London, UK – 15 October 2025
World’s First Ammonia-fueled Tugboat Operation Validated for Creating Environmental Value.
In a watershed moment for the global maritime industry’s pursuit of decarbonisation, a landmark project has achieved the world’s first validation of environmental value derived from the commercial operation of an ammonia-fueled vessel. The ammonia-fueled tugboat Sakigake, a pioneer in next-generation marine power, has proven that switching from traditional fossil fuels to ammonia can deliver quantifiable greenhouse gas (GHG) reductions that can be officially certified and traded. This monumental validation for creating environmental value sets a crucial precedent, accelerating the shipping industry’s momentum toward meeting the International Maritime Organization’s (IMO) ambitious net-zero emissions target by 2050. The successful operation, centred in Tokyo Bay, Japan, has definitively confirmed ammonia’s potential as a powerful and commercially viable next-generation marine fuel.
A Global Decarbonisation Milestone Confirmed
The environmental validation was officially granted following the successful commercial-use operation of the ammonia-fueled tugboat Sakigake in Japanese waters. Operated by Shin-Nippon Kaiyosha, a company within the NYK Line Group, the vessel recently received third-party certification for the environmental value created through its towage services. This value represents the quantified reduction in greenhouse gas (GHG) emissions achieved by using ammonia instead of conventional marine fuel.
This development is significant because it marks the first time globally that the environmental benefit of an ammonia-fueled vessel’s operation has been officially certified and quantified. The certification effectively converts the vessel’s real-world decarbonisation performance into a tangible, tradable commodity, potentially integrating it into green credit systems. This creates a powerful financial incentive for the global shipping industry to adopt ammonia and other low-carbon fuels.
The Sakigake was originally completed in August 2024 as the world’s first commercial-use ammonia-fueled vessel. The tugboat is a converted LNG-fueled vessel, demonstrating a pathway for existing fleet assets to transition to new, cleaner fuel sources. The conversion, which involved replacing the main engine with a domestically produced four-stroke ammonia-fueled engine from IHI Power Systems Co., Ltd., was a core part of a Green Innovation Fund Project supported by Japan’s New Energy and Industrial Technology Development Organization (NEDO). The project’s success confirms the viability of the engine and fuel supply systems in an operational, commercial environment.
Operational Success and High Emission Reduction Rates
The extensive operation of the Sakigake, which included a three-month demonstration voyage in Tokyo Bay followed by commercial service in Yokohama Port, provided compelling technical data. The results confirmed that the vessel could achieve substantial GHG reductions through high rates of ammonia co-firing.
During the demonstration tests, the engine operations consistently showed ammonia co-firing rates well over 90 per cent across various main engine load ranges, reaching as high as 95.2 per cent. Critically, this directly correlated to a massive reduction in GHG emissions. The test results confirmed that the vessel achieved a GHG-emission reduction of up to approximately 95 per cent compared to using conventional heavy fuel oil. These figures far exceed expectations, cementing ammonia as one of the most promising and powerful alternatives to fossil fuels in the maritime sector.
Furthermore, the operation highlighted the feasibility of the ammonia fuel supply chain. The tugboat is notably powered by the low-environmental-impact ammonia known as “ECOANN,” which is manufactured using post-consumer plastics as part of the raw materials. This innovative fuel source, provided by JERA Co., Ltd. and manufactured by Resonac Corporation, contributes not only to reduced GHG emissions but also to the broader goal of a circular economy by reducing waste.
Ammonia: The Future Fuel of Global Shipping
The validation of the Sakigake’s environmental value comes at a critical time for the global maritime industry, which is under immense pressure to decarbonise a sector responsible for approximately 2 to 3 per cent of all global emissions. Ammonia is emerging as a leading candidate for future marine fuel for several compelling reasons:
1- Zero-Carbon at Combustion:
Ammonia (\text{NH}_3) contains no carbon, meaning its combustion does not produce carbon dioxide (\text{CO}_2), the primary GHG responsible for global warming.
2- Existing Infrastructure:
Unlike other future fuels like hydrogen, a global supply chain and infrastructure for handling and transporting ammonia already exists due to its widespread use in agriculture (fertilizers) and other industrial applications.
3-Energy Density:
Ammonia is more energy-dense than hydrogen, requiring less storage space on board, a vital consideration for long-haul shipping.
However, the industry must still address challenges associated with ammonia, particularly its toxicity and the need to mitigate the emission of nitrous oxide (\text{N}_2\text{O}), a potent greenhouse gas, and Nitrogen Oxides (\text{NO}_x). Projects like the Sakigake, which use advanced engines and co-firing techniques, are essential for overcoming these technical hurdles and establishing robust global safety guidelines.
The success of the Sakigake has now cleared a path for larger vessels. The NYK Group is already pressing ahead with the development of an ammonia-fueled medium gas carrier (AFMGC), scheduled for completion in November 2026, demonstrating that the technology proven on the tugboat is scalable to larger segments of the global fleet.
This certified creation of environmental value is not merely a technical achievement; it is a breakthrough that connects environmental performance directly to economic incentives, offering the global shipping industry a clear, validated route to a cleaner, net-zero future.
Headline Points
Environmental Value Certified:
The operation of the Sakigake tugboat in Japan achieved the world’s first third-party certification for the environmental value created by reduced GHG emissions.
GHG Reduction up to 95%:
Operational data confirmed the ammonia-fueled vessel achieved a Greenhouse Gas (GHG) emission reduction of up to approximately 95 per cent compared to conventional heavy fuel oil.
Pioneer Vessel:
The Sakigake, a former LNG-fueled vessel converted as part of a Japanese Green Innovation Fund Project, is the world’s first ammonia-fueled vessel for commercial use.
Commercial Operation Success:
The vessel successfully completed a three-month demonstration in Tokyo Bay and is now providing low-carbon towage services in Yokohama Port.
Fuel Supply Chain Proven:
The tugboat uses “ECOANN,” a low-environmental-impact ammonia produced partly from recycled post-consumer plastics, demonstrating a viable, low-carbon fuel pathway.
Maritime Decarbonisation Catalyst:
The validation creates a new model for the shipping industry by quantifying emissions reduction for tradable environmental credits, accelerating the adoption of ammonia as a next-generation fuel.
