Ammonia bunkering: moving from demonstrations to operations
By on July 28, 2025
In our July episode of Project Features, Duna Uribe, Cees Boon (both from the Port of Rotterdam), and Joe Boyland (Global Maritime Forum) joined us to discuss outcomes from ammonia bunkering demonstrations in the Port of Rotterdam and other global locations. The recording is available here, and you can also download the speaker presentations.
Context: regulations, vessels and engines are all ready
Following the 109th meeting of the IMO’s Maritime Safety Committee (MSC) in December 2024, interim guidelines for the use of ammonia fuel onboard vessels have been approved. In terms of the use of ammonia cargo as fuel (currently prohibited by IMO regulations), changes to the IGC code will enter into force on 1 July 2026 that allow for this fuel pathway. This aligns with the first large-scale ammonia-fueled vessels hitting the waters in 2026.
The AEA’s LEAD: Vessels database shows that 64 ammonia-fueled vessels have been ordered as of June 2025, of which 29 vessels are ammonia carriers, and 29 vessels are bulk carriers (primarily for iron ore transport). Various tugboats and supply vessels are already operational using ammonia as a fuel.
More recently, global shipping got its first-ever emissions pricing mechanism at MEPC 83. This marks an important step towards establishing a legally binding framework to reduce greenhouse gas (GHG) emissions. The regulation will be mandatory for ocean-going ships over 5,000 gross tons (a vessel cohort responsible for 85% of the total CO2 emissions from international shipping).
Full-scale two-stroke and four-stroke engine tests have been performed using ammonia as fuel, providing evidence of low-emissions from ammonia-fueled engines, and indicating lower emission profiles than using fuel oil. Emission profiles of two-stroke engines indicate NOX profiles already well below IMO Tier II limits without DeNOX, and meeting IMO Tier III limits with DeNOX. N2O levels are typically below 3-5 ppm, while NH3 slip emissions are below 10 ppm.
Here, we explore the readiness for another key step in the marine ammonia fuel supply chain: bunkering.
Ship-to-ship bunkering demonstration in Rotterdam, April 2025
The Port of Rotterdam is a major global bunker hub, the largest port in Europe, and one of Europe’s largest energy hubs, with about 13% of all energy utilized on the continent passing through the port. The Port of Rotterdam is also the second largest bunking hub globally. By 2050, the Port of Rotterdam aims to import up to 18 million tons of hydrogen equivalents. Various projects have already been announced in the port to help realize this target, with many focusing on ammonia imports. One of these projects is a recent ammonia bunker pilot facilitated by the Port of Rotterdam.
Click to expand. Bunker pilot partners from the April demonstration at the Port of Rotterdam. From Duna Uribe and Cees Boon, Ammonia bunkering pilot in the Port of Rotterdam (July 2025).
In April 2025, the ship-to-ship ammonia transfer was successfully completed between the vessels Oceanic Moon and Gas Utopia, berthed at APM Terminals Maasvlakte. OCI supplied the ammonia, carried aboard Trammo’s vessels, and James Fisher Fendercare provided equipment and operational expertise. Bunker barge operator Victrol, the DCMR Environmental Protection Agency, Rijnmond Safety Region, and the Joint Fire Service were also involved to ensure smooth execution of the bunker transfer.
Increasing Port Readiness
Click to expand. Port Readiness Level for bunkering (multiple fuels), including the status of ammonia fuel after the recent demonstration. From Duna Uribe and Cees Boon, Ammonia bunkering pilot in the Port of Rotterdam (July 2025).
The bunking pilot demonstration took place within the Port of Rotterdam’s Port Readiness Level (PRL) assessment scale (shown to the left also applied to methanol, LNG, and liquid hydrogen fuel). In 2024, a comprehensive framework for ship-to-ship ammonia bunkering was finalized, also building on existing ammonia handling and transfer guidelines. The pilot in April was designed to validate this framework, with reporting and proposed amendments to the framework for ship-to-ship ammonia bunkering expected later this year. No emissions/leaks were reported for the ship-to-ship ammonia bunkering pilot, with around 500 tons of refrigerated ammonia transferred over 2.5 hours between vessels. The overall duration of the operation was much longer, with purging of the ammonia lines taking much, much longer than the actual transfer.
The ammonia bunkering framework includes items such as governance (regulations in place, communication, strategic stakeholder management), external safety (distance to the public), control zones (distance to all other parties in direct vicinity of bunkering operations), terminal preparation, nautical safety (safe locations for mooring), vessel safety (sufficiently equipped for ammonia bunkering), mooring safety, bunker safety (how to prepare operations, mooring, connections, transfer, purging, disconnection), SIMOPS safety, and operational safety (supervision by experts, checklists).
