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Friday, September 18, 2020 

In a recent presentation, MAN Energy Solutions announced plans to develop and commercialise a retrofit package that would enable certain existing two-stroke engines to operate on low-carbon ammonia fuel, allowing ship operators to comply economically with IMO decarbonisation targets.

Brian Østergaard Sørensen (pictured), VP and Head of R&D for MAN's two-stroke business, said: “We are working to have a package ready for retrofits by early 2025, approximately one year after the first ammonia engine is delivered. We want to retain the modules and architecture of existing engine platforms as far as possible, only touching on the components needed.”

Sørensen added that the retrofit will initially be available for existing ME-C, ME-LGIP and ME-LGI engines, through the company was considering similar upgrades for other dual-fuel prime movers. 

Although the company understands that there are still hurdles to be overcome with regulatory approval for large-scale use of ammonia fuel, which will prompt the need for amendments to the IMO IGF and IGC Codes, as well as infrastructure and pricing considerations, Sørensen said that the retrofit availability would offer peace of mind through fuel flexibility, avoiding the possibility of premature scrapping of current vessels and power units. Building on MAN Energy Systems’ modular approach to designing and upgrading engines is expected to retain efficiency and keep costs down.

Other areas needing to be addressed for the future include the need for a pilot fuel, possibly at a ratio of around 20%, to overcome the ammonia fuel’s inherently less favourable combustion characteristics. This has implications in exhaust emissions, so MAN is considering using a carbon-neutral pilot fuel, or even injecting hydrogen as an accelerant. Emissions of nitrogen oxide gases will need to be reduced, either through the use of SCR technology or by adapting other processes used in the chemical industry. Eliminating ammonia slip and ensuring safety through purging and venting the engines are further likely areas needing attention.

Availablity and price of ammonia fuel, probably aided through a carbon pricing scheme, are key points. “We strongly believe that CO2 pricing will need to be in place to drive the development of the ammonia engine,” said Sørensen.

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