Optimization of biofuel supply chains based on liquefaction technologies

About the project

Traditional bioenergy supply chains design considers a centralized facility around which the bio­mass is collected. In the centralized supply chain design the benefits from economies of scale are counterbalanced by rising upstream transport costs as a higher scale requires a larger feedstock collection radius. Distributed supply chains configurations (i.e. including a pre-treatment step in which the biomass is densified) are often proposed to reduce the upstream transportation costs. It is hypothesized that such configuration allows for further upscaling and can hence decrease bioenergy production costs, particularly when using liquefaction technologies which are able to convert bio­mass into a transportable biocrude with a much high energy and bulk density compared to biomass.

This project has explored the preconditions under which distributed supply chain configurations (based on hydrothermal liquefaction, HTL) are preferred over centralized supply chains. A spatially ex­plicit optimization model based on Swedish data on biomass supply and price, intermodal transport infrastructure, competing demand, and potential conversion sites (including integration benefits) was evaluated at different biofuel demands.

It was found that distributed supply chains may reduce upstream transport cost. Nonetheless, the additional costs for conversion and intermediate transpor­tation associated with distributed supply chains generally leads to a preference for centralized sup­ply chains at biofuel demands below 75 PJ_out/yr (21 TWh/yr). Distributed supply chains were shown to be useful in cases in which the feedstock cost-supply curves are steep, biofuel production beyond 75 PJ_out/yr is targeted, or the available biomass resource base is almost fully utilized.