Technology group Wärtsilä has unveiled its innovative NextDF feature designed to significantly reduce methane emissions from the Wärtsilä 25DF dual-fuel engine. When operating on liquefied natural gas (LNG), the NextDF feature lowers methane emissions to less than 2% of fuel use across all load points, achieving levels as low as 1.1% in a wide operational range. Notably, the nitrogen oxide (NOx) emissions of the 25DF engine equipped with this new technology are also lower than those of the already low-emission standard Wärtsilä 25DF engine, which meets requirements below the IMO Tier III standards.
As the maritime industry looks towards cleaner alternatives, LNG stands out as a crucial transitional marine fuel. It serves as a bridge between conventional diesel fuels and future carbon-neutral or carbon-free options. However, the primary component of LNG is methane, and when used as a fuel, a small fraction may not combust fully, potentially leading to methane emissions into the atmosphere.
The push for LNG usage and the reduction of methane emissions is deemed one of the most effective strategies for minimizing overall greenhouse gas (GHG) emissions from marine engines in the coming decade. This aligns with efforts to lower CO2 emissions and responds to emerging regulations from the International Maritime Organisation (IMO), which is set to address methane emissions in forthcoming GHG regulatory frameworks. Regionally, the European Union is initiating a suite of methane-focused measures under the FuelEU Maritime directive starting in 2025, alongside provisions in the EU Emission Trading System (ETS) commencing in 2026.
Under the new EU regulations, the impact of methane emissions will be calculated as a percentage of the mass of the fuel consumed by the engine. For four-stroke engines lacking certification for lower emissions, the default methane emission will be set at 3.1% of fuel use. The FuelEU Maritime regulation aims to incentivize compliance, allowing vessels to capitalize on overcompliance through banking or pooling excess compliance between reporting periods.
Stefan Nysjö, Vice President of Power Supply at Wärtsilä Marine, emphasized the significance of advancing dual-fuel technology to mitigate methane emissions. “Enhancing dual fuel technology to further reduce methane emissions will have a major impact on the long-term viability of LNG as a marine fuel. Our ongoing work to diminish methane slip and GHG emissions reflects Wärtsilä’s commitment to enhancing the efficiency and reducing the emissions of our products. This innovation is a vital step on the path to decarbonisation,” he stated.
The Wärtsilä 25 engine platform, launched in 2022, boasts a modular, upgradeable design that allows operators to considerably lower fuel consumption and emissions, thereby enhancing vessel efficiency and supporting the adoption of sustainable fuels. The integration of NextDF technology improves engine efficiency by an additional 0.5 percentage points.
With the Wärtsilä 25DF engine already setting a benchmark for low methane slip at levels as low as 1.4% at certain load points, the introduction of the NextDF feature enables operators to further reduce methane emissions. This positions them to exceed EU regulatory standards, offering substantial financial benefits while future-proofing their vessels for the evolving regulatory landscape.
Wärtsilä has previously introduced the NextDF technology for its Wärtsilä 31DF engine in 2023. Due to the modular design of its engine platform, the NextDF feature can also be retrofitted to existing Wärtsilä 31DF and Wärtsilä 25DF engines, with availability for the 25DF model anticipated in the second half of 2025.
About Wärtsilä Marine
Wärtsilä Marine is at the forefront of power, propulsion, and lifecycle solutions for the maritime industry. By developing leading-edge technologies, Wärtsilä facilitates the transition to new fuels and promotes a connected digital ecosystem for vessels and ports. The company’s comprehensive portfolio includes engines, propulsion systems, hybrid technology, exhaust treatment solutions, and integrated powertrain systems. Through performance-based agreements and lifecycle services, Wärtsilä is committed to driving the shipping sector towards a decarbonised and sustainable future.
About Wärtsilä
Wärtsilä is a global leader in innovative technologies and lifecycle solutions for the marine and energy sectors. Focused on sustainability, Wärtsilä aims to help customers enhance their environmental and economic performance. With a dedicated team of 17,800 professionals across 280 locations in 79 countries, Wärtsilä is shaping the global transition toward decarbonisation. The company reported net sales of EUR 6.0 billion in 2023 and is listed on Nasdaq Helsinki.
Source Wartsila