UK and EU SAF Blending Mandates Take Effect, Locking In 2% Jet Fuel Floor

Two separate rulebooks came into force on 1 January that change the arithmetic of the jet fuel barrel across Western Europe. In the European Union, Regulation (EU) 2023/2405, known as ReFuelEU Aviation, now requires that at least 2% of the jet fuel made available to aircraft operators at EU airports be sustainable aviation fuel. In the United Kingdom, the Renewable Transport Fuel Obligations (Sustainable Aviation Fuel) Order 2024 imposes the same 2% floor on fuel suppliers. For the first time, SAF is not a voluntary sustainability gesture priced at a premium airlines can decline. It is a legal quota, and the meter starts now.

The scale of what 2% means is easy to underrate. The EU burns roughly 46 million tonnes of jet fuel a year and the UK about 11.9 million tonnes. Meeting a 2% obligation across both markets calls for something in the order of 1.2 million tonnes of SAF in 2025 alone. Global SAF output in 2024 sat at around half a percent of total jet fuel demand. So these mandates are not asking the market to keep pace with production. They are asking it to sprint ahead of it.

What the EU rule actually requires

ReFuelEU Aviation puts the obligation on aviation fuel suppliers, not airlines and not airports. Suppliers must ensure the fuel they place at each EU airport meets the minimum SAF share, and the percentage climbs on a fixed schedule: 2% in 2025, 6% in 2030, 20% in 2035, 34% in 2040, 42% in 2045, and 70% in 2050. That end point is the headline nobody in a refinery planning meeting can ignore. By mid-century, more than two thirds of the jet fuel supplied at EU airports has to be sustainable.

There is a second obligation buried inside the first, and it is the harder one. A sub-mandate specifically for synthetic aviation fuel, the electricity-derived e-kerosene made from green hydrogen and captured carbon, kicks in at the start of the next decade. It begins at an average of 1.2% across 2030 and 2031, rises to 2% averaged over 2032 to 2034, then 5% in 2035, and on to 35% by 2050. Synthetic fuel barely exists at commercial volume today. The regulation is effectively a demand signal aimed at plants that have not yet been built.

To stop suppliers gaming the system by buying cheap fuel outside the bloc, ReFuelEU also carries an anti-tankering provision. Aircraft operators must uplift at least 90% of the fuel they actually need at each EU departure airport, which blocks the old trick of loading extra fuel at a cheaper, unregulated hub to avoid buying mandated blends.

How the UK went its own way

The UK left the EU rulebook and wrote its own, and the design choices differ in ways that matter to anyone trading the molecule. The British trajectory is steeper in the near term: 2% in 2025, 10% in 2030, and 22% by 2040. Where the EU sets a hard percentage of physical volume, the UK runs a tradeable certificate scheme administered by the Department for Transport, closer in spirit to the existing Renewable Transport Fuel Obligation that governs road fuel.

Under the UK order, suppliers earn certificates for the SAF they supply, weighted by the greenhouse gas savings each batch delivers against fossil kerosene. Fuel must beat conventional jet by at least 40% on a lifecycle basis to count. Certificates can be traded, and a supplier can carry forward up to 25% of an obligation into the following year, which gives the market some breathing room in a tight supply year.

The safety valve is a buy-out price. A supplier that cannot source enough SAF can instead pay 4.70 pounds per litre against the main obligation, and 5.00 pounds per litre against the power-to-liquid obligation that starts in 2028. Those numbers are not a subsidy. They are a ceiling on the pain, and they tell you roughly what the government thinks non-compliance should cost. The UK also runs its own e-fuel sub-mandate, opening at 0.2% in 2028, reaching 0.5% in 2030, and 3.5% by 2040.

The feedstock problem nobody solved

Both regimes lean, for now, on the same fuel: HEFA, made from waste fats, used cooking oil, and similar oleochemical feedstocks. It is the only SAF pathway producing at real scale today, and it is already the cheapest and most contested. The UK order caps how much of the obligation HEFA can satisfy, starting at 92% in 2027 and falling to 35% by 2040. The intent is deliberate. Regulators want to force capital toward advanced pathways and synthetic fuel rather than let the whole mandate ride on a waste-oil supply chain that is finite and heavily fought over by road diesel producers.

That is the tension at the heart of both mandates. The 2% start is comfortably met with HEFA. The steep years, the ones that arrive after 2030, cannot be. Meeting them depends on advanced biofuels and e-kerosene plants reaching final investment decision, securing green hydrogen, and financing on the strength of a demand curve that exists on paper. The mandates are the demand curve. Whether they are bankable enough to pull those plants into existence is the open question.

What suppliers and airlines feel first

The immediate effect is cost, and it lands unevenly. Fuel suppliers carry the legal obligation and the compliance risk, but the SAF premium flows through to airlines and, eventually, to fares. SAF still costs several times more than fossil jet fuel, and a 2% blend spreads that premium thinly across the barrel. As the percentage ratchets up, the pass-through grows with it.

Enforcement matters too. The UK backs its order with civil penalties modelled on the existing road-fuel obligation for suppliers that miss their number without paying the buy-out. The EU leaves penalties to member states, which introduces the usual risk of uneven implementation across 27 jurisdictions. A trader watching the SAF market in 2025 should expect the physical volumes to be small, the certificate and compliance mechanics to be where the real action is, and the first review points, 2030 in the UK, to be when the mandates either bend to reality or hold the line. The floor is in. The climb is what will hurt.