Modeling Sustainable Logistics System For Woody Biomass-to-Bioenergy Supply Chain

The scope of this thesis is applying distribution centers in woody biomass supply chain and returning the produced ash from poly-generation plants to the forest land. This method is proven to be efficient practices for a Sustainable Logistics System and could minimize the total costs and environmental damage of biomass supply chain significantly. Decision, also comprising whether or not to build distribution centers and how many of them lead to the most optimal results. In addition, this study investigates which type of woody biomass would result in less carbon dioxide emissions and costs. The supply chain model formulated and implemented by multi objective Mixed Integer Linear Programming (MILP) model in two separate sections including forward supply chain for transporting energy wood from supply sites to the poly-generation plants and reverse supply chain for ash disposal and ash return to the proposed forest lands. In both forward and reverse supply chain, the impact of distribution center on total costs and carbon dioxide emissions were analyzed. The planning horizon for one year applied to a proposed case of Austria with thirty poly-generation plants and eighty supply sites and examined distribution center numbers and potential locations in ten different scenario with three types of feedstock's including mixed of both wood chips and pellets, merely pellets and wood chips respectively. The feed stock types were presented in eleventh scenarios with different proportion of wood chips and pellets. As a consequence, the numerical results show an influential relationship between different energy woods proportions, number of distribution centers. These factors impact were examined on both carbon dioxide emissions and total costs in forward and reverse supply chain. The major costs in optimization model are transportation costs which could be mitigated by applying distribution centers significantly. The proposed model has proven the fact that applying the specific number of distribution center cut the total system costs. This research also concluded in the large-scale cases, distribution center construction primary costs and emissions could be compensated by the considerable transportation costs and carbon dioxide emission reduction. In contrast, in the small-case including Austria, implementing more than two distribution center would not be economically and environmentally beneficial. In addition, the results of sensitivity analysis shown although pellets production and conversion costs and carbon dioxide emissions are comparatively higher in amount than those for wood chips in European case, transportation costs reduction by implementing DC would make it the most appealing feedstock.