Wärtsilä’s LNG-Fueled 31DF Engine Powers Marine Methane Reductions

Wärtsilä has introduced a new ultra-low emissions version of its Wärtsilä 31DF engine. When operating on liquefied natural gas (LNG), this new version can reduce methane emissions on a 50% load point by up to 56% and NO_x by up to 86%. On a weighted average, this technology can reduce methane emissions by 41% more than the standard Wärtsilä 31DF engine, which, according to Wärtsilä, already has the lowest emissions levels on the market.

The new version, which is applied on one of the four engines on board Wasaline’s Aurora Botnia ferry, has helped the Finnish-Swedish ferry operator further reduce the Aurora Botnia’s methane emissions by 10%. As part of the EU co-funded Green Ray and SeaTech projects, Wärtsilä piloted the ultra-low emissions concept onboard the Aurora Botnia with results verified through an independent study conducted in December 2022 by VTT, the Technical Research Centre of Finland. Encouraged by the positive results, Wärtsilä has now launched the new ultra-low emissions version of the Wärtsilä 31DF engine to the commercial market.

This latest collaboration forms part of a long-term partnership between Wärtsilä and Wasaline to reduce emissions onboard the Aurora Botnia, which the companies say is the world’s most environmentally friendly roll-on/roll-off passenger (RoPax) ferry today. “We are very committed to decarbonization, and we have worked closely with Wärtsilä to make sustainable shipping a reality,” said Peter Ståhlberg, managing director of Wasaline. “It is a goal-oriented partnership that benefits both companies, as well as the industry as a whole. We have been pleased to allow the ‘Aurora Botnia’ to be used as a floating laboratory, and we are excited to see the success of this latest Wärtsilä technology breakthrough.”

Launched in 2015, the Wärtsilä 31DF engine platform features fuel economy, high performance, and minimal greenhouse gas impact. The engine, as a standard version, already meets today’s regulatory requirements. The new version will enable operators to go even further in reducing methane emissions, helping to futureproof their vessels in the longer term against tightening global requirements. What’s more, improving dual-fuel technology to enable methane emissions reduction will have a major impact on the long-term viability of LNG as a marine fuel.

“Our work around reducing methane slip and greenhouse gas emissions is part of Wärtsilä’s effort to continuously improve efficiency and reduce emissions of our products, and this new innovation is one more very important step along the road to decarbonization,” commented Stefan Nysjö, vice president of power supply for Wärtsilä Marine Power. “The building of an LNG fuel infrastructure has been an important factor in shipping’s transition toward cleaner operations, and Wärtsilä continues to create solutions that support this journey. Our focus has always been to improve and optimize existing solutions, and to develop exciting new ones. With this latest introduction, we are clearly delivering on this commitment.”

Although methane slip from engines is a relatively small amount, from a percentage standpoint, it is significantly more potent than carbon dioxide (CO₂) — up to 28 times greater. Across the shipping industry, cutting methane emissions is one of the most effective ways to decrease overall greenhouse gas emissions from engines over the next 10 years, complementing other efforts to reduce CO₂ emissions.