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# J-ENG Completes World's First Hydrogen Engine for Large Commercial Vessels
- URL: https://review.iffw.sg/j-eng-completes-worlds-first-hydrogen-engine-for-large-commercial-vessels/
- Published: 2026-10-03T00:30:15.000Z
- Updated: 2026-10-03T00:30:14.000Z
- Description: J-ENG completed the 6UEC35LSGH, the world's first hydrogen-fuelled engine for large commercial vessels, achieving 95% hydrogen co-firing and over 95% GHG reduction in factory testing. It will be installed on a MOL multipurpose vessel in 2027, with onboard demonstration starting April 2028.
- Author: Editor
- Tags: News, Hydrogen, Maritime

Japan Engine Corporation (J-ENG) has completed the 6UEC35LSGH, which the company describes as the world's first hydrogen-fuelled engine for large commercial vessels, developed under Japan's NEDO Green Innovation Fund Project alongside Kawasaki Heavy Industries, Yanmar Power Solutions, Mitsui O.S.K. Lines (MOL), MOL Drybulk, Onomichi Dockyard and classification society ClassNK. During factory testing, the engine achieved a hydrogen co-firing rate of at least 95%, reducing greenhouse gas emissions by more than 95% compared with conventional heavy-fuel-oil engines.

### How the Engine Actually Achieves Stable Hydrogen Combustion 

The engine uses a high-pressure direct injection system, injecting fuel directly into the cylinder at high pressure, which J-ENG states is what enables stable hydrogen combustion specifically. Safety measures built into the design include a robust structure intended to prevent hydrogen leakage and double-walled piping for the hydrogen supply lines. Approval testing was conducted with ClassNK present and completed successfully, with ClassNK continuing to provide safety assessments at each subsequent stage of the engine's development and the vessel's design, construction and operation.

### Why This Is a Distinct Milestone From the Company's Earlier Ammonia Engine 

J-ENG frames this specifically as building on, rather than replacing, its prior work: in August 2025 the company completed what it describes as the world's first ammonia-fuelled marine low-speed two-stroke engine, positioning itself as a pioneer developing a range of next-generation fuel engines in parallel rather than committing exclusively to a single alternative fuel pathway. This hydrogen engine is a separate model built for a different vessel class and application, not an upgrade or successor to the ammonia-fuelled design.

### What Happens Next, and on What Timeline 

The engine is scheduled for installation in January 2027 on a 17,500 DWT multipurpose vessel being built by Onomichi Dockyard for MOL and MOL Drybulk, under the project name "Blue Harmony." Hydrogen fuel will be supplied through a Marine Hydrogen Fuel System (MHFS), consisting of hydrogen fuel tanks and a supply system developed and manufactured by Kawasaki, which will also develop and manufacture the bunkering equipment needed to supply liquefied hydrogen to the vessel. Following sea trials, onboard demonstration testing is scheduled to begin in April 2028, more than a year after the engine's planned installation, intended specifically to evaluate the engine's durability and performance under actual operating conditions rather than only factory-test conditions.

### Why the Gap Between Installation and Demonstration Testing Matters 

A roughly 15-month gap between the engine's planned installation and the start of onboard demonstration testing reflects the additional steps, including sea trials, required before a newly installed engine and its supporting hydrogen fuel system can be properly evaluated under real operating conditions at sea, rather than the project treating installation itself as the final milestone.

*Source:* [*Mitsui O.S.K. Lines*](https://www.mol.co.jp/en/pr/2026/26046.html?ref=review.iffw.sg)*, 18 September 2026.*