Maritime

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Maritime transport moves goods, people and resources by sea, river and through ports. It includes international shipping, coastal freight, bulk export vessels, ferries, workboats, cruise vessels, fishing vessels and port operations. Low carbon liquid fuels (LCLFs) can play a role where vessels need long range, high power, fast refuelling and reliable operation away from shore.

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Reducing emissions Fuels for maritime Bunkering and ports Policy and regulation Resources

Maritime at a glance

99%

of Australia’s international trade by volume

About 1.6 billion tonnes of imports and exports move through Australian ports each year .

About 31,000

ship visits a year

Bulk carriers, container ships, tankers, ferries and cruise vessels all call at Australian ports .

Almost 3%

of global greenhouse gas emissions

International shipping carries about 80% of world trade. Long routes and heavy vessels leave few alternatives to liquid fuel .

Net zero

by or around 2050

The IMO’s 2023 strategy target for international shipping, with checkpoints for 2030 and 2040 .

How maritime is reducing emissions

Maritime decarbonisation involves a combination of measures rather than a single solution. The mix differs by vessel type, route and cargo.

1

More efficient vessel design and engines

Newer hull designs, propulsion systems and engine improvements reduce fuel use per tonne-kilometre. For ships on international voyages these gains are not optional: the Energy Efficiency Existing Ship Index sets a technical standard that vessels must meet .

2

Operational improvements

Slow steaming, weather routing, just-in-time arrivals at ports, hull cleaning and trim optimisation reduce fuel burn on existing vessels. Ships must also track operational carbon intensity and set out how they will improve it in a ship energy efficiency management plan .

3

Increased use of low carbon liquid fuels

Drop-in fuels such as renewable diesel can be supplied through some existing bunkering networks once they meet the relevant marine fuel specification. The current marine fuel standard also allows far higher biofuel content than its predecessor. Other low carbon fuels need vessels and infrastructure designed for them .

4

Wind-assist, shore power and emerging propulsion

Wind-assisted propulsion, shore power at berth, batteries on shorter routes and hydrogen fuel cells are being trialled but are not yet mainstream replacements for liquid fuels in deep-sea shipping .

Fuels for maritime

Several low carbon liquid fuels are being explored for marine use. They differ in feedstock, maturity, energy density and how they interact with existing engines and bunkering infrastructure. Uptake is at an early stage globally, and the fleet changes slowly because ships have long operating lives and fuel choice affects vessel design as well as port infrastructure.

A diesel-equivalent hydrocarbon fuel produced from oils, fats and residues through hydrotreating (HVO/HEFA) or through synthetic pathways (PtL). Chemically and functionally different from biodiesel.

How it can fit in maritime

  • Ferries
  • Tugs and workboats
  • Fishing vessels
  • Coastal freight vessels
  • Harbour and port craft

Considerations

ISO 8217:2024 covers paraffinic diesel from renewable sources. Suitability remains subject to engine-maker approval and operating conditions. Supply is limited and competes with road and aviation demand for the same feedstocks .

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A liquid fuel made by reacting fats or oils, such as vegetable oils, used cooking oil or tallow, with an alcohol. Reacting with methanol produces fatty acid methyl esters (FAME); reacting with ethanol produces fatty acid ethyl esters (FAEE).

How it can fit in maritime

  • Ferries and harbour craft (blends)
  • Fishing vessels
  • Offshore support vessels
  • Bulk and container ships (bio-residual blends)

Considerations

Storage stability, oxidation and microbial growth need managing on longer voyages. Compatibility depends on the vessel, fuel grade, storage conditions, fuel testing and engine-maker guidance .

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An alcohol fuel produced from biomass, or from captured carbon dioxide combined with renewable hydrogen. Liquid at ambient temperature and pressure, so it needs no cryogenic storage.

How it can fit in maritime

  • Methanol-ready container ships
  • Dual-fuel new-build vessels
  • Methanol-compatible ferries

Considerations

Energy density is around half that of marine distillate, so more tank volume is needed for the same range. It is toxic and has a low flashpoint, so the IGF Code safety requirements apply .

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Liquefied methane produced from biogas, or from renewable hydrogen and captured carbon dioxide, rather than from natural gas. Chemically the same as fossil LNG.

How it can fit in maritime

  • LNG-fuelled vessels
  • Dual-fuel ships

Considerations

Requires cryogenic storage at around minus 162 degrees and LNG bunkering infrastructure, so it suits vessels already built or converted for LNG rather than conventional ships. Unburnt methane passing through the engine reduces the lifecycle benefit and varies by engine type .

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A nitrogen and hydrogen fuel produced from renewable hydrogen. It contains no carbon, so combustion produces no carbon dioxide at the point of use.

How it can fit in maritime

  • Purpose-designed new-build vessels
  • Bulk carriers and tankers (pilot stage)

Considerations

Ammonia is toxic and corrosive, so handling, detection and crew safety requirements are strict. Combustion can produce nitrous oxide and unburnt ammonia, both of which affect the overall greenhouse gas outcome. The IMO issued interim safety guidelines in 2025, and marine engines are still reaching commercial availability .

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Bunkering and port logistics

Step 1

Move it to port

Bunkering means supplying fuel to a vessel through fixed port infrastructure, road tankers, barges or ship-to-ship transfer. The fuel first has to reach the right port and sit in suitable tanks.

Step 2

Test and document

Fuel quality is tested and documented before transfer. ISO 8217:2024 sets the marine fuel specifications, including distillate grades with up to 100% FAME and a new table for bio-residual blends.

Step 3

Transfer and use

Drop-in diesel-type fuels can use much of the existing bunkering network where they meet specifications, with compatible on-board equipment and trained crew.

