HEFA

HEFA stands for hydroprocessed esters and fatty acids, a category of renewable aviation fuel produced from fats, oils, and greases. It is designed as a drop-in replacement for conventional jet fuel (Jet A-1) when blended and is one of the best-known SAF (sustainable aviation fuel) pathways used in commercial aviation.

Production and feedstocks

HEFA fuels are created by hydroprocessing feedstocks such as used cooking oil, yellow grease, animal fats, and various vegetable oils. Through hydrotreating, the oxygen is removed and the fats and oils are converted into long-chain, paraffinic hydrocarbons suitable for aviation fuel. The resulting product is a hydrocarbon fuel with properties compatible with Jet A-1.

Use and certification

HEFA fuels can be blended with conventional Jet A-1 up to a specified limit, commonly up to 50% by volume, under industry standards such as ASTM D7566. Because they are drop-in fuels, HEFA blends can be used in existing aircraft engines and infrastructure without major modifications. Commercial airlines have operated flights using HEFA-blended fuels, contributing to the growth of SAF.

Environmental and sustainability considerations

Lifecycle greenhouse gas emissions for HEFA depend on the feedstock and production pathway. When sustainable feedstocks are used, HEFA can provide substantial reductions in lifecycle emissions relative to fossil jet fuel, along with reductions in sulfur compounds and particulate matter. However, feedstock supply, land-use impacts, and certification requirements influence overall environmental benefits and cost.

Market status and challenges

HEFA is one of the most widely implemented SAF pathways, but its availability is limited by feedstock supply, production capacity, and regulatory frameworks. Ongoing development aims to expand feedstock options, lower costs, and increase compatible supply for broader adoption.