According to Mitsui O.S.K. Lines (MOL), Kanadevia Corporation, and Yanmar Power Solutions, a Japanese consortium has achieved a 98% reduction in methane slip during onboard trials of LNG-fuelled vessels.

The companies said the result, obtained during full-scale demonstration trials that began in May, far exceeded their target of a 70% reduction. The trials are being conducted on routes, including those between Japan and Australia, using the LNG-fuelled coal carrier Reimei.

The project, spanning six years from fiscal 2021 to 2026, is part of the Green Innovation Fund Project "Development of Next-Generation Vessels," led by the New Energy and Industrial Technology Development Organization (NEDO). The consortium is developing methane slip reduction technology through improvements to catalysts and engines.

Methane slip refers to unburned methane from LNG fuel that is emitted into the atmosphere. Since methane has a higher greenhouse effect than CO2, reducing these emissions is considered crucial for reducing greenhouse gases in shipping.

The companies previously achieved a 93.8% methane slip reduction rate at 100% load in land-based trials. This achievement earned them certification from the classification society Nippon Kaiji Kyokai (ClassNK).

For the onboard trials, the consortium modified the land-based test equipment for use on board ships. The system achieved a 98% reduction rate at 75% load, described as the practical operating range. This result is despite engines operating under constantly changing environmental conditions and load fluctuations due to weather.

The onboard trials will continue through the end of fiscal 2026 to evaluate overall system performance and catalyst durability. The companies aim to implement the technology socially from fiscal 2027 onwards.

Under the project structure, Kanadevia serves as the managing company, while MOL and Yanmar Power Solutions act as joint executors. The initiative aims to be the first to implement a method for reducing methane slip in the maritime sector globally—a solution that the companies claim has not yet been developed, even for use on land.

The project builds on previous milestones, including NEDO's selection of the methane slip reduction project in October 2021 and design approval for what the companies describe as the world's first methane oxidation catalyst system in March 2022.