Step 4

Plan for new fuels

Renewable methanol and renewable ammonia generally need new or modified storage, transfer equipment and procedures, and port and environmental approvals. Pilbara Ports is planning Australia’s first ammonia bunkering trial for late 2026.

Learn more about fuel types

Maritime fuels today

Low carbon liquid fuel use in maritime is at an early stage globally. A number of demonstration vessels are now operating on renewable diesel, biodiesel blends, renewable methanol or renewable ammonia, and a growing number of standards and policy frameworks are in place to guide expanded use.

More than 2,000 alternative-fuelled vessels

In operation or on order globally, including ships using liquefied natural gas, methanol, ammonia, and battery-hybrid systems .

Bunkering at major international ports

Renewable methanol bunkering is operating or being established at a number of major international ports including Singapore, Rotterdam, Antwerp, Houston and Brisbane .

Policy, regulation and technical guidance

The sections below cover the standards, policy, certification criteria and mandates shaping low carbon liquid fuel use across the maritime sector, grouped by the role they play.

Fuel quality and technical standards

These decide whether a fuel is legal to sell in Australia and fit to bunker and burn on board.

Certification criteria

If a marine fuel is claimed as low carbon, these schemes and methods decide whether it counts and how the claim is proven, including the well-to-wake method used in international shipping, which counts emissions from feedstock production through to combustion on board.

Mandates and targets

The rules and plans that create demand: Australia’s national action plan for maritime emissions, and International Maritime Organization (IMO) and European Union (EU) measures that set the emissions ships must meet and decide which fuels qualify.

Keep exploring
Shipping and emerging fuels Storage and blending Funding initiatives

Resources

A selection from the library related to this page.

    • Report
    • 2025

    Opportunities and Priorities for a Low Carbon Liquid Fuel Industry in Australia
    Commonwealth Scientific and Industrial Research Organisation (CSIRO), prepared in partnership with the Australian Government
    CSIRO report, prepared in partnership with the Australian Government, outlining opportunities for a low carbon liquid fuel industry in Australia and identifying priorities to progress projects from development through to commercial scale.
    Read more
    • Report
    • 2025

    Refined Ambitions: Exploring Australia’s low carbon liquid fuel potential
    Clean Energy Finance Corporation (CEFC), prepared by Deloitte
    CEFC’s Refined Ambitions report assesses Australia’s low carbon liquid fuel potential, covering supply chains, investment considerations and policy levers across fuels such as SAF and renewable diesel.
    Read more
    • Guidance
    • 2024

    IMO framework on life cycle GHG intensity of marine fuels (LCA)
    International Maritime Organization (IMO)
    IMO framework setting the methodology for assessing the life cycle greenhouse gas intensity of marine fuels on a well-to-wake basis, underpinning the IMO Net-Zero Framework.
    Read more
    • Guidance
    • 2026

    International Code of Safety for Ship Using Gases or Other Low-flashpoint Fuels (IGF Code)
    International Maritime Organization (IMO)
    IMO webpage on the IGF Code, the mandatory international safety standard for ships using gases or other low-flashpoint fuels such as LNG and methanol. Adopted in 2015 and in force from 1 January 2017, it sets goal-based provisions for the arrangement, installation, control and monitoring of machinery, equipment and systems using low-flashpoint fuels.
    Read more
    • Legislation & regulation
    • 2022

    Marine Order 97 (Marine pollution prevention – air pollution)
    Australian Maritime Safety Authority (AMSA)
    Australian Maritime Safety Authority (AMSA) Marine Order 97 implements the air pollution requirements of MARPOL Annex VI for ships in Australian waters, including limits on sulfur oxide (SOx), nitrogen oxide (NOx) and particulate matter emissions, and energy efficiency requirements.
    Read more
    • Guidance
    • 2025

    Global low sulphur fuel requirements
    Australian Maritime Safety Authority (AMSA)
    AMSA webpage explaining low sulfur fuel requirements for ships operating under Australian maritime rules.
    Read more
    • Technical & scientific report
    • 2024

    Update on drop-in biofuel and co-processing commercialization
    International Energy Agency Bioenergy Technology Collaboration Programme (IEA Bioenergy) Task 39
    IEA Bioenergy Task 39 report on progress in drop-in biofuel and co-processing commercialisation, updating its 2022 report on low carbon intensity drop-in fuels. Finds that the hydrotreated esters and fatty acids (HEFA) pathway remains the only fully commercial route to drop-in biofuels, with a substantial increase in announced facilities and in sustainable aviation fuel output driven by supportive policy.
    Read more
    • Report
    • 2024

    2024 Economic Impact Study – State of Trade
    Ports Australia
    Ports Australia economic impact study of the Australian port sector, covering trade volumes, employment and the role of ports in domestic and international supply chains.
    Read more
    • Policy & program
    • 2025

    IMO Net-Zero Framework
    International Maritime Organization (IMO)
    The IMO Net-Zero Framework was approved at the 83rd session of the Marine Environment Protection Committee (MEPC 83) in April 2025 as a new Chapter 5 of MARPOL Annex VI. It would introduce a global fuel standard with annual greenhouse gas fuel intensity reduction targets and a credit trading scheme for ocean-going ships over 5,000 gross tonnage. Adoption was deferred at the extraordinary MEPC session in October 2025 with the session adjourned for 12 months to reconvene in late 2026, pushing earliest entry into force to 2028.
    Read more
    • Report
    • 2019

    Navigating the way to a renewable future: Solutions to decarbonise shipping
    International Renewable Energy Agency (IRENA)
    IRENA report reviewing options to decarbonise international shipping, including alternative fuels and propulsion, infrastructure needs and policy measures that can support a transition.
    Read more
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