Measurement-informed life cycle analysis of greenhouse gas emissions from global liquefied natural gas and plastic supply chains

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🔬研究者:Methodology for integrating top-down measurements into LCA, and the empirical findings on emission underestimation.

🏢実務担当者:Differentiated emission factors for U.S. LNG basins help procurement teams assess Scope 3 impacts of fuel sourcing.

🏛政策担当者:Evidence that official inventories undercount methane, supporting adoption of measurement-informed reporting and differentiated policies.

Growth in U.S. liquefied natural gas (LNG) exports has increased concerns about the climate impacts of methane leakage along the natural gas supply chain. To date, many scholars have employed life cycle analysis (LCA) as an effective tool to estimate the greenhouse gas (GHG) footprint of the LNG supply chain. However, the official inventory of methane emissions submitted to state and federal regulatory agencies has been demonstrated to significantly underestimate emissions. In addition, top-down measurements of methane emissions show significant differences across U.S. basins. It is critical to establish a measurement-informed, geospatial LCA framework for accurate emission estimation for global LNG supply chains. In this dissertation, we establish a measurement-informed and geospatial LCA model for accurate emission estimation across global major LNG supply chains. We incorporate recent top-down field measurements of methane emissions into the geospatial LCA model to examine differences in GHG emissions of the U.S. LNG supply chains for delivery to Europe and China. The model results show a significant difference across basin-specific LNG supply chains, providing a basis for a differentiated global natural gas market. To fill the gap of no available measurement data at the liquefaction stage, we conduct multiscale measurements at two U.S. liquefaction sites to analyze the GHG emission characteristics. We employ two aerial measurement technologies and one ground-level technology through an over 16-month campaign and reconcile measurements with inventory estimates. The results show significant variation in methane emissions across different surveys. More importantly, this study highlights the dominant contribution of CO₂ emissions at the liquefaction site, which account for over 95% of total GHG emissions when using the 100-year global warming potential (GWP) for methane. We synthesize all the measurement data from a three-year measurement campaign across upstream, midstream, and liquefaction stages of the LNG supply chain into the LCA framework to assess the GHG emission intensity (EI) of U.S. LNG supply chains, representing the first direct integration of facility-level measurement data into emission accounting. The results show a substantial contribution of stages downstream of gas production to total supply chain intensity, suggesting that relying on aggregate production-only EIs as the basis to assess the emissions impact of the LNG is likely to underestimate emissions and leads to potentially ineffective public and corporate policies. Finally, we extend our analysis from the U.S. LNG supply chains to fossil-based plastic supply chains by developing a measurement-informed, geospatial LCA model. This study covers 68 distinct plastic pathways for different plastic resins, with their fossil feedstock sourced from major U.S. domestic basins and international imports. The results show that the GHG EI of plastic ranges from 495 to 2184 g CO₂e/kg plastic production, depending on the plastic type and geospatial-specific supply chain pathway. Critically, this study finds that the national inventory-based estimates underestimate emissions by 48% compared to measurement-informed estimates and obscure regional differences. These findings underscore the need for geospatially resolved, measurement-informed LCA for plastic supply chains to better identify emissions hotspots and guide mitigation strategies.

• openaire https://doi.org/10.26153/tsw/63269first seen 2026-07-09 04:41:33