Who Is Liable, and When
If you supply 450,000 liters or more of relevant transport fuel in the United Kingdom during a commitment year (January 1 through December 31), registration with the RTFO is mandatory.
Under the SAF mandate, which replaced the RTFO support for aviation fuels on January 1, 2025, suppliers must register as soon as they hold and supply 15.9 terajoules or more of aviation turbine fuel during a commitment year.²
Each year, obligated suppliers must surrender sufficient certificates to meet their obligation or pay the buyout price for any shortfall. Unused certificates may be carried over for one obligation year, while certificates from the previous year may cover up to 25% of the current obligation, providing flexibility without creating a long-term shortfall.¹
Verification takes place with every application
Each certificate is verified before issuance—not just once a year.
Verifiers must be accredited by the DfT administrator, with verification reports that comply with ISAE 3000 or equivalent standards. ³
Voluntary schemes such as ISCC or RSB can serve as evidence, but do not replace accredited verification.
For SAF, the evidence trail includes invoices, waybills, and weighbridge data—the physical quantity is just as important as sustainability.
Once a methodology for emissions or suitability has been selected, it must be applied consistently and may not be altered on a per-batch basis to influence the results. ³
Not all raw materials are the same
Eligibility of raw materials is determined based on DfT raw material tables, which are updated periodically.⁴
- Waste materials and byproducts (used cooking oil, agricultural and fishery residues) can yield double credits per liter or kilogram.
- RFNBOs such as green hydrogen are eligible only if strict energy-input requirements are met.
- Recycled carbon fuels must meet the established RTFO eligibility criteria.
- For crop-based fuels, a cap applies under the RTFO policy, and this cap is being gradually reduced.⁵
- Blended or co-processed fuels yield certificates only for the renewable portion, which is assessed on a per-shipment basis.
Eligibility is not transferable between programs: materials eligible under the RTFO may be excluded under the SAF mandate.
SAF is no longer traceable once it is in the tank
SAF is typically blended with conventional Jet A-1, as aircraft fuel systems require specific performance characteristics. ²
Once blended, sustainable and fossil molecules are physically indistinguishable—the sustainability claim is supported solely by documentation.
Three elements support that claim:
- Blend ratio—supported by test and production data
- Proof of Sustainability (PoS)—issued under recognized certification schemes
- Chain-of-custody documentation and invoices linking the material to the claim
If any of these elements weakens, so does the underlying certificate.
Where double counting comes into play
The risk of double-counting sustainability attributes exists in both the fuel and carbon markets; therefore, traceability and independent verification are central to both schemes.
RTFO, the SAF mandate, UK ETS, EU ETS, and CORSIA operate under different rules, so a claim accepted in one system cannot automatically be considered valid in another system without separate verification. This is precisely what independent verification is designed to detect: the same metric ton of feedstock or the same certificate appearing in two schemes, or a methodology applied one way in one submission and another way in the next.
The Heart of the Matter
Meeting targets makes the headlines. Certificates are only meaningful if the underlying evidence of sustainability, the chain of custody, and the blending data are accurate, and if controls prevent the same environmental label from being claimed twice.
That is the aspect that rarely makes the news. That is the area in which Normec Verifavia operates.
About Us
Normec Verifavia is a leader in third-party verification and has recently been added to the list of officially recognized verification bodies for RTFO and SAF mandates.
Sources
¹ RTFO: An Essential Guide – Department for Transport
² UK SAF Mandate: An Essential Guide – Department for Transport
³ Sustainability Criteria and Verification Requirements for the SAF Mandate – GOV.UK
⁴ List of feedstocks for the RTFO and SAF mandates – GOV.UK
⁵ Regulatory review of the RTFO and the future of the scheme – GOV.UK
