Helsinki, Finland | November 4, 2025 – Spanish shipping company Grupo Ibaizabal has advanced its decarbonisation efforts by selecting Wärtsilä 25DF dual-fuel engines with NextDF technology for its latest 18,600 m³ LNG bunkering vessel. Factory acceptance tests show the new engines significantly reduce methane slip, a key environmental challenge for LNG-fuelled ships.
The newbuild, which will operate under charter to a major global energy supplier, reflects the growing focus on reducing greenhouse gas emissions across the LNG bunkering segment.
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Addressing the Methane Slip Challenge
Methane slip — the small portion of methane that escapes unburned from LNG-fuelled engines — remains a key environmental challenge for operators using LNG as a marine fuel. Methane is a potent greenhouse gas, and minimising its release is critical for both compliance and environmental credibility.
Ibaizabal’s decision to adopt Wärtsilä’s NextDF technology was driven by the need to meet and exceed FuelEU Maritime requirements while improving the vessel’s attractiveness to charterers and financiers. Lower methane slip not only reduces emissions but also mitigates potential financial penalties associated with regulatory non-compliance.
“Customers have put their trust in us because of our pioneering approach to vessel design, which prioritises low emissions and high operational flexibility,” said Jose Maria Torre, Fleet Director, Grupo Ibaizabal. “LNG bunkering vessels have an important role in supporting the decarbonisation of shipping because LNG remains a key transitional fuel for the maritime industry.”
Collaboration and Technology Selection
Ibaizabal and Wärtsilä worked closely from the early stages of vessel design to identify a propulsion solution that balanced efficiency, flexibility, and emissions performance.
The Wärtsilä 25DF engine, featuring NextDF combustion technology, achieves methane slip levels well below the FuelEU Maritime default value of 3.1% for dual-fuel medium-speed engines. This performance provides a measurable economic advantage, particularly for long-term LNG bunkering operations in European waters.
In addition to the main engines, Wärtsilä’s scope of supply includes a closed-loop crankcase ventilation system to further reduce methane slip, and steerable thrusters that improve propulsion efficiency and manoeuvrability during bunkering operations.
“Wärtsilä offered guarantees for engine performance, especially around methane slip reduction,” said Torre. “The Wärtsilä 25DF can operate from 0 to 100% load in gas mode, minimising the use of diesel fuel. Our close collaboration with Wärtsilä made it easier to convince both the shipyard and charterers that this technology was the right choice.”
Testing Confirms Strong Performance
According to Wärtsilä, factory acceptance tests (FAT) attended by the vessel’s charterers demonstrated exhaust methane slip levels of just 0.9%, significantly outperforming the regulatory baseline. The tests also showed 30% lower pilot diesel fuel consumption than initially projected, improving both efficiency and emissions outcomes.
“Our charterers are very satisfied with the engine performance,” Torre noted. “It’s a milestone in the industry and provides significant reputational value for all stakeholders.”
Driving Decarbonisation in LNG Bunkering
The project underlines how advanced dual-fuel engine technology can help bridge the gap between today’s LNG-fuelled operations and future low-carbon fuels.
By deploying the Wärtsilä 25DF with NextDF technology, Ibaizabal has positioned its fleet to meet evolving EU regulations while supporting the broader maritime industry’s decarbonisation pathway.
About Ibaizabal
Ibaizabal Group is a leading provider of integrated ship management services to the International Shipping and Offshore industries, committed to the highest standards of quality assurance. With a rich history dating back to the 1860s, Ibaizabal Group, through its various subsidiaries, has been deeply involved in the operation and management of both its own fleet and third-party owned vessels.
The Group specializes in fleet management, with responsibilities distributed across various management companies, each focusing on specific vessel types and trades. Ibaizabal is dedicated to maintaining excellence in Health, Safety, Quality, and Environmental management, while meeting regulatory and organizational requirements. Ibaizabal Bunkers, a recognized leader in the marine bunkering sector, offers expert technical, commercial, and operational services to oil majors and global marine fuel suppliers, ensuring safety, quality, and environmental responsibility in key ports worldwide.
About Wärtsilä Marine
Wärtsilä Marine is a global frontrunner in power, propulsion, and lifecycle solutions tailored for the maritime industry. The company spearheads the transition to new, sustainable fuels, pioneering a future where vessels and ports operate within a fully connected digital ecosystem.
Its product portfolio spans:
- High-efficiency engines and propulsion systems
- Advanced hybrid and battery solutions
- Exhaust gas treatment systems
- Shaft line and energy management solutions
- Integrated powertrains and automation
- Digital vessel optimization and AI-driven lifecycle support
Underpinned by performance-based service agreements and supported by one of the world’s largest maritime networks, Wärtsilä’s innovations are helping customers navigate a complex energy transition with reliability, safety, and sustainability at the forefront.
Source Wartsila Technology Group