Author: Daniel G. Teleoaca – Marine Chief Engineer
MAN Energy Solutions (MAN ES) has announced a breakthrough in its research and development of a two-stroke engine that can run on ammonia, a carbon-free and sulphur-free fuel. The company successfully completed the first test of its MAN B&W engine operating on ammonia at its Research Center Copenhagen (RCC) in July 2023.
Ammonia is considered one of the most promising candidates for the future of green shipping, as it can be produced from renewable energy sources and does not emit any greenhouse gases or air pollutants when burned in an engine. According to the International Maritime Organization (IMO), maritime shipping is responsible for around 2.5 percent of global greenhouse gas emissions and needs to reduce them by 70 percent by 2050.

Source and credit: maritimemag.com
MAN ES started working on a B&W two-stroke engine operating on ammonia back in 2019 with a pre-study of the fuel supply and injection concept combined with several hazard and hazard and operability studies (hazid/hazop) together with classification societies, shipowners, yards, and system suppliers. The following year, a second test engine arrived in Copenhagen, enabling a parallel-test engine setup with different fuels at RCC.
The first test of the ammonia engine was conducted on a 50 percent load at RCC’s testbed no. 5, which is equipped with a newly developed ammonia injection system and a newly designed combustion chamber. The test showed that the engine can run stably and efficiently on ammonia with low NOx emissions. The test also demonstrated that the engine can switch seamlessly between ammonia and conventional fuels such as diesel or liquefied natural gas (LNG).
Brian Østergaard Sørensen, Head of Two-Stroke Research and Development at MAN ES, said: “This is obviously an ambitious undertaking, but we can meet it. The industry is already on board and working intensively with us towards greener maritime shipping.” He added that the company aims to have a commercially available two-stroke ammonia engine by as early as 2024, followed by a retrofit package for the gradual rebuild of existing maritime vessels by 2025.
The development of the ammonia engine is part of MAN ES’s strategy to offer a fuel-flexible portfolio of two-stroke engines that can run on almost any fuel or fuel quality. The company has already developed engines that can run on methanol, ethanol, liquefied petroleum gas (LPG), and hydrogen. The final goal for two-stroke engines is to run them entirely on carbon-neutral and carbon-free fuels.
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