Rolls-Royce tests clean marine propulsion with methanol

Rolls-Royce has developed a high-speed marine engine that runs on a clean fuel. According to the manufacturer, a test was successful.

The engine runs exclusively on methanol. It is the first high-speed, pure methanol engine. It is based on the 4000 series from Rolls-Royce subsidiary MTU Friedrichshafen, which normally runs on diesel but can be replaced by drop-in fuels such as hydrogenated vegetable oil (HVO) or synthetic fuels.

“This is a genuine world first,” said Jörg Stratmann, CEO of Rolls-Royce Power Systems AG. “To date, there is no other high-speed engine in this performance class that runs purely on methanol.” A high-speed engine also reaches speeds of more than 2000 revolutions per minute.

2 Megawatt output

The methanol-powered version has an output of 2 megawatts. This means it is not powerful enough for large container ships. The 4000 series is used in frigates, tugs, inland vessels, and large yachts, for example.

Since methanol is not a drop-in fuel, the engine had to be converted. Among other things, the engineers developed a new injection system, as methanol does not ignite itself like diesel. Other functions, such as mixture formation and turbocharging, also had to be adapted.

This applied not only to the engine itself; the test bench in Friedrichshafen also had to be modified for methanol operation. “The initial tests show: the engine runs stably – now it's about fine-tuning,” said Johannes Kech, who led the development of the methanol engine.

Tests in Friedrichshafen

The propulsion system has been developed since 2023 as part of the meOHmare project. In addition to Rolls-Royce, the Stuttgart-based mechanical engineering company Woodward L'Orange and the non-profit Scientific-Technical Center (WTZ) for Engine and Machine Research Roßlau in Dessau are also involved. The engine was tested on the test bench in Friedrichshafen.

The concept involves operating the engine with green methanol, i.e., methanol produced from hydrogen generated with electricity from renewable sources and captured or atmospheric carbon dioxide. Then the fuel is climate-neutral. As an interim solution, Rolls-Royce is also working on a dual-fuel engine that can run on methanol and diesel. This is “a bridging technology as long as green methanol is not yet widely available.”

Approximately 90 percent of global trade is handled by sea. Shipping accounts for almost 3 percent of carbon dioxide emissions, 13 percent of sulfur, and about 30 percent of nitrogen oxide emissions. In addition, there are soot particles and fine dust. By 2050, ships must be climate-neutral.

(wpl)