October 2025

Biofuels, Alternative/Renewable Fuels

Sustainable aviation fuel: Powering the future of clean air travel

IP: 10.2.76.72

The aviation industry contributes approximately 2% of global carbon dioxide (CO₂) emissions.¹ As demand for air transportation continues to grow, there is increasing pressure on the aviation industry to lower greenhouse gas (GHG) emissions. Sustainable aviation fuel (SAF) is a viable sustainable pathway that could cut up to 80% of the lifecycle GHG emissions from kerosene or conventional jet fuel.² 

SAF is produced from renewable resources (made with minor changes to hardware), making it compatible with petroleum-based jet fuels. Adopting machine-learning (ML) and artificial intelligence (AI) in SAF research has improved feedstock identification, production and fuel forecasting. These tools support the fast achievement of dictated commercial aviation standards of SAF, thus enriching the development process.²  

This article outlines several SAF production routes, their lifecycle effects, the contribution of ML and AI in developing new generations of SAFs, existing policies that encourage SAF implementation, challenges faced and possible ways of incorporating SAF in the aviation industry. 

SAF production pathways. SAF can be produced through several technologically efficient processes, including using different feedstocks and conversion technologies. The most common are hydroprocessed esters and fatty acids (HEFA), Fischer-Tropsch (FT) synthesis, alcohol-to-jet (ATJ) and power-to-liquid (PtL).³ These pathways differ in their level of development, costs and potential for large-scale implementation and provide flexibility in terms of a portfolio of measures to decrease aviation’s reliance on fossil fuels. HEFA uses cooking oil or tallow as feedstock. Conversely, FT synthesizes hydrocarbons from biomass-derived syngas.³ ATJ synthesizes bio-derived alcohols and converts them to jet-range hydrocarbons, and PtL synthesizes fuel from renewable electricity, water and CO2.³ These methods signify a new path toward the decarbonization of the global aviation industry. 

HEFA. From a commercial perspective, HEFA—using food waste poultry, tallow and vegetable oil feedstocks—is the most advanced process for SAF production. These feedstocks are then subjected to hydroprocessing, which converts them to hydrocarbons resembling commercial jet fuel.4 Literature asserts that SAF derived from HEFA has been authorized to blend up to 50% with conventional jet fuel by the ASTM D7566 standard.⁴ 

FT synthesis. The FT process converts syngas, hydrogen (H2) and carbon monoxide from various carbonaceous feedstocks, including biomass and municipal solid waste, into liquid hydrocarbons. SAF produced from FT synthesis has a high energy density. Naef, et al. state that FT synthesis can accept multiple feedstock types, making production scalability possible.⁵ This versatility gives SAF a central function in promoting sustainable aviation and reducing the aviation industry’s dependence on conventional fossil fuels. 

ATJ. ATJ technology is a process that is used to transform alcohols, including ethanol and butanol, into jet fuel through several processes like dehydration, oligomerization and hydrogenation.⁶ This enlarges the feedstock source options for SAF production because this pathway is flexible enough to accommodate other biomass-derived alcohols.⁶ Therefore, using ATJ technology expands the range of SAFs. 

PtL. This technology uses power to split water through the electrolysis process, followed by further chemical processes—using the captured CO₂ from the air—to form liquid hydrocarbons.⁷ Despite being at a relatively early stage of development, PtL may be a valuable source of carbon-neutral fuels, especially if applied with renewable energy.⁷ This attractive strategy may significantly decrease GHG emissions in the aviation industry. 

Comparative efficiency and economic feasibility. SAF pathways have been proven to be more or less efficient and economically viable simultaneously. HEFA is currently the most ready for the market—with cost varying from $3/gal to $6/gal—because the technology is relatively developed and feedstocks for this process are relatively easy to obtain.⁸ FT processes are versatile in feedstocks, as they can accept a wide range of biomass feedstocks. However, the capital cost of the technology is relatively high, and the yield is low.⁹  

Able to process different forms of bio-alcohols, ATJ has several conversion stages. In turn, the process consumes more energy, making it more costly:⁶ prices range between $8/gal and $12/gal. Local feedstock, infrastructure and policies concerning feedstocks will determine the chosen pathway. Therefore, the strategy will entail using predefined and next-generation technologies to make SAF deployment global and cost effective. 

