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

Growth in US liquefied natural gas (LNG) exports has 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 emission estimates in national inventories that have been demonstrated to significantly underestimate emissions. In addition, recent top–down measurements of methane emissions exhibit significant subnational spatial and temporal variations 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) emission 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 emission intensity of the Permian-UK LNG supply chain is 42% higher compared to the Marcellus-UK LNG supply chain. Differences in basin-specific, measurement-informed inventories are a key driver of disparities in supply chain LNG emission intensity. Developing measurement-informed, supply chain-specific lifecycle GHG emission assessments is critical to enabling a global market for differentiated natural gas.