Ammonia Fuel Promises Big Benefits For Big Ships

Ammonia engine

In a concerted effort to clean up the maritime shipping industry and reduce hydrocarbon outputs, there is an ongoing initiative to build new ships with efficient engines that use alternative fuels.

Story by Doug Switzer, Moto/ology Publisher

Last year, some notable progress was made in the ongoing effort to build a replacement fleet of large, ocean-going vessels that will eschew the old diesel, and other oil-derived fuels for cleaner alternatives. Among the potential candidates for powering the maritime fleet are natural gas, methanol, hydrogen, methane, and ammonia, with ammonia being one of the leading favourites for the immediate development and application.

Wait a minute… ammonia, you say? But isn’t that a toxic and deadly substance? Well, yes, if it’s handled improperly. There are advantages and disadvantages to an ammonia-based marine fuel economy, and these have been considered in great detail by some very well-versed players. There are several manufacturers of those giant, two-stroke ship engines that have done a lot of research and development into alternative fuels, and they have identified ammonia fuel as the most promising path to follow for rapid deployment and maximum return when it comes to reducing or eliminating unwanted carbon emissions.

WinGD is one of the leading manufacturers of large marine powerplants for the shipping sector and they have provided some in-depth information and insights on these recent developments.

Ammonia fuels… the good part.

Princeton University completed a study of the potential advantages and disadvantages of using ammonia as a fuel and came up with some interesting conclusions. Ammonia, a chemical composed of hydrogen and nitrogen (NH3) can be burned as a zero-carbon fuel. It is relatively easy to liquify, transport and store. Some have said it is similar to propane for storage and transport. There are several ways and means to produce ammonia with established processes that date back over a century and have proven standards of reliability and safety. There are also newer ammonia production procedures being proposed that are more efficient and less energy-intensive, greatly improving the economic attractiveness of the fuel.

The actual “fuel” in ammonia is the hydrogen component and when ammonia is efficiently burned, hydrogen is the combustible element, and it produces no hydrocarbons. The fact that ammonia is stable and understood, makes it especially attractive for transport applications that cover long distances, like maritime shipping.

Now… what could possibly go wrong?


OK, so ammonia looks like it could be our saviour and the solution to our carbon emissions problems, but as the old TV ad folks used to say: “But wait…there’s more!”

The basic uptick is that burning ammonia would only produce nitrogen and water as by-products, both harmless and in fact, desirable components in our earthly environment. However, initial experiments with ammonia-fueled engines demonstrated a very undesirable tendency to release nitrogen oxide and nitrous oxide, both being greenhouse gases and significant contributors to atmospheric warming. These potential pollutants are a result of problems or disruptions in the combustion process. It should be pointed out, however that these undesirable emissions are clearly understood and occur when the engine’s combustion efficiency is compromised. Technical development of clean-burning, efficient ammonia engines has been established and working powerplants that are free of these “undesirables” are now in production.

Raw ammonia is also toxic to humans and careful steps must be taken to ensure the proper storage, safety and handling of the fuel both in port and onboard/enroute. These safety protocols are essential in protecting shipboard crews and dockside handlers who work and live aboard and near these vessels. With that said, all these potential problems and issues can be addressed and mitigated. We have the required knowledge, technology and engineering practices in place to solve the problems arising from the use of ammonia as a fuel.


Engine manufacturer WinGD announces ammonia engine production.

The Swiss marine power company WinGD and Japanese shipbuilder and technology developer Mitsubishi Shipbuilding Co., Ltd. have undertaken the joint development of ammonia-fueled vessels.

The project will see WinGD applying its X-DF dual-fuel engine technology to an ammonia-fueled range allowing this new fuel to be used in a broad range of vessel designs, with Mitsubishi both designing the vessels and completing the fuel chain with its ammonia fuel supply system (AFSS).

Manabu Kawakado, Head of Marine Engineering Centre, Mitsubishi Shipbuilding Co., Ltd. said: “This collaboration will give both Mitsubishi and WinGD an important first-mover advantage in using ammonia in marine engines to meet the IMO decarbonization targets. It will set the path for the new generation of technology applicable to a wide range of vessels over the coming decades.”

Under the partnership, WinGD will develop X-DF-A engines at appropriate sizes for the vessel designs, providing Mitsubishi with the specifications for installing the engines and the requirements for all auxiliary fuel systems. Mitsubishi will design the vessels, set performance parameters for the engines and further develop its existing AFSS for use with WinGD’s ammonia engines.

Dominik Schneiter, Vice President R&D, WinGD said: “This project will allow WinGD and Mitsubishi to make further progress in bringing ammonia fueled capability to merchant vessels within our established future fuel development timeframe. It is a timely opportunity to apply X-DF-A engines across a wider range of bore sizes. Our aim is to develop the applicability of these engines and their critical fuel elements across multiple vessel types, while upholding the highest standards for environmental impact and for the safety of the crew on board.”

 The project commenced in the third quarter of 2023, with a timeline projected that could place vessels in service by 2027.

WinGD inks deal to increase engine manufacturing capability in Japan.

WinGD also concluded an agreement with Mitsui E&S Diesel United (MESDU), part of the Mitsui Engineering & Shipbuilding group, that will see WinGD engines being built at the company’s Tamano works for the first time. The agreement adds considerable engine building capacity and enables WinGD to meet growing demand in the Japanese shipbuilding market.

WinGD engines were previously built only at the Mitsui’s Aioi Factory, which was acquired earlier last year. The new agreement means that WinGD engines can now be built at both the Aioi and Tamano Factories.

WinGD Director Operations Rudolf Holtbecker said: “Expanding in Japan with MESDU is a natural step as we see significant changes in vessel specifications from Japanese shipyards. As new designs emerge for vessels using alternative fuels and hybrid technologies, we will now be ready to fulfil the increased demand for WinGD engines.”

MESDU President Hiroyuki Takumi said: “This agreement gives MITSUI E&S even more capacity to offer shipyards and shipowners the quality main engines that will power future generations of sustainable vessels. We are happy to be able to bring efficient and reliable WinGD engine designs to even more Japanese vessels through the coming marine energy transition.”

Along with WinGD’s existing diesel-fueled X-Engines and their LNG dual-fuel X-DF engines, the additional capacity at the Tamano Factory can now accommodate X-DF-A ammonia-fueled and X-DF-M methanol-fueled engines, which will be available for delivery from Q1 2025.

Japan is a key market for WinGD engines, with recent engine and system integration orders for LNG-hybrid vessels for NYK Line and K Line. For a long time, the country has also been a core element of WinGD’s technology development process. WinGD teamed with MESDU and its forerunner Diesel United many years ago and the new Variable Compression Ratio (VCR) technology, which allows dual-fuel engines to dynamically optimise combustion for each fuel, was the result of more than a decade of co-development between the two companies


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