Environmental benefits. Regarding total GHG emissions, SAF provides far-reaching advantages compared to conventional jet fuels. SAF also reduces carbon intensity in aviation production, using renewable feedstocks and other fuel production processes.¹¹  

Lifecycle emissions reduction. SAF can significantly reduce CO2 lifecycle emissions compared to petroleum-based jet fuel—the extent of reduced emissions depends on the derivatives and pathways of its production. For instance, SAF diesel produced from HEFA-renewable sources has shown significant reductions in emissions and does not use arable land or feedstock.¹¹ This makes HEFA a particularly effective option for lowering environmental emissions from aviation fuel production. 

Non-CO2 emissions. The use of SAF decreases particulate matter and sulfur oxide emissions during combustion. This helps reduce pollutants in the air, resulting in an improvement in air quality and, consequently, the prevention of climate-warming contrails.⁵ Through these additional impacts, SAF helps reduce the overall environmental impact of aviation. 

Compliance with sustainability standards. The importance of sustainability certifications [e.g., Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA)] cannot be underestimated, especially in the environmental management of SAF. Certifications aim to protect the environment, maintain accountability and enhance global compliance², which helps to minimize the adverse effects of aviation on the environment, and to achieve long-term objectives of emissions reduction within the global aviation industry. 

ML and AI in SAF research. ML and AI have contributed to significant improvements in aviation SAF identification, assessment and optimization. These digital technologies help to make inflections along the stages of SAF for selecting feedstocks and molecules to use in the production of SAFs, improving the production process and creating a business case for using SAFs.¹² Therefore, ML and AI enhance fuel quality, reduce experimental loads and contribute to the transition to non-polluting aircraft fuel solutions. 

Fuel property prediction and molecule screening. The realized molecular descriptor data of diverse fuels have been incorporated in developing predictive ML models to determine valuable characteristics of fuels, such as net heat of combustion, density, viscosity and boiling point. Wang and Rijal¹¹ employed support vector machine (SVM) algorithms to predict net heat of combustion (NHOC) for polycyclic hydrocarbons, achieving a high level of accuracy and thus reducing the number of experiments. These models play an appropriate role in determining fuel molecules and helping chemists to identify thousands of compounds quickly. ML is incorporated with density functional theory to predict the energy and reactivity of two novel SAF molecules. Gao and Mavris suggest that integrating quantum chemistry and ML can assist scientists in achieving a reasonable computational cost, along with chemical accuracy regarding the performance and emissions of fuels.¹³ 

Beyond SAF-specific applications, structure-property prediction frameworks (developed in materials science) are also proving highly valuable. For example, atomistic simulations and ML techniques have been successfully employed to understand complex structure-property relationships in metallic glasses, which face similar challenges in terms of predicting thermal, mechanical and transport properties from disordered atomic structures.¹⁴ These approaches, particularly when integrated with potential energy landscape models and molecular dynamics, could inspire novel SAF molecule design strategies where disorder and property optimization coexist. 

Process optimization. AI can provide a simulation of the thermochemical conversion of biomass resources to SAF and the desirable operating conditions. For instance, Lau, et al. employed ML in their techno-economic uncertainty analysis to identify which synthesis route is superior in producing SAFs, since some technologies offer better value propositions, scalability and compatibility with large-scale production.¹⁵ ML has also been used to optimize process parameters like temperature, amount of catalyst and the time the reagents are kept in the reactor to improve the process’s overall efficiency and throughput. 

Spectroscopic analysis and high-throughput screening. Comesana, et al. suggest that developing a structured and supervised ML framework that employs liquid-phase Fourier transform infrared (FTIR) spectroscopy to support experimentation is possible.¹⁶ This integration also assists researchers in identifying spectra and even forecasting the qualities of fuels (e.g., volatility, density). This approach is practical for a quick introduction to SAF fuels and will slow the time required for such development, thus reducing laboratory experimentation costs. 

