Integrated Hybrid Life Cycle Assessment and Optimization of Shale Gas

This paper analyzes the life cycle environmental impacts of shale gas by using an integrated hybrid life cycle analysis (LCA) and optimization approach. Unlike the process-based LCA that suffers system truncation, the integrated hybrid LCA supplements the truncated system with a comprehensive economic input-output system. Compared with the economic input–output-based LCA that loses accuracy from process aggregation, the integrated hybrid LCA retains the precision in modeling major unit processes within the well-to-wire system boundary. Three environmental categories, namely, life cycle greenhouse gas emissions, water consumption, and energy consumption, are considered. Based on this integrated hybrid LCA framework, we further developed an integrated hybrid life cycle optimization model, which enables automatic identification of sustainable alternatives in the design and operations of shale gas supply chains. We applied the model to a well-to-wire shale gas supply chain in the UK to illustrate the applicability. According to the optimization results, the lowest levelized cost of electricity generated from shale gas is £51.8/MWh, and the optimal life cycle GHG emissions, water consumption, and energy consumption are 473.5 kg CO 2 -eq/MWh, 2263 kg/MWh, and 1009 MJ/MWh, respectively.