems now capable of reaching the multi-megawatt-hour level in confined carriage spaces.

Systems up to 14 MWh are being installed currently in the largest trains, known as battery electric locomotives (BELs).

In the future, the vast energy requirements of rail will eventually lead to some of the largest traction battery deployments across all electric vehicle markets – potentially beyond 20 MWh a train.

Initial rail electrification will be led by multiple units, which are trains used for passenger operations. Battery-electric multiple unit trains are being developed to replace the diesel multiple units currently operating between regional and intercity lines. Initial deployments have focused on route lengths of up to about 100 km, which requires battery systems comparable to existing commercial road vehicles.

In the longer term, electrification will be led by locomotives, with adoption timelines provided in the report for mainline locomotives and shunter locomotives, also known as switchers. Shunters are railyard vehicles used for moving various cars around yards or stations. Range is not as crucial for this sector, and there is greater potential for opportunity charging.

Mainline locomotives are largely commercial and industrial freight trains, although this varies between key electrification regions such as the US, Europe and China.

Locomotives have a larger addressable market than multiple units, and since they are larger and more expensive, often with long range requirements, they require multi-megawatt-hour battery systems from the start.

Locomotives represent a great opportunity for the heavy-duty battery supply chain, with future battery demand, in the gigawatt-hour range, growing at 36% compounded annually over the next decade.