One batch becomes two things
At the blending point, a batch of certified sustainable aviation fuel (SAF) splits into two things. The physical fuel stays local: it is uplifted at a nearby airport and sold without its sustainability characteristics. The environmental attribute is registered separately, transferred to one owner, and retired once.
That split is not a loophole. It is a recognised chain of custody model, one of three defined in international practice alongside physical segregation and mass balance, and it runs on rules strict enough to survive an audit. Here is the settlement, step by step.
Step 1: certified fuel is made and delivered
Only certified fuel can enter the system. Under the RSB’s rulebook, that means fuel certified by RSB itself, an EU-recognised voluntary scheme, or a scheme recognised under ICAO’s CORSIA. The physical blend is delivered and used near where it was made, and from the moment its attribute is booked, the fuel itself is sold as ordinary fuel, with no green claim attached.
Step 2: the attribute is booked
The supplier registers the batch on a registry as Book and Claim Units. One BCU equals one tonne of neat, certified SAF, and it records the batch’s full sustainability data: feedstock, pathway, lifecycle emissions value, and certification. Registration must happen within 90 days of physical delivery, and no operator can register more certified product than it actually acquired. Only certified chain-of-custody traders can do this; Future Energy Global holds that certification from both RSB and ISCC, audited externally.
Step 3: the attribute changes hands
BCUs are held, transferred, and sold between registry account holders: producers, traders, airlines, and corporate buyers. IATA’s accounting methodology is explicit that Scope 1 claims are not limited by where the fuel was uplifted. Distance is not a defect in this market. It is the design.
Step 4: the claim is retired
Retirement is the moment a claim becomes real. The registry permanently assigns the reduction to named parties, publishes a retirement statement, and takes the unit out of circulation. Retired BCUs cannot be resold. Every unit must be retired within 24 months of registration.
The ordering matters: the airline’s Scope 1 claim is retired or assigned before any corporate Scope 3 claim can be. That sequence proves the fuel was actually used before anyone claims against it. It is how a credible registry is built.
One claim, one owner, counted once.
Who pays, and why it works
The corporate buyer pays for the Scope 3 attribute, and that payment shares the SAF premium that would otherwise fall on the airline alone. The RSB names cost-sharing of the premium as one of Book and Claim’s design goals. Two buyers fund one physical intervention, each receives a verified claim in its own scope, and the producer gets demand it could never have reached locally.
Who claims what, and why that is not double counting, is the whose-emission-is-it lesson. What you actually receive at the end is a retirement statement, and the next lesson reads a real one, field by field.