Geospatial Life Cycle Analysis of Greenhouse Gas Emissions from US Liquefied Natural Gas Supply Chains

Growth in US liquefied natural gas (LNG) exports have increased concerns about the climate impacts of methane leakage along LNG supply chains. Current life cycle analysis (LCA) models of US LNG supply chains are based on emissions estimates in national inventories that have been demonstrated to significantly underestimate emissions. In addition, recent top-down measurements of methane emissions exhibit significant sub-national spatial and temporal variation across oil and gas (O&G) basins. In this study, we develop a geospatial, measurement informed LCA model that incorporates recent top-down methane measurements to examine regional differences in greenhouse gas (GHG) emissions intensity of US LNG supply chains for delivery to Europe and Asia. For every megajoule of LNG shipped from the US, the energy allocated GHG emissions intensity of the Permian-UK LNG supply chain is 42% higher compared to the Marcellus-UK LNG supply chain. Disparities in LNG emissions intensity across source basins can be directly attributed to higher measured methane emissions compared to inventory estimates. Developing measurement informed, supply-chain specific lifecycle GHG emissions assessments is critical to enabling a global market for differentiated natural gas.