Comparative Assessment of Sustainable Aviation Fuel Pathways: Performance, Sustainability, Certification, and Scale-Up Constraints

Abstract

Sustainable aviation fuel (SAF) is widely regarded as the most practical near-term route to lower aviation emissions without replacing today’s aircraft and airport fuel systems. This review synthesizes the current state of SAF development across biomass-derived and synthetic pathways, with emphasis on feedstock sustainability, conversion performance, lifecycle greenhouse-gas mitigation, production cost, certification status, and deployment readiness. Certified routes such as HEFA, Fischer–Tropsch, and Alcohol-to-Jet are assessed alongside emerging Power-to-Liquid systems that couple renewable hydrogen with CO₂. The comparison shows that no single pathway simultaneously maximizes yield, scalability, cost competitiveness, and climate benefit. Waste-based HEFA is commercially mature but feedstock-limited; FT and ATJ broaden the resource base but require stronger process and capital optimization; PtL offers the deepest long-term decarbonization potential but remains highly dependent on renewable electricity, low-cost hydrogen, and supportive policy. The review concludes that accelerated certification, durable market incentives, and region-specific supply-chain strategies will be essential if SAF is to move from niche deployment to meaningful global scale.