The evolving role of SAF in aviation’s energy transition
Decarbonizing flight will not happen overnight, but the journey for innovative pathways to create sustainable jet fuel has already taken off. The aviation sector is responsible for about 2.5% of global greenhouse gas (GHG) emissions and in the U.S., approximately 98% of aviation-related emissions result from jet fuel combustion.1,2 This highlights the critical role of fuel decarbonization strategies, with sustainable aviation fuel (SAF) being considered among the more feasible options available for reducing emissions from medium- to long-haul flights.3 Governments in the European Union (EU) and UK are pushing this transformation forward by setting mandates for the progressive use of aviation fuel originating from sustainable materials.4 For example, as of January 1, 2025, commercial flights taking off from EU airports must carry at least 2% of SAF in their tanks. By 2030, the mandate requires a minimum of 6% of SAF, including a 1.2% synthetic aviation fuel (eSAF) blend with conventional jet fuel.5 In addition, many airline members of the International Air Transport Association (IATA) have committed to a 10% reduction by 2030, aiming for net zero by 2050.6
The state of SAF. There are two primary categories of SAF: bio-SAF, derived from biomass and eSAF (also known as synthetic or power-to-liquid SAF), produced by combining green hydrogen (H₂) from water electrolysis with captured carbon dioxide (CO₂). These intermediates can be converted into hydrocarbons through several pathways, including Fischer–Tropsch synthesis, methanol-to-jet (MtJ) and alcohol-to-jet (AtJ) processes. Each route upgrades intermediates into jet-range hydrocarbons through a series of catalytic steps, which may include oligomerization, hydrogenation and hydroprocessing to meet jet fuel specifications.7,8 When produced from waste-based feedstocks, SAF can reduce lifecycle CO₂ emissions by up to 80%–90% compared to conventional jet fuel, depending on the production pathway.9
Today, SAF deployment faces investment barriers. Cost estimates indicate that SAF is 2─10 times more expensive than conventional jet fuel, depending on the feedstock and conversion technology used, largely due to high capital expenditure (CAPEX) for early-stage facilities, limited economies of scale and the expense of green H2 for eSAF pathways.10,11 While SAF is technically mature and scalable, achieving cost competitiveness will require coordinated investment, supportive policy and continued innovation across the value chain.12
Moreover, feedstock availability is limited. The Air Transport Action Group (ATAG) projects global SAF demand could reach 330 MM metric t (MMt)–450 MMt by 2050; however, production is only a fraction of this target.13 For example, Neste (an SAF producer) produces approximately 1.5 MMtpy,14 while Spanish energy company Moeve delivered 14,400 metric t of SAF in 2024 and aims to scale to 800,000 metric tpy by 2030 through a second-generation biofuels plant in Huelva, Spain.15 These figures underscore the scale-up challenge and the need for coordinated policy, investment and technology development to close the gap between capacity and future demand.
While there is a massive SAF market on the rise, the limited availability of waste-based feedstock makes it difficult to meet alternative fuel mandates with bio-based SAF alone. This opens the need for eSAF, made with green H2 and captured biogenic CO2, which is a byproduct of many industrial processes.
Different pathways and types of SAF. The production of SAF can follow many different, and often interconnected, routes. Each pathway has its own feedstocks, conversion processes and advantages, but together they highlight the opportunities and challenges of scaling SAF for global aviation.
