Switch from diesel to electric in rail transportation

The transport industry accounts for 16.2% (1) of annual global carbon dioxide emissions, producing approximately 7.3 gigatonnes of CO2 emissions per year (2) – with rail transport or freight representing around 2% of these emissions (85 metric tonnes of CO2e per year). As of today, the pre-dominant fuel for rail is based on the internal combustion of fuels, representing 54% of total rail energy consumption, compared to 45% for electric trains (using overhead lines or an onboard battery) (3).

Switching from diesel-powered to electricity-based rail transport, for example a locomotive powered by electricity from overhead lines, third rail or on-board energy storage (battery/supercapacitor) (4) can reduce direct fuel combustion emissions from diesel. The estimated emission reduction potential ranges from 50 to 60% – dependent on regional energy mixes to generate electricity (5).

The rail transport and freight market is valued at US$ 281 billion in 2022 and is expected to grow to US$ 436 billion by 2030, with a CAGR of 4.4% over 8 years. The growth of rail transport and investments is most significant in China, where more than 5,000 km were built in the last five years, and 80% of these were completed in China only. The efficiency of urban mobility results in lower per capita transport emissions, when compared to cities without metro networks. Investment in rail infrastructure could potentially help China meet its net zero CO2 emissions commitments.

Climate impact

Targeted emissions sources

Switching from diesel to electric trains in transportation or freight targets carbon dioxide emissions along three phases of the railway life cycle:

• Manufacturing phase

• Use phase

• End-of-life treatment phase

This typically impacts Scope 1 and Scope 2 emissions, e.g. through increased electricity usage, while also impacting Scope 3 emissions:

• Category 1 (purchased goods and services)

• Category 11 (use of sold products)

• Category 12 (end-of-life treatment of sold products)

Decarbonization impact

This results from three phases:

• The manufacturing and installation of electric infrastructure (overhead lines or battery storage), leading to 10 to 20% higher carbon dioxide emissions, compared to diesel trains. Minimizing of initial carbon dioxide emissions can be achieved through responsible material sourcing strategies (e.g. input materials for batteries, infrastructure cement and others)

• Use phase carbon dioxide emissions of electric trains can be up to 65% lower or in some instances nearly zero emission – as available local electricity mix is a key driver for Scope 2 CO2 emissions generation during usage

• End-of-life treatment emissions from electric trains are hard to estimate, although electric trains have higher component end-of-life value and increased recycling potential

Business impact

Benefits

Lower life cycle emissions, lower fuel/electricity costs, lighter weight (overhead lines option), better acceleration, shorter journey times, quieter operation, greater customer accommodation space.

Costs

• Impact on operating costs

Operating costs for electric trains are lower compared to diesel counterparts by more than 40% as of 2022, and are expected to remain within these levels by 2030.

• Investment required

Capital investment in electric trains (overhead lines or battery storage) is 10 to 15% higher (2022). By 2030, capital investment cost is expected to remain within the same levels, with marginal changes for electric options.

• Eventual subsidies used

Regional and country-specific subsidies may apply.

Indicative abatement cost

Abatement cost for electric trains (overhead lines/battery storage) compared to diesel trains:

• <-200 USD/tCO2e (2022)

• Similar cost in 2030

Impact beyond climate and business

Co-benefits

Lower noise level, no local carbon dioxide emissions, health benefits in densely populated regions, circular.

Potential side-effects

Possibility of general increased carbon dioxide emissions due to the country’s available electricity mix, potentially longer delay times if charging infrastructure problems occur.

Typical business profile

Transportation companies involved in passenger or goods transportation and all units operating or owning trains within their business activity.

Approach

Electric trains are currently widely adopted, representing 45% of total global rail energy consumption. When installing electric (overhead lines or battery storage) infrastructure, the cost of investment and infrastructure maintenance must be considered. This is particularly the case when considering that implementation in existing diesel train infrastructure cost might rise, as overhead lines must be integrated into tunnels and remote regions.

Stakeholders involved

• Company functions: Logistics, operations, procurement

• Main providers: Top leading train manufacturers by 2019 revenue – CRRC Corporation, Bombardier Transportation, Siemens Mobility, Alstrom Transport, GE Transportation

• Other: Maintenance services and providers

Key parameters to consider

• Solution maturity: well known, established solution across all global regions and leading rail manufacturers

• Lifetime: around 25-35 years

• Technical constraints or pre-requisites: Possibility of diesel infrastructure need of renovation

• Additional specificities (e.g., geographical, sector or regulation): country-specific electricity mix

• Eventual subsidies available: dependent on region of application

• Other: N/A

Implementation and operations tips

Electric trains (overheard line or battery storage) are widely available. During implementation, the cost of investment into electric trains is higher, therefore the total cost of complete infrastructure will be substantially different. Geophysical challenges during implementation may occur. Battery storage trains are not advised for longer distances.

Due to potential charging infrastructure damage, effective maintenance and repair services must be put in place to avoid long delay times and low customer satisfaction.