This morning’s announcement by Wärtsilä that it is was adding a dual-fuel engine capable of operating on ammonia to its product portfolio is a stunning technical achievement.

The introduction of a new alternative fuel into the maritime fuel mix has previously been likened to manned space travel. “Introducing a new fuel is like space travel – to get to Mars, you do not have to fix one problem, but all of them,” GTT’s Julien Bec, Vice President, LNG as Fuel, told me in 2020, when discussing hydrogen combustion. 

Sadly, there are no David Bowie songs waiting to accompany footage of this morning’s announcement - and the decline in technical literacy among the mainstream media means few outside the industry will appreciate the scale of this achievement. 

Regular readers of The Motorship’s coverage of research into ammonia-fuelled engine technology over recent years will know that ammonia-fuelled combustion has required the development of solutions for the ammonia containment and fuel supply systems, the fuel injection system, the engine’s lubrication requirements, component material choices, the aftertreatment system, turbocharging solutions and efforts to limit the emissions profile (including minimising nitrous oxide, N2O, formation). These efforts have required sustained research and development work from suppliers as well as Wärtsilä’s engine development team.

However, it would be churlish not to recognise the combustion challenges that have been overcome. Ammonia as a fuel presents technical challenges for engine designers as it is both harder to ignite and slower burning and has a lower energy density than fuel oil, requiring larger fuel injection volumes.

For Wärtsilä to deliver an engine capable of delivering similar power output to that offered by its existing natural gas engine is a testament to Wärtsilä’s engine development engineers. It also lays down a strong challenge to other 4-stroke developers who are currently developing their own alternatives. Wärtsilä’s reluctance to discuss just how they overcame these challenges is more than than customary Finnish modesty.