What is SAF
Sustainable Aviation Fuel is an alternative fuel that is being marketed as a solution to the aviation industry’s carbon intense nature. It is made by collecting waste materials such as cooking and vegetable oils, animal fats, and food scraps as feedstock. This feedstock is then pre-treated, removing any impurities and contaminants. The feedstock is then refined by removing the oxygen from the feedstock by adding additional Hydrogen in a process called hydrodeoxygenation, the resulting Hydrocarbons then go through a process called isomerisation which adjust the properties of the fuel. After this step, the fuel is further distilled to meet fuel quality specifications (namely ASTM 7566). The final result of this distillation process is Sustainable Aviation Fuel.
The SAF is then blended with conventional aviation fuel in a mixture of up to 50% SAF to comply with the fuel quality specifications.
SAF brings a multitude of benefits to the aviation industry aside from the lower Green House Gas emissions at the point of use. It can be safely added to the existing fuel infrastructure as a drop-in fuel, which allows for it to be easily integrated into an airports infrastructure thus making it more attractive for airport operators. In addition, SAF is suitable for long term storage due to its stability and low water solubility which makes it well suited to be used in fuel reserves. The blending process with Jet fuel is safe and creates a fuel that is completely stable, maintaining the very high safety standards of aviation. Increased use of SAF also allows for the utilisation of waste products in a way that directly reduces greenhouse gas emissions by way of reducing the emissions of air travel. If this could be done at scale, it could rapidly change the face of aviation from a highly polluting industry to an eco-friendly one. Another positive of SAF is that it does not require the retrofitting of new engines to any aircraft that use it as it is fully interoperable with conventional fossil fuel based aviation fuel.
The primary factor that is holding SAF back now is simply the availability of the fuel. Even if an airline wanted to switch to SAF, only 7 airports currently supply SAF (Frankfurt, Paris CDG, Amsterdam, Helsinki, Stockholm-Arlanda, Hamburg and Munich) for aircraft departing from these airports. This is the greatest challenge that will have to be overcame to allow for the wider adoption of SAF in the industry.
Another challenge faced is the blending process due to the possibility of greenwashing where an airline blends a mixture of 10-90 SAF to Aviation Fuel, but will still use the SAF label so consumers will fly on these planes unaware that they are not really making all that much of a difference. A way to combat this perhaps would be a mandated minimum mixture for SAF to fuel so flyers could be confident in the sustainability of the fuel their plane is using.
In the last week, Lufthansa Group and Shell signed a memorandum of understanding to examine the global supply of SAF to airports and to see how the supply situation could be improved across the globe as this will require a global solution. This is to be welcomed as aviation is quite unique in its internationality as if only Europe was to readily adopt SAF, this would make no impact on the multitude of flights from outside Europe like Dubai, New York or Beijing, it also couldn’t impact trans-European flights such as Dubai to New York. Climate change in a global challenge and organisations such as IATA (International Air Transport Association) must push for a global solution.