Swiss marine power company WinGD completed both type approval testing (TAT) and factory acceptance testing (FAT) of its X52DF-A-1.0 ammonia-fuelled two-stroke marine engine in January 2026. Testing was carried out at the HD Hyundai Heavy Industries’ Engine & Machinery (HHI-EMD) facility in South Korea.  

The 52-bore engine is to be installed on a 46,000 m³ LPG/ammonia carrier that is on order for Belgian-based shipping company Exmar. According to Exmar, the vessel will be one of a series that will be the first ammonia-fuelled gas carriers to enter commercial service.

The completion of both TAT and FAT marks a world first for an ammonia-fuelled two-stroke engine, reports WinGD.

The green appeal of ammonia (NH₃) lies in its carbon-free molecular structure: when combusted, it produces no CO₂. It is already traded globally, with established storage and transport infrastructure. However, safety, toxicity and combustion control remain critical considerations.

Sotiris Topaloglou, Global Head of Testing & Validation at WinGD, said: ‘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.’

According to WinGD, testing showed nitrogen oxides (NO_x) emissions during ammonia operation were well below those generated during diesel use. Results for nitrous oxide (N₂O) were also described as ‘excellent’, with a negligible contribution to the overall greenhouse gas footprint.  

The X-DF-A platform is said to feature high-pressure ammonia injection supplemented by a targeted pilot fuel dose of around 5% at full load. WinGD claims that the engine’s load handling, dynamic response and fuel efficiency are on par with its equivalent diesel-fuelled X-engines in both ammonia and diesel modes.

WinGD adds that it has secured an early order book of around 30 X-DF-A engines across gas and bulk carriers, tankers and container vessels. The company says this ‘reflects growing confidence across the maritime value chain as engine technology, ship design and operational frameworks progress in parallel’.

For Exmar, the focus now shifts to sea trials. Kristof Coppé, Director Fleet Operations & Technical Business Development, said the next phase will ‘validate the seamless integration and performance of all onboard systems’ when running on ammonia. Trials are scheduled to take place in the coming months, with preparations already under way, he added.

WinGD’s X52DF-A-1.0 ammonia-fuelled two-stroke marine engine

Photo: WinGD 
 

Skarv Shipping selects Wärtsilä ammonia package

Meanwhile, Norway-based Skarv Shipping Solutions, a joint venture between Grieg Edge and Peak CSL Group, has announced that its new cargo vessel will be powered by an ammonia engine from Wärtsilä. The vessel is to be built at the Huanghai shipyard in China.

Wärtsilä will supply a fully integrated package, including its 25 Ammonia engine, an AmmoniaPac fuel gas supply system, an ammonia release mitigation system and a selective catalytic reduction system tailored for ammonia operation. The company says that, compared with equivalent diesel engines, this solution will reduce total greenhouse gas emissions by at least 90% when operating on green ammonia produced using renewable electricity.

The Wärtsilä 25 platform is a medium-speed marine engine capable of operating on multiple fuels, including diesel, LNG and ammonia. The ammonia variant is positioned as a ‘future-proof option’ for shipowners seeking compliance with tightening EU and International Maritime Organization (IMO) emissions frameworks.