Techno-economic and emissions modeling. ML has been adopted in the planning and implementation of SAF techno-economic analyses. Qasem, et al. proposed using synthetic data and generative adversarial networks (GANs) to predict the minimum selling price (MSP) of pyrolysis-based SAF.⁵ These models considered market factors and production parameters, thus expanding the capability to find viable economic options in production. ML has also been used for emissions prediction and product lifecycle analysis. ML models have been used to perform combustion analysis and to predict the emissions/release of GHG under various fuel mixes.5 These tools offer refined, scenario-specific information on SAF’s environmental impact and complement lifecycle assessments.¹⁷ It is especially important to establish that SAF will not only decrease CO2 emissions, but will also satisfy the total scorecard for climate impact. 

Future trends: Generative AI and autonomous labs. In the future, advanced generative AI tools like variational autoencoders (VAEs) and GANs can be used in developing new SAFs that are designed to achieve the desired combustion and emissions characteristics. This involves enlarging a chemical design space and putting forward new compounds with conditions specified by energy density and sustainability.¹²  

An automated chemistry laboratory is another emerging frontier of technology. Such AI-assisted platforms allow chemists to perform syntheses, and to test and update models simultaneously with experiments.¹² Through the application of experimental results feedback, the formulation of fuels can be improved by ML algorithms in a very effective manner, rapidly shortening the concept to the certification process. 

Policy and industry implementation. Governments and intergovernmental organizations have continued to adopt policies that support the production and utilization of SAFs. Such regulatory tools include mandates, tax incentives and carbon offsets.¹⁸ European countries have implemented the ReFuelEU Aviation policy, which aims to gradually add SAF up to 2% in 2025 and up to 70% by 2050.¹⁹ As per the U.S. Department of Energy, the Inflation Reduction Act’s (IRA’s) available tax credits to SAF producers are $1.75/gal for the lifecycle of GHG reductions.¹⁸ 

The International Civil Aviation Organization (ICAO) and the International Air Transport Association (IATA) have established ambitious international goals for decarbonizing CO2 emissions from aircraft. The ICAO has adopted CORSIA, where every eligible flight comes with sustainable fuel, and lifecycle emissions accounting is considered.1 The IATA has set the goal of net-zero aviation emissions by 2050, with SAF accounting for as much as 65% of this goal.1 These frameworks are critical to support long-term financing and address the cost difference between SAF and fossil jet fuel. 

Much like the U.S. chemical process industry, where a complex regulatory framework ensures safety and environmental compliance,^8,20 the successful scale-up of SAF will require equally cohesive regulatory alignment across federal and state agencies. 

Real-world industry initiatives. Several industry players are increasingly pledging billions of dollars to support the growth and development of the SAF production and supply chain. Neste, World Energy and SkyNRG are some of the major manufacturers of commercial-scale SAF utilizing the HEFA process, one of the most common bioconversion methods.²⁰ For example, Neste aims to achieve 1.5 MMtpy of SAF production by the end of 2025.²² In addition, major airlines like United Airlines and Lufthansa have promised to purchase SAF and form innovative partnerships to grow its market share in the aviation industry. This increase in commercial activity shows the aviation industry’s efforts to shift toward more sustainable sources of revenue. 

Public–private partnerships and research alliances. The World Economic Forum is spearheading programs (such as its Clean Skies for Tomorrow initiative) and encouraging cooperation among governments, research organizations and industry members to create a stable SAF market. These partnerships involve sharing technical know-how, planning and implementing pilot projects to use SAF, and establishing standards for the certification of SAF globally.²² Through facilitating dialogues and coordinating joint actions, such alliances provide a crucial contribution to the deployment of SAF on a global scale. 

