Rail already offers strong transport efficiency, but much of Australia’s freight, regional passenger and heavy-haul tasks still depend on diesel-powered rollingstock operating on non-electrified corridors. For this part of the sector, low carbon liquid fuels are one option for reducing emissions while longer-term pathways such as electrification, batteries and hydrogen continue to develop.
Quick links:
6.6 MtCO₂-e from rail each year
Australia’s rail sector produced about 6.5 to 6.6 Mt carbon dioxide equivalent (CO₂-e) in full fuel-cycle greenhouse gas emissions in 2024-25, made up of 1.9 Mt CO₂-e from passenger rail and 4.7 Mt CO₂-e from freight rail.
Freight rail is the main liquid-fuel source
Freight rail accounts for most rail emissions because many freight and heavy-haul locomotives rely on diesel, while many passenger networks use electricity.
1.4 billion litresdiesel-equivalent for freight rail
Expressing 2024-25 freight rail full fuel-cycle emissions as diesel-equivalent energy gives an indicative estimate of about 1.4 billion litres. This is a conversion estimate, not a reported fuel sales figure.
~5%of domestic transport emissions
Rail has accounted for a small share of Australia’s domestic transport full fuel-cycle emissions compared with road transport, while carrying important freight and passenger tasks.
How rail is reducing emissions
Rail decarbonisation differs across the network because some corridors are already electrified while others rely on diesel traction over long distances, heavy payloads and remote routes.
Network electrification where viable
Electrification can reduce direct diesel use where traffic density, infrastructure cost and power supply make it practical.
Operational improvements
Train planning, energy management, regenerative braking, maintenance and better network performance can reduce fuel or electricity use
Battery and hydrogen options
Battery-electric and hydrogen rollingstock are being developed for selected route types, especially shorter or well-defined operations.
Drop-in low carbon liquid fuels
Renewable diesel, biodiesel blends and synthetic diesel-type fuels can support non-electrified corridors during the transition.
Low carbon liquid fuels for rail
For existing diesel rail fleets, the main low carbon liquid fuel options are renewable diesel, biodiesel and, over a longer timeframe, synthetic diesel-type fuels. Low carbon liquid fuels are most relevant for non-electrified freight, regional passenger and heavy-haul services.
Renewable diesel
A diesel-equivalent hydrocarbon fuel produced from oils, fats and residues through hydrotreating (HVO/HEFA). Chemically and functionally different from biodiesel.
How it can fit in rail
Often seen as the strongest near-term drop-in low carbon liquid fuel for existing diesel rail fleets.
Considerations
It can align with paraffinic diesel specifications and may be suitable for some existing engines, subject to original equipment manufacturer (OEM) approval and operating conditions.
Biodiesel and fatty acid methyl ester (FAME) blends
A liquid fuel made by reacting fats or oils, such as vegetable oils, used cooking oil or tallow, with an alcohol.
How it can fit in rail
May offer a lower-carbon substitute or blend component for diesel rail applications.
Considerations
Usually requires closer attention to blend limits, storage, maintenance practice and OEM requirements.
Depot refuelling and bulk supply
Rail fuel supply commonly occurs through locomotive depots, wayside refuelling points, mobile refuelling and bulk storage. A fuel change needs to consider supply reliability, tank compatibility, fuel testing, documentation, maintenance practice and operator safety-management processes.
How fuel moves through the rail sector
Diesel is refined locally or imported for rail operations.
Fuel is delivered to rail depots and maintenance facilities.
Fuel is stored securely in dedicated depot tanks.
Samples are tested for quality, safety, and compliance.
Fuel is dispensed into locomotives or rail equipment.
Fuel powers locomotives and rail maintenance equipment.
Policy, regulation and technical guidance
The sections below cover the fuel standards and certification criteria shaping low carbon liquid fuel use across the rail sector, grouped by the role they play.
A standards organization that develops and publishes voluntary consensus technical international standards for a wide range of materials, products, systems and services.
International railway body with technical publications and reference documents relevant to diesel traction, emissions and rail decarbonisation.
Australia’s Guarantee of Origin scheme, which is administered by the Clean Energy Regulator, provides a transparent, publicly accessible record of the emissions associated with the production of key commodities, including low carbon liquid fuels. The scheme is being expanded to cover low carbon liquid fuels.
Independent global certification scheme covering sustainable biomass, bio-based materials, renewable fuels and circular economy products. ISCC is one of the certification schemes recognised under the International Civil Aviation Organization’s (ICAO) Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA), and is widely used across European Union renewable fuel pathways.
Ask the Hub
Not sure where to start? Ask a question or let the Assistant help you make sense of the basics.