Production and application challenges of sustainable aviation fuels in air transport sector decarbonisation

Abstract

Sustainable aviation fuels (SAF) represent one of the key solutions for reducing GHG emissions and decarbonising air transport, especially in segments where electrification and the use of hydrogen still have significant technical limitations. This paper analyses contemporary achievements in the field of SAF production and application, with a special focus on available feedstocks, technological conversion processes, fuel quality, sustainability criteria and obstacles to wider application. Lipid raw materials, lignocellulosic biomass, agricultural and forest residues, municipal waste, sugar and starch raw materials, microalgae, as well as CO₂ and renewable hydrogen for the production of synthetic fuels were considered. Particular attention is paid to hydroprocessed esters and fatty acids, Fischer-Tropsch, alcohol-to-jet, hydrothermal and power-to-liquid technologies. The key physical and chemical properties of SAF and their impact on compatibility with existing aircraft engines and infrastructure were analysed, as well as the requirements related to certification and the possibility of use in mixtures or as 100% SAF. Sustainability was considered through a life-cycle approach, including the origin of the raw material, energy and hydrogen consumption, land-use changes and overall emissions. Based on a literature review, the main obstacles to the further application of SAF were identified: high production costs, limited availability of sustainable raw materials, insufficient production capacities, energy requirements and regulatory constraints. It was concluded that the future decarbonisation of air transport requires the parallel development of multiple SAF technological path-ways and their adaptation to regionally available resources.