Decarbonising Australia’s Working Waterfront
The Water Side of the Port Problem
When ports talk about decarbonisation, the conversation often focuses on cranes, straddle carriers and landside logistics. But on the water, a different set of diesel engines runs continuously - and they are, if anything, harder to transition away from.
Tugboats, pilot vessels, harbour ferries and coastal workboats are the essential infrastructure of any working port. They guide vessels in and out, assist berthing, move crew and equipment, and keep port operations running around the clock. They are also almost universally powered by conventional diesel, and given the age and capital cost of these fleets - they are likely to remain so for many years.
In the US, where fleet data is available, tugboats alone account for approximately a quarter of all domestic maritime fleet emissions, despite being among the smallest vessel type by size.[1] The average US harbour tug is 35 years old, and Australian fleets look broadly similar. Electrification and alternative propulsion are not realistic near-term options for most operators. What is realistic is a fuel switch that requires no new engines, no infrastructure changes, and no capital disruption.
Why Harbour Craft Emissions Matter More Than Their Size Suggests
A harbour tugboat rated at 3,000 to 5,000 hp burns between 100 and 200 gallons - roughly 380 to 760 litres - of diesel per hour at full power.[2] That is a significant fuel load for a vessel operating metres from the wharf, within a port precinct that is typically surrounded by workers, community areas and sensitive coastal environments.
Unlike ocean-going vessels, whose emissions disperse at sea, harbour craft emit in concentrated, near-shore environments where the health impact is disproportionately high. Research consistently shows that harbour vessel emissions have a greater impact on surrounding communities than equivalent emissions produced offshore, simply because of proximity.[3]
The pollutants coming from diesel-powered harbour vessels are not abstract environmental statistics. Particulate matter (PM), nitrogen oxides (NOx), sulfur oxides (SOx) and carbon monoxide are released every time an engine runs, and in a port environment, the people most exposed are the workers, communities and nearby residents who live with these operations daily.
Why HVO Works for Harbour Fleets and Marine
Hydrotreated Vegetable Oil (HVO) is produced from renewable waste feedstocks - used cooking oils, animal fats, agricultural residues - through a hydrotreatment process. The result is a fuel that is chemically near-identical to fossil diesel. It works in existing engines without modification, without blending restrictions, and without any change to refuelling infrastructure.
This matters enormously for harbour fleets. Operators of tugboats and pilot vessels are not in a position to modify engines, invest in new propulsion systems or change their fuelling arrangements at short notice. HVO asks nothing of them except to use a different fuel.
Beyond its emissions profile, HVO also avoids the fuel quality risks that increasingly affect conventional marine diesel. As a refined paraffinic product, it contains no catalytic fines, no risk of microbial contamination, and none of the sediment or blending issues that have driven a 37% increase in global marine fuel quality alerts in 2025, the majority of which relate to residual fossil fuel blends.[4]
Lifecycle GHG Emissions Compared to Fossil Diesel Baseline:
HVO also delivers significant reductions in air pollutants beyond CO₂, directly relevant in the confined harbour environment:
HVO Air Pollutants Comparison to Fossil Diesel Baseline:
The Port of London Authority demonstrated this on its harbour service vessel Kew - a vessel directly comparable to Australian harbour craft - finding that switching to HVO delivered meaningful NOx and PM reductions from day one, with no engine modifications and no operational disruption.
How HVO Compares to other Low Emission Marine Fuels
Not all low-emission fuels are equally practical for harbour operations. The table below compares the options available to marine operators today.
ISO 8217 is the primary international standard for marine fuel quality, specifying the physical and chemical properties that fuels must meet to be considered fit for use in ship engines. It is referenced in bunker purchase contracts, charterparties, engine OEM approvals and port state control inspections globally. Australia has no dedicated domestic marine fuel quality standard - Australian vessel operators and bunker suppliers reference ISO 8217 as the contractual and commercial benchmark.
The 2024 revision (seventh edition, published May 2024) introduced a dedicated Clause 9 - "Requirements for marine fuel consisting of 100% FAME or paraffinic diesel fuel" - which formally brings HVO (along with GTL and BTL) within the standard's specification framework. Clause 5 was also extended to explicitly incorporate HVO. LNG, hydrogen and methanol are governed by entirely separate standards and are not covered by ISO 8217.
Australian regulatory context: In February 2025, Australia introduced the Fuel Quality Standards (Paraffinic Diesel) Determination 2025 - the first time Australia formally recognised HVO as a distinct fuel category under Australian law. While a supply-side regulation rather than a marine-specific fuel standard, it provides the foundational regulatory certainty needed for HVO to be legally supplied to marine operators in Australia. The standard is aligned with EN 15940, which underpins ISO 8217:2024's treatment of HVO.
