Japan’s Nippon Yusen Kaisha (NYK) has moved to retrofit its liquefied natural gas (LNG)-fuelled tugboat to run on ammonia fuel.

Yokohama-based Keihin Dock Co., part of NYK Group, will carry out the modifications on the Sakigake it built in 2015.

The vessel, which operates in Tokyo Bay for another NYK Group company, Shin-Nippon Kaiyosha Corporation, should be ready to operate on ammonia in 2024.

The initiative is part of the development of vessels equipped with a domestically produced ammonia-fueled engine, which was initiated in October 2021 by NYK and IHI Power Systems.

Earlier in July, the two companies obtained approval in principle from the Japanese class society Nippon Kaiji Kyokai (ClassNK) for an ammonia-fueled tugboat.

“In the development process, there were various design challenges in using ammonia as fuel, but the two companies overcame these challenges without changing the size of the conventional tugboat,” NYK said.

Japanese shipowners, yards, and trading houses have been heavily involved in the development of the country’s ammonia (NH3) supply chain, including ammonia-powered deepsea ships expected to enter the market by as early as 2028. The government of Japan forecasts domestic ammonia demand of 3m tons in 2030 and 30m tons in 2050 and several owners have already contracted fellow shipbuilder Kawasaki Heavy Industries (KHI) to build NH3 carriers alongside liquefied petroleum gas (LPG).

NYK’s domestic rival, Kawasaki Kisen Kaisha (K Line), has also recently embarked on a project, through its harbour logistics business unit, Seagate Corporation, to roll out a new battery-powered tugboat in the first half of 2025.