The world’s first ammonia-powered ship engine was unveiled in Japan. Developed by Japan Engine Corporation (J-ENG), this engine heralds a new era in maritime transport. It will reportedly be used on a cargo ship that will enter service in 2026.
Ammonia-powered ships are coming
Kobe-based J-ENG announced on August 30 that its 7UEC50LSJA-HPSCR engine, unveiled on August 30, is a dual-fuel engine powered by ammonia and heavy fuel oil (HFO). This feature facilitates the transition from fossil fuels to renewable energy. The engine has seven cylinders and a diameter of 50 centimeters. Its high-pressure Selective Catalytic Reduction (SCR) system minimizes nitrogen emissions.
The engine was tested under the supervision of industry-leading companies such as NYK Line, Nihon Shipyard, and Japan Marine United Corporation. ClassNK, the world’s largest maritime classification society, certified the engine for its environmental performance and operational safety.
The engine, scheduled for delivery in October 2025, will be installed on a gas carrier being built at JMU Ariake Shipyard. This vessel will become the first full-scale commercial ammonia-powered vessel when it begins commercial operations in 2026. To achieve this success, J-ENG conducted single-cylinder prototype tests in 2023-2024 and completed full-scale engine tests this year.
The test results are impressive. The engine achieves nearly zero emissions even at high ammonia usage. Greenhouse gas emissions are reduced by over 90 percent. Nitrogen oxide emissions are halved compared to conventional engines. Unburned ammonia is virtually eliminated, while the engine’s thermal efficiency is comparable to, or even better than, heavy fuel oil systems.
Following this success, J-ENG announced the development of a new 60 cm diameter ammonia engine to meet growing demand. This new engine is expected to enter service in 2028.
