Wärtsilä introduces NextDF methane slip reduction for a third engine

Wärtsilä 46TS-DF with NextDF

Wärtsilä has introduced its NextDF technology for a third engine, the Wärtsilä 46TS-DF dual-fuel engine. While operating on liquefied natural gas (LNG), the Wärtsilä 46TS-DF engine with NextDF feature reduces methane emissions to less than 1.4% of fuel use across all load points, achieving emissions as low as 1.1% in a wide load range. This is nearly three times lower than the default methane slip factor of 3.1% specified in the FuelEU Maritime and IMO lifecycle guidelines for Otto-cycle four-stroke dual-fuel engines. Through improvements made to the combustion control, and through optimizing engine performance, the feature also minimizes nitrogen oxide (NOx) and CO2 emissions.

The initial installation of the Wärtsilä 46TS-DF engine with NextDF feature will be onboard the cruise ship, MSC World Asia, being built by Chantiers de l’Atlantique for MSC Cruises.

Wärtsilä first introduced the NextDF technology for its Wärtsilä 31DF engine in 2023 and made it available on its In 2023, and made it available on the Wärtsilä 25DF in November 2024.

LNG is an important transition fuel as the marine industry strives to reduce its carbon footprint. However, the main component of LNG is methane and when burned as a fuel, a small amount may not combust properly, leading to methane escaping into the atmosphere.

“NextDF technology reduces the environmental impact of vessels that use LNG as fuel, without compromising on performance or operational stability ,” says Stefan Nysjö, vice president of power supply at Wärtsilä Marine. “Importantly, this makes it easier for ship owners to comply with increasingly stringent decarbonization targets and legislation.”

Launched in 2022, the Wärtsilä 46TS-DF engine has a two-stage turbocharging to deliver high levels of efficiency and power density across a wide operational range for vessels in all segments of the industry. This level of efficiency reduces fuel consumption and lowers emissions, while being easily retrofittable for sustainable fuels as they become widely available. By applying the NextDF feature, says Wärtsilä, the engine will have the lowest methane emissions and GHG emissions in the 1MW+/cylinder power range.

The Wärtsilä 46TS-DF with NextDF feature was developed as part of the EU co-funded GREEN RAY project]—short for New GeneRation marinE ENgines and Retrofit solutions to Achieve methane abatement flexibilitY—a five-year initiative launched in June 2022 under the Horizon Europe program