LIFE CYCLE ASSESSMENT OF LNG: CONTEMPORARY ISSUES RELATED TO ENVIRONMENTAL FOOTPRINT OF LNG

摘要

While end use of natural gas contributes numerous environmental benefits over other fossil fuels, conversion of natural gas to LNG for transport and storage has received increasing public attention in terms of its contribution to life cycle air emissions associated with natural gas development and end use. This paper summarizes some recent life cycle assessment (LCA) efforts to inform policies regarding LNG trade and projects and identifies various technical difficulties and biases in development of LCAs as they have been applied to LNG, including proper development of relevant LCA environmental criteria, clear and meaningful definition of system boundaries for analysis across competing fuel forms as well as LNG, and development of reliable data for LNG value chain elements while accounting for uncertainty and variability in technologies and commercial approaches. The paper focuses upon recent applications of LCA to address U. S. domestic issues associated with LNG exports and broader international aspects of developing and applying LCA methods. The paper also presents straight-forward and modest recommendations for increasing the reliability and validity of LCAs to study LNG impacts associated with the international LNG industry. Due to limitations of page length and presentation, the paper focuses on qualitative descriptions and arguments. However, the underlying issues raised here present enduring needs and challenges for expanded use of LCA as a methodology particularly applicable to LNG industry activity and expansion.