HomeNYK Completes World-First Ship-to-Ship Ammonia Bunkering in Japan

NYK Completes World-First Ship-to-Ship Ammonia Bunkering in Japan

September 18, 2026

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NYK Line and four Japanese partners completed what the companies describe as the world’s first ship-to-ship transfer of ammonia as marine fuel into an ammonia-fueled vessel on September 17, 2026, at Japan Marine United’s Ariake Shipyard in Kumamoto Prefecture. Ammonia was transferred from the 998-GT carrier Shoei Maru to NYK’s new 40,000-cbm ammonia-fueled medium gas carrier, which is being prepared for ammonia-fueled sea trials ahead of delivery in November. Japan Marine United, Nihon Shipyard, Mitsubishi Gas Chemical and Kokuka Sangyo participated with NYK. The amount of ammonia transferred and the bunkering rate were not disclosed. The receiving vessel is 180 metres long, will fly the Japanese flag and is already committed to Yara Clean Ammonia under a long-term charter.

Ammonia Fuel Supply Milestone

Ammonia moves from one vessel directly into the fuel system of another

The September 17 operation supplied fuel ammonia from an existing ammonia carrier to NYK's new oceangoing ammonia-fueled gas carrier ahead of its first ammonia-powered sea trials.

WORLD-FIRST CLAIM: STS AMMONIA BUNKERING TO AN AMMONIA-FUELED VESSEL
Receiving Vessel 40K cubic metres cargo capacity
Fuel Supplier 998 GT Shoei Maru ammonia carrier
Location Ariake JMU shipyard, Kumamoto Prefecture
Delivery Nov. 2026 scheduled AFMGC completion
Transfer Volume Not Given NYK did not disclose bunker quantity
September 17 fuel transfer
Shoei Maru 71.5 m ammonia carrier
Owned by Kokuka Sangyo
Fuel-supply vessel
→
NYK AFMGC 40,000-cbm newbuild
180 m × 32 m
Receiving ammonia as propulsion fuel
The precise world-first

Ammonia had previously been transferred ship-to-ship as cargo. This operation is being claimed as the first STS transfer where ammonia was bunkered specifically as fuel into an ammonia-powered ship.

Safety is central to the fuel

Ammonia's toxicity requires dedicated detection, containment, emergency-release arrangements, procedures, training and exclusion controls that go beyond simply transferring another liquid fuel.

From Ammonia Cargo to Ammonia Fuel

Several milestones preceded the September bunkering operation. The distinction is whether ammonia was merely transferred as cargo, whether equipment was certified for bunkering, or whether fuel was actually delivered to a ship designed to burn it.
Date Milestone Vessels / Equipment What Happened What It Proved Status
July 2024 Ammonia bunkering boom receives ClassNK AiP NYK / TB Global Technologies bunkering boom with emergency-release system ClassNK granted Approval in Principle for an STS ammonia-fuel transfer system. A dedicated connection and emergency-disconnection concept could satisfy classification review at the design stage. Equipment AiP
June 2025 Japan publishes ammonia bunkering guidelines Applicable to ship-to-ship and other ammonia bunkering operations National guidance addressed gas detection, emergency release, controlled areas, training and protective measures. Japan established an operational framework before larger commercial ammonia-fuel activity began. Rules Framework
September 2025 Large-scale ammonia STS cargo transfer BERLIAN EKUATOR → ECO ENCHANTED Approximately 23,000 tonnes of liquid ammonia were transferred between ammonia carriers off Ceuta. Large quantities of ammonia could be transferred STS under near-commercial cargo-transfer conditions. Cargo Transfer
September 2026 Operational ammonia bunker vessel enters service Shenghang Yongle A converted 5,500-cbm gas carrier was reported operationally ready for liquid-ammonia STS bunkering and received an ammonia-bunkering class certificate. A dedicated bunker vessel could progress from design into operational readiness. Bunker Vessel
September 17, 2026 Ammonia bunkered as fuel Shoei Maru → NYK 40,000-cbm AFMGC Ammonia was transferred ship-to-ship directly into an ammonia-fueled vessel at JMU's Ariake Shipyard. NYK describes this as the world's first STS ammonia bunkering operation to an ammonia-powered receiving vessel. World-First Claim
Next Ammonia-powered sea trials NYK AFMGC The newly bunkered ship is preparing to run its propulsion plant using ammonia during sea trials. Moves the project from shore-based engine validation and fuel-transfer work into integrated vessel operation. Upcoming
November 2026 Scheduled commercial delivery NYK AFMGC / Yara Clean Ammonia The 40,000-cbm vessel is scheduled for completion and subsequent operation under its charter to Yara Clean Ammonia. Creates an oceangoing commercial operating case combining ammonia cargo carriage and ammonia-fueled propulsion. Scheduled
AFMGC Length 180 m 32 m beam and 18.45 m molded depth
Main Engine 7UEC50LSJA J-ENG ammonia dual-fuel two-stroke
Tested NH₃ Ratio 95% Full-load main-engine test condition
Charterer Yara Yara Clean Ammonia Switzerland SA

Ammonia Bunkering Turnaround Model

Test how bunker quantity, transfer capacity and non-transfer time affect the total port window required for a future ship-to-ship ammonia fueling operation.

Scenario input. NYK did not disclose the September 17 bunker quantity.
Allows for a lower effective average rate than the equipment's nominal maximum.
User-defined planning allowance for vessel positioning and pre-transfer activities.
User-defined planning allowance after liquid transfer is completed.
Effective Transfer Rate
127.5 t/h
Rated capacity × utilization assumption
Liquid Transfer Time
3.92 h
Fuel quantity ÷ effective transfer rate
Total Operation Window
6.42 h
Pre-transfer + transfer + post-transfer
Fuel per Port Hour
77.9 t
Quantity divided by total occupied window
Annual Fuel Delivered
20,000 t
At the selected number of annual operations
Annual Bunkering Hours
257 h
Total modeled operational window per year
Modeled Bunkering Window
PRE
TRANSFER
POST
1.5 h pre-transfer
3.92 h liquid transfer
1.0 h post-transfer
Planning model only. It is not an ammonia-bunkering procedure or safety standard. Actual transfer limits, operating sequences, exclusion zones, personnel requirements, emergency systems and permissible conditions must follow the applicable flag, port, class, vessel and regulatory requirements. No quantity or transfer-rate data from NYK's September 17 operation has been used because those figures were not publicly disclosed.
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