How to De-risk SAF Investments: A Financial & Tech Due Diligence Framework

Sustainable aviation fuel has no shortage of demand and no shortage of technology. It has a shortage of bankable projects. Mandates are tightening, airlines are signing agreements, and capital is queued, yet most SAF proposals still fail to clear an investment committee, because the proforma oversells the upside and hides the three risks that actually decide whether a deal funds. None of them is the IRR on the cover slide. De-risking SAF means running a financial lens and a technical lens over the deal, then scoring it on the dimensions a spreadsheet never captures: whether the offtake converts, whether the fuel is certified, and whether the environmental claim survives scrutiny.

The Problem Is Bankability, Not Demand

Start with the number that should frame every SAF diligence. To meet the EU’s 2030 targets, roughly 5.8 million tonnes of new capacity needs to reach a final investment decision by 2026. Of the synthetic e-SAF specifically required for 2030, about 0.71 percent has actually passed FID. The rest is a wall of memoranda and conditional purchase agreements that have not converted into financed plants.

The consequence is not a soft market. It is a hard penalty. ReFuelEU fines fuel suppliers and airlines that miss the mandate at no less than twice the price gap between SAF and fossil jet, multiplied by the shortfall, and the gap between the e-SAF Europe has mandated and the e-SAF it has financed implies a potential penalty bill of seven to nine billion euros. Demand, in other words, is legislated and enormous. Bankability is scarce. The entire investment question is which side of that gap a given project sits on, and the answer is rarely visible in its returns model.

The cancellations are already on the board. No European e-SAF project had reached a final investment decision by the end of 2025, and Sweden alone saw three flagship projects fall away, among them HySkies, backed by Shell and Vattenfall, and SkyFuelH2, backed by Sasol and Uniper. Roughly one in six announced projects, about half a million tonnes of intended capacity, has been paused or cancelled. These were not fringe developers; they were some of the most capable names in the industry, and they stalled on the same wall: the offtake and the financing would not close at a price the buyer would bear. The failure mode is commercial, not chemical.

The Financial Lens: What Actually Moves the Return

The first discipline is brutal clarity on what drives the economics, because subsidy-led returns evaporate when costs or yields slip by ten or fifteen percent, as a generation of renewables projects has shown. We have modelled this in detail elsewhere, and the ranking is consistent: the operating margin is the master variable. Feedstock and cash operating cost are 50 to 70 percent of the SAF cost stack, and a 25 percent rise in them can turn a high-single-digit IRR negative on its own. Policy exposure is next: a return that collapses when 45Z lapses in 2029 or when LCFS and RIN prices halve was never resilient. Then capital discipline, with EPC quotes inflated 25 to 40 percent since 2021, and uptime, where first-of-a-kind plants routinely miss the 90 percent the model assumed. Leverage cannot rescue a thin return; when the unlevered asset barely clears the cost of debt, gearing adds almost nothing to the equity case while making every downside scenario sharper.

What is absent from that list is the reactor. Across pathways, the technology working is rarely the question that decides the outcome, which is why “proven technology” is one of the least useful phrases in a SAF pitch. The financial lens should therefore probe capex per gallon against peer benchmarks, interrogate whether yields come from pilot data or extrapolation, stress the operating cost, and above all ask whether the revenue is durable: a flat-price offtake that never converts is worth nothing, and an unhedged crude-spread exposure is a different asset in a high-oil world than a low one.

The Three Risks the Proforma Hides

Here is where SAF diligence departs from a generic energy model, and where most deals are actually won or lost.

The first is offtake quality. Airlines have signed a wave of agreements, but a memorandum of understanding is not a financing instrument. Developers consistently struggle to convert conditional, flexible commitments into the long-dated, fixed-price, creditworthy contracts that a lender or an equity committee needs to underwrite, and that conversion gap is the single largest reason projects stall short of FID. When American Airlines and Google sign a record SAF agreement, or Infinium wins a Sustainable Aviation Buyers Alliance tender, what matters for diligence is not the headline volume but the contract’s tenor, price mechanism and counterparty credit. An offtake that indexes sensibly, lasts a decade and is signed by an investment-grade buyer is worth more than a larger one that is really an option to walk away.

The second is certification. SAF only earns its premium if it qualifies, and the rules are specific and moving. To be a CORSIA Eligible Fuel a batch must be certified against an ICAO-recognised scheme such as RSB or ISCC, and the standard itself is live: the RSB CORSIA Standard reached version 1.7, and updated CORSIA default values apply to new batches from April 2026 with a short transition window. A project whose carbon-intensity case rests on a default value that is about to change, or on a certification it has not yet secured, is carrying a risk that never appears as a line in the model.

The third is book-and-claim integrity. Most SAF is sold not as a physical molecule to a specific buyer but as an environmental attribute booked and claimed across registries, and the registries are fragmented. That creates a real risk of double-issuance, the same batch claimed twice, and weak traceability turns a SAF environmental benefit into a reputational liability. It is the carbon-market lesson applied to fuel: the credit is a claim, not a commodity, and a claim that cannot be traced cleanly can be re-rated to zero after the deal closes. Diligence on the registry and the chain of custody is not administrative detail. It is underwriting the revenue.

Where the Crude Spike Cuts Both Ways

The 2026 oil environment is not a simple tailwind for SAF, and the diligence point is subtler than the headline. A higher crude price lifts the value of the jet fuel that SAF displaces, which improves SAF’s relative competitiveness and the revenue of any producer selling on a crude-linked basis. But it does the opposite to a producer locked into a flat, fixed-price offtake signed when oil was low: that contract now sits below the market, transferring the upside to the airline and leaving the producer with the original thin margin. So the crude question in SAF diligence is really an offtake-structure question. A fixed-price contract is a hedge that can become a giveaway; a crude-indexed contract shares the move but reintroduces volatility. Underwrite which one the project signed, and at what reference price, because the same plant has a very different return profile under each as oil swings.

The Technical Lens: Sorting Pathways Without Hype

SAF has no single dominant chemistry, and each pathway carries its own maturity, capex intensity and feedstock constraint. The technical lens maps them honestly rather than betting on the one in the pitch.

HEFA is commercial and refinery-friendly but runs on scarce waste lipids; alcohol-to-jet is scaling and feedstock-flexible but still carries a yield and cost penalty; Fischer-Tropsch takes almost any biomass or waste but is capital-heavy and operationally complex; power-to-liquids has effectively unlimited feedstock in CO2 and hydrogen but is the least mature and the most expensive. No pathway scores at the top on every axis, which is the whole point. The de-risked SAF book is a portfolio across maturity and feedstock, not a single-pathway conviction, and the maturity bar for any of them should be concrete: a demonstrated continuous run beyond a thousand hours and a clear ASTM-approved blend pathway, not a slide that says the chemistry is known.

The Bankability Scorecard

Put the two lenses together and a SAF deal resolves into seven scoreable dimensions. The exercise that matters is that two deals can carry the same headline IRR and score completely differently.

Dimension	Weight	What clears it
Offtake quality	20%	Long-dated, fixed-price, creditworthy contract, not an MoU
Feedstock security & carbon intensity	20%	Contracted, multi-feedstock, low-CI position
Technology readiness	15%	Demonstrated >1,000-hour runs; ASTM blend pathway
Policy & credit durability	15%	Stacked RIN, LCFS, 45Z; each leg stressed independently
Certification & book-and-claim integrity	10%	CORSIA-eligible certification; clean, traceable registry
Execution / EPC discipline	10%	Capable, fixed-price EPC; validated end-to-end design
Returns resilience under stress	10%	Survives feedstock, policy and uptime stress tests

Scored this way, a genuinely bankable deal lands near 4.3 out of 5 and a superficially similar but marginal one near 2.1, even when their cover-slide IRRs match. The difference is concentrated in the three hidden risks: offtake, certification and claim integrity. A score below roughly 3.5 should not clear an investment committee, however attractive the headline.

The Execution Reminder

One dimension deserves a specific caution, because it has bankrupted otherwise sound SAF projects: execution. The clearest case is a fully funded plant with a licensed, proven process and airline offtakes that still collapsed into Chapter 11, not because the chemistry failed but because a late, unvalidated design change damaged equipment at start-up and an underbid EPC contractor went bankrupt mid-build. Capital, technology and offtake were all present; execution was not. The lesson for diligence is to weight the contractor, the design-freeze discipline and the start-up plan as heavily as the technology, and to treat any post-pilot design change as a red flag rather than a detail.

What to Watch: The Penalty Becomes the Price Floor

The most important thing to watch is structural, and it cuts the other way from the gloom. ReFuelEU’s penalty is deliberately set at no less than twice the price gap between SAF and fossil jet, so that paying the fine is always more expensive than buying the fuel. That design makes the penalty a de facto price floor: once it bites, a compliance buyer is economically forced to pay up rather than pay the fine, and unmet quotas carry over and compound year after year. The numbers are striking. A SAF shortfall penalty runs on the order of EUR 2,700 a tonne, and the e-SAF sub-mandate penalty, which begins in 2030, is far higher, around EUR 14,000 a tonne. A penalty of that size sitting above a stalled FID pipeline is exactly the kind of forced-demand signal that converts hesitant airline MoUs into the bankable, fixed-price offtake that has been missing. The inflection to watch is the moment the market prices the penalty as a floor rather than a risk, because that is when the de-risked, certified, offtake-backed projects, the ones that score well on the framework here, get funded first and fastest.

How We’d Underwrite It

Lead with the offtake, not the IRR. A long-dated, fixed-price, investment-grade contract is the single strongest signal that a SAF project will clear FID, and its absence is the single most common reason one does not. Confirm the certification pathway and the carbon-intensity values before, not after, committing, because the rules move and the premium depends on them. Underwrite the registry and chain of custody as carefully as the plant, since a SAF claim that cannot be traced is a revenue line that can vanish. Run the financial stress tests, feedstock, policy and uptime, and discard any case that only clears with every variable intact. Diligence the EPC and the design freeze as hard as the process. And size the book as a portfolio across pathways and feedstocks rather than a single-chemistry bet, because no pathway yet wins on both maturity and feedstock. The SAF deals that get funded in this decade will not be the ones with the best slides. They will be the ones where the offtake is real, the claim is clean, and the return survives being stressed.

What Clears an Investment Committee

1. Underwrite the offtake first. Long-dated, fixed-price, creditworthy, not an MoU. The conversion gap is the main reason SAF projects miss FID.

2. Confirm certification and CI before committing. CORSIA-eligible scheme, current default values, ASTM blend pathway. The premium depends on it.

3. Diligence book-and-claim integrity. Registry quality and chain of custody. A claim that cannot be traced can be re-rated to zero.

4. Stress the operating margin and policy. Feedstock and opex are the master variable; the case must survive a 45Z lapse and softer credits.

5. Weight execution and the EPC. A late design change or an underbid contractor has killed funded, proven-technology SAF plants. Treat both as gating risks.

De-risking SAF: Investor FAQ

Why do so many SAF projects fail to reach final investment decision?

Because demand is not the same as bankability. Airlines sign MoUs and conditional agreements, but developers struggle to convert them into the long-dated, fixed-price, creditworthy offtake that financing requires. Only about 0.71 percent of the e-SAF needed for the EU 2030 target has passed FID, against a potential ReFuelEU penalty bill of seven to nine billion euros, evidence that the constraint is bankable projects, not demand.

What is the biggest risk in a SAF investment?

Offtake quality, followed by feedstock and certification. The operating margin (feedstock is 50 to 70 percent of cost) is the master financial variable, but the risk that most often blocks a deal is an offtake that never converts from a memorandum into a fixed-price contract. Certification and book-and-claim integrity are the two other risks a proforma typically hides.

What is CORSIA Eligible Fuel certification and why does it matter?

To count under CORSIA, SAF must be certified against an ICAO-recognised scheme such as RSB or ISCC; without it the fuel cannot be classified as eligible and loses access to that market. The standard is live and moving: the RSB CORSIA Standard reached version 1.7 and updated default carbon-intensity values apply to new batches from April 2026. A project relying on a value that is about to change carries an unpriced risk.

What is book-and-claim risk in SAF?

Most SAF is sold as an environmental attribute booked and claimed across registries rather than as a physical molecule. Fragmented registries create a risk of double-issuance, the same batch claimed twice, and weak traceability turns the environmental benefit into a reputational liability. It is the carbon-market lesson applied to fuel: the claim is only as good as the registry behind it, and a claim that cannot be traced can be re-rated after the deal closes.

Which SAF pathway is the safest investment?

None wins outright. HEFA is the most mature but feedstock-scarce; alcohol-to-jet is scaling and feedstock-flexible but still carries a cost penalty; Fischer-Tropsch is feedstock-flexible but capital-heavy; power-to-liquids has unlimited feedstock but is the least mature and dearest. The de-risked approach is a portfolio across maturity and feedstock, with a hard technology bar of demonstrated 1,000-hour-plus runs and an ASTM-approved blend pathway.

Will the ReFuelEU penalty force SAF demand?

Increasingly, yes. The penalty is set at a minimum of twice the price gap between SAF and fossil jet, so non-compliance is designed to cost more than buying the fuel, and unmet quotas carry over and compound. A SAF shortfall penalty is roughly EUR 2,700 a tonne, and the e-SAF penalty from 2030 is around EUR 14,000 a tonne. As the market prices the penalty as a de facto floor, hesitant buyers are pushed toward the bankable, fixed-price offtake that stalled projects need, which should fund the best-diligenced projects first.

Does the 2026 crude oil spike help or hurt SAF investments?

Both, depending on the offtake. A higher crude price lifts the value of the jet fuel SAF displaces, helping producers who sell on a crude-linked basis, but it leaves a producer locked into a flat fixed-price contract below the market and hands the upside to the airline. The crude question in SAF diligence is really an offtake-structure question: underwrite whether the contract is fixed or indexed, and at what reference price.

Methodology: the bankability scorecard, weights and pathway scores are Trident’s framework; IRR mechanics draw on our Fischer-Tropsch SAF model (operating margin as master variable, ~8% unlevered base). FID and penalty figures per Transport & Environment and ICCT analysis of ReFuelEU. Companies named (American Airlines, Google, Infinium, Technip Energies, Airbus, Safran, Tereos) are illustrative examples, not recommendations. ReFuelEU penalty = >=2x the SAF-vs-jet price gap x shortfall; SAF penalty ~EUR 2,700/t, e-SAF ~EUR 14,000/t (T&E). Named cancellations (HySkies, SkyFuelH2) per Transport & Environment e-SAF analysis. Sources: WEF SAF financing; IATA; ICCT; RSB / ICAO CORSIA; Transport & Environment; SAF Investor; Carbon Direct. Analysis, not investment advice.