Revolutionary Ammonia-Powered Engine by MAN B&W Paves the Way for Sustainable Shipping

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.

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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.


Mitsubishi is poised to showcase its ammonia fuel handling system designed for maritime vessels.

Date: August 27, 2023

By: Daniel G. Teleoaca – Marine Chief Engineer

Mitsubishi Shipbuilding, a part of Mitsubishi Heavy Industries (MHI) Group, is developing a new system to support the use of ammonia as a marine fuel, which can significantly reduce greenhouse gas (GHG) emissions from ships. The system, called Mitsubishi Ammonia Supply and Safety System (MAmmoSS), is a package of subsystems that handle ammonia safely and efficiently on board vessels. As an integral component of the ongoing development initiative, Mitsubishi Shipbuilding has recently started the process of conducting demonstration testing on a specific subsystem known as the Ammonia Gas Abatement System (AGAS). This system is designed to effectively manage and mitigate the excess ammonia generated by vessels using ammonia as a fuel source.

Ammonia is a carbon-free fuel that can be produced from renewable energy sources, such as solar, wind, or hydro power. It has a high energy density and can be stored and transported easily. Ammonia is also compatible with existing marine engines and fuel systems, with some modifications. Hence, ammonia is seen as a viable alternative fuel with significant potential for reducing carbon emissions within the maritime sector. Read more about this in HERE.

However, ammonia also poses some challenges and risks, such as toxicity, flammability, and corrosiveness. To address these issues, Mitsubishi Shipbuilding has designed MAmmoSS, which consists of several subsystems that handle ammonia safely and efficiently on board vessels. These subsystems include:

  • An ammonia fuel supply system (AFSS), which delivers ammonia from the fuel tank to the engine or boiler at the required pressure and temperature.
  • An ammonia fuel tank system, which stores ammonia in a liquid state under high pressure and low temperature.
  • An ammonia gas abatement system (AGAS), which treats surplus ammonia from the engine or boiler exhaust gas or from the fuel tank venting system.

    Mitsubishi Ammonia Gas Abatement System (AGAS) demonstration facility. Source and credit: MHI

The AGAS is a key component of MAmmoSS, as it ensures that no ammonia is released into the atmosphere or the sea. The AGAS uses a catalytic converter to decompose ammonia into nitrogen and water, which are harmless to the environment. The AGAS also has a scrubber to remove any residual ammonia from the gas stream. The Ammonia Gas Analysis System (AGAS) is capable of effectively managing a range of ammonia operations, including routine operational procedures, emergency shutdown protocols, and maintenance activities.

Mitsubishi Shipbuilding has recently completed the construction of an AGAS demonstration facility at the Nagasaki District MHI Research & Innovation Center. The facility simulates the onboard conditions of an ammonia-fueled vessel and allows Mitsubishi Shipbuilding to conduct demonstration tests of the AGAS performance under different scenarios. The tests will also help Mitsubishi Shipbuilding to explore the potential applications of ammonia technology for various industries.

Mitsubishi Shipbuilding aims to launch MAmmoSS in the market by 2025, in line with MHI Group’s strategy for advancing the energy transition. By providing MAmmoSS as a modular package, Mitsubishi Shipbuilding can offer customized solutions for different types of vessels and onboard plants. Furthermore, Mitsubishi Shipbuilding will provide shipbuilding engineering services, construction support, and various other services for ships powered by ammonia. This will be facilitated by using the company’s extensive knowledge and experience in ammonia handling, which has been acquired over the course of its history in constructing transport carriers.

Mitsubishi Shipbuilding is set to demonstrate its innovative ammonia fuel handling system for ships, which can contribute to the further development of marine logistics and the reduction of its environmental impact on a global scale. By using ammonia as a marine fuel, ships can achieve zero carbon emissions and help mitigate climate change.