The Cardano Foundation has published a case study describing a collaboration among Brazil's state-controlled oil company Petrobras, Ledger Labs at PUC-Rio University, and the Foundation itself. The resulting platform, known as CS-SAF, represents fuel sustainability attributes as digital tokens whose metadata is aligned with CORSIA, the aviation emissions framework overseen by the International Civil Aviation Organization (ICAO).

Why Fuel Claims Need a Separate Record

The platform is built around a book-and-claim model, under which a buyer can acquire the environmental attributes of sustainable aviation fuel (SAF) without taking delivery of the fuel itself. According to the Roundtable on Sustainable Biomaterials, these attributes are transferred separately through a registry, allowing buyers to support sustainable fuel use even when they cannot access the physical supply.

Separating the claim from the physical delivery makes accurate accounting essential. The record must connect each attribute to the certified fuel, track its allocation, and show when it has been claimed. Otherwise, participants may struggle to establish whether the same environmental benefit has already been used.

The case study also describes a dedicated app through which passengers can claim tokens and receive a certificate.

Petrobras Already Produces Fuel That Requires This Accounting

Petrobras says its sustainable aviation fuel, produced at the Duque de Caxias refinery, has obtained CORSIA sustainability certification. Production involves co-processing conventional petroleum feedstocks with renewable material, according to the company.

The company also produces R Diesel by co-processing petroleum diesel with inputs such as vegetable oil or animal fat. It markets versions with different renewable shares, including R5 at 5% and R10 at 10%.

Those percentages help explain why precise records matter. A fuel's renewable content, its calculated lifecycle emissions, and the benefit a buyer may report are distinct pieces of information. Buyers and auditors need to know exactly what a certificate covers.

Certification Determines Whether a Claim Is Valid

For aviation claims, ICAO's CORSIA framework requires eligible fuels to come from producers certified through an approved sustainability certification scheme. These checks establish whether the applicable sustainability criteria and lifecycle-emissions methodology have been met.

An auditable transaction history can help an auditor follow an attribute after issuance. Assessing its environmental value, however, still requires evidence about the feedstock, the production process, and the emissions calculation. Token retirement also needs safeguards against the same underlying benefit being issued again or claimed through another registry.

Fuel certification and acceptance of a digital record are separate questions. A certificate aligned with CORSIA requirements does not, by itself, establish that regulators accept a particular blockchain platform for reporting.

Commercial Use Remains the Unanswered Question

The Foundation's public case study does not identify participating airline customers, quantify the fuel volumes represented by the tokens, or report how many claims have been retired. Those details would help establish the extent of operational use.

For Petrobras and its customers, the practical measure of success would be whether the system makes certificate reconciliation faster, gives auditors sufficient evidence, and interoperates with other registries. Documented results on those points would strengthen the case for adopting the platform across the fuel supply chain.

This article is for informational purposes only and does not constitute investment,, or environmental-compliance advice.