Rystad Energy has published groundbreaking research showing that liquefied natural gas (LNG) used as marine fuel produces significantly lower well-to-tank emissions than previously estimated by regulators.

The independent study, commissioned by SEA-LNG, found global well-to-tank emissions intensity for LNG bunkering fuel in 2024 is 13.9g CO2e/MJ (LHV), substantially below the EU’s default value of 18.5g CO2e/MJ used in FuelEU Maritime regulations.

The research analyzed emissions from five key lifecycle stages: upstream production, transportation and processing, liquefaction, shipping, and distribution and bunkering operations. It was conducted following IMO well-to-tank lifecycle analysis guidelines and IPCC AR5 GHG definitions.

“Our analysis is based on asset-level data that ties specific gas fields to liquefaction facilities,” explained Patrick King, Vice President Emissions Research at Rystad Energy. “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asset information, gives a more accurate picture of the LNG actually used for bunkering, rather than relying on outdated or overly broad averages.”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 determined that carbon dioxide dominates global WtT emissions at 84% of the total, with methane responsible for the remaining 16% (equivalent to 2.2 g CO2e/MJ). Notably, the liquefaction stage generated 43% of all emissions, while upstream gas production accounted for 30%.

Results showed significant variation between regions and cargoes due to differences in gas sources, liquefaction technologies, and shipping distances. In some cases, emissions intensities varied by as much as 6.6 g CO2e/MJ.

With approximately 95% of vessels still using oil-based fuels, LNG has emerged as the leading alternative, now representing nearly 20% of the global vessel orderbook. As the shipping industry works toward decarbonization goals, understanding accurate lifecycle emissions data becomes increasingly critical for regulatory and investment decisions.

Peter Keller, Chairman of SEA-LNG, called the report a landmark study that “sets the high standards the IMO should demand on such a key topic as alternative fuel emissions and performance within the Net-Zero Framework.”

The findings suggest that regulators, particularly those behind the EU’s FuelEU Maritime initiative, should revise their emissions factors downward to reflect the latest research.

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