The utilization of greenhouse gas (GHG) life cycle assessments (LCAs) of liquefied natural gas (LNG) has increased over the past decade. In this study, a novel framework for improved supply chain-specific LCAs for GHGs is presented using a gas pathing algorithm aligned with how gas is purchased, sold, and transported within the U.S. Utilizing supply chain emissions and gas purchase data specific to two U.S. liquefaction facilities, we identify 138 distinct gas pathways with GHG emission profiles that can vary by nearly a factor of 6. Reference case GHG intensities are 22–53% lower than prior studies for U.S. LNG delivered to Europe (production through regasification, 100-yr GWP). This study also incorporates recent supply chain measurement data. GHG intensities based on measurement data for U.S. LNG delivered to Europe are 41–52% higher than the reference case (production through regasification 100-yr GWP) and 8–11% higher for production through power generation boundaries (all market destinations, 100-yr GWP) but 20–28% lower than prior estimates employing national or regional nonempirical data. Supply chain-specific LCAs and the integration of emission measurements in LCAs are critical to accurately characterize the differences in GHG emissions from natural gas and LNG supply chains.

中文翻译：

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气体路径：通过增强供应链解决能力改进液化天然气出口的温室气体排放估算


在过去十年中，液化天然气 （LNG） 的温室气体 （GHG） 生命周期评估 （LCA） 的利用率有所增加。在这项研究中，使用与美国境内天然气购买、销售和运输方式相一致的气体路径算法，提出了一个改进温室气体供应链特定 LCA 的新框架。利用特定于两个美国液化设施的供应链排放和天然气购买数据，我们确定了 138 种不同的气体途径，其温室气体排放曲线可能相差近 6 倍。参考案例温室气体强度比之前对美国输送到欧洲的液化天然气的研究（通过再气化生产，100 年 GWP）低 22-53%。本研究还纳入了最近的供应链测量数据。根据美国输送到欧洲的液化天然气的测量数据，温室气体强度比参考案例（通过再气化生产 100 年 GWP）高 41-52%，通过发电边界生产（所有市场目的地，100 年 GWP）高 8-11%，但比之前使用国家或区域非实证数据的估计低 20-28%。供应链特定的 LCA 以及将排放测量整合到 LCA 中对于准确描述天然气和 LNG 供应链的温室气体排放差异至关重要。