Wartsila Introduces NextDF for 25DF Engine – Cruise Industry News

Wartsila has announced the NextDF feature for its 25 DF dual fuel engine, promising that when operating on LNG, the NextDF feature reduces methane emissions to less than 2 percent of fuel use across all load points, achieving as low as 1.1 percent in a wide load range. Also, the company said that nitrogen oxide (NOx) emissions are lower than on the standard 25DF engine which already has emission levels below IMO Tier III.

The Finnish technology group stated further that LNG is considered an important transition marine fuel, bridging the gap between conventional diesel fuels and future carbon-neutral or carbon-free alternatives. However, the main component of LNG is methane and when burned as a fuel, a very small amount may not combust properly, leading to methane escaping into the atmosphere.

Across the shipping industry, the use of LNG and cutting methane emissions is one of the most effective ways to decrease overall greenhouse gas (GHG) emissions from engines over the next 10 years, complementing other efforts to reduce CO2 emissions, according to Wärtsilä. From an international shipping perspective, the IMO is considering methane emissions in upcoming GHG regulations. At a regional level, the EU is implementing a set of methane-related measures in FuelEU Maritime (2025 onwards) and in EU Emission Trading System (EU ETS) (2026 onwards).

Wartsila said further that the effect of methane emissions will be introduced as a percentage of the mass of the fuel used by engines. For EU regulation, four-stroke engines not certified with lower emission values will have to adhere to a default methane emission of 3.1 percent of fuel use. To provide flexibility in meeting the GHG intensity limits, the FuelEU Maritime regulation will not only impose costs if a vessel does not comply, it will also allow vessels to capture value from overcompliance through banking or pooling compliance surplus between reporting periods.

Launched in 2022, the Wartsila25 engine platform offers a modular, upgradeable design promises to reduce fuel consumption and emissions, improving efficiencies, and facilitating the adoption of sustainable fuels. With the NextDF technology, engine efficiency is further improved by up to 0.5 percentage points, the company stated.

This is the second Wartsila dual-fuel engine platform to be made available with NextDF technology. In 2023, Wartsila introduced the technology for its 31DF engine series, and it can be retrofitted to existing 31DF and 25DF engines. The NextDF feature for the 25DF engine will be available for delivery in the second half of 2025.