Independent research firm Rystad Energy has published a study showing that well-to-tank emissions for LNG used as marine fuel averaged 13.9g CO2e/MJ in 2024, significantly below the EU's default assumption of 18.5g CO2e/MJ used in FuelEU Maritime regulation.

The study, commissioned by industry group SEA-LNG, analysed emissions across five lifecycle stages: upstream production, transportation and processing, liquefaction, shipping, and distribution and bunkering operations. The research was conducted according to International Maritime Organization guidelines and used asset-specific 2024 data.

Carbon dioxide accounted for 84% of total well-to-tank emissions, with the liquefaction stage responsible for 99% of CO2 emissions at that stage. Methane emissions represented 16% of total emissions, equivalent to 2.2g CO2e/MJ, and were most prevalent during upstream gas production.

The analysis found that upstream gas production and liquefaction were responsible for 30% and 43% of bunker supply chain emissions respectively, suggesting these areas should be prioritised for future decarbonisation efforts.

Results showed wide variation between regions and cargoes, with emissions intensities differing by as much as 6.6g CO2e/MJ in some cases, reflecting differences in gas sources, liquefaction technologies, and shipping distances.

Patrick King, Vice President Emissions Research at Rystad Energy, commented: "Our analysis is based on asset-level data that ties specific gas fields to liquefaction facilities. This approach, supported by satellite-detected methane plume data and reported asset information, gives a more accurate picture of the LNG actually used for bunkering, rather than relying on outdated or overly broad averages."

The study recommends that regulations should incentivise participants in the LNG bunker supply chain to continue reducing greenhouse gas emissions, particularly in natural gas production and liquefaction. It also suggests policymakers should introduce processes to regularly update well-to-tank default emissions factors used in regulation.

Steve Esau, Chief Operating Officer of SEA-LNG, said: "Policymakers must create regulations that reflect the true carbon intensity of marine fuels, rewarding reductions across the supply chain. Marine regulators should incentivise participants in the LNG bunker supply chain to continue to reduce GHG emissions."

With around 95% of vessels still powered by oil-based marine fuels, LNG accounts for nearly 20% of the vessel orderbook as the industry transitions toward net-zero emissions. The study aims to provide data to help shape effective regulation and guide future investment decisions as the fleet of LNG-fuelled vessels expands.

Peter Keller, Chairman of SEA-LNG, concluded: "This report sets the high standards the IMO should demand on such a key topic as alternative fuel emissions and performance within the Net-Zero Framework. Decisions must be based on real and recent data or risk undermining the significant progress already made along the practical and realistic LNG pathway to decarbonisation."