A system dynamics tool to assess the development potential of HEFA-SAF supply chains at national and regional scales

The aviation sector faces a critical challenge in achieving decarbonization while meeting growing fuel demand. Sustainable aviation fuel (SAF) derived from hydroprocessed esters and fatty acids (HEFA) represents the most mature pathway, yet its deployment is constrained by feedstock availability, cost, and policy uncertainty. This study applies a System Dynamics (SD) model to evaluate the long-term feasibility and development of HEFA supply chains, integrating feedbacks among feedstock supply, land use, economic performance, and policy incentives. Results show that feedstock cost and facility scale are the dominant drivers of economic viability, with resource constraints significantly limiting industry growth. A Monte Carlo analysis is used to assess uncertainty, demonstrating that without incentives, SAF production is not economically viable, while moderate incentives introduce limited probability of success. Stronger incentives (0.70 USD/L) enable robust profitability for large-scale facilities, reaching up to 98% probability of positive NPV. These findings highlight the importance of scale, stable feedstock supply, and sustained policy support for enabling SAF deployment under real-world uncertainty.