For the past ten years, LNG has been promoted as a smart transition fuel for shipowners. It is cleaner than heavy fuel oil, widely accessible, and supported by established engine technology, making it a clear choice for new vessels.
According to Paul Morgan from gCaptain, the statistics support this trend. The latest mid-year market review from SEA-LNG estimates that there are over 1,550 LNG-powered ships either in service or on order. This is a significant increase from just 81 when the coalition was established in 2016.
The demand for new orders remains strong. Data from DNV, as cited by SEA-LNG, reveals that 73 LNG dual-fuel vessels were ordered in the first half of 2026, accounting for about 90% of all alternative fuel orders. In August alone, 46 more vessels were added, primarily consisting of container ships and car carriers.
However, there is a significant concern regarding LNG: not all of the methane that enters the engine is burned. Some of it escapes through the funnel, and methane is a much stronger greenhouse gas than CO2 over short timeframes.
Previously, this issue was mainly about reputation. Starting from 2026, it has a direct financial impact as well. The EU Emissions Trading System now includes methane and nitrous oxide from ships, not just CO2. As of January 1, 2026, ship operators must account for 100% of their verified emissions.
FuelEU Maritime is currently factoring in methane slip into its greenhouse gas intensity calculations. The standard value for uncertified engines is set at 3.1% of the fuel consumed. This percentage is crucial because it is applied to every tonne of LNG consumed on EU-related voyages.
The pressing issue is whether the 3.1% accurately reflects reality. Independent studies indicate that this value is likely underestimated for the most common types of engines.
The FUMES project, published in January 2024 by the International Council on Clean Transportation along with the Dutch research organization TNO, examined methane emissions from 18 LNG-fueled ships. The study used drones, helicopters, and onboard measurements.
For low-pressure dual-fuel four-stroke engines, which are commonly used in the LNG fleet, the average real-world methane slip was found to be 6.4%. This is nearly double the EU's assumed 3.1% and above the IMO's 3.5% estimate.
The slip was highest at low engine loads, where many vessels operate for significant portions of their journey. The ICCT has recommended increasing the default figure for this engine type to at least 6%.
On the flip side, in May 2026, MSC Cruises became the first cruise line to get independent verification and flag state recognition for measured methane slip for FuelEU compliance.
Bureau Veritas confirmed values of 1.67% for MSC World Europa and 1.48% for MSC Euribia, both below the standard default. This verification followed IMO Resolution MEPC.402(83), which outlines accepted measurement methods, alongside the European Commission's FuelEU guidelines.
Engine manufacturers are also making strides. Wärtsilä reports a weighted average slip of about 0.9% for its four-stroke engines equipped with NextDF technology and states that slip from its dual-fuel engines has decreased by 75% over the last 25 years.
These figures highlight an important lesson: methane slip is not just one number. It varies depending on engine design, age, load profile, and actual operational methods.
Using a single default value oversimplifies this complexity. It can underestimate the environmental impact for poorly performing vessels while overcounting costs for well-performing ones. Consequently, it does not provide owners with accurate information about their ships.
This is why accurate measurement is crucial before attempting to reduce emissions. Operators need to know what actually escapes from the stack before they can invest in solutions or defend their measurements to verifiers.
The industry is working on building this knowledge together. In September 2022, the Safetytech Accelerator, initiated by Lloyd's Register, launched the Methane Abatement in Maritime Innovation Initiative (MAMII).
Founding backers included Maran Gas Maritime, MSC, Carnival Corporation, Seaspan, Shell, Knutsen, and Lloyd's Register. The initiative aims to identify, test, and promote technologies that can measure and reduce methane emissions from LNG-powered ships.
The first round of feasibility studies, reported in 2024, selected four companies from twenty applicants, each proposing different solutions for the exhaust issue.
CDTi Advanced Materials suggested passive oxidation catalysts that achieved an 80% methane conversion at lower temperatures across various engine loads. Daphne Technology proposed a plasma-catalysis unit placed in the exhaust, assuming 80% removal.
