Japan Engine Corporation (J‑Eng) and Kawasaki Heavy Industries have been jointly engaged in Japan’s New Energy and Industrial Technology Development Organization (NEDO) Green Innovation Fund projects for the development of marine hydrogen engines and marine hydrogen fuel systems.
The project is being undertaken in cooperation with Mitsui OSK Lines (MOL), MOL Drybulk, Onomichi Dockyard and ClassNK. Within the project, J‑Eng has been developing a fully Japan-made, large, low‑speed, two‑stroke hydrogen-fuelled engine. The 6UEC35LSGH engine, which according to J-Eng is the world’s first full‑scale example intended for installation on an actual vessel, has successfully begun hydrogen co‑firing operation in all cylinders. To date, the engine has achieved a hydrogen co‑firing ratio of over 95% at 100% load, confirming both GHG reduction effects and stable operation. Verification testing will continue to further optimise performance under hydrogen co‑firing conditions.
In recent years, the development and demonstration of hydrogen‑fuelled vessels has progressed in Japan and abroad. However, most initiatives focus on short‑distance, short‑duration, and low‑output operations—such as passenger vessels and tugs using compressed hydrogen—primarily for domestic coastal or port‑area applications. In contrast, the current project combines the high‑efficiency, high‑output, low‑speed two‑stroke hydrogen‑fuelled 6UEC35LSGH engine with liquefied hydrogen fuel, thereby enabling long‑distance, long‑duration, and high‑output operations. This is considered a major technological milestone toward the practical use of large ocean-going hydrogen‑fuelled merchant ships.
J‑Eng has accumulated experience through fundamental studies on hydrogen‑related materials and combustion, as well as durability testing of hydrogen fuel injection systems. The new engine has been developed based on this accumulated knowledge. Once full-scale verification is complete, the engine is scheduled for shipment in January 2027 and will be installed as the main engine of a 17,500 dwt hydrogen‑fuelled multi-purpose vessel designed and built by Onomichi Dockyard. The hydrogen fuel supply system, which will also be installed o the vessel, for this engine is being developed and manufactured by Kawasaki.
MOL and Onomichi Dockyard have concluded a series of contracts for the construction of the vessel. In addition, through discussions among the relevant parties, agreements were reached on the specifications of various facilities required for the hydrogen‑fuelled vessel, and related contracts were executed. The detailed design of the vessel is currently said to be progressing smoothly.
The vessel is scheduled to undergo three years of demonstration operation starting in 2028 under the operation of MOL and MOL Drybulk. Throughout the development of the engine and fuel system, as well as the design, construction, and operation of the vessel, ClassNK will conduct safety evaluations.
With NEDO’s support, J‑Eng and Kawasaki, in collaboration with MOL, MOL Drybulk, Onomichi Dockyard, and ClassNK, will continue taking on the challenge of realising the practical operation of merchant vessels powered by hydrogen fuel—paving the way toward a sustainable future for the maritime industry.
Image: 17,500 dwt Hydrogen-fuelled multi-purpose vessel (source: Mitsui OSK Lines)
