A new approach to making jet fuel from food waste has the potential to massively reduce carbon emissions from flying, scientists say.
Globally, most of the food waste that is used for energy is currently converted into methane gas. But US researchers have discovered a way to turn this waste into a type of paraffin that works in jet engines, in a joined-up solution avoiding both use of fossil fuels and organic waste’s release of methane.
The authors of the new study found a way to make this “wet-waste” produce volatile fatty acids (VFA) instead of methane. The researchers were then able to use a form of catalytic conversion to upgrade the VFA to two different forms of sustainable paraffin. When the two forms were combined, they were able to blend 70% of the mixture with regular jet fuel, which meets the very strict quality criteria that Federal authorities impose on aircraft fuels.
Another major advantage is that this new fuel produces around 34% less soot than current standards. This is important because soot plays a key role in the formation of contrails from airplanes which adds a powerful warming effect to CO2 coming from the engines.
The research team say they are planning to scale up the production of the new fuel and aim to have test flights with Southwest Airlines in 2023. Many environmental groups are sceptical about attempts to develop sustainable aviation fuels, believing that it justifies carbon emissions: They argue that people should just fly less.
Even lead author on the study, senior research engineer at the US National Renewable Energy Laboratory, Derek Vardon says: “Sustainable aviation fuel is not a silver bullet. So we do want to definitely emphasise that reduction is the most important and most significant change you can make. But there’s also pragmatism and need for aviation solutions now, so that’s where we want to strike a balance as we need a basket of measures, to really start getting our carbon footprint down in a variety of sectors, including aviation.”