World's First Ship-to-Ship Ammonia Bunkering to an Ammonia-Fueled Vessel

Demonstrating a Fuel-Supply Operation Essential for Deployment of Next-Generation Fueled Vessels

18 September 2026

NYK Line, with Japan Marine United Corporation, Nihon Shipyard Co., Ltd., Mitsubishi Gas Chemical Company, Inc., and Kokuka Sangyo Co., Ltd., has completed the world's first ship-to-ship (STS) ammonia bunkering operation to an ammonia-fueled vessel on September 17. At a quay within Japan Marine United Corporation's Ariake Shipyard, ammonia fuel was transferred from the ammonia carrier Shoei Maru* via the STS method** to an ammonia-fueled medium gas carrier (AFMGC)*** scheduled for delivery in November 2026. The operation was conducted in preparation for sea trials of the AFMGC using fuel ammonia.

This achievement represents an important initiative that has put into practice an operation essential for the future practical deployment of ammonia-fueled vessels.


Image by NYK.

Ammonia is expected to play an important role as a next-generation marine fuel because it emits no carbon dioxide (CO₂) during combustion and can contribute to the decarbonization of international shipping. At the same time, its toxicity makes it difficult to handle, and establishing highly safe and reliable operations remains a challenge for practical use.

The bunkering operation was conducted following extensive discussions among the companies involved. Safe operating procedures and work processes were established prior to the operation, enabling the transfer to be completed safely. Through this initiative, we have accumulated practical insights regarding safe fuel supply operations.

This operation serves as a pioneering example of the fuel-supply framework that will be required for the widespread adoption of ammonia-fueled vessels. The AFMGC is currently in the final stage of construction and is scheduled for delivery in November 2026. The successful completion of this operation marks a significant milestone toward the broader commercial use of fuel ammonia and the practical deployment of ammonia-fueled vessels. It also represents an important step forward in establishing an ammonia supply chain.

* Ammonia Carrier Shoei Maru
Owner: Kokuka Sangyo Co., Ltd.
Principal particulars: Gross tonnage 998 tons, length overall 71.5 m, breadth 12.5 m
The vessel is primarily engaged in transporting ammonia for Mitsubishi Gas Chemical Company's Niigata Plant.

** Ship-to-Ship (STS) Method
A method of directly supplying fuel by connecting a bunkering vessel and a receiving vessel via transfer hoses.

*** AFMGC
The vessel development is under the Green Innovation Fund Project**** by Japan's New Energy and Industrial Technology Development Organization (NEDO).

**** Green Innovation Fund Project
A 2 trillion-yen NEDO fund created to significantly accelerate current efforts such as structural transformation of the energy and industrial sector and innovation through bold investment toward carbon neutrality by 2050. The fund provides continual support from R&D and demonstration to social implementation for up to 10 years for companies that share ambitious and concrete goals with the public and private sectors and tackle them as management issues. NEDO mainly provides support in 14 priority areas for which action plans are being formulated in the green growth strategy.

NYK Group, press release