What is SAF anyways?

The aviation industry, in 2022, accounted for 2% of global energy-related CO2 emissions. With Net Zero Emissions by 2050 as the goal, the industry needs a solution to help reduce emissions that isn't "reduce the number of flights". Demand for flights continues to increase globally, and that isn't projected to slow down over the next few decades, as showcased by the Sustainable Aero Labs recent "Aviation's CO2 Crisis" article.

So what is SAF and why could it have an impact on the aviation industry? Sustainable Aviation Fuel (SAF) is a type of fuel that can be used for airplanes that has a smaller carbon footprint than conventional fossil jet fuel but has similar properties. There are many different methods for producing SAF and the industry is still working to bring the price of SAF to be comparable to conventional jet fuel, but from a CO2 emissions perspective, SAF can deliver big reductions. In some production methodologies, SAF can reduce emissions by up to 90% compared to conventional fossil fuels. Claims from credible research institutions, such as the National Renewable Energy Laboratory, state that some production methods will provide carbon-negative fuels.

Planes purchased today by any airline will have a typical operating life of between 20 to 30 years. Given it is 2024, that means the plane just put into service is likely to still be operating in 2050 when the aviation industry expects to be Net Zero. The key benefit that SAF provides the industry is that it can be used with existing aircraft; it is a drop in replacement with existing airplane and airport infrastructure. Although blending with fossil jet fuel is still required today, the future of 100% SAF commercial flights isn't far away. Rolls-Royce recently announced 100% SAF compatibility testing is complete for all its in-production civil aero engine types, and in the same month, Emirates successfully completed the first 100% SAF A380 test flight.

Hydrogen powered planes, or electric planes, are not viable in the near-term for long haul flights. Not only are both technologies not mature enough, airlines don't replace the planes within their fleet overnight. Given the majority of emissions produced are a result of long haul flights (51.9% of emissions come from just 6.2% of all flights!), a solution is needed for the industry to reduce emissions and that solution is SAF.

The main problem today is that commercially available SAF is typically 3x more expensive than fossil jet fuel. For airlines, that's a premium that they can't stomach. Regulations will help, such as the European Union's ReFuelEU and the United State's Inflationary Reduction Act, but they are only a start. SAF companies need to develop technologies that, at scale, can provide a cost competitive product to fossil jet fuel. Luckily for us, there are a lot of companies working on this problem as the demand for SAF is only going to increase.

For more information on SAF production techniques, please see the US Department of Energy SAF webpage or this excellent article, "High-flying fuels", by Oliver Booth.