Shipowners will be able to choose between competing low-pressure dual-fuel two-stroke designs for the first time from 2022.
MAN Energy Solutions, which has previously designed only high-pressure engines, has decided to develop a low-pressure engine because of strong market demand.
Although high-pressure engines dominate the dual-fuel two-stroke market, with MAN’s ME-GI series registering 280 orders to date, low-pressure engines have taken nearly 90% of sales over the past year according to data seen by Marine Propulsion. Winterthur Gas & Diesel is currently the only designer of low-pressure two-stroke gas engines.
The development will make MAN the only two-stroke engine designer to offer both high-pressure and low-pressure gas engines. MAN Energy Solutions head of two-stroke business Bjarne Foldager said that the high-pressure ME-GI range will “continue to be the most attractive solution within many market segments”.
“The low-pressure engine will fill a gap within our portfolio,” he said.
The new project joins a busy roster of gas engine developments. Earlier in the year MAN confirmed its intention to develop an ammonia-fuelled two-stroke engine, potentially using ammonia sourced from renewable electricity generated by windfarms.
WinGD’s first low-pressure X-DF engine entered service in 2016. It now has an orderbook of more than 200 engines, with 32 ordered in the first quarter of 2019.
Dual-fuel two-stroke engines use either the Diesel combustion cycle, requiring high-pressure injection, or the low-pressure intake Otto cycle. While Otto-cycle engines suffer from more methane slip, reducing the greenhouse gas emission benefits of using LNG, they can reach IMO Tier III NOx levels without aftertreatment, unlike high-pressure engines. Low-pressure fuel gas supply systems are also cheaper to buy and install. High-pressure engines benefit from being easier to retrofit and offering the same performance as similarly sized diesel engines.
Marine Propulsion has asked whether the new engine will be capable of burning other gases handled by its current dual-fuel range, including LPG, ethane and methanol – currently handled by high-pressure ME-LGI engines. This story will be updated with further detail as it emerges.