References: ISO 8217:2024 - iso.org · CIMAC FAQ on ISO 8217:2024 (PDF) · Paraffinic Diesel Determination 2025 - legislation.gov.au · Regulating Australian Fuel Quality - DCCEEW
It’s Already Happening Globally
HVO adoption in harbour and port vessel operations is no longer experimental - it is in regular service across multiple countries, with tugboats and pilot vessels consistently the first vessel types to make the switch.
UK & Netherlands - Svitzer & Caterpillar
100% HVO Tugboat Fleets in London and Rotterdam
Svitzer, the world's largest tug operator, ran Cat-powered tugboats on 100% HVO across London and Rotterdam. All main and auxiliary engines operated on pure HVO without modification. Caterpillar confirmed no adverse effects on engine health, filters or gaskets after extended running. This programme became the foundation for the EcoTow service now operating in Australia.
Scotland - Montrose Port
HVO Deployed Quayside for Pilot Boats
Highland Fuels made HVO available quayside at Montrose Port in 2024 - the first time renewable marine fuel was available dockside in Scotland. The port's pilot boats were the first to switch, with the Harbour Master noting it was a significant step toward becoming Scotland's greenest port.
Ireland - Dublin Port
Dublin Port adopted HVO as a replacement fuel in its pilot boats - among the most operationally demanding vessels in any port. The port confirmed full drop-in compatibility with no engine modifications required.
Canada - Ocean Group, British Columbia
Fleet-Wide HVO Across All Port Towing Operations
Ocean Group adopted HVO across all port towing operations in BC - one of the first towage operators in North America to commit to a full fleet switch. The decision required no engine modifications and was driven by HVO's drop-in compatibility and emissions credentials.
Brazil - Wilson Sons & Port of Açu
First HVO Tugboat Trial in the Brazilian Maritime Sector
Wilson Sons Towage, EFEN and the Port of Açu conducted Brazil's first maritime HVO trial using tugboats as the test platform. The Southern Hemisphere context is directly relevant to Australian port operators facing the same fleet profile and decarbonisation pressures.
What This Means for Australian Marine Operators and Emissions Reporting
For Australian marine operators navigating sustainability reporting, HVO performs well across every framework:
Scope 1 — NGER
Zero CO₂
HVO's biogenic carbon is not counted as a net atmospheric emission under the National Greenhouse Accounts.
Scope 3 — Supply Chain
Verified
Port authorities and government clients increasingly require Scope 3 data from operators. HVO provides a credible, auditable reduction.
Well-to-Wake Lifecycle
↓ 90-92%
Vs fossil diesel across the complete fuel chain — the figure for net-zero strategy and sustainability disclosures.
The AMSA roundtable in February 2025 identified HVO as a practical option for long-lived diesel fleets - but also flagged supply availability as the key near-term constraint. HVO competes with road transport for the same feedstock, and without clear government signals prioritising marine access, the marine sector risks being last in the queue. Operators who establish supply relationships now will be better positioned as demand from other sectors continues to grow.[5]
The message is straightforward: you do not need to wait for a new vessel, new infrastructure or new government policy to start reducing emissions from your harbour fleet. The fuel exists, the engines are compatible, the frameworks recognise the benefit - and international examples show it is already working.
Sources:
[1]
US Environmental Protection Agency (EPA). Harbour Craft Emissions Data. Tugboats accounting for approximately 25% of US domestic maritime fleet emissions; average tug age 35 years. Applied as indicative context for Australian harbour fleets.
[2]
Professional Mariner (US maritime trade publication). Harbour tug fuel consumption: 100-200 gallons per hour at 3,000-5,000 hp at full power. Note: no equivalent Australian harbour craft consumption data is publicly published.
[3]
Corbett et al. Peer-reviewed international shipping emissions and health impact research. Approximately 265,000 annual premature deaths attributable to shipping-sourced air pollution; harbour vessel proximity effect documented.
[4]
Veritas Petroleum Services. VPS 2025 Annual Marine Fuel Review. Global data from Rotterdam, Singapore, Houston and Fujairah laboratories. Bunker alerts up 37% vs 2024; all 37 alerts related to fossil fuel grades; biofuel testing volumes up 50%. View summary
[5]
Australian Maritime Safety Authority. AMSA Decarbonisation Industry Roundtable, Sydney, February 2025. Also references Maritime Emissions Reduction National Action Plan (MERNAP) consultation, Australian Government / AMSA, 2024. View AMSA
[6]
International Organization for Standardization. ISO 8217:2024 - Petroleum products. Fuels (class F). Specifications of marine fuels, including formal inclusion of HVO (Clause 9). Australian Government DCCEEW. National Greenhouse Accounts Factors 2024 - HVO Scope 1 CO2 factor zero (biogenic carbon). View ISO standard · View NGA factors