A framework for supply chain configuration for a biomass-to-energy pre-treatment process
A transition from fossil fuel to renewable energy sources such as biomass is an environmentally sustainable pathway. However, increased use of biomass is hampered by a number of barriers regarding movement of energy: through place, through time and through existing energy infrastructure. One means to overcome these barriers is to introduce a pre-treatment process such as torrefaction, which enhances the biomass product properties. In a supply chain perspective, there are a number of decisions to make regarding feedstock, supply system, torrefaction plant, distribution system, and customer demand. This renders a number of possible supply chain configurations. Hence, the purpose of this thesis is to understand the logistics implications of a pre-treatment process in order to propose supply chain configurations. This thesis is a compilation of four papers and the methods used are literature reviews, interviews and techno-economic modelling.
The major result of the thesis is a number of frameworks that can assist actors involved in configuration of torrefaction supply chains. First of all, biomass-to-energy supply chains without torrefaction were reviewed. The findings were classified into characteristics of the physical flow and further refined into three minor frameworks for supply chain configuration. Secondly, a framework for torrefaction configuration was developed, which entailed propositions on torrefaction configuration for three types of demand, represented by three customers: households, medium-sized bioenergy CHP and coal CHP. Finally, the cost of a feasible torrefaction supply chain under Swedish conditions was assessed. The optimal size of a torrefaction plant was calculated and a number of central parameters affecting supply chain cost and plant size were identified. In order to provide a foundation for evaluation in other cases, a framework describing the relation between torrefaction configuration and supply chain performance was proposed.