An integrated optimization model for switchgrass-based bioethanol supply chain

Bioethanol produced from lignocellulosic feedstock show enormous potential as an economically and environmentally sustainable renewable energy source. Switchgrass (panicum virgatum) is considered as one of the best second generation feedstock for bioethanol production. In order to commercialize the production of switchgrass-based bioethanol, it is essential to design an efficient switchgrass-based bioethanol supply chain (SBSC) and effectively manage the logistics operation. This paper proposes an integrated mathematical model to determine the optimal comprehensive supply chain/logistics decisions to minimize the total SBSC cost by considering existing constraints. A case study based on North Dakota state (ND) in the United States illustrates the application of the proposed model. The results demonstrate that by using only 61% of the available marginal land for production of switchgrass feedstock, 100% of the annual gasoline energy equivalent requirement of ND can be economically and sustainably met from the produced bioethanol. Sensitivity analysis is conducted to provide insights for efficiently managing the entire SBSC and minimizing the total cost.