Japan Engine Corporation (J-ENG) and Kawasaki Heavy Industries, Ltd. are advancing development of a next-generation hydrogen ship engine under the Green Innovation Fund Project “Development of Marine Hydrogen Engines and MHFS” led by New Energy and Industrial Technology Development Organization (NEDO). The initiative also involves Mitsui O.S.K. Lines, Ltd. (MOL), MOL Drybulk Ltd., Onomichi Dockyard Co., Ltd., and Nippon Kaiji Kyokai (ClassNK). As part of this effort, J-ENG has developed a fully Japan-made, large, low-speed, two-stroke hydrogen ship engine, marking a significant step in marine decarbonization.
The engine, identified as 6UEC35LSGH, has reached a key milestone by initiating hydrogen co-firing operations across all cylinders. Designed as the world’s first full-scale unit intended for installation on an operational vessel, the hydrogen ship engine has already achieved a hydrogen co-firing ratio exceeding 95% at 100% load. This performance demonstrates both greenhouse gas reduction benefits and stable functionality. Further verification testing is planned to refine performance under hydrogen co-firing conditions, as developers continue to validate the system’s operational capabilities.
While hydrogen-powered vessels have gained traction in recent years both in Japan and internationally, most existing projects have focused on smaller-scale applications such as sightseeing boats or tugboats using compressed hydrogen for short-distance and low-output operations. In contrast, this initiative combines the high-efficiency, high-output, low-speed two-stroke 6UEC35LSGH hydrogen ship engine with liquefied hydrogen fuel. This approach is designed to support long-distance, long-duration, and high-output maritime operations, positioning it as a notable technological breakthrough toward the deployment of large oceangoing hydrogen-fueled merchant vessels.
J-ENG’s development draws on extensive research into hydrogen-compatible materials, combustion behavior, and durability of fuel injection systems. The engine is scheduled for shipment in January 2027, after completion of full-scale verification, and will be installed as the main propulsion unit on a 17,500-DWT hydrogen-fueled multi-purpose vessel being designed and constructed by Onomichi Dockyard. Kawasaki is simultaneously developing the MHFS hydrogen fuel supply system, which will be integrated into the vessel. MOL and Onomichi Dockyard have finalized contracts covering the vessel’s construction, while agreements on required onboard systems have also been concluded. The vessel’s detailed design is progressing steadily, with plans for a three-year demonstration phase beginning in FY2028 under MOL and MOL Drybulk operations. Throughout development, construction, and operation, ClassNK will oversee safety evaluations, as project partners continue efforts—supported by NEDO—to advance the practical deployment of the hydrogen ship engine and hydrogen-powered merchant shipping.
