PTQ Q4 2026 Issue

The ATJ two-step production chain

Ethanol is classied as a biointermediate – both steps require a Quality Assurance Programme (QAP)

BIOMASS FEEDSTOCK Corn, sugarcane, agricultural residues

ETHANOL PRODUCTION Fermentation (BIOINTERMEDIATE)

ALCOHOL-TO-JET CONVERSION Dehydration, oligomerisation

SAF BLENDING Up to 50% blend with Jet-A

AVIATION FUEL ASTM D7566 compliant

QAP required: f eedstock

Ethanol

Each QAP enrolment is site-specic and supply-chain specic, EPA petition required for RIN generation.

QAP required: e thanol SAF

Figure 2 Ethanol as a biointermediate in the ATJ production chain

Obtaining ASTM approval for a new pathway is a lengthy, safety-driven process that can take years. For investors coming to market now, working within the already-ap- proved pathways is the most practical approach (see Table 1 ). US federal credits: RFS and the biointermediate challenge The RFS assigns Renewable Identification Numbers (RINs) based on the referenced Table 1 available in the programme, which sets out eligible feedstock-process combinations and their D-code. The D-code determines RIN value. For ATJ, there is a critical gap: no default ATJ pathway appears in the programme’s Table 1. A producer wanting to generate RINs from ATJ-produced SAF must first petition the US Environmental Protection Agency (USEPA) for a pathway determination, a process that typically takes well over a year. The only currently approved commercial examples are LanzaJet’s facility in Georgia and Summit Next Gen’s facil - ity in Texas. These approvals cover ethanol sourced from a specific plant in Brazil, shipped in a specific way, and processed at that specific US site. They cannot be applied to other producers, other supply chains, or other feedstock origins. Each new producer needs a separate petition. There is a further complication from the two-step nature of ATJ production. Ethanol is produced first, then converted to jet fuel. Since the products are processed at different locations and can technically enter the transportation fuel market independently, the EPA classifies the ethanol as a biointermediate under the RFS (see Figure 2 ).

The use of biointermediates requires a quality assurance programme (QAP): both the ethanol producer and the jet fuel producer must be enrolled in a QAP. This adds both complexity and time, though it can also create additional client opportunities for QAP providers with a broad supply chain footprint. A detail that catches many producers off guard is the same-supplier requirement within the QAP framework. The organisation providing QAP verification for the bioint - ermediate producer and the SAF facility must be the same accredited body. A producer cannot use one QAP provider for ethanol verification and a different one for the SAF stage. This means selecting a QAP provider with full supply chain coverage is a decision that needs to be made before the first petition is filed, not after the plant is running. 45Z clean fuel production credit The US Inflation Reduction Act introduced the 45Z Clean Fuel Production Credit, worth up to $1.00 per gallon for SAF meeting qualifying CI thresholds. Eligible ATJ feed - stocks include US corn starch, US sorghum grain, Brazilian sugarcane, and US corn stover. Other feedstocks can apply, but this requires a length - ier Provisional Emissions Rate application. The prescribed lifecycle analysis (LCA) model is the 45ZCF-GREET model or, alternatively, the CORSIA emissions model, which is a different framework from those used in California or Europe and has practical implications for CI scoring strategy. A key constraint is the no-stacking rule. A producer can - not claim 45Z credits for the ethanol production step and then claim them again for the SAF conversion step on the

same feedstock. Where ethanol is purchased from a third-party pro - ducer that is also claiming credits on that ethanol, the SAF producer captures the 45Z value and the ethanol producer may negotiate a small fraction of the contract, which must be resolved contractu - ally before project economics can be finalised. One further advantage in value of the 45Z framework for producers using agricultural feedstocks is that the current model does not explicitly

ASTM D7566 approved SAF pathways

Pathway name 1 Fischer-Tropsch

Abbreviation

Approved feedstock

Blend limit

FT-SPK

Biomass, MSW Biomass, MSW

50% 50% 50% 10% 50% 50% 50%

2 FT with aromatics 3 Hydroprocessed oils 4 Fermented sugars

FT-SPK/A HEFA-SPK

Used oils, fats, crops Sugarcane, corn Ethanol, isobutanol Plant oils, animal fats

HFS-SIP ATJ-SPK

5 Alcohol-to-Jet

6 Hydrothermolysis 7 CHJ + aromatics 8 Co-processed HEFA

CHJ

CHJ+A

Similar to CHJ Fossil + bio-oils

Co-HEFA

Source: ASTM International D7566/ICAO

Table 1

PTQ Q4 2026