Sustainable aviation fuel, or SAF, is jet fuel made from non-petroleum sources such as waste fats, oils, and plant matter instead of crude oil. It works in today’s aircraft and is usually blended with regular jet fuel.
Aircraft burn jet fuel, a kerosene-based product, and a plane cannot easily switch to a battery or another fuel the way a car might. SAF answers that by making a fuel with the same properties as ordinary jet fuel, but from renewable raw materials rather than crude oil.
Because it matches the spec of regular jet fuel, SAF is a drop-in fuel. It can go through the same pipelines, fueling trucks, and aircraft with no changes. In practice it is blended with conventional jet fuel up to an allowed share rather than used straight.
The point of SAF is its much lower carbon score over its life, since the carbon in plant or waste feedstock was recently pulled from the air rather than dug up. That lower score is what airlines and rules are after, and it is what earns SAF its credits and its premium.
For the fuel trade, SAF is a specialized aviation product sold to airlines and airports. It is one of the main uses for renewable feedstocks like used cooking oil, alongside renewable diesel.
In useAn airline buys a blend of SAF and regular jet fuel at a major airport, cutting the carbon score of those flights without changing a single aircraft.
See also Jet fuel, Used cooking oil (UCO), Renewable diesel