Japan's Gemi Leads Green Revolution with Ammonia-Powered Marine Engine Cutting Emissions by 90%

Japan Engine Corporation (J-ENG), based in Akashi, has introduced the world's first commercial ammonia-powered low-speed marine engine, marking a potential revolution in maritime transport. This new-generation engine, labeled 7UEC50LSJA-HPSCR, is designed to operate on both ammonia and heavy fuel oil, showcasing a dual-fuel capability that significantly cuts greenhouse gas emissions by over 90%. Following rigorous tests under the oversight of industry giants like NYK Line, Nihon Shipyard, Japan Marine United Corporation, and ClassNK, the engine was officially certified by ClassNK for both its environmental performance and operational safety.

The engine's design features 50 centimeter diameter cylinders in a seven-cylinder configuration, incorporating a high-pressure selective catalytic reduction (SCR) system to effectively reduce nitrogen emissions. Tests revealed that at a 95% ammonia co-firing rate, the engine generated only three parts per million of nitrous oxide (N₂O), while achieving a reduction in greenhouse gases surpassing 90% and minimal ammonia slip post-exhaust treatment. It is set to be supplied to a vessel currently being constructed at JMU Ariake Shipyard, which will begin commercial operations in 2026. Over 1,000 hours were devoted to prototype testing, followed by 700 hours of full-scale trials in its development phase.

Looking ahead, Japan Engine Corporation is working on a 60-centimeter diameter version designed for larger vessels, expected to be operational by 2028. This advancement is part of J-ENG's broader strategy to support Japan's shipbuilding industry and contribute to achieving carbon neutrality by 2050. The company is also planning to enhance its production capability by establishing a new factory to support its expansion.

J-ENG proudly claims this development as a pivotal step in the long-term program for zero-emission maritime transport, emphasizing the significance of the first safe and reliable commercial ammonia-powered main engines as essential tools in global decarbonization efforts. This innovation positions Japan at the forefront of maritime engineering and environmental responsibility in the evolving landscape of global shipping.