Multistage Optimization of Sustainable Supply Chain of Biofuels

A sustainable biofuel supply chain must be not only economically viable but also environmentally benign. This study addressed a strategic multistage expansion (e.g., a decade) of a cellulosic biofuel supply chain system with supplements of corn grain biofuels. A multiobjective, multiyear optimization framework was proposed, and the compromise method was used to seek best-compromise solutions between economic competitiveness and environmental quality of the supply chain while satisfying evolving fuel demand, feedstock resources, and technological constraints. The model was implemented in an illustrative case study of planning an in-state ethanol supply chain in California between 2015 and 2025. The results indicated that significant trade-offs existed between cost and greenhouse gas emissions in the supply chain and that cellulosic ethanol produced from corn stover and forest residues could be an important alternative to corn ethanol with a low cost of $2.20/gal and emissions of 1.5 carbon dioxide equivalent kg/gal.