Shipping’s LNG Boom Faces a Methane Problem

On October 12, gCaptain reported that the LNG-fuelled fleet is facing a new challenge: methane from ship engines is increasingly affecting climate compliance costs.

LNG Remains Central to Ordering

According to SEA-LNG figures cited by gCaptain, the LNG-fuelled fleet in service and on order exceeded 1,550 ships by mid-2026. In 2016, when SEA-LNG was founded, the figure was 81.

DNV data quoted by SEA-LNG shows that 73 LNG dual-fuel vessels were ordered in the first half of 2026, around 90% of all alternative-fuel orders. August alone added 46 LNG dual-fuel vessels, mainly container ships and car carriers.

Methane Has Become a Cost Item

The issue with methane slip is that not all methane burns inside the cylinder: some passes through the engine and exits through the funnel. Since January 1, 2026, the EU ETS has covered not only CO2 but also methane and nitrous oxide from ships. The same date ended the phase-in period, with operators now surrendering allowances for 100% of verified in-scope emissions.

FuelEU Maritime also counts methane slip in its greenhouse gas intensity calculation. For an uncertified engine, the default value is 3.1% of fuel consumed.

The FUMES project, published in January 2024 by the International Council on Clean Transportation with Explicit and TNO, measured methane in the exhaust plumes of 18 LNG-fuelled ships. For low-pressure four-stroke dual-fuel engines, average real-world methane slip was 6.4% — roughly double the European 3.1% default and above the IMO’s 3.5% value.

The Industry Moves Toward Measurement

In May 2026, MSC Cruises became the first cruise line to secure independent verification and flag-state recognition of measured methane slip for FuelEU purposes. Bureau Veritas verified values of 1.67% on MSC World Europa and 1.48% on MSC Euribia.

MAMII, launched by Safetytech Accelerator in September 2022, is testing technologies to measure and reduce methane from LNG-fuelled shipping. Its founding backers included Maran Gas Maritime, MSC, Carnival Corporation, Seaspan, Shell, Knutsen and Lloyd’s Register.

In its first round of feasibility studies, reported in 2024, MAMII selected four companies from twenty applicants. CDTi Advanced Materials proposed passive oxidation catalysts with 80% methane conversion. Daphne Technology worked on an exhaust-fitted plasma-catalysis unit, with the study assuming 80% removal. Plenesys reported a 78% slip reduction using plasma torches, while Rotoboost proposed thermo-catalytic methane decomposition to produce hydrogen on board.

For LNG shipowners, the issue is no longer only using a fuel with lower claimed emissions, but proving real performance. A ship that can verify low methane slip can face a lower compliance bill, while one without such data will carry the default value.