Petrobras, Brazil's state-controlled energy company, is testing Cardano to track sustainable aviation fuel benefits and prevent double-counting.

The Cardano Foundation said on Sept. 30 that an ongoing research and development collaboration had delivered applications for sustainable aviation fuel (SAF) and Diesel R, Petrobras' renewable fuel brand.

The SAF project addresses a problem that arises when the buyer of a fuel's environmental benefit is different from the buyer or user of the fuel itself. Its Book-and-Claim model lets an airline, company, or passenger receive that benefit even when the SAF is produced or used elsewhere.

Petrobras developed the SAF platform with PUC-Rio University's Ledger Labs and the Cardano Foundation. According to the Foundation's case study , it represents SAF environmental attributes as standardized CS-SAF tokens on Cardano.

Those tokens can be created, transferred, checked, and retired. Retirement prevents the same attribute from being claimed again, while the digital record traces the allocation back to the original fuel certificate.

The crypto analogy is double spending: preventing reuse of a digital asset, applied here to an environmental claim.

Travelers can enter departure and destination airports, calculate a CS-SAF allocation and receive a certificate showing their route, distance and allocation, the Foundation says. That claim remains linked to the original SAF certificate.

The tokens carry metadata aligned with CORSIA, the Carbon Offsetting and Reduction Scheme for International Aviation.