Given the limited feasibility of electrification for long-haul flights, the aviation industry faces significant challenges in achieving net-zero emissions by 2050. Sustainable Aviation Fuel (SAF) is widely considered the most viable alternative to conventional jet fuel, offering potential emissions reductions of up to 68%. However, despite its promise, SAF adoption remains below 0.1% of total aviation fuel use in 2024, largely due to high costs, supply chain constraints, and policy uncertainty.
SAF as a decarbonisation pathway
SAF is a ‘drop-in’ fuel, meaning it can be blended with traditional jet fuel without requiring modifications to aircraft or infrastructure. This makes it an attractive option for immediate carbon reductions. However, current production methods face limitations due to feedstock availability.
Lead author Yuchao Xu from UniSA Aviation joined C-EDGE researchers Professor Shane Zhang and Dr Xin Deng and international researchers from The Hong Kong Polytechnic University and Tongji University to analyse the academic literature.
As a result, five key themes were identified that influence SAF's role in aviation decarbonisation:
- Sustainable certification of pathways and feedstocks – SAF production relies on certified pathways and sustainable feedstocks to ensure environmental integrity. However, ensuring sustainable sourcing is critical with the rising global demand for biomass. While HEFA from waste oils is currently the most mature technology, its scalability is limited. Future research must explore novel feedstocks such as lignocellulosic biomass, industrial waste gases, and algae-based oils.
- Economic simulation of alternative solutions – While SAF is the most promising near-term solution, alternative decarbonisation strategies such as improved aircraft efficiency, route optimisation, and demand management (e.g., carbon pricing and voluntary flight reductions) could complement SAF adoption. Economic simulations suggest that without SAF, airlines may need to reduce flight distances by up to 27% or increase fares by 48% to meet climate goals, which would have negative economic impacts on tourism and global connectivity.
- Economic feasibility and market challenges – SAF is 3.5 times more expensive than conventional jet fuel, with prices averaging USD 2,500 per tonne compared to USD 690 per tonne for fossil-based alternatives. The high production cost, coupled with limited government incentives and inconsistent policy frameworks, makes SAF financially unattractive for airlines. Cost reductions will require investment in larger production facilities, improved logistics, and policy-driven financial mechanisms.
- Supply chain dynamics and stakeholder involvement – The SAF supply chain involves feedstock suppliers, refineries, airlines, airports, and regulators. Ensuring a stable and cost-effective supply will require coordinated efforts across multiple stakeholders. The research underscores the importance of international collaboration to prevent market fragmentation and ensure equitable SAF availability across different regions.
- Policy interventions and market incentives – Governments are crucial in breaking the deadlock between airlines, fuel producers, and infrastructure providers. The European Union, Japan, and Singapore have introduced SAF mandates, requiring airlines to increase SAF percentages over the next three decades. However, researchers warn that poorly designed mandates could create market distortions, favouring certain fuel types and limiting innovation. Instead, a mix of carbon pricing, subsidies, and research incentives may be more effective in scaling SAF production.
The need for global collaboration
The aviation industry cannot drive SAF adoption alone; it requires coordinated global action. The International Civil Aviation Organization (ICAO) and the Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA) are critical in setting international standards and ensuring compliance. However, current policies remain fragmented, with different countries adopting varying regulatory approaches.
One of the most significant challenges is the economic competitiveness of SAF. Without financial incentives such as tax credits, production grants, or subsidies, airlines are unlikely to switch to SAF at scale voluntarily. Researchers propose that carbon pricing mechanisms, such as emissions trading schemes (ETS), may be more effective than blending mandates, as they provide flexibility while incentivising cost-effective emissions reductions.
Future research directions
The research identifies additional research opportunities to accelerate SAF adoption:
- Regulatory concerns remain a significant topic.
- Understanding decarbonisation scenarios without SAF in place across different jurisdictions.
- Engineering economic analyses are needed to understand cost-benefit scenarios.
- The dynamics between various stakeholders, such as farmers, logistics agencies, and regulatory bodies, remain underexplored.
- Investigating existing treaties and agreements between jurisdictions is essential for understanding their real impacts and understanding opportunities for international collaboration.
- Understanding to what extent passengers can influence airlines’ adoptions of SAF is critical.
- Greater attention to be paid to grey literature, including technical certification, sustainability certification, technological analysis, prediction, and policy considerations.
In summary
The aviation sector is at a critical juncture, with SAF playing a pivotal role in its decarbonisation efforts. While technological advancements and policy interventions are helping to scale SAF production, high costs and supply chain challenges remain significant barriers. This review of the current literature underscores the need for coordinated global action, market-based incentives, and continued innovation in feedstocks and production methods.
For the full paper, visit > https://doi.org/10.1016/j.tranpol.2024.11.014
For more information, contact >
