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Ammonia: a milestone in decarbonising the marine industry

Minimizing the impact of shipping on the climate and the environment is a crucial contribution to reaching the global climate targets. One of the ultimate goals is carbon neutral or carbon free transportation.

Currently, worldwide maritime transport emits around 3% of the global greenhouse gas (GHG) emissions. The International Maritime Organization (IMO) has set a target of net-zero CO2 emissions from shipping by or around 2050. An ambitious goal that requires technological changes in the industry.

The MAN B&W two-stroke ammonia engine will meet future market demands for green ship propulsion including retrofits. This makes it a valuable addition to the MAN B&W two-stroke dual-fuel engine portfolio. Gain further insights on the ammonia powered engine.

1st engine delivery targeted to yard
Target is 5% pilot oil energy fraction and 95% ammonia based on L1 rating at 100% load

Proven two-stroke engine design

The ammonia two-stroke engine is based on the proven and trusted MAN B&W engine designs. It will be available as a newbuild engine or as a retrofit option for existing electronically controlled ME-C engines.

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Ammonia engine: key benefits

Energy density and efficiency

Ammonia_EfficiencyAmmonia can be used as an energy carrier of sustainable hydrogen and is carbon free. The two-stroke ammonia engine technology development aims for a small percentage of just 5% pilot oil at 100% load based on L1 rating. The remaining 95% of the energy will be provided by ammonia while supplying you with high power, energy density, efficiency and extremely low emissions.

Carbon- and sulphur-free

Ammonia_CarbonSulphur-FreeAmmonia is carbon- and sulphur-free and gives a clean combustion. Green ammonia as a fuel for shipping has the potential to become the sustainable future fuel choice, especially due to the expected lower production cost compared to other e-fuels.


Ammonia_RetrofitsThe future installation of an ammonia combusting engine can be adapted to the customer. For example, as a dual-fuel, modular retrofit solution for existing electronically controlled engines, or as an ammonia-ready engine, or from newbuilding. Talk to our experts about the best solution for your company.

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Talk to our experts for ammonia engines

You want to know more about our two-stroke ammonia engine and how it can suit your goals? Our global network of dedicated engineers will help you find the perfect solution for your business. Start your change process now and reach out to us today.

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Injection system for ammonia


The MAN B&W ammonia engine design philosophy

Ammonia mode

A small pilot flame is needed to start ammonia combustion. Initial tests were conducted with 10-15% pilot as a first step. The R&D target is around 5% pilot oil at 100% load for L1-rated engines.

We target for the same heat rate as “fuel oil mode”. The ammonia engine concept will be based on the Liquid Gas Injection engine concept, which is well known from the existing methanol and LPG-fueled MAN B&W two-stroke dual-fuel engines.

Fuel oil mode

We target identical performance as a conventionally fueled diesel engine.

Ammonia auxiliary systems 

The auxiliary systems provide additional support to the MAN B&W ammonia engine and together ensure safe and efficient combustion. The ammonia catch system and the addition of absorbers make sure that no ammonia will be vented to the atmosphere above 5 ppm at our Research Centre Copenhagen.


Selective catalytic reduction technology 

To reduce emissions of nitrogen oxides and to fulfil IMO Tier III emission regulations, engines from MAN Energy Solutions have been equipped with selective catalytic reduction (SCR) technology for many years. 

The SCR system using ammonia was introduced in the 1990s in four bulk carriers. 

It is an after-treatment process, where NOX formed during combustion is removed from the exhaust gas in a catalytic reduction. Additionally, the SCR unit will be utilized to remove any ammonia slip from the exhaust. 

Pending the outcome of the first engine test results, an increase in SCR volume and ammonia consumption may be necessary to achieve compliance in Tier III mode.

  • Learn more about the two-stroke ammonia engine

    MAN B&W ammonia engine development: Groundbreaking first engine test.

    Learn about the progress of the development process and the successful combustion that was performed on a MAN B&W two-stroke 4T50ME-X type. Further, get insights about the design of the safety systems for fuel handling and the positive results that revealed particularly promising data regarding combustion stability.

    Go to recording

Download the paper and learn more about the ammonia engine

  • MAN B&W two-stroke engine operating on ammonia
    pdf, 733 KB

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MAN B&W ammonia engine development: Groundbreaking first engine test

Are you ready to dive into the details of the groundbreaking first two-stroke ammonia engine test that was completed at our Research Centre Copenhagen this summer? Then sign up for this MAN ExpertTalk!

You can look forward to learn about the progress of the development process and the  successful combustion that was performed on a MAN B&W two-stroke 4T50ME-X type.

We will also take a closer look at the design of the safety systems for fuel handling and the  positive results that revealed particularly promising data regarding combustion stability.

Go to recording