New version of the Wärtsilä 31DF engine reduces methane emissions

Technology group Wärtsilä has introduced a new ultra-low emissions version of its already efficient Wärtsilä 31DF engine. When operating on LNG, this new version can further reduce methane emissions on a 50% load point by up to 56% and nitrogen oxide (NOx) by up to 86%.

On a weighted average, this new technology can reduce methane emissions by 41 percent more than the standard Wärtsilä 31DF engine, which has already the lowest emission levels on the market.

The Wärtsilä 31 is an efficient medium-speed 4-stroke marine engine; it is available in cylinder configurations from 8 to 16 and with a power output ranging from 4.6 to 10.4 MW at 720 and 750 rpm.

The new ultra-low emissions version, which is applied on one of the four engines on board Wasaline’s Aurora Botnia ferry, has already 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 exceptional 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, the world’s most environmentally friendly RoPax ferry today.

Launched in 2015, the Wärtsilä 31DF engine platform is recognized for its exceptional fuel economy, high performance, and minimal GHG 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 potentially tightening global requirements. 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.

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