Japan Completes First Ship-to-Ship Ammonia Bunkering for Ammonia-Fuelled Vessel

NYK Line, together with Japan Marine United Corporation, Nihon Shipyard Co., Ltd., Mitsubishi Gas Chemical Company, Inc. and Kokuka Sangyo Co., Ltd., has completed a ship-to-ship (STS) ammonia bunkering operation for an ammonia-fuelled vessel in Japan.

The operation was carried out on September 17 at a quay within Japan Marine United Corporation’s Ariake Shipyard. Ammonia fuel was transferred from the ammonia carrier Shoei Maru to an ammonia-fuelled medium gas carrier (AFMGC) through the STS method.

The AFMGC is scheduled for delivery in November 2026, with the bunkering operation conducted in preparation for its sea trials using fuel ammonia.

Ammonia Transfer Conducted Ahead of Sea Trials

The operation involved transferring ammonia between two vessels rather than supplying the fuel through conventional shore-based infrastructure. The participating companies developed operating procedures and work processes ahead of the bunkering operation following discussions focused on safe ammonia handling.

The companies said the operation enabled them to gain practical experience in fuel supply procedures and establish processes for the safe transfer of ammonia.

The operation also provides a reference for fuel-supply arrangements that could be required as ammonia-fuelled vessels move towards wider commercial deployment.

Safety Remains a Key Challenge for Ammonia Bunkering

Ammonia is being considered as a marine fuel because it does not emit carbon dioxide during combustion and could contribute to reducing emissions from international shipping.

However, ammonia is toxic and requires specialised handling procedures. Establishing safe and reliable bunkering operations is therefore a key consideration for its wider use as a marine fuel.

The companies involved in the project focused on establishing safe operating procedures before carrying out the STS transfer. The experience gained from the operation is expected to contribute to the development of ammonia fuel supply and bunkering practices.

Ammonia-Fuelled Carrier Set for November Delivery

The AFMGC is in the final stage of construction and is scheduled for delivery in November 2026. The completed bunkering operation was carried out as part of preparations for the vessel’s fuel-ammonia sea trials.

The project is being developed under the Green Innovation Fund Project administered by Japan’s New Energy and Industrial Technology Development Organization (NEDO). The ¥2 trillion fund was established to accelerate changes in Japan’s energy and industrial sectors towards carbon neutrality by 2050.

The operation also contributes to efforts to establish an ammonia supply chain and develop the infrastructure and operational procedures required for ammonia-fuelled shipping.

Shoei Maru Supports Ammonia Fuel Transfer

The ammonia carrier Shoei Maru, owned by Kokuka Sangyo Co., Ltd., has a gross tonnage of 998 tonnes, an overall length of 71.5 metres and a breadth of 12.5 metres.

The vessel is primarily used to transport ammonia for Mitsubishi Gas Chemical Company’s Niigata Plant.