Japanese shipping company NYK Line has completed its first ship-to-ship (STS) transfer of liquefied ammonia, moving approximately 23,000 tonnes of the cargo between two vessels off the coast of Ceuta, Spain, on September 2.

The transfer was conducted from the ammonia carrier Berlian Ekuator — owned by NYK and time-chartered by Mitsui & Co. — to the ammonia carrier Eco Enchanted, operated by ammonia trader Trammo.

While NYK has experience with STS transfers involving crude oil, LNG, and liquefied petroleum gas, this marks the company's first operation involving liquefied ammonia. The transfer was supported by Trammo's experience and their designated STS specialist provider, International Fender Providers.

NYK said it leveraged its safety management system and STS operational knowledge to transfer the entire cargo of liquefied ammonia to Berlian Ekuator.

NYK also noted that the STS method, which is not constrained by port size or onshore equipment, is attracting attention as a flexible supply method compared to conventional land-based cargo handling methods.

"The success of this operation marks a significant milestone in developing an international supply network for ammonia. NYK will build on the insights and experience gained from this successful transfer to further advance next-generation fuels and strengthen safe maritime transportation systems, thereby contributing to the broader goal of achieving a decarbonized society," the shipping firm said.