Financial barriers. However, SAF as a biofuel still lags economically compared to fossil jet fuel. SAF is generally more expensive than conventional fuels: SAF costs two to five times the price of conventional fuels due to low production scale, high fixed costs and fluctuations in feedstock prices.⁸ SAFs remain vulnerable to policy changes, feedstock supplies and fluctuations in crude oil prices, making them very volatile in price and supply. Adopting SAF may be infeasible in the aviation industry if direct government subsidies or mandatory blending provisions are not provided.²³ This cost puts a constraint on SAF uptake, particularly in developing nations, because resource constraints, in addition to inadequate infrastructure, increase the risk of high monetary loss.  

Challenges and the road ahead. Extending the application of SAF from demo projects to general adoption is one of the most significant dilemmas in the aviation industry. Although several such technologies are demonstrated to be technologically feasible, the challenges of scaling them to meet projected fuel demand are immense. For example, according to the SAF Grand Challenge, SAF fuel demand is forecast to reach approximately 35 Bgpy in the U.S. alone by 2050 (FIG. 1). This requires substantial investment, innovation and coordinated policy support.²⁴ Numerous barriers persist across upstream and downstream components of the SAF supply chain, including limited feedstock availability, constrained production infrastructure and underdeveloped global distribution networks. 

Feedstock constraints and competition. Feedstock availability and sustainability are significant challenges in scaling SAF production. Lipid-based feedstocks (primarily used cooking oil and tallow) are scarce and limited in their availability, and availability is also a competitor to other sectors like biodiesel and animal feed.²⁵ Additionally, unpredictable movements of these feedstocks in the market increase the price fluctuation risk. These structural challenges are in addition with biomass being a relatively less accessible and less efficient feedstock. These combined problems prevent SAF from growing and becoming a more universal solution to the aviation fuel problem. 

Infrastructure and logistics. Supporting infrastructure is missing, and this factor leads to the inability of SAF to be cost competitive. SAF costs are two to five times the price of conventional jet fuel because of long production processes, poorly developed value chains and high initial investment.8 Also, the current airport fueling infrastructure is unsuitable for blending or segregating SAF, which will require massive capital investments in terminals, pipelines and refueling infrastructure.²⁶ The lack of specific SAF logistics poses further challenges to integrating SAF into existing aviation operations—hence, the call for a coordinated approach to infrastructure upgrades. 

Bridging gaps with technology. However, technologies are being created to close SAF production and distribution gaps. Technologies such as modular biorefineries could be used to provide SAF near the consumption point, thus cutting back on transport costs and corresponding emissions.⁹ These terminals, known as hybrid SAF blending terminals, are under consideration in aviation centers to improve fuel delivery.²⁷ Other opportunities include fundamental research in synthetic biology, and transforming thermochemical conversion and gas fermentation to address feedstock and yield challenges.⁴ With the help of data-driven modeling tools, these opportunities are gradually reducing scaling challenges. 

The role of ML/AI in overcoming barriers. SAF production remains challenging, and ML and AI can be considered enablers in solving these challenges. For example, the more traditional feedstocks are expensive compared to newly discovered feedstocks, and recognizing molecular patterns is critical for improving the design and utilization of SAFs.^11,16 Predictive analytics are increasingly being incorporated to adjust actual variables in a reactor to gauge and optimize yields and energy efficiency, and to minimize waste products.²⁸ Additionally, applying ML to enhance the development of new SAFs, with the desired properties listed in ASTM D7566, saves significant time for certification. These future possibilities encompass self-contained laboratory systems, wherein raw SAFs and testing are synthesized with minimal human manipulation and real-time monitoring systems to confirm emissions.⁹ These tools greatly enhance research and development (R&D) while reducing the cost of fuel marketing.  

Policy gaps and market maturity. The sustainability policies set out in the European Union’s ReFuelEU Aviation directive, and in the U.S. through the IRA’s SAF tax credits, aim to boost SAF demand. Presently, no coherent global policy exists.^18,19 Most nations, particularly in developing countries, lack the infrastructure, financial resources and technical capacity needed to implement SAF production and certification standards. The lack of SAF standardization and certification increases complexities in international trade.¹⁶ To build a global market for SAF, normative frameworks are needed, including the ICAO’s CORSIA scheme, to try to align the actualization of lifecycle emissions measurements with international fuel compatibility. 