Plenesys took an alternative approach by using plasma torches to break down methane into hydrogen and solid carbon, with the hydrogen redirected back to the engine, resulting in a 78% reduction in slip. Rotoboost suggested thermo-catalytic decomposition to generate hydrogen on board as a blend with LNG.
A second round, reported in January 2025 with partners including Chevron, Carnival, Shell, and Seapeak, focused on fugitive methane emissions from leaks and venting that occur between the bunker manifold and the engine.
Xplorobot examined handheld devices and an AI platform for quantifying leaks. Sorama used acoustic cameras to map sound and locate leaks on LNG carriers, while Framergy investigated a metal-organic framework material to capture vented methane.
The findings were both encouraging and sobering. Xplorobot's analysis was based on desktop evaluations, indicating an accuracy of about 30% for large leaks and around 50% for smaller ones. Sorama's work aimed for a six-month pilot instead of a report.
The gap between theoretical solutions and practical applications is where many potential innovations struggle. A tool designed to detect a leaking valve may not work well in a hot and rapidly moving exhaust plume, while a stack analyzer cannot identify which joint is leaking within the gas valve unit room.
Each emission source requires its own measurement tool, which must be durable enough for the realities of working vessels. Space constraints, gas hazard regulations, and any modifications to the exhaust system must all be accounted for.
Fuel chemistry can add to the complexities as well. Research from Finland's VTT in 2021 highlighted that methane oxidation catalysts on lean-burn LNG engines are prone to sulphur poisoning. Efficiency decreased over time, requiring daily regeneration to maintain performance.
This isn't an argument against catalysts but rather a call to validate their effectiveness at sea, under real-world conditions and loads, before considering the issues resolved.
Some of this validation is now coming to light. In Japan, a project funded by NEDO, involving Kanadevia, Yanmar Power Technology, and Mitsui O.S.K. Lines, installed a methane oxidation catalyst combined with exhaust gas recirculation on the Panamax bulk carrier, Reimei.
Sea trials commenced in May 2025, and at around 75% engine load, the system reduced methane slip by 98%, a result verified by ClassNK. Land tests in December 2023 had already shown a 93.8% reduction at full load.
The partners emphasize that trials will continue throughout 2026 to assess durability and long-term performance, aiming for commercial availability by 2027.
At MAMII's first members’ event in Brussels in late November 2025, attendees heard that several engine types had already achieved a 60% to 70% reduction in slip in recent years, and aftertreatment could provide an additional 80% to 90% cut.
Shell's in-house methane catalyst was expected to begin shipboard trials in December 2025, marking the third aftertreatment trial among MAMII members. Initial results across member trials were described as promising, with commercial readiness projected as early as 2027.
Collaboration with classification societies has been a key aspect of successful projects. ClassNK verified the Japanese trial results, Bureau Veritas supported MSC's certification, and Lloyd's Register is at the core of MAMII.
This highlights an essential lesson for technology developers: engaging classification societies and engine manufacturers from the beginning, rather than after the prototype stage, facilitates smoother approval processes and can boost chances of receiving purchase orders from shipowners.
Some challenges persist. There are not enough onboard pilots using standardized measurement methods, making it difficult to compare results. Additionally, there is a lack of verified data from real-world operations that is available publicly.
Fugitive emissions from bunkering, cargo handling, and floating regasification have not been prioritized as much as the exhaust emissions. Moreover, the costs associated with initial trials are still predominantly borne by a small group of pioneering shipowners and developers.
As regulatory deadlines approach, there is added pressure. The IMO's Marine Environment Protection Committee will meet for MEPC 85 from November 30 to December 3, 2026, with an extraordinary session on December 4 to discuss adopting the Net-Zero Framework.
Whatever decisions come out of London, the direction is clear. Europe is already implementing a price for methane, and the global framework under negotiation is focused on total greenhouse gas emissions from well to wake.
For owners of LNG vessels, this alters their cost calculations. A ship that can demonstrate low methane slip will incur a lower compliance cost. In contrast, those that cannot will face the default rate, or worse, if thresholds are increased as recommended by ICCT.
LNG secured its position in the order book by promising lower emissions. Maintaining this position now relies on verifiable proof of emissions reductions as measured at the stack, confirmed by third parties, and demonstrated through real-world operations.