As global air travel surges toward 8 billion passengers by 2040, the aviation industry is under growing pressure to address its climate impact. Already responsible for 2% to 3% of global carbon emissions, aviation is one of the hardest sectors to decarbonize. Without intervention, emissions from air travel are expected to more than double over the next two decades. That reality has spurred global momentum toward one clear solution: sustainable aviation fuel (SAF).
Source: Global Outlook for Air Transport (June 2023) and International Energy Agency
Aviation’s growing emissions and the push to decarbonize
The challenge is simple. Most of aviation’s emissions come from burning fossil-based jet fuel. While engine efficiency improvements and operational optimizations offer some progress, they are not nearly enough. According to the International Air Transport Association (IATA), 317 member airlines from over 120 countries have pledged to achieve net-zero carbon emissions by 2050. To get there, SAF must replace a significant share of traditional jet fuel in the decades ahead.
Global mandates and airline commitments
Governments are beginning to mandate action. The European Union and the United Kingdom have already introduced mandates that require airlines to blend a small percentage of SAF with conventional jet fuel. These mandates start at just 2% in 2025 but scale up rapidly. The EU’s targets call for a 70% SAF blend by 2050, with 35% of that coming from so-called e-fuels. Airlines are also stepping up. For example, Air France has committed to reaching a 10% SAF blend by 2030, well ahead of the regulatory curve.
Despite this progress, the production gap is significant. Only 1 million tonne of SAF were produced globally in 2024 — far short of the 5 million tonne needed by 2030 to meet current blending mandates, signaling a need for major investment and innovation in the next few years.
Why SAF is a game-changer for aviation
Unlike hydrogen or electric aircraft, which are still in early development and not viable for long-haul flights, SAF is compatible with today’s jet engines and airport infrastructure. This drop-in compatibility lets airlines decarbonize without needing to overhaul their fleets. More importantly, SAF can reduce life cycle greenhouse gas emissions by up to 80%, making it one of the most powerful tools available for immediate emissions reductions.
What is SAF?
“Sustainable aviation fuel” is a broad term that refers to nonpetroleum-based jet fuels made from renewable or waste-based feedstocks. SAF is chemically similar to traditional kerosene, which means it can be blended with fossil jet fuel and used in existing aircraft without modifications. The fuels must meet strict ASTM standards to ensure safety and performance.
A look at the four main SAF pathways
The SAF landscape is built around four primary production pathways, each with its own strengths, challenges, and level of commercial readiness:
Bio-oil to SAF
This method uses waste oils, such as used cooking oil and animal fats, or vegetable oils as feedstock. These oils are processed through hydrotreatment and hydrocracking to produce jet fuel in a technology known as hydrotreated esters and fatty acids, or HEFA. Companies like Neste have scaled this technology at biorefineries in Singapore and the Netherlands. While bio-oil to SAF is proven and scalable, its long-term growth is constrained by limited availability of sustainable waste oil feedstock. Regulatory restrictions also prohibit the use of food-based oils in many regions, further tightening supply.
Biomass to SAF
This process converts solid biomass, including forestry residue and agricultural waste, into jet fuel. The most advanced approach involves gasifying the biomass into synthesis gas and converting it through the Fischer-Tropsch process. Another method under development is pyrolysis, which liquefies the biomass into a biocrude that can then be upgraded. Although biomass is an abundant and sustainable feedstock, the technology is still in development. Fulcrum BioEnergy’s demonstration plant in the United States was a step forward but ultimately shut down due to technical complications, highlighting the challenges of scaling this pathway.
Ethanol to SAF
In this process, ethanol is converted into jet fuel through a series of catalytic steps, including dehydration, oligomerization, and hydrogenation. LanzaJet is leading the field with a demonstration plant launched in 2024. However, this pathway faces a complex regulatory landscape. In the EU and the U.K., first-generation ethanol made from food crops is not allowed, requiring the use of second-generation cellulosic ethanol instead. Unfortunately, cellulosic ethanol production is still underdeveloped and limited in scale, making this pathway more viable in regions like the U.S. and Brazil where first-generation ethanol is permitted.
CO2 to SAF
Also known as e-fuel, this method involves capturing CO2 from the air or industrial sources and combining it with green hydrogen to create synthetic fuel. The most common technologies use reverse water-gas shift reactions followed by Fischer-Tropsch synthesis or convert CO2 into methanol, which is then refined into jet fuel. While this approach offers abundant and sustainable feedstock, the cost is prohibitively high. Producing SAF from direct air capture of CO2 and electrolysis can be five to six times more expensive than conventional jet fuel. Despite this, several companies, including Infinium and Johnson Matthey, are pushing forward with pilot projects.
The benefits of SAF
SAF offers numerous environmental and strategic advantages. It can cut life cycle emissions by up to 80%, helping the aviation industry align with global net-zero targets. SAF can be produced from a wide variety of feedstocks, offering regional flexibility. It also enhances energy security by reducing dependence on fossil fuels and opens opportunities for rural economic development through the use of agricultural and forestry residues.
From an operational standpoint, SAF’s compatibility with existing aircraft and fueling infrastructure makes it uniquely positioned for near-term deployment. Airlines can adopt SAF without waiting for new aircraft technologies or major infrastructure upgrades.
The challenges of SAF
Despite its promise, SAF faces significant challenges. The most pressing is cost. In a best-case scenario, SAF made from bio-oil still costs about 30% more than fossil jet fuel. Other pathways, such as biomass to jet and e-fuels, can be two to six times more expensive than conventional jet fuel. These price premiums create real financial strain for airlines, especially on long-haul international routes.
Feedstock availability is another concern. HEFA production is constrained by the global supply of waste oil, and advanced feedstocks like cellulosic biomass and CO2 are either expensive or technologically immature. The lack of proven, scalable technology for many SAF pathways further complicates the path to market.
Policy support is also a mixed bag. While mandates help drive demand, they do little to reduce the high cost of production. Without subsidies, tax incentives, or carbon pricing mechanisms, SAF may remain financially out of reach for many airlines.
Looking ahead: Trends shaping the SAF landscape
The next five years will be critical for scaling SAF production. We can expect increased investment in demonstration projects for ethanol, biomass, and CO2-based fuels. As green hydrogen and carbon capture technologies improve, e-fuels may become more cost competitive.
In the U.S., policy flexibility around feedstock use is likely to support the growth of HEFA and ethanol-to-jet fuels. In contrast, the EU’s stricter feedstock regulations and aggressive SAF targets may drive innovation in biomass and CO2-based pathways, albeit at a higher cost.
Corporate partnerships will also shape the future. Oil majors, airlines, and technology developers are increasingly joining forces to de-risk SAF projects and accelerate commercialization. The space is also seeing greater involvement from startups focused on unlocking new feedstocks and improving conversion technologies.
To dive deeper into SAF pricing, technologies, and opportunities, watch our webinar Flight Path to SAF: Innovation, Economics, and the 2030 Mandate.