Japan Engine Completes World-First Hydrogen Marine Engine

Japan Engine Corporation (J-ENG) has completed what it describes as the world’s first hydrogen-powered main engine designed for a large commercial vessel, marking another important step toward full-scale sea trials.

The 6UEC35LSGH low-speed, two-stroke engine was unveiled this week at J-ENG’s Akashi factory after factory testing achieved a hydrogen co-firing ratio of more than 95%.

According to Japan’s New Energy and Industrial Technology Development Organization (NEDO), the engine produced over 95% fewer greenhouse gas emissions compared with an equivalent engine operating on heavy fuel oil.

The new engine uses high-pressure direct hydrogen injection technology to maintain stable combustion and is set to be installed aboard a 17,500 dwt multipurpose vessel under construction at Onomichi Dockyard for Mitsui OSK Lines (MOL). The project forms part of Japan’s Blue Harmony initiative.

The engine is expected to leave the factory in January 2027, while demonstration voyages using the completed vessel are scheduled to start in April 2028.

Kawasaki Heavy Industries is responsible for developing the vessel’s hydrogen fuel supply system, while Yanmar Power Solutions is developing hydrogen-powered auxiliary engines. ClassNK is carrying out safety assessments throughout the project, covering engine development as well as the vessel’s design, construction and operational stages.

The project is part of Japan’s Green Innovation Fund initiative, which aims to develop technologies capable of supporting zero-emission oceangoing vessels.