WOODY BIOMASS TRANSPORTATION AND LOGISTICS - MODELING STUDIES FOR THE GREAT LAKES REGION

Bioenergy has received increasing attention as potential replacement for fossil fuels in energy production. This is to a great extend due to the expected environmental benefits from such replacement. However, the share of the US energy generated by biomass has remained stagnant over the past decade, as the implementation of bioenergy can increase only if it can be justified from economic, environmental and social perspective. One of the critical aspects required for increase is cost-effective transportation. Transportation is critical to bioenergy production, as the intrinsic characteristics of biomass cause transportation to account for a high proportion of costs in the overall biomass supply chain. This also makes transportation one of the most important criteria in terms of optimized supply chain. This dissertation concentrates on investigation of multimodal alternatives for woody biomass transportation and logistics. More specifically, the research developed and three MILP transportation optimization models that use region specific data in the Great Lakes States to evaluate alternative logistics systems for dedicated and co-firing bioenergy plants. The research first reviewed peer-reviewed articles focusing on the biomass transportation and logistics to enhance the understanding of the current state of research on this topic (Chapter 1). Based on the knowledge obtained from past literature and the acquisition of region specific data set, analytical models were developed and tested in case studies. In addition, sensitivity analysis was used to investigate the importance of individual parameters on the modeling outcomes. The first analytical model was developed to investigate the relationship between sustainable transportation cost and location of a dedicated bioenergy plant. This sustainability is incorporated in the analysis by combining all three main sustainability components: economic, environmental, and social factors (Chapter 2). The next two models concentrated on transportation logistics as part of decision-making for biomass co-firing on existing coal power plants. To take advantage of co-firing, a plant must pay attention to the sourcing and blending strategy of feedstocks and combine them as efficiently as possible. An analytical model was developed to determine the preferred logistics system for biomass co-firing that compares the conventional woody biomass logistics system with the option for advanced woody biomass logistics system that includes torrefaction process to upgrade the feedstock (Chapter 3). Finally, an analytical model was developed to determine optimal co-firing ratio that minimized total logistics costs. The approach also integrated the advanced logistics system and the optimized co-firing ratio to investigate the impact of potential government tax credits on the strategy (Chapter 4). To test the models in Chapters 3 and 4, they were both applied to case studies of 26 actual coal power plants in the Great Lakes States. The studies covered in this dissertation revealed that 1) multimodal transportation is essential when establishing larger biomass plants or increasing the scale of co-firing. On the other hand, the larger plants help to reduce the transportation and logistics costs, and as such support the increase in the use of biomass. 2) Local conditions have great impact on biomass transportation logistics, as the performance of woody biomass logistics system highly depends on accessibility of local transportation network, such as loading/unloading sites along rail lines. 3) When investigating logistics cost differences, plant capacity, biomass availability nearby, and average distance from biomass collecting sites are parameters with consistently high impact on the preferred solution, although the impact of a certain parameter may be opposite on a specific model or case study. 4) There would be potential benefits from woody biomass in the Great Lakes States, but inclusion of transportation and logistics system analysis that consider various types of supply networks and torrefaction process are essential to select the most suitable system