SGMF: Up to 29% tank-to-wake GHG emissions reduction on LNG

This progress contributes to overall well-to-wake GHG emissions reductions of up to 25%, supported in part by well-to-tank emissions reductions of up to 9% compared to the first LNG LCA study published in 2019.

Following its full LCA of LNG as marine fuel in 2019, SGMF’s emissions calculations are based on the performance of a wide range of engine types, including medium-speed 4-stroke and low-speed-2-stroke engines, with the findings reflecting industry progress on emissions reductions with LNG, both upstream and downstream.

This 3rd GHG study analyses the life cycle GHG emissions of the use of fossil liquified natural gas (LNG) as marine fuel compared with biogenic LNG, synthetic LNG produced from hydrogen and captured carbon dioxide (CO2). These results are benchmarked against results for conventional marine fuels (i.e., MGO0.1 and VLSFO). In addition, air quality impacts are assessed by comparing local combustion pollutants from the operation of the engines using these different fuels

Emma Scheiris, Deputy Director-Environment at INTERTANKO said: “Independent and transparent Life Cycle Assessments are essential for tanker owners and operators. INTERTANKO supports this study’s commitment to robust Well-to-Wake principles that can apply consistently across all fuels and reflect actual supply pathways. It offers a structured assessment to evaluate environmental impact and helps our Members assess their decarbonisation strategies.”

Twelve LNG pathways considered in the study. Biogenic LNG is considered anaerobic digestion of manure and residuals, landfill gas, and gasification of forest residues. Synthetic LNG considered H2 from electrolysis powered by renewable electricity and as a co-product from the chlor-alkali process. Considered CO2 sources included direct air capture (DAC), a biomass combined heat and power plant, and a coal-fired combined heat and power plant.

Findings of the Tank-to-Wake analysis

• As new primary TtW data was only obtained for two types of LNG engines: 2-stroke slowspeed Otto dual-fuel and 4-stroke medium-speed Otto dual-fuel engines, other types of LNG engines were not considered (e.g. 2-stroke slow-speed Diesel dual-fuel).
• Methane slip in LNG accounts for 7% to 13% of engine related (TtW) GHG emissions, depending on the engine design for 2-stroke slow speed Otto engines and for around 15% of the 4-stroke medium speed engines.
• The use of LNG reduces SOx emissions by ≥96% due to the much lower sulphur content of LNG compared to MGO0.1.
• NOX emissions are mainly dependent on the underlying combustion cycle and not directly on the fuel used. However, LNG engines reduce NOx emissions compared to MGO0.1 by 38% and ~80% in 4-stroke medium speed engines and 2-stroke slow speed Otto engines, respectively. It should be noted that different NOx reduction targets apply to other engine technologies, and these depend on exhaust after-treatment systems.
• PM emissions are reduced by 92% for 4-stroke medium speed engines.
• No quantitative comparative statements can be made about BC due to a lack of data from engines using MGO0.1. However, BC from engines using MGO0.1 is almost certainly greater than engines using LNG based on emission factors from other combustion processes, and the substantially lower level of PM emissions, of which BC is a component.

In addition to its LNG studies, SGMF expects to publish its first LCA on methanol as a marine fuel in mid-2026, which follows its LCA on ammonia as marine fuel, published in 2024.

LNG is helping to decarbonize shipping by replacing oil and helping the sector meet increasingly strict environmental regulations. According to Shell’s LNG Outlook 2026, global demand for LNG is expected to increase from 422 mtpa in 2025 to between 650 mtpa and 710 mtpa by 2040, or by around 54–68%.