Traditional fuels used in aviation, such as kerosene, are responsible of 3% of Global GHG emissions. With the long-term climate goal of net-zero emissions by 2025, the ambition is to reduce aviation net CO₂ emissions by 50% by 2050 (compared to 2005 levels). In this context, Sustainable Aviation Fuel (SAF) is an alternative to traditional fossil jet fuel since it is considered as a promising solution to reduce carbon emissions in the aviation sector and combat climate change.
SAF is typically made from renewable sources including agricultural waste.
This article provides a definition of SAF and gives the context of its emergence in the aviation industry. With the advent of SAF, airlines are now able to significantly reduce their carbon emissions and contribute to a more sustainable future for air travel.
SAF is produced from renewable or waste-derived bio-based resources that meet sustainability criteria depending on their origins. These resources include renewable oils and fats, lignocellulosic biomass, wastes, sugars, and low carbon intensity inedible starches. In all cases, these residues and other waste products do not compete with food crops.
e-SAF, also known as Power-to-X, synthetic fuel, renewable fuel of non biological origin, or e-fuel is manufactured from captured CO₂ combined with renewable hydrogen or low-carbon hydrogen:
Main Sustainable Fuel Pathways
One of the key advantages of SAF is that it is considered a drop-in fuel, meaning it can be blended with traditional jet kerosene and does not require any equipment change in the plane. Currently, SAF can be blended up to 50% by volume maximum for the main pathways certified by ASTM*1, including FT-SPK*2, ATJ-SPK*3, and HEFA-SPK*4. The blending process does not require any equipment changes, special infrastructure, which helps limit the overall supply chain investments.
*1 ASTM: American Society for Testing and Materials. Compliance with ASTM standards is often required for the certification and use of SAF in the aviation industry.
*2 FT-SPK: Fischer-Tropsch Synthetic Paraffinic Kerosene.
*3 ATJ-SPK: Alcohol-to-Jet Synthetic Paraffinic Kerosene.
*4 HEFA-SPK: Hydroprocessed Esters and Fatty Acids Synthetic Paraffinic Kerosene.
The use of SAF in aviation has several environmental benefits:
The adoption of SAF in the aviation industry is gaining momentum, with several airlines and airports committing to increasing the use of sustainable aviation fuel in their operations. Governments and regulatory bodies are also supporting the development and deployment of SAF through incentives and mandates.
Abbreviations
SAF is an alternative to traditional fossil jet fuel that offers a promising solution to reduce carbon emissions in the aviation sector. It is produced from renewable or waste-derived bio-based resources. When using captured CO₂ combined with renewable or low-carbon hydrogen, it is called e-SAF.
Both SAF and e-SAF are considered a drop-in fuel and can be blended with traditional jet kerosene without requiring any equipment changes or modifications to the supply chain. Its adoption in the aviation industry has significant environmental benefits and contributes to the circular economy.