Click to expand. Pilot governance: safety zones at the Port of Rotterdam. From Duna Uribe and Cees Boon, Ammonia bunkering pilot in the Port of Rotterdam (July 2025).
In the past, similar frameworks developed for LNG and methanol bunkering have been formally adopted by the Port of Rotterdam, in the process setting global standards for bunkering operations with new fuels.
Examples of studies performed in preparation for the ship-to-ship ammonia bunkering pilot include a quantitative risk assessment (QRA) for external safety, a gas dispersion study for leak scenarios and associated control zones, and HAZID/HAZOP studies (Hazard Identifications). A map with locations for safe ammonia bunkering will be established, based on the QRA and other variables. It was also found that refrigerated, low-pressure ammonia has smaller risk contours than atmospheric temperature, pressurized ammonia, and therefore refrigerated ammonia will be preferred for bunkering.
Click to expand. Execution details of the April ammonia bunker pilot. From Duna Uribe and Cees Boon, Ammonia bunkering pilot in the Port of Rotterdam (July 2025).
In 2026, the Port of Rotterdam is expected to allow ammonia bunkering on a project-by-project basis, with bunkering established in an operational environment, with subsequent opening to the market for ammonia bunkering.
Mapping of Zero-Emission Pilots and Demonstration Projects: 6th edition
The ammonia bunkering pilot in the Port of Rotterdam is one of many projects being tracked and mapped by the Getting to Zero Coalition, an industry-led platform managed by the Global Maritime Forum. In August 2025, the Coalition will publish the sixth iteration of its annual mapping report, highlighting ammonia bunkering activities around the globe and the overall readiness of ammonia as a maritime fuel, including the progress made on ammonia-fueled engines.
Click to expand. The Global Maritime Forum has tracked thirteen different ammonia bunker trials across nine global locations, with insights to be published in an upcoming report. From Joe Boyland, The status of ammonia as a shipping fuel today (July 2025).
Since last year, 13 ammonia transfer and bunkering demonstrations have occurred in 9 locations in the world. Examples of ammonia bunkering locations include Fortescue’s Green Pioneer in the Port of Singapore, COSCO’s Yuantuo 1 bunkering in the Port of Dalian (once in Jan 2025, once in July 2025), NYK’s Sakigake in Yokohama Port, and Amogy’s NH3 Kraken on the Hudson River. Various modalities were used for ammonia bunkering and transfer in these demonstrations, including truck-to-ship and shore-to-ship. Ship-to-ship ammonia transfers simulating bunker operations have occurred between Trafigura’s vessels in the Straits of Gibraltar, Navigator Gas’ vessels in the Port of Ngqura, and MOL’s and Navigator Gas’ vessels in the Port of Dampier.
All these ammonia transfer and bunkering demonstrations were a success, with no safety incidents reported. Progress has been made for the port readiness for future bunkering, with regulatory frameworks coming into place at several of the ports in question. Secondly, valuable technical insights were gained, indicating that risk assessments were “better than expected”, and not significantly different from risk contours for LNG refueling. Cold ammonia bunkering is preferred over pressurized ammonia bunkering, and Ammonia Release Mitigation Systems (ARMS) are advised to mitigate potential ammonia emissions.
The knowledge level and risk appetite varies between ports, implying community engagement needs to be mapped, and that proactive engagements with shared learnings will be critical. Lastly, the remaining gaps have been identified. While ship-to-ship ammonia transfers and bunkering demonstrations have occurred between gas carriers, they have not yet involved an ammonia-fueled vessel (GMF notes that the first ammonia-fueled, ammonia bunker vessel was recently ordered by ITOCHU). Also, simultaneous operations (SIMOPS) have not been demonstrated yet for ammonia bunkering: e.g. fueling while also handling cargo on the vessel.
Click to expand. Current development status of ammonia and methanol as maritime fuels, according to the Global Maritime Forum. From Joe Boyland, The status of ammonia as a shipping fuel today (July 2025).
The Getting to Zero Coalition has developed a framework for new shipping fuel introduction, from “proof of concept” via “initial scale” to “maturity”. Ammonia is currently considered just before “proof of concept”, with ammonia bunkering demonstrations ongoing, initial low-emission ammonia fuel supply for bunkering online (in Dalian, China), and the first ammonia-fueled two-stroke engines installed in vessels.
Next steps include large-scale ammonia-fueled vessels bunkering ammonia, rather than small-scale supply vessels and barges. Dedicated bunkering vessels will be relevant, as well as a scale-up of low-emission ammonia supply. As indicated in the AEA’s LEAD: Plants database, low-emission ammonia fuel production starts to scale from this year onward. This supply is sufficient to meet the initial demand of the maritime sector. The Port of Rotterdam expects to reach full maturity for ammonia bunkering by 2030-2033.