What lies ahead: A transitional or permanent solution? The fate of SAF lies in breaking through the production barriers and integrating it into a larger decarbonization plan. Some experts see the fluctuation as more moderate, since SAF is still considered a transition fuel that will be replaced by such developments as H2-powered jets or battery-electric solutions.²⁹ Some industry professionals believe that, due to its suitability with many current engines and infrastructure, SAF could maintain a continued position in long-range commercial flights for years to come, especially in intercontinental travel, which presents a general issue in power-to-weight challenges of competing technologies. Other essential factors include H2 and electrical energy storage, and the suitability of e-fuels for hybridization with SAF. PtL fuels derived from synthesizing renewable H2 and captured CO₂ are assayed for blending with SAF to raise synthetic volumes and lessen biomass requirements. These will be critical in implementing future and potent strategies for decentralized and global aviation decarbonization.^7,10 

Takeaways. SAF has been proven to align with the aviation industry’s transformation toward a more sustainable environment. Produced through HEFA, FT synthesis, ATJ and PtL, SAF provides many emissions improvements throughout its lifecycle that are crucial for the aviation industry to support climate goals. This change is essential for industry to reduce carbon emissions by transitioning away from using fossil fuels. 

ML and AI can be adopted for advancing SAF technologies with regard to the fuel molecule—screening and predicting properties and enhancing optimal fuel production methods. Although these technologies help advance SAF R&D faster, their contributions to large-scale commercial employment have not yet been established. However, with sustained commitment in terms of investment, policies and participation from industry players, SAF is expected to supply a significant portion of global aviation fuel by 2050. 

Several factors must be considered to achieve this vision, including sustainable feedstock supplies, cost control integrated with regions and countries on policy, and many others. The next 10 yrs are predicted to be the most decisive for the development of SAF production and for closing the technological gaps required for the future of air transportation based on the utilization of green fuel. Facing these challenges accordingly will help lay the foundations for a more sustainable future for the global aviation industry. 

LITERATURE CITED 

1 International Air Transport Association, “Net zero by 2050: A vision for sustainable aviation,” 2021, online: https://www.iata.org/en/pressroom/ 

2 International Civil Aviation Organization, “CORSIA sustainability criteria for CORSIA eligible fuels,” November 2021, online: https://www2023.icao.int/environmental-protection/CORSIA/Documents/ICAO%20document%2005%20-%20Sustainability%20Criteria%20-%20November%202021.pdf  

3 Vertes, A. A., et al., Green Energy to Sustainability: Strategies for Global Industries, John Wiley & Sons Ltd., April 3, 2020. 

4 Van Dyk, S. and J. Saddler, “Progress in commercialization of biojet/sustainable aviation fuels (SAF): Technologies and policies,” IEA Bioenergy, January 2024, online: https://task39.ieabioenergy.com/wp-content/uploads/sites/37/2024/05/IEA-Bioenergy-Task-39-SAF-report.pdf  

5 Qasam, N. A. A., et al., “A recent review of aviation fuels and sustainable aviation fuels,” Journal of Thermal Analysis and Calorimetry, March 2024.  

6 Amhamed, A. I., A. H. Al Assaf, L. M. Le Page and O. F. Alrebei, “Alternative sustainable aviation fuel and energy (SAFE)—A review with selected simulation cases of study,” Energy Reports, June 2024. 

7 Griffiths, S., et al., “Green flight paths: A catalyst for net-zero aviation by 2050,” Energy & Environmental Science, December 2024. 

8 Watson, M. J., et al., “Sustainable aviation fuel technologies, costs, emissions, policies and markets: A critical review,” Journal of Cleaner Production, April 2024. 

9 Peter, M. A., C. T. Alves and J. A. Onwudili, “A review of current and emerging production technologies for biomass-derived sustainable aviation fuels,” Energies, 2023. 

