Swiss WinGD has completed both type approval testing (TAT) and factory acceptance testing (FAT) of its ammonia-fuelled two-stroke marine engine. Both test programmes were completed in January 2026.
Testing of the X52DF-A-1.0 engine was carried out at the HD Hyundai Heavy Industries’ Engine & Machinery (HHI-EMD) facility in South Korea, witnessed by classification society Lloyd’s Register (LR), together with representatives from all major classification societies, under the supervision of Exmar.
The testing programmes took place on a 52-bore engine to be installed on a 46,000m3 LPG/ammonia carrier on order for Exmar. The vessels in the series are set to become the first ammonia-fuelled gas carriers to enter commercial service, marking a significant milestone for the shipping industry’s decarbonisation efforts.
Sotiris Topaloglou, Global Head of Testing & Validation at WinGD: ‘As first movers, we are addressing a completely new fuel landscape, where safety, control and system integration are paramount. We have developed an engine that has been well proven to be safe and efficient by tackling, one by one, all the technical challenges we faced. Demonstrating the world’s first TAT for an ammonia-fuelled two-stroke engine with strong results demonstrates that ammonia propulsion can meet the highest standards of reliability, performance and safety expected by the industry for commercial marine application.’
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Growing confidence
Throughout a rigorous multi-year development and testing process, good performance has been demonstrated. Emissions data from the X DF A engine has impressed with NOX emissions during ammonia operation well below those generated during diesel use. Good results have also been recorded for emissions of N2O, with a negligible contribution to the overall greenhouse gas emissions footprint.
Confidence in ammonia as a future marine fuel continues to grow, with WinGD securing an early orderbook of around thirty X-DF-A engines across multiple vessel segments, including gas and bulk carriers, tankers and container vessels. This momentum reflects growing confidence across the maritime value chain as engine technology, ship design and operational frameworks progress in parallel.
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Next: sea trials
Kristof Coppé, Director Fleet Operations & Technical Business Development at Exmar, states the company’s development of ammonia as a marine fuel started in 2021: ‘Drawing on more than forty years of experience in transporting ammonia as cargo, Exmar has been able to critically assess both the engine design and the test programme, with particular attention to the safety considerations associated with using a toxic cargo as fuel.’
He adds: ‘Exmar now looks ahead to the next phase, which will involve sea trials on ammonia fuel. These trials will have to validate the seamless integration and performance of all onboard systems. Preparations are currently underway, with the trials scheduled to take place in the coming months.’
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High-pressure ammonia injection
The first delivered engines are now approaching service. Design optimisation undertaken throughout the development and testing programme will be applied across the vessel series, supporting consistent performance, safety and operational reliability as the ships enter service.
The X-DF-A engine features high-pressure ammonia injection supplemented by a low, targeted pilot fuel dose of around five per cent at full load. The engine delivers load handling, dynamic response and fuel efficiency on par with WinGD’s equivalent diesel-fuelled X-Engines in both ammonia and diesel operating modes.
