MAN Energy Solutions is dedicated to meeting the needs of the shipping industry by retrofitting its engines to run on methanol fuel. The maritime energy transition is taking another leap forward with the testing of a methanol dual-fuel four-stroke engine, designed to cut carbon emissions for ferries and cruise ships.

　　In July 2023, the International Maritime Organization (IMO) adopted a strategy to reduce greenhouse gas emissions, and the aim is to reach climate neutrality in maritime transport by 2050. The framework for the future of maritime transport is clear: the solution is to gradually replace oil with climate-neutral energy sources such as green hydrogen, ammonia and methanol. “The shipowners are feeling the pressure to reduce their emissions,” says Bernd Siebert, Head of Retrofit and Upgrades at MAN Energy Solutions, “Otherwise they’ll be forced to buy CO₂ certificates, pay fines or even decommission ships.

　　While methanol newbuilds and retrofits for MAN’s two-stroke dual-fuel engines for large container ships are already in full swing, the retrofit package for a methanol dual-fuel solution for their four-stroke engines (widely installed on passenger ferries and cruise ships) is set for release next year. In autumn 2025, MAN PrimeServ is planning to convert the first four-stroke engines for a pilot customer. From then, customers will be able to have their conventional MAN 48/60 engines converted to the status of a modern MAN 51/60R-DF-M engine, both with and without a common-rail system. That means that Auer and his team of 50 running the R&D test bench in Augsburg have around one year to find the best optimization of performance, efficiency and emissions.

　　Right now they are testing the boost pressure, the emissions, the security system and the strength of the components under extreme conditions. Sensors have been installed around and inside the engine to collect data. “After the tests,” says Auer, “we’ll take apart the whole engine and each design engineer will inspect the component their in charge of. It’s true teamwork – and we’ve got a very experienced team here in Augsburg.

　　The key issue of the dual-fuel engine is the injection of the methanol. “We’re figuring out what’s the ideal dosage and which pressure should be applied,” says Auer. The clear aim is to maintain engine efficiency – no matter the fuel. Because the reality at this moment is that methanol, especially green methanol, is not widely available in ports around the world. But that is expected to change over the coming years.

　　Different from the installation of new engines that affords the cutting open of the ship and thus means long vessel downtimes, the retrofitting of engines can be done in a relatively short time in the dry dock. “Depending on the number of cylinders, the retrofitting takes four to eight weeks depending on the number of cylinder,” says Siebert. MAN Energy Solutions will release further methanol-powered dual-fuel four-stroke engine across the entire bore range. Based on engine type and application, the company will add both port fuel injection and high pressure direct injection solutions to its portfolio. For retrofit of legacy engines, the PFI technology has been identified as the clear favorite. Of the 2,000 MAN four-stroke engines viable for a methanol conversion and currently in operation worldwide, Siebert sees a retrofit potential for just under half. “We have decided to start with the retrofit solution first, because we see a huge emission saving potential in retrofitting the existing fleet already in the next years,” adds Siebert. “All these ships are already on sea and powered by fossil fuels. With the new retrofit option we can now upgrade them to climate-neutral operation and contribute to reaching IMO climate goals.” 

　　Source from MAN Energy Solutions website