The world’s first ammonia-powered ship, the Japanese tugboat “Sakigake”, has completed a three-month demonstration run in Tokyo Bay.
Measurements from this period show a clear environmental advantage of the alternative fuel: the tugboat emitted up to 95% less greenhouse gases.
The “Sakigake” was completed in August 2024 by NYK and IHI Power Systems (IPS) in collaboration with the classification society ClassNK. The newbuild is part of a project of the Green Innovation Fund of the Japanese New Energy and Industrial Technology Development Organization (NEDO). It is the first commercially used ship with a pure ammonia propulsion system. After delivery, Shin-Nippon Kaiyosha, a company of the NYK Group, started a three-month demonstration voyage in tugboat operation in Tokyo Bay.
Ammonia engine significantly reduces emissions
NYK and IPS analyzed the ammonia co-combustion and greenhouse gas reduction rates during ship operation and confirmed that these are consistently above 90%, increasing to around 95% in each of the engine’s main load ranges. “The demonstration tests in tug operations are the world’s first trial and confirm that ammonia is one of the most viable and promising options as a next-generation marine fuel,” NYK announced.
The vessel will continue to be used for tugboat operations in Tokyo Bay, and NYK will continue to accumulate knowledge related to the development and operation of ammonia-powered vessels.
In addition, NYK, Japan Engine Corporation, IPS and Nippon Shipyard are working together to develop an ammonia-powered ammonia gas tanker, which is scheduled for delivery in November 2026. The newbuilding is also part of the NEDO project. NYK has announced that it will continue to develop next-generation vessels, including ammonia-powered vessels, in pursuit of the goal of net zero emissions.
Ammonia (chemical formula NH3) is a promising alternative fuel to minimize emissions in shipping. As the compound is already widely used in agriculture, for example, large capacities already exist. One issue, however, is that ammonia is toxic to humans and cannot simply be stored without safety measures.
