Aviation biofuel

An aviation biofuel (also known as bio-jet fuel^[1] or bio-aviation fuel (BAF);^[2]) is a biofuel used to power aircraft and is a sustainable aviation fuel (SAF). The International Air Transport Association (IATA) considers it a key element in reducing the environmental impact of aviation.^[3] Aviation biofuel is used to decarbonize medium and long-haul air travel. These types of travel generate the most emissions, and could extend the life of older aircraft types by lowering their carbon footprint. Synthetic paraffinic kerosene (SPK) refers to any non-petroleum-based fuel designed to replace kerosene jet fuel, which is often, but not always, made from biomass.

Biofuels are biomass-derived fuels from plants, animals, or waste; depending on which type of biomass is used, they could lower CO₂ emissions by 20–98% compared to conventional jet fuel.^[4] The first test flight using blended biofuel was in 2008,and in 2011, blended fuels with 50% biofuels were allowed on commercial flights. In 2023 SAF production was 600 million liters, representing 0.2% of global jet fuel use.^[5]

Aviation biofuel can be produced from plant or animal sources such as Jatropha, algae, tallows, waste oils, palm oil, Babassu, and Camelina (bio-SPK); from solid biomass using pyrolysis processed with a Fischer–Tropsch process (FT-SPK); with an alcohol-to-jet (ATJ) process from waste fermentation; or from synthetic biology through a solar reactor. Small piston engines can be modified to burn ethanol.

Sustainable biofuels are an alternative to electrofuels.^[6] Sustainable aviation fuel is certified as being sustainable by a third-party organisation.

SAF technology faces significant challenges due to feedstock constraints. The oils and fats known as hydrotreated esters and fatty acids (Hefa), crucial for SAF production, are in limited supply as demand increases. Although advanced e-fuels technology, which combines waste CO₂ with clean hydrogen, presents a promising solution, it is still under development and comes with high costs. To overcome these issues, SAF developers are exploring more readily available feedstocks such as woody biomass and agricultural and municipal waste, aiming to produce lower-carbon jet fuel more sustainably and efficiently.^[7]