Life cycle emissions and unit production cost of sustainable aviation fuel from logging residues in Georgia, United States

Abstract

Production of Sustainable Aviation Fuel (SAF) has gained popularity for reducing carbon emissions from the aviation sector. To evaluate the environmental and economic tradeoffs related to SAF production and its potential use, this study estimates the life cycle carbon emissions and unit production cost of SAF produced from logging residues generated during harvest and thinning operations in Georgia, a major roundwood producing state in the Southern United States. We considered two production pathways, i.e., Ethanol-to-Jet (ETJ) and Iso-Butanol-to-Jet (Iso-BTJ), to compute the carbon savings and unit production costs. A sensitivity analysis was performed to identify significant factors contributing to the overall carbon savings and unit production costs for the selected pathways. After considering revenues generated from co-products, the minimum aviation fuel selling price (MASP) was $2.71 L-1 and $2.44 L-1 for ETJ and Iso-BTJ pathways, respectively. Capital investment cost at biorefinery accounted for most of the MASP, followed by the minimum haul rate for transporting biomass and variable cost for alcohol intermediate production. Finally, after considering tax credit from the Inflation Reduction Act of 2022 and RIN (Renewable Identification Number) credit along with co-product revenue, the MASP ranged between $2.29 L-1 and 0.83 L-1 for the ETJ pathway and between $2.04 L-1 and $0.59 L-1 for the Iso-BTJ pathway. In addition, the carbon intensity of both the ETJ and Iso-BTJ pathways were 758 g CO2e L−1 and 976 g CO2e L−1, with relative carbon savings of 70.6 % and 62.1 % compared to conventional aviation fuel. The production cost suggests a minimum abatement cost of $59 t CO2e−1 for the ETJ and -$59.3 t CO2e−1 for the Iso-BTJ pathways in the presence of federal incentives. Our study shows that logging residues-based SAF could reduce the overall carbon footprint of the aviation sector; however, policy support is needed to support its production in light of higher production costs.