Spatial optimization of the sustainable aviation fuel supply chains from forest residues via fast pyrolysis/hydrotreatment considering feedstock ash content variability

Policymakers and the aviation industry are working to decarbonize commercial flights by replacing conventional jet fuel with sustainable aviation fuel (SAF). Logging residues have been identified as a valuable resource for SAF production. However, the quality of the feedstock, particularly the ash content, can adversely affect bio-oil yield and SAF production using the fast pyrolysis/hydrotreatment process, and potentially its supply chain optimization. Previous research often assumes fixed biofuel yields and neglects the variability in feedstock quality when optimizing the supply chain. Thus, this study seeks to address this gap in the literature by employing a two-stage mixed-integer linear programming (MILP) model to investigate the influence of varying ash content in logging residues on the potential maximum supply quantity (MSQ) and net revenue (NR) of SAF production. Two scenarios were conducted in the Southeastern United States (US): one assuming constant ash content and the other accounting for heterogeneous ash content in logging residues. Results indicate that ignoring ash variability in the feedstock could lead to overestimation of SAF MSQ and NR by 14.15 % and 18.27 %, respectively, in the study area. Additionally, higher ash content leads to lower bio-oil yields, resulting in fewer refineries and reduced capacity. The study emphasizes the need for best management practices to mitigate soil contamination during feedstock processing and improve the resilience of the biomass-based SAF supply chain. Furthermore, it is crucial to effectively manage the mechanisms of mineral uptake and their integration into the structure of lignocellulosic materials.