Design of Cellulosic Ethanol Supply Chains with Regional Depots

The conversion of lignocellulosic biomass to fuels has the potential to reduce our dependence on fossil fuels. To ensure biomass supply meets biofuel demand, it is necessary to have an effective biomass supply network. Toward this end, the concept of regional biomass processing depot, where biomass is pretreated and/or densified to a higher density intermediate, has been introduced to improve the performance of supply network in terms of costs and emissions. In this article, we develop a mixed-integer nonlinear programming model for the capacity and inventory planning problem of biofuels supply chain including depots. Importantly, the proposed model accounts for variable locations of depots, which is a subject that has not been studied in the literature. In addition, our models account for biomass selection and allocation, technology selection and capacity planning at depots and biorefineries, and biomass seasonality.