The maritime industry’s pivot towards low- and zero-carbon fuels is gaining momentum, and engine developers are under pressure to deliver propulsion solutions that are clean, safe, and scalable. WinGD, a leading marine engine developer, is at the forefront of this transition with its ammonia-fuelled X-DF-A engine. In an exclusive interview, Sebastian Hensel, Vice President of R&D at WinGD, shared insights into the company’s progress, innovations, and the future of ammonia as a marine fuel.
WinGD commenced its ammonia fuel technology development in 2019, with combustion development starting in 2021. The company has since achieved significant milestones, including the use of proprietary technology like the full-scale Spray Combustion Chamber and testing on a unique single-cylinder engine. These efforts have culminated in the imminent delivery of the first commercially available ammonia-fuelled engines from 2025 onwards. “Our well-structured development approach has paid off,” Hensel stated. “After intensive efforts to understand the principles of ammonia injection and combustion, we are the first two-stroke engine designer to demonstrate 100% ammonia operation with 5% pilot fuel consumption and such low emissions.”
The latest emissions data from WinGD’s ammonia engine testing show ammonia emissions below 10ppm and nitrous oxide (N2O) emissions below 3ppm. Nitrogen oxide (NOx) emissions for ammonia operation are also well below those generated during diesel use. Importantly, these low emissions are achieved without the use of exhaust gas after-treatment, confirming that no ammonia slip catalyst (ASC) will be needed to operate the engine with ammonia fuel. The WinGD X-DF-A engine is designed to be fully compliant with IMO regulations.
Addressing concerns about NOx and N2O emissions, Hensel pointed out that NOx emissions are significantly lower when using ammonia fuel compared to diesel. This not only keeps the engine compliant with IMO’s recently updated NOx Technical Code but also provides a larger margin to use engine tunings to improve efficiency. “As a result, our X-DF-A engine will have better fuel consumption than conventional diesel engines,” Hensel explained. “This will be crucial to controlling operating costs, as renewably-produced ammonia is expected to be considerably more expensive than diesel.”
The X-DF-A engine’s development programme has been carefully structured to ensure its capability to operate efficiently, safely, and sustainably. Early combustion tests and the validation of critical systems on dedicated test rigs were followed by single-cylinder testing, and later by multi-cylinder engine testing representing real-world marine operation. These tests validated the effectiveness of the full-scale engine, turbocharger configuration, and control system when operating with ammonia fuel. Multiple class approvals of the safety concept have also been awarded.
In terms of energy efficiency, the X-DF-A dual-fuel engine matches the efficiency of WinGD’s standard X-engines, regardless of whether it is being run on diesel or ammonia fuel. There are no major differences in the engine load acceptance and dynamic behaviour between the X-DF-A engine and conventional diesel engines. “The same high-pressure injection concept applied to our X-Engines is well suited to operating with ammonia fuel,” Hensel noted. “This means that the X-DF-A’s engine efficiency is high at all times, regardless of the fuel being used.”
Safety is a critical issue with ammonia as a fuel, and WinGD has addressed this in both the design and development of the X-DF-A engine and its training methodology. The company takes an open and transparent approach to making it clear to owners and operators that modifications and additional engineering work are needed for ships to be capable of operating with ammonia-fuelled engines. WinGD has developed its X-DF-A ammonia technology with a systematic approach that prioritises safety and a deep understanding of the fuel’s combustion characteristics. The concept has been granted approvals in principle from several leading classification societies, giving ship operators the assurances they need to deploy them safely, with the first engines set to enter service in 2026.
WinGD is now working closely with shipyards and early customers to translate safe design into safe installation and operation. The company holds training courses to provide detailed information on all aspects of working with ammonia fuel, including a strong focus on safety, as well as training on control system logic and mechanical components. WinGD is also actively assisting operators and maritime academies in preparing training syllabuses for the use of ammonia as a marine fuel.
The maritime industry’s transition to low- and zero-carbon fuels is not just about meeting regulatory requirements; it’s about shaping a greener future for global shipping. WinGD’s ammonia-fuelled X-DF-A engine represents a significant step in this direction, offering a clean, safe, and scalable propulsion solution. As the industry continues to evolve, the insights and innovations shared by Hensel and WinGD