10 Singh, H., C. Li, P. Cheng, X. Wang and Q. Liu, “A critical review of technologies, costs and projects for production of carbon-neutral liquid e-fuels from hydrogen and captured CO2,” Energy Advances, September 2022. 

11 Wang, F. and D. Rijal, “Sustainable aviation fuels for clean skies: Exploring the potential and perspectives of strained hydrocarbons,” Energy & Fuels, March 2024. 

12 Undavalli, V., et al., “Recent advancements in sustainable aviation fuels,” Progress in Aerospace Sciences, January 2023. 

13 Gao, Z. and D. N. Mavris, “Statistics and machine learning in aviation environmental impact analysis: A survey of recent progress,” Aerospace, September 2022. 

14 Kumar, G. R. A., et al., “Structure—property predictions in metallic glasses: Insights from data-driven atomistic simulations,” Journal of Materials Research, November 2024. 

15 Lau, J. I. C., et al., “Emerging technologies, policies and challenges toward implementing sustainable aviation fuel (SAF),” Biomass and Bioenergy, July 2024. 

16 Comesana, A. E., S. S. Chen, K. E. Niemeyer and V. H. Rapp, “A structured framework for predicting sustainable aviation fuel properties using liquid-phase FTIR and machine learning,” Chemical Physics, August 2024. 

17 Xu, Y., et al., “Bibliometric analysis and literature review on sustainable aviation fuel (SAF): Economic and management perspective,” Transport Policy, March 2025. 

18 U.S. DOE, “Sustainable aviation fuel: Review of technical pathways,” Office of Energy Efficiency & Renewable Energy, September 2020, online: https://www.energy.gov/sites/prod/files/2020/09/f78/beto-sust-aviation-fuel-sep-2020.pdf  

19 European Commission, “REFuelEU aviation,” online: https://transport.ec.europa.eu/transport-modes/air/environment/refueleu-aviation_en  

20 Aggarwal, M., “Laws and regulations governing the chemical process industries in the U.S.,” Chemical Engineering Progress, June 2025.  

21 Grimme, W., “The introduction of sustainable aviation fuels—A discussion of challenges, options and alternatives,” Aerospace, February 2023. 

22 Nest, “Neste MY Sustainable Aviation Fuel—An easy leap towards sustainable aviation,” online: https://www.neste.com/products-and-innovation/sustainable-aviation/sustainable-aviation-fuel  

23 Ambrosio, W., et al., “Sustainable aviation fuels: Opportunities, alternatives and challenges for decarbonizing the aviation industry and foster the renewable chemicals,” General Economics, April 2025. 

24 U.S. DOE, “SAF Grand Challenge roadmap: Flight plan for sustainable aviation fuel,” September 2022, online: https://www.energy.gov/sites/default/files/2022-09/beto-saf-gc-roadmap-report-sept-2022.pdf   

25 Ng, K. S., D. Farooq and A. Yang, “Global renewable development strategies for sustainable aviation fuel production,” Renewable and Sustainable Energy Reviews, October 2021. 

26 Moriarty, K. and R. McCormick, “Sustainable aviation fuel blending and logistics,” NREL, September 2024, online: https://docs.nrel.gov/docs/fy24osti/90979.pdf  

27 Braun, M., W. Grimme and K. Oesingmann, “Pathway to net zero: Reviewing sustainable aviation fuels, environmental impacts and pricing,” Journal of Air Transport Management, May 2024. 

28 Boehm, R. C., C. Faulhaber, L. Behnke and J. Heyne, “The effect of theoretical SAF composition on calculated engine and aircraft efficiency,” Fuel, September 2024. 

29 Raab, M., R.-U. Dietrich, P. Philippi, J. Gibbs and W. Grimme, “Aviation fuels of the future—A techno-economic assessment of distribution, fueling and utilizing electricity-based LH2, LCH4 and kerosene (SAF),” Energy Conversion and Management: X, July 2024. 

The Author

Related Articles

From the Archive

Comments