A huge leap for green shipping! Japan Engine Corporation has successfully tested the world's first commercial ammonia-fueled engine, cutting GHG emissions by over 90%.
Japan's J-ENG Unveils World's First Commercial Ammonia Engine
Tokyo, Japan – In a landmark achievement that signals a new dawn for the global shipping industry's decarbonization efforts, Japan Engine Corporation (J-ENG) has successfully completed and tested the world's first fully-functional, full-scale commercial engine designed to be powered by ammonia. The engine, a 7-cylinder model designated 7UEC50LSJA-HPSCR, represents a critical and tangible step forward in the complex journey of developing next-generation, zero-emission ships. This success is a cornerstone in the industry's ambitious and necessary goal of achieving full carbon neutrality by 2050.
Building on its success, J-ENG is also concurrently developing a larger ammonia-fueled engine with a 60cm bore to address the wide variety of ammonia-fueled ships expected to emerge in the future market To meet this demand, the company is constructing a new factory scheduled to commence operations in fiscal year 2028 .
The successful completion and official test runs of this pioneering engine took place at J-ENG's factory over a four-day period, from August 27 to August 30, 2025. This significant milestone is a key deliverable of the "Next-Generation Ship Development" initiative, which itself is a vital part of the much larger Green Innovation Fund Project. This fund is administered by Japan's New Energy and Industrial Technology Development Organization (NEDO), a governmental body dedicated to fostering innovation in technology and energy for a sustainable future.
The rigorous and comprehensive testing process was conducted under the close and expert supervision of a consortium of major industry partners, underscoring the collaborative nature of this achievement. These partners included the global shipping giant Nippon Yusen Kaisya (NYK Line), Nihon Shipyard Co., Ltd. (NSY), the shipbuilder Japan Marine United Corporation (JMU), and the internationally recognized maritime classification society, Nippon Kaiji Kyokai (ClassNK). The engine was put through a demanding series of performance verification tests, successfully demonstrating its robust capabilities in both ammonia fuel operation mode and, crucially, in traditional heavy fuel oil operation mode, proving its effectiveness as a versatile dual-fuel engine.
Following the successful operational tests, meticulous post-operation inspections of the engine's major internal and external components were carried out. This led to ClassNK officially certifying the engine's outstanding environmental performance and safety. This certification is a non-negotiable and crucial step that validates the engine's readiness for commercial application. The engine is now scheduled to be shipped in October 2025 for its historic installation on an Ammonia-Fueled Medium Gas Carrier (AFMGC). This state-of-the-art vessel is currently under construction at the JMU Ariake Shipyard. The pioneering vessel is expected to enter commercial service in 2026, at which point it will become the first of its kind, marking the dawn of a new era in sustainable marine transport.
This remarkable achievement was not an overnight success but the direct result of a meticulously planned, multi-year, long-term development program. J-ENG had previously conducted approximately 1,000 hours of intensive test runs on a single-cylinder ammonia-fuel test engine. These foundational tests took place at the Mitsubishi Heavy Industries Research & Development Center in Nagasaki between May 2023 and September 2024. The valuable and extensive insights, data, and engineering know-how gained from these initial tests were instrumental in the successful design and manufacturing of the first full-scale commercial engine.
Test runs on this full-scale engine using ammonia fuel commenced in April 2025. Over the subsequent five months, the engine underwent an additional 700 hours of meticulous and detailed testing. This extensive period was dedicated not only to validating its core functions but also to optimizing a wide range of performance aspects. Concurrently, the engineering team focused on confirming the engine's high reliability and its suite of advanced safety features, which include sophisticated leak prevention and monitoring systems for the potentially toxic ammonia fuel. The engine was thus completed, equipped with sufficient and certified functionality to ensure the safe operation of actual vessels and, most importantly, the safety of the crew members who will operate them.
The performance data gleaned from the trial runs is highly promising and exceeds many industry expectations. At 100% engine load and a 95% ammonia co-firing rate, the engine achieved a remarkable reduction in greenhouse gas (GHG) emissions of over 90% compared to conventional fuel. Nitrous oxide (N₂O), another potent greenhouse gas and a potential byproduct of ammonia combustion, was measured at an impressively low level of approximately 3 parts per million (ppm). Furthermore, nitrogen oxide (NOx) emissions were confirmed to be about half those of conventional heavy oil engines, and critically, unburned ammonia emissions were virtually zero after passing through the engine's High-Pressure NOx Selective Catalytic Reduction (SCR) system. The engine's thermal efficiency in ammonia fuel operation mode was also confirmed to be equivalent to, or even slightly higher than, its performance on heavy fuel oil.
Building on this monumental success, J-ENG is already looking to the future and scaling its technology. The company is concurrently developing a larger ammonia-fueled engine with a 60cm bore to cater to the wide variety of larger ammonia-fueled ships that are expected to enter the market in the coming years. J-ENG has also stated that it is actively working on several promising follow-on projects, cementing its position as a clear first mover in the field of next-generation marine fuel engines.
To support the anticipated demand and facilitate the mass production of these new engines, J-ENG is proceeding with the construction of a new, state-of-the-art factory. This significant expansion is being supported by a subsidized project jointly run by Japan's Ministry of the Environment and the Ministry of Land, Infrastructure, Transport and Tourism, utilizing innovative financing from GX Economic Transition Bonds. The new factory, which is scheduled to commence operations in fiscal year 2028, will allow J-ENG to significantly expand its production volume of ammonia-fueled engines in a product mix with its existing heavy oil engines, a crucial step to further promote the widespread adoption of zero-emission ships.
In a press release, the company stated, “As a first mover in next-generation fuel engines, J-ENG will contribute to the development of Japan’s shipping and shipbuilding industries by promoting the early market introduction and widespread adoption of those engines, while also contributing to the reduction of GHG (greenhouse gas) emissions in the shipping industry and the realization of carbon neutrality by 2050” .