Forecasting sustainable aviation fuel adoption and cost parity with a hybrid systems model

This study presents an expert-informed hybrid systems framework combining Integer Code Series, technology S-curves, Fuzzy Cognitive Maps (FCM), and Q-ROF DEMATEL to examine the adoption, technological readiness, and cost dynamics of key Sustainable Aviation Fuel (SAF) pathways: HEFA, PtL, and other electricity-based eSAF routes. The framework integrates structured elicitation from nine domain experts with recent quantitative and documentary evidence and constrains scenario parameters against statutory trajectories, capacity envelopes, cost benchmarks, and technology-readiness evidence. The analytical components are used to structure expert judgement and develop conditional scenario projections rather than to treat expert assessments as stand-alone empirical estimates. Results indicate a sequenced diffusion pattern in which HEFA consolidates as the near-term workhorse, PtL scales in the medium term as power and hydrogen infrastructure expand, and eSAF options follow later as system integration progresses. Cost analysis indicates substantial current premiums over fossil jet fuel, with HEFA closest to parity, PtL following, and eSAF furthest away; the timing of cost convergence remains conditional on policy design, financing conditions, energy prices, and infrastructure development. The FCM/DEMATEL analysis identifies regulatory support as the principal upstream system driver, with financial investment and technological readiness linking policy to market formation and production costs. The resulting diffusion and cost-parity windows should therefore be interpreted as indicative, policy-contingent scenarios rather than precise forecasts. Together, the findings combine expert-derived insight with external SAF evidence to clarify pathway sequencing and the policy, investment, and infrastructure conditions required to support aviation decarbonisation.