Brazil state-controlled oil company Petrobras has developed a platform built on Cardano, a proof-of-stake blockchain, to track environmental claims for sustainable aviation fuel (SAF), according to a case study published by the Cardano Foundation. The project, known as CS-SAF, brings together Petrobras, Ledger Labs at PUC-Rio University, and the Cardano Foundation, and records fuel sustainability attributes as digital tokens aligned with CORSIA requirements.

Cardano System Tracks Fuel Claims

CS-SAF operates on a book-and-claim model, which separates the environmental benefits of the fuel from its physical delivery. Under this arrangement, buyers can purchase the sustainability benefit of certified fuel even when they cannot take delivery of that fuel directly. Similar certificate registries have long operated in renewable electricity markets, making book-and-claim an established accounting pattern that CS-SAF adapts for jet fuel.

Before creating tokens that represent approved fuel attributes, the platform verifies the underlying certificates. It can then allocate tokens to airlines or individual passenger journeys based on emissions calculations. When a buyer makes a claim, the system retires the corresponding token on-chain, a step designed to reduce duplicate claims.

This separation between fuel delivery and environmental claims creates a requirement for reliable records. Each record must show where an attribute originