Sustainable Aviation Fuel: The Molecule Is Only Part of the Product
SAF is not a value chain in which physical fuel alone determines value. Feedstock origin, conversion pathway, lifecycle emissions, certification, blending, delivery and the compliance regime all affect whether a technically usable fuel can capture the economic value attached to being recognised as sustainable aviation fuel. The chain therefore produces two coupled outputs: a molecule that can power an aircraft and credible evidence that allows the market and regulation to recognise what that molecule represents.
The Brief in One Sentence
In SAF, value does not travel in the molecule alone: a fuel becomes commercially and regulatorily more valuable when its feedstock, pathway, lifecycle emissions and chain of custody can be verified and recognised at the point where someone needs to claim that value.
Why It Matters
Aviation cannot easily electrify long-haul flight with today's technology, so liquid fuels remain strategically important. That makes SAF one of the most consequential low-emissions fuel chains now being scaled.
But scale is often discussed as if the only question were how many tonnes a refinery can make. That misses where value is actually created and lost. A technically usable tonne may carry very different compliance value depending on the feedstock, conversion route, verified lifecycle emissions, certification and the rules of the market in which it is sold.
Explain It Simply
Imagine two tanks of aviation fuel that both work in an aircraft. One comes with verified information showing that it was made from an eligible feedstock through a recognised process with a measured lifecycle emissions benefit. The other cannot prove where its feedstock came from or how its carbon impact was calculated.
The aircraft may be able to burn both. But a regulator, fuel supplier or airline may not be able to treat both as the same thing. That is the essential SAF value-chain insight.
The Physical Chain
The physical chain begins with a feedstock: used cooking oil, other fats and greases, residues, wastes, alcohols, biomass, captured carbon plus hydrogen, or other eligible inputs depending on the pathway and framework. That feedstock must be collected or produced, pre-treated, converted, refined, tested, blended where required, transported and delivered into aviation-fuel infrastructure.
Each hand-off can change cost, yield, quality and timing. Feedstock can be scarce. Conversion can destroy yield. A plant can be far from a blending or airport market. Logistics can make technically successful fuel commercially weak.
The Proof Chain
Parallel to the fuel is an information chain. Feedstock identity and origin, conversion pathway, lifecycle-emissions data, sustainability criteria, certification, batch records and claims must remain coherent enough for the final environmental value to be recognised.
Under CORSIA, eligible-fuel claims are monitored, reported and verified, and approved sustainability certification schemes are part of the architecture. Lifecycle value also depends on the feedstock and pathway rather than on the label SAF alone.
Sidy's synthesis: the refinery creates the fuel; the evidence chain makes the fuel legible to the market and the rulebook.
Observed Market Economics: The Premium Is Real
EASA's 2026 report on the 2025 EU market records 1.1 million tonnes of SAF, or 2.79% of reported aviation-fuel supply. The same report gives an average 2025 SAF reference price of about €1,925 per tonne versus €640 per tonne for conventional aviation fuel.
That gap is not a universal SAF price and should not be exported mechanically to every region or pathway. But it makes one fact hard to ignore: in the observed EU market, the low-carbon product still carried a large cost premium. That premium has to be absorbed, supported, passed through or compensated somewhere in the chain.
Feedstock Can Become the Hidden Bottleneck
EU data also shows how concentrated the early market can become. About 80% of SAF supplied in 2025 was aviation biofuel, the feedstock base was overwhelmingly used cooking oil, 85% of reported feedstocks were imported and China represented 61% of reported feedstock origin.
This does not describe the global SAF market. It does show a structural risk: a mandate can create demand for SAF faster than diversified eligible feedstock and conversion pathways develop. When that happens, the value chain can move the bottleneck upstream into collection, feedstock verification, trade and competing uses.
Policy Creates Demand, Not Automatic Profit
ReFuelEU creates mandatory demand by requiring increasing SAF shares at covered EU airports. ICAO's 2026 policy guidance, however, still identifies high production cost, limited sustainable feedstock, investment constraints and policy design as critical scale-up issues.
The distinction matters. A mandate can make a buyer need the product without making every producer able to supply it profitably. IEA has also documented periods of tight or negative margins in biofuel and SAF-adjacent production when feedstock costs, policy uncertainty and credit values move against producers.
Where Value Is Lost
- Feedstock eligibility: an input can be physically convertible but fail the rules required for a target claim.
- Traceability: weak chain-of-custody evidence can reduce or block recognised environmental value.
- Conversion: low yield, high energy use or capital intensity can erode project economics.
- Lifecycle performance: two fuels that both fly can carry different recognised emissions values.
- Logistics: fuel can exist but be expensive to move to the blending point or airport where compliance demand sits.
- Rule fragmentation: different frameworks can recognise attributes differently, reducing fungibility.
- Finance: announced capacity has no value to an airline until the project is financed, built, certified and actually delivers.
Evidence Map
- Observed EU market: 2025 SAF volume, share, average reference prices, feedstock mix, import dependence and airport distribution come from EASA's 2026 ReFuelEU report.
- Regulatory facts: EU blending obligations come from ReFuelEU; CORSIA eligibility, monitoring, verification and lifecycle methods come from ICAO.
- Global outlook: IEA projections support the view that SAF grows materially but remains policy-dependent and a minority of aviation fuel through 2030.
- Inference: the proof chain carries economic value because recognised environmental attributes affect compliance and claims.
- Uncertain: future feedstock mix, pathway mix, project delivery, prices and cross-regime fungibility remain highly dynamic.
What Most People Miss
People often describe SAF as a refinery problem: find a feedstock, convert it and sell the fuel. The deeper value-chain problem is coordination across physical production and institutional recognition.
A producer can solve the chemistry and still lose value through feedstock documentation, certification, lifecycle accounting, financing, logistics or a mismatch between the attribute produced and the rule the customer must satisfy.
Critical View
- Do not treat all SAF as equivalent. Feedstock, pathway and lifecycle values differ.
- Do not extrapolate EU 2025 feedstock shares globally. They are observed regional data.
- Do not confuse compatibility with eligibility. A fuel can work physically while failing a target regulatory claim.
- Do not turn mandates into guaranteed margins. Costs, feedstock and policy support still determine project economics.
- Do not count announced capacity as supply. Final investment decision, construction, certification and delivery still stand between an announcement and a usable tonne.
Sidy's Synthesis
My synthesis is to treat SAF as a dual-ledger value chain. The physical ledger asks: what feedstock became how much certified aviation fuel, where, at what yield and delivered cost? The evidence ledger asks: what can be proven about origin, pathway and lifecycle emissions, under which rule, and who can legitimately claim the resulting value?
The useful chain is: eligible feedstock → conversion → verified lifecycle performance → recognised claim → deliverable compliance value.
This is not a new formal framework. It is simply a discipline for refusing to count tonnes as equivalent when the market and regulation do not.
AI & Future Lens
AI can improve feedstock forecasting, fraud detection, chain-of-custody anomaly detection, plant optimisation, logistics and document review. But automation cannot decide the sustainability rule itself; it can only help apply and monitor rules set by institutions.
A more interesting future question is whether digital chain-of-custody systems make verified attributes easier to transfer across markets without weakening assurance. If they do, information infrastructure may become almost as strategically important as fuel infrastructure.
Build From This
- SAF chain ledger: map physical tonnes, feedstock origin, pathway, lifecycle value, certification, delivery point and claim owner in one operational record.
- Feedstock-risk map: separate supply volume from eligible, traceable and economically reachable volume.
- Project bankability check: test feedstock cost, yield, policy support, offtake, certification and logistics together rather than evaluating the refinery alone.
- Claim-integrity control: reconcile physical batch evidence with the environmental attribute being sold or claimed.
Remember This
- SAF value is shaped by the molecule and the recognised evidence attached to it.
- Technical compatibility is not the same as regulatory eligibility.
- Mandates create demand but do not guarantee producer profitability.
- Feedstock concentration can move the bottleneck upstream even as refinery capacity expands.
- The most useful tonne is not an announced tonne or even a produced tonne; it is a verified, deliverable tonne whose attributes the buyer can actually use.