Low Carbon Fuel (LCF) Program and Insetting Audit
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SAF and RTFO: The Certificate Is Only as Good as What's Behind It
RTFO and the SAF Mandate are the UK’s two principal schemes for reducing transport fuel emissions.¹
Suppliers prove compliance with certificates tied to qualifying fuel or pay a buy-out price for any shortfall.
Both schemes work the same way: a supplier makes a sustainability claim, earns a certificate, and trades or redeems it against a target. Simple in theory—but only as solid as the claim behind it.
Supply 450,000 litres or more of relevant transport fuel in the UK during an obligation year (1 January to 31 December), and RTFO registration becomes mandatory.
Under the SAF Mandate, which replaced RTFO support for aviation fuels on 1 January 2025, suppliers must register once they own and supply 15.9 terajoules or more of aviation turbine fuel in an obligation year.²
Each year, obligated suppliers must surrender enough certificates to meet their obligation or pay the buy-out price on any shortfall. Unused certificates can be carried forward for one obligation year, while prior-year certificates can cover up to 25% of the current obligation, providing flexibility without allowing long-term deficit accumulation.¹
Every certificate is checked before issue—not once a year.
Verifiers must be recognised by the DfT Administrator, with assurance opinions meeting ISAE 3000 or equivalent standards. ³
Voluntary schemes such as ISCC or RSB can support evidence but do not replace recognised verification.
For SAF, the evidence trail includes invoices, bills of lading and weighbridge records—physical quantity is as important as sustainability.
Once a methodology for emissions or eligibility is chosen, it must be applied consistently, not changed batch by batch to influence results. ³
Eligibility is defined through DfT feedstock tables that are updated periodically.⁴
Eligibility does not transfer between schemes materials eligible under RTFO may be excluded under the SAF Mandate.
SAF is typically blended with conventional Jet A-1 because aircraft fuel systems require specific performance characteristics. ²
Once blended, sustainable and fossil molecules are physically indistinguishable—the sustainability claim survives only through documentation.
Three elements carry that claim:
If any one of these weakens, the certificate behind it weakens too.
The risk of double-claiming sustainability attributes exists across fuel and carbon markets, which is why traceability and independent verification are central to both schemes.
RTFO, SAF Mandate, UK ETS, EU ETS and CORSIA operate under different rules, so a claim accepted in one system cannot automatically be assumed valid in another without separate verification. This is exactly what independent verification is designed to catch: the same tonne of feedstock or the same certificate surfacing across two schemes, or a methodology applied one way in one submission and differently in the next.
Targets make headlines. Certificates only matter if the Proof of Sustainability, chain of custody and blend data behind them hold up and if controls prevent the same environmental attribute being claimed twice.
That’s the layer that rarely makes the news. That’s the layer Normec Verifavia works in.
Normec Verifavia is a leader in third-party verification and has recently been added to the list of officially recognised RTFO and SAF mandate verifiers.
¹ RTFO: An Essential Guide – Department for Transport
² UK SAF Mandate: An Essential Guide – Department for Transport
³ SAF Mandate Sustainability Criteria and Verification Requirements – GOV.UK
⁴ RTFO and SAF Mandate List of Feedstocks – GOV.UK
⁵ RTFO Statutory Review and Future of the Scheme – GOV.UK
