What Fraction of Sustainable Aviation Fuel (SAF) is Actually Used Cooking Oil? (Is this fraction itself sustainable?)

Question

The November 23, 2022 CNN article Etihad's 'Greenliner' shows a glimpse of a more sustainable future for aviation includes a photo with the caption:

On March 25 2022, an Airbus A380, the world's largest commercial passenger airliner, completed a test flight powered entirely by SAF -- sustainable aviation fuel -- composed mainly of cooking oil.

Below is the photo along with an enlarged and enhanced cropped area showing that painted on the front of the aircraft are the words

100% Sustainable Aviation Fuel on board

The caption suggests SAF is composed "mainly of cooking oil" and I don't think they are going to the supermarket and buying bottles of new, unused cooking oil off the shelf, but it's not clear to me exactly what "cooking oil" means here.

So I'd like to ask:

Question: What fraction of the sustainable aviation fuel (SAF) being used today is actually used cooking oil?

I'm just curious and don't mean to imply that the used cooking oil fraction is necessarily essential to the fuel's sustainability.

"bonus points" for addressing if that fraction is itself sustainable¹, or if there really isn't enough suitable used cooking oil available to maintain this fraction if the use of SAF really "takes off" (pun intended).

---

¹thus the defining-sustainability tag.

---

Answer 1

One of the main companies creating sustainable aviation fuel is Neste.

They say here: https://www.neste.com/products/all-products/raw-materials/waste-and-residues#3f0293d6

...that "In 2021, the share of waste and residues increased to 92% of Neste’s total renewable raw material inputs globally. Our refineries of renewable products have been technically capable of running on 100% waste and residues since 2015."

I'm not sure if all of that waste is used cooking oil, though. It could be other types of food waste, or even non-food waste. Finding more accurate information is probably impossible, since Neste wants to keep full details of their material sourcing as confidential trade secret.

Aviation fuels are nice that if we want to create all of them from sustainable sources, we probably can. For road transportation fuels, that is not possible because road transportation uses so much fuel and we don't have enough waste streams to create all of that.