A system dynamics model for sugarcane-based alcohol-to-jet sustainable aviation fuel supply chains

Sustainable aviation fuel (SAF) is a key pathway for decarbonizing aviation, but its deployment depends on integrating supply-chain, economic, and policy conditions. This study develops a generalized system dynamics model of a sugarcane alcohol-to-jet (ATJ) supply chain and demonstrates its application using Ecuador as a case study. The model integrates four subsystems: upstream (land allocation, sugar and ethanol production), midstream (ethanol allocation and ATJ conversion), downstream (SAF blending with fossil jet fuel and use), and finance (economic viability). Under baseline conditions, SAF production reaches 50 million liters, corresponding to a blend ratio of 9.7% at a minimum selling price (SAF MSP) of 1.8 USD/L. Sensitivity analysis identified sugarcane yield as the main production driver, while uncertainty analysis also identified ethanol price as the dominant driver of SAF MSP. Policy scenarios showed that stacked interventions, including ethanol price support and an incentive for SAF producers, improved financial viability. Monetizing the avoided emissions from SAF use could accelerate plant deployment, but only at carbon prices well above current levels. Alternative construction paradigms mainly reduced fixed capital investment (FCI), with limited direct effect on SAF MSP, although combining co-location with policy support increased the number of SAF plants that could potentially be deployed and reduced the time required to reach a positive net present value (NPV). The Ecuadorian case study results show that feedstock availability alone is insufficient to enable SAF industry growth, and project economics remain the main limiting factor. The model provides a dynamic framework for evaluating how ATJ industries may evolve under different structural and policy conditions.