SAF pathways are being evaluated under policy systems that are not yet fully aligned on tax treatment, feedstock eligibility, life-cycle emissions, and fuel-standard limits. For producers, airlines, fuel suppliers, and procurement teams, the technical question is no longer only whether a fuel can be made. It is whether a specific production route can be certified, credited, blended, sold, and counted in the jurisdiction where it is needed.

The uncertainty is not theoretical. On September 8, 2026, the IRS issued Notice 2026-53 for the Section 45Z Clean Fuel Production Tax Credit, including a 2026 emissions rate table and clarifications for manure-derived and regenerative agriculture-derived fuels, while February 4, 2026 proposed regulations still awaited finalization as of September 24, 2026 IRS notice. That timing matters because investment and offtake decisions depend on how emissions rates, eligible feedstocks, and production certification are treated in binding rules rather than draft or interim guidance.

Why SAF pathways Are Policy-Sensitive

How SAF pathways Are Classified

Sustainable aviation fuel is not one uniform fuel from a regulatory point of view. It may be produced through different conversion technologies, from different feedstocks, and under different accounting systems. A pathway that can meet one program’s technical or tax requirements may still fail another program’s feedstock, indirect land-use change, or sustainability test.

This creates a practical classification problem. ASTM approval can address fuel quality and blending use, but it does not by itself establish tax-credit eligibility, renewable fuel credit generation, EU mandate compliance, or CORSIA life-cycle treatment. Conversely, a policy incentive does not replace the need to meet aviation fuel specifications.

For SAF pathways, the same molecule may therefore carry different commercial value depending on its documentation package. The production route, feedstock origin, chain-of-custody evidence, emissions model, and jurisdiction all affect whether the fuel can be used for a particular compliance purpose.

Why Jurisdictional Alignment Is Limited

The European Union’s ReFuelEU Aviation framework began applying from January 1, 2025. The research record states that aviation fuel suppliers must meet a minimum 2% SAF supply level for flights departing EU airports in 2025, with the obligation rising gradually to 70% by 2050. It also includes a synthetic aviation fuel sub-mandate that begins later and rises over time.

The United States policy setting is different. Section 45Z is designed as a production tax credit, while the Renewable Fuel Standard and aviation fuel specifications create separate layers of qualification. That difference can create cross-border friction. A fuel route that appears acceptable under a U.S. credit or fuel-standard framework may not qualify under EU sustainability criteria if feedstock rules, land-use accounting, or documentation expectations diverge.

Tax Credit Rules Affect Pathway Economics

Section 45Z Changes The Cost Calculation

Section 45Z became effective from January 1, 2025. The research notes state that renewable jet fuel can receive up to $1.00 per gallon if wage and apprenticeship requirements are met. The credit is important because SAF production has remained small compared with total jet fuel demand, so policy support can affect whether a route is financeable or whether an offtake price is credible.

The technical issue is that the value of the credit depends on emissions-rate calculation, feedstock treatment, certification method, and compliance evidence. Notice 2026-53 reduced some uncertainty by providing a 2026 emissions rate table and addressing certain manure-derived and regenerative agriculture-derived fuel treatment. It did not, by itself, remove all uncertainty because the proposed regulations from February 4, 2026 still had not been finalized as of September 24, 2026.

Interim Guidance Is Not The Same As Settled Treatment

Project developers can model a credit under available guidance, but they should avoid treating every modeled outcome as fixed. Feedstock sourcing, wage compliance, production records, emissions inputs, and third-party certifications may all need to survive later review. A conservative commercial specification should identify which policy assumptions are confirmed, which are based on proposed guidance, and which require future agency action.

Industrial reference networks like Mengo Industrial provide a comprehensive view into specifications, aiding procurement teams in making informed decisions. Nonetheless, credit eligibility hinges on aligning with law, agency guidance, and validated production data.

Feedstock And LCA Alignment Remain Unsettled

Life-Cycle Boundaries Drive Eligibility

Life-cycle assessment is central to SAF qualification because fuel carbon intensity is not determined only at the refinery gate. Feedstock cultivation, collection, processing, transport, conversion efficiency, co-product treatment, and indirect land-use assumptions can materially affect a pathway’s reported emissions rate.

