Minimizing driving times and greenhouse gas emissions in timber transport with a near-exact solution approach

Abstract

Efficient transport of timber for supplying industrial conversion and biomass power plants is a crucial factor for competitiveness in the forest industry. Throughout the recent years minimizing driving times has been the main focus of optimizations in this field. In addition to this aim the objective of reducing environmental impacts, represented by carbon dioxide equivalent (CO₂ e) emissions, is discussed. The underlying problem is formulated as a multi-depot vehicle routing problem with pickup and delivery and time windows (MDVRPPDTW) and a new iterative solution method is proposed. For the numerical studies, real-life data are used to generate test instances of different scales concerning the supply chain of biomass power plants. Small ones are taken to validate the optimality of the new approach. Medium and large test instances are solved with respect to minimizing driving times and fuel consumptions separately. This study shows that the selection of the objective of minimizing fuel consumption leads to a significant reduction of CO₂ e emissions compared to a minimization of driving times.