Quantify NGL-Derived LPG Used in the Marine Sector

Determine the global quantity of liquefied petroleum gas derived from natural gas liquids that enters marine sector usage to support accurate well-to-tank and well-to-wake carbon intensity assessments of LPG pathways.

Background

The paper evaluates well-to-tank carbon intensity for HSFO and well-to-refinery (exit gate) carbon intensity for refinery-sourced LPG. A substantial share of global LPG originates from natural gas liquids (NGLs) rather than refineries, but the authors restrict the LPG boundary to the refinery exit gate because shipping flows often mix NGL- and refinery-sourced LPG.

This data gap—specifically, the lack of clarity on how much NGL-derived LPG is actually used by the marine sector—prevents inclusion of shipping emissions for LPG and complicates comprehensive well-to-tank or well-to-wake lifecycle comparisons across fuels.

References

Global statistics indicate that a substantial portion of total LPG (often over 60%) derives from natural gas liquids (NGLs) rather than refineries, and it remains uncertain how much of this pool enters marine usage.

— Well-to-Tank Carbon Intensity Variability of Fossil Marine Fuels: A Country-Level Assessment  (2502.07201 - Long et al., 11 Feb 2025) in Results and Discussion — Refinery-Sourced LPG Well-to-Refinery Exit Gate Carbon Intensity variability subsection