Techno-economic analysis with a dynamic optimization approach integrating electrical and chemical engineering: A case study for aviation decarbonization in Japan

Decarbonizing the aviation sector—one of the hardest-to-abate industries—is essential for achieving global climate goals. Power-to-X (P2X) technologies offer a promising pathway for producing synthetic sustainable aviation fuel (e-SAF), a viable alternative to fossil-based jet fuels. However, integrated system evaluations and cost-reduction strategies remain limited. This study addresses key cost drivers—intermittent renewables and process technologies—for converting CO₂ into heavy hydrocarbons. We developed a flexible electrical–chemical optimization model that accommodates regional energy profiles while remaining globally applicable to small- and medium-scale e-SAF commercialization. To capture the impact of annual renewable fluctuations, we applied a mixed-integer linear programming (MILP) approach that models partial-load operation of water electrolysis and its efficiency. MILP also enables capacity-specific cost optimization across energy storage, hydrogen production, and e-SAF synthesis. A dynamic cash flow model for renewable energy, hydrogen, and e-SAF was incorporated, enabling ten scenario analyses that address fluctuations in electricity, feedstock, and load. These scenarios integrate meteorological and power data across upstream, midstream, and downstream processes to optimize energy flows and costs. Results show e-SAF prices ranging from 45.3 USD/L-SAF under suboptimal conditions to 11.7 USD/L-SAF with capacity optimization, and subsidies can reduce costs to 2.1 USD/L-SAF. We quantitatively identified the most influential parameters and policy levers affecting the levelized cost of SAF (LCO-SAF). This study provides a robust decision-making framework for investors and regulators in Japan and globally, accelerating the deployment of low-carbon aviation fuel systems.