Sustainable Aviation Fuel (SAF) Mandate

The Sustainable Aviation Fuel (SAF) Mandate is the UK’s key policy to decarbonise jet fuel and is the UK’s key policy mechanism to secure demand for SAF. It is focused on delivering greenhouse gas (GHG) emission savings by encouraging the supply of SAF within the aviation industry.

The mandate sets a legal obligation on fossil jet fuel suppliers in the UK to supply an increasing proportion of SAF over time. Suppliers will receive certificates for the SAF they supply. The number of certificates they receive will be issued in proportion to the level of GHG emission reductions that fuel delivered[1]

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Context

Sustainable Aviation Fuel (SAF) is one of six key measures to meet net zero in aviation in the UK by 2050, supporting the Government's Transport Decarbonisation Plan[2] and wider Net Zero Strategy[3] in a Waste to Chemicals approach.

In March 2023 a consultation commenced which was published in 2024[3] on proposals for the UK Sustainable Aviation Fuel (SAF) mandate, removing it from the RTFO framework.

It commenced in 2025 with an initial obligation at 2% of UK jet fuel demand from biofuels derived from wastes or residues, recycled carbon fuels (RCFs) or power to liquid (PtL) using low carbon electricity.

The mandate increases to 10% by 2030 and then to 22% by 2040[1].

The International Air Transport Association (IATA) estimates that SAF could contribute to a reduction of 65% of emissions in aviation to reach net zero by 2050[5]

Key Waste Streams

The key wastes under consideration for the production of SAF are:

  • Used cooking oil
  • Tallow
  • Forestry Residues
  • Municipal Solid Waste (residual MSW)

Each bring different technical challenges. The current commercial scale process for producing SAF is from HEFA (Hydrogenated Esters and Fatty Acids) - mainly based around used cooking oils[6]. Arguably the hardest will be based on MSW residual waste.

Future Pathways

There are 7 biofuel production pathways (with 11 planned by 2025) which are certified to produce SAF, to perform at operationally equivalent levels to JetA1 fuel[7].

The development of pathways and technologies to process waste to meet the specification required will be required at an international level. A recent report by Philip New[8] was an independent report commissioned by the Government to explore the challenges and opportunities for the market.

References:

  1. Sustainable Aviation Fuel (SAF) Mandate statistics (.gov website May 2026)
  2. Transport decarbonisation plan (.gov policy paper Jan 2023)
  3. Net Zero Strategy: Build Back Greener (.gov policy paper Apr 2022)
  4. Pathway to net zero aviation: developing the UK sustainable aviation fuel mandate (consultation outcome Apr 2024)
  5. IATA Website Article
  6. The SAF Mandate: an essential guide (.gov guidance Dec 2024)
  7. IATA Fact Sheet Dec 2025
  8. Developing a UK Sustainable Aviation Fuel Industry (Independent report by Philip New)