J-ENG in hydrogen-fueled two stroke first

Hydrogen-fueled J-ENG 6UEC35LSGH will power a 17,500‑DWT multi-purpose vessel. [Image: J-ENG/MOL/Onomichi Dockyard]

Japan Engine Corporation (J‑ENG) has successfully begun hydrogen co‑firing operation in all cylinders of a fully Japanese-made, large, low‑speed, two‑stroke hydrogen-fueled engine. According to J-ENG, the 6UEC35LSGH engine is the world’s first full‑scale hydrogen engine intended for installation on an actual vessel — a 17,500‑DWT hydrogen‑fueled multi-purpose vessel designed and built by Onomichi Dockyard.

The vessel is scheduled to undergo three years of demonstration operation starting in FY2028 under the operation of MOL and MOL Drybulk. The detailed design of the vessel is currently progressing smoothly following the conclusion of a series of contracts for its construction between MOL and Onomichi Dockyard. In addition, discussions among relevant parties saw agreements reached on the specifications of several facilities required for the hydrogen‑fueled vessel.

To date, the 6UEC35LSGH engine has reportedly 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 optimize performance under hydrogen co‑firing conditions.

In recent years, the development and demonstration of hydrogen‑fueled vessels have progressed in Japan and internationally. However, most initiatives focus on short‑distance, short‑duration, and low‑output operations—such as sightseeing boats or tugboats using compressed hydrogen—primarily for domestic coastal or port‑area applications. In contrast, this project combines the high‑efficiency, high‑output, low‑speed two‑stroke hydrogen‑fueled 6UEC35LSGH engine with liquefied hydrogen fuel, enabling long‑distance, long‑duration, and high‑output operations. This marks a major technological milestone on the road to practical use of large oceangoing hydrogen‑fueled merchant ships.

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‑fueled multi-purpose vessel (“the Vessel”) designed and built by Onomichi Dockyard. The vessel’s hydrogen fuel supply system is being developed and manufactured by Kawasaki.

The Vessel is scheduled to undergo three years of demonstration operation starting in FY2028 under the operation of MOL and MOL Drybulk. Throughout the development of the engine and MHFS, as well as the design, construction, and operation of the vessel, ClassNK will conduct safety evaluations.

Hydrogen-fueled J-ENG 6UEC35LSGH engine