Regardless of policy provisions or fuel production scenario, the feedstock production and feedstock conversion stages are the main contributors to the total SAF CI (Table , SI Figure ). According to methods specified by the CFR, the feedstock production stage contributes -10.4 g CO2e×MJ -1 to the total SAF CI. This result is comparable to the results of spatially explicit LCA on a hybrid allocation basis, where this stage contributes -16.0 g CO2e×MJ -1 to the total -75.5 g CO2e×MJ -1 CI (median values). In all cases, the negative emissions during feedstock production stem from modeled increases in soil organic carbon. The relative similarity of the CFR-based and spatially explicit LCA CIs illustrates the benefits of accounting for key site-specific production factors (e.g., farming inputs and biogeochemistry in the case of the miscanthus CI used for these two analyses).