Japanese shipowner NYK has completed what it calls the world’s first ship-to-ship bunkering of an ammonia-fuelled vessel in Japan, according to a company statement.
The operation took place on 17 September at Japan Marine United’s Ariake Shipyard in Nagasu, Kumamoto prefecture, with Japan Marine United, Nihon Shipyard, Mitsubishi Gas Chemical and Kokuka Sangyo taking part alongside NYK.
Fuel ammonia was transferred from the 998-gt carrier Shoei Maru to a 40,000-cbm ammonia-fuelled medium gas carrier under construction ahead of sea trials using ammonia fuel. Shoei Maru is 71.5 metres long and 12.5 metres wide and is primarily used to transport ammonia for Mitsubishi Gas Chemical’s Niigata plant.
The Japanese-flagged newbuilding is due for delivery in November 2026. It will be 180 metres long, 32 metres wide and 18.45 metres deep. The vessel is being developed under Japan’s New Energy and Industrial Technology Development Organization Green Innovation Fund project by NYK, Nihon Shipyard, Japan Engine Corporation and IHI Power Systems, with ClassNK participating.
Japan Engine Corporation is supplying an ammonia dual-fuel two-stroke main engine, while IHI Power Systems is providing an ammonia dual-fuel four-stroke auxiliary engine. The project targets an ammonia co-firing ratio of up to 95% for the main engine, at least 80% for the auxiliary engine and an overall greenhouse-gas reduction of at least 80%.
After delivery, the ship is due to enter a time charter with Yara Clean Ammonia Switzerland SA. NYK and Yara signed the charter agreement in February 2025 after working on the practical application of an ammonia-fuelled ammonia carrier since 2021.
NYK’s world-first claim applies specifically to bunkering ammonia as marine fuel into an ammonia-fuelled vessel, rather than to the first ship-to-ship transfer of ammonia.
NYK, formally Nippon Yusen Kabushiki Kaisha, is a Tokyo-headquartered shipping and logistics group founded in 1885 and had 39,830 employees on a consolidated basis as of 31 March 2026.
Japan Marine United and Nihon Shipyard are Japanese shipbuilding companies. Mitsubishi Gas Chemical is a Japanese chemical company, while Kokuka Sangyo owns Shoei Maru.
Japan Engine Corporation is a marine engine manufacturer, IHI Power Systems is a marine power systems supplier, and ClassNK is a Japanese classification society.