The need for Sustainable Aviation Fuel (SAF) arose from a growing recognition of the significant environmental impact of the aviation industry, particularly its contribution to climate change.
The need for SAF emerged from the urgent imperative to decarbonize the rapidly growing aviation sector in the face of climate change.
While significant progress has been made in demonstrating its viability and increasing production, the current state of play highlights the immense challenge of scaling SAF to the levels required to achieve net-zero aviation emissions by 2050, necessitating continued innovation, investment, and strong policy support.
Prior to the widespread focus on climate change, aviation primarily relied on conventional jet fuel (kerosene) derived from fossil resources. While there was some early interest in alternative fuels in the 1940s, driven by concerns over fossil fuel dependence, the urgency for SAF really gained momentum in the late 20th and early 21st centuries due to several key factors:
- Growing Emissions: As global air travel expanded rapidly, so did the carbon footprint of the aviation sector. Air transport currently accounts for approximately 2-3% of global human-induced greenhouse gas (GHG) emissions. When factoring in non-CO2 effects like contrails (condensation trails that also have a warming effect), the overall impact can be even higher.
- Climate Change Awareness: Increased scientific understanding and public awareness of climate change, driven by reports from organizations like the Intergovernmental Panel on Climate Change (IPCC), highlighted the need for all sectors, including aviation, to reduce their emissions.
- International Commitments: International bodies and national governments began setting targets for emissions reductions. For example, the International Air Transport Association (IATA) committed to achieving carbon-neutral growth by 2020 and halving carbon emissions by 2050 (later updated to net-zero by 2050). The International Civil Aviation Organization (ICAO) also adopted a Long-Term Aspirational Goal (LTAG) of net-zero CO2 emissions by 2050.
- Limited Decarbonization Options: Unlike other transport sectors that could pursue electrification or hydrogen power more readily, long-haul aviation faced unique challenges due to weight and energy density requirements. SAF emerged as the most viable near-to-mid-term solution for decarbonizing the existing fleet, as it is a “drop-in” fuel that can be blended with conventional jet fuel without requiring modifications to aircraft engines or infrastructure.
- Early Demonstrations: Early commercial flights using biofuel blends, such as Virgin Atlantic’s flight in 2008, demonstrated the technical feasibility of using alternative fuels, paving the way for further development and certification.
SAF a safe drop-in replacement
In November 2023, Virgin’s ‘Flight100’ flew from London Heathrow to New York JFK, operated by a Boeing 787-9 aircraft powered by Rolls-Royce Trent 1000 engines using 100 per cent SAF.
The aircraft did not require any modification to its engine, airframe or fuel infrastructure, and operated on safety standards equivalent to every other commercial flight.
The flight was designed to prove that SAF is a safe drop-in replacement for fossil fuel for use in commercial flights, as well as boost awareness of the technology and drive further investment into the production of sustainable aviation fuel across the industry.
Virgin’s report, released last year, reveals that the flight saved 95 tonnes of CO2 compared to a standard Virgin flight from LHR to JFK – equivalent to a 64 per cent reduction of emissions.
Current State of Play
As of mid-2025, the SAF landscape is characterized by increasing momentum, but also significant challenges:
Production and Supply:
- Growing Production: SAF production is increasing rapidly, albeit from a very low base. In 2024, global SAF production reached 1 million tonnes (1.25 billion liters), doubling the amount produced in 2023. IATA expects this to double again to 2 million tonnes (2.5 billion liters) by 2025.
- Dominant Pathways: The most common SAF production pathway currently is Hydroprocessed Esters and Fatty Acids (HEFA), derived from feedstocks like used cooking oil and animal fats. Other pathways, such as those converting municipal waste or agricultural residues, are also being developed.
- Regional Growth: The U.S. and Europe are seeing significant growth in SAF production capacity, driven by policy incentives and mandates.
- Limited Volume: Despite the growth, SAF still represents a very small fraction of overall jet fuel consumption. In 2025, it is projected to account for only about 0.7% of total aviation fuel needs.
- High Costs: SAF remains significantly more expensive than conventional jet fuel, which is a major barrier to wider adoption.
- Feedstock Availability: Securing sufficient sustainable feedstock is a crucial challenge for scaling up SAF production.
Adoption and Demand:
- Airline Commitments: Many airlines have committed to using increasing amounts of SAF and are actively seeking off-take agreements with producers.
- Regulatory Mandates: Policies like the EU’s ReFuelEU Aviation Regulation are setting minimum SAF blending mandates for fuel suppliers, starting with a 2% minimum blend in 2025 and rising significantly in subsequent years. Other countries like India and the US are also implementing policies and targets.
- Voluntary Uptake: Beyond mandates, some airlines and corporate travelers are voluntarily purchasing SAF to reduce their carbon footprint.
- Technological Approvals: ASTM International has approved multiple SAF production pathways, ensuring their safety and compatibility with existing aircraft. Research continues into new pathways, including those utilizing direct air capture of CO2.
Challenges:
- Scaling Production: The biggest hurdle is rapidly scaling up SAF production to meet ambitious decarbonization targets. This requires massive investment in new production facilities.
- Cost: The price differential between SAF and conventional jet fuel is a significant barrier for airlines, impacting their operating costs.
- Feedstock Sustainability: Ensuring the sustainability of feedstocks used for SAF production is critical to avoid unintended negative environmental or social consequences (e.g., deforestation or competition with food production).
- Policy Certainty and Harmonization: Consistent and clear policy signals, along with international harmonization of regulations, are crucial to de-risk investments and accelerate the market.
- Infrastructure: While SAF is a “drop-in” fuel, ensuring adequate supply chain and distribution infrastructure is still a consideration.
Willie Walsh, Director General of IATA, recently delivered a sobering assessment of the aviation industry’s progress towards its net-zero carbon emissions by 2050 goal, emphasizing that while airlines are committed, a genuine partnership with governments, manufacturers, infrastructure operators, and fuel suppliers is severely lacking.
Disconnect Between Words and Action
Walsh highlighted the early support from all stakeholders for the 2050 net-zero target, and ICAO’s subsequent agreement to it, including CORSIA, the Carbon Offsetting and Reduction Scheme for International Aviation, as the sole global market-based measure to address CO2 emissions from international flights.
However, he expressed strong disapproval of the interim 2030 target of a 5% emissions reduction through SAF on international flights, stating: “The following year governments agreed an interim target of a 5% emissions reduction by 2030 through SAF on international flights. We did not and do not support this interim target.”
Walsh pointed out the stark reality of SAF production: “So while SAF production will double to 2 million tonnes in 2025 it will only meet 0.7% of airline fuel needs. What’s gone wrong?” He attributed this failure directly to governments’ inability to “create supportive policy frameworks” and the uncertainty surrounding vital incentives like US tax credits. Furthermore, he criticized major players like BP and Shell for “cutback or delayed investment plans” in SAF production.
The ‘Great Green Scam’
Walsh condemned the trend of increasing aviation taxes, with the EU’s SAF blending mandate being a prime example. He called the situation an “outrage that suppliers are charging airlines compliance fees that value SAF at double its market premium over conventional jet fuel. That’s a billion-dollar windfall for fuel suppliers. This is the EU great green scam.”
He also lamented the weakening government support for CORSIA, with many states “seeking to milk aviation for more taxes.”
Call for True Partnership
Walsh stressed that “there is no time for delay and no tolerance for government greenwashing and unnecessary cost increases.” He called for urgent actions, including:
- Successful implementation of CORSIA: “CORSIA must be successful. It is a credible and verifiable system... We’re ready to help it succeed with IATA’s Aviation Carbon Exchange permanently open to facilitate transactions.” He urged more governments to follow Guyana’s lead in certifying carbon credits.
- Alarm bells on SAF production: He called for “more effective leadership” from governments, particularly in delivering “production incentives” with a proven track record.
- Ramping up SAF production: He challenged companies capable of producing SAF to “stop procrastinating and get to work at ramping-up production capacity,” highlighting IATA’s initiatives to facilitate a global SAF market.
- Action on all decarbonization levers: Beyond SAF, he emphasized the need for ANSPs and airports to deliver greater efficiency and for aircraft and engine manufacturers to fulfill their promises of bringing more efficient and carbon-reducing technologies to market quickly.
Walsh concluded with a powerful questioning of the commitment from other parts of the value chain: “Am I being cynical for wondering if other parts of the value chain are committed to net zero because they see it as an opportunity to generate additional profit?” He asserted that “Good intentions will not get us to net zero. Action is what we need,” and expressed optimism that it’s “not too late to pick up pace and realign us on the path to success” through a true and active partnership.
