• An A380 Airbus recently flew for three hours with one engine powered entirely by sustainable aviation fuel (SAF), made from used cooking oil and other fats.
• Switching from petroleum-based kerosene to sustainable fuels plays a big part in aviation’s efforts to cut CO2 emissions in the race to net-zero.
• But supply and demand for SAFs is still fledgling and needs both the aviation industry and policy-makers’ support to reach the scale needed to make a dent in emissions.

Used cooking oil is probably not the first thing that springs to mind when you think about your next holiday flight. But that could soon change. Airbus has just completed its first test flight of an A380 jumbo jet with one engine powered entirely by sustainable aviation fuel (SAF). The fuel used was a mix of used cooking oil and other waste fats, purified to extract sulphur and other contaminants.

Decarbonizing a hard-to-abate industry

The aviation industry is widely acknowledged as one of the hardest to decarbonize and its share in global emissions is around 2%.

The industry has already made major investments in electric and hydrogen-powered aircraft. Switching to alternative propulsion and sustainable fuels plays another big part in its efforts to cut CO2 emissions in the race to reach net-zero by 2050. The first test flight with bio jet fuel goes back to 2008. By the end of 2019, more than 200,000 commercial flights had used SAF, mainly blended with kerosene.

Airbus has now added further momentum by flying the largest passenger aircraft in the world for three hours using a mix of kerosene and SAF. One of the outer engines was powered entirely by sustainable aviation fuel during the test. The A380 joins its smaller relatives, the Airbus A350 and the A319neo, which went through similar tests last year.

What is sustainable aviation fuel (SAF)?

Sustainable aviation fuel comes in a variety of guises, all of which have in common that they can deliver performance on a par with kerosene jet fuel but with a fraction of the CO2 emissions.

SAF (sustainable aviation fuel) can be made from a wide variety of sources. These include corn grain, algae, agricultural and forestry residues, solid waste and dedicated energy crops. Many SAFs contain fewer aromatic components than kerosene, enabling them to burn cleaner. This improves aircraft performance and also reduces emissions of pollutants other than CO2.

SAF could contribute between 53% and 71% of the sector’s required emission reductions by 2050, according to a 2021 report from the Air Transport Action Group (ATAG).

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