ICAO’s Committee on Aviation Environmental Protection established Working Group 5 during the CAEP/13 cycle in 2025 for work during 2025-2028. The research notes identify its work areas as life-cycle assessment, indirect land-use change methodology, Annex 16 Volume IV updates for CORSIA, feedstock classification, and SAF policy guidance. Because those elements were still under development, pathway validation remains exposed to methodological change.

Feedstock Claims Need Specific Evidence

Feedstock labels can be too broad for compliance use. “Waste,” “residue,” “low carbon,” or “regenerative” may not have the same meaning across programs. A procurement document should therefore define the feedstock category, origin, sustainability criteria, and chain-of-custody evidence needed for the intended market.

The risk is not limited to legal wording. If a pathway’s emissions score depends on a feedstock attribute that later fails certification, the economic value of the fuel can change after production. That is why feedstock evidence should be tied to the specific credit, mandate, or standard being claimed.

Fuel Standards Limit Technical Claims

ASTM Qualification Does Not Mean Unlimited Use

ASTM D7566 is central to aviation fuel qualification for approved synthetic blending components. The research notes state that eight SAF production processes had been standardized by ASTM as of October 2024, and that three co-processing pathways had been qualified in petroleum refineries subject to feedstock blending limits up to 24%. They also state that there were ambitions to increase co-processing blend limits to 30% by 2025, while standards and infrastructure gaps remained.

Those facts support a cautious interpretation: ASTM qualification is pathway-specific and limit-specific. It does not mean that all renewable feedstocks, all co-processing routes, or all blend levels are automatically accepted. Fuel quality, material compatibility, safety testing, engine approval, and supply-chain segregation can still constrain implementation.

Neat Fuel Use Remains A Separate Question

Many approved fuels are blended with conventional ASTM D1655 jet fuel after meeting ASTM D7566 requirements. Fully neat, or 100%, SAF use has not been certificated across many pathways according to the research notes. Work on enabling higher or full use continues, but that should not be described as settled certification.

For procurement teams, the safe specification language is narrow. State the approved pathway, maximum blend level, applicable standard, and documentation needed for release into aviation service. Avoid language suggesting unrestricted drop-in use unless the relevant certification supports that claim.

Scale And Supply Do Not Yet Remove Risk

Production Growth Is Still Small Relative To Demand

U.S. renewable jet fuel production increased from approximately 110 million gallons in 2024 to approximately 290 million gallons in 2025, while SAF represented less than 2% of U.S. jet fuel consumption in 2025-2026 according to the EPA’s rulemaking record EPA rulemaking record. The increase is meaningful, but the base remains small compared with aviation fuel demand.

Limited supply magnifies policy uncertainty. If one jurisdiction accepts a pathway and another does not, producers may need to redirect volumes, revise offtake terms, or carry additional certification costs. Airlines and fuel suppliers may also face difficulty matching physical supply to mandate obligations when documentation, geography, and eligibility do not align.

Compliance Flexibility Has Boundaries

The ReFuelEU flexibility mechanism for 2025-2034 allows compliance using average SAF supply over EU airports rather than requiring exact per-airport or per-flight matching. That may reduce short-term logistical pressure, but it does not eliminate the need for qualifying fuel. Book-and-claim and other accounting systems remain under discussion in the research notes and should not be treated as finalized substitutes for physical or certified supply unless adopted by the relevant program.

SAF pathways Need Controlled Policy Assumptions

Policy uncertainty does not mean that SAF investment or procurement must stop. It means that specifications should separate confirmed requirements from assumptions that depend on pending rules, future standard changes, or jurisdiction-specific interpretation.

• Identify the exact production route, feedstock, and intended compliance market.
• State the applicable aviation fuel standard and any blend limit.
• Link carbon-intensity claims to a named calculation method and evidence package.
• Flag whether tax-credit treatment relies on proposed, interim, or final guidance.
• Keep U.S., EU, and CORSIA eligibility claims separate unless equivalence is documented.

For SAF pathways, the near-term discipline is documentary as much as technical. A fuel may be physically usable, but its policy value depends on whether the pathway, feedstock, emissions score, and certification trail match the rule under which the claim is made. Until major systems are more closely aligned, cautious contracting and clear technical records are the best protection against overvaluing a pathway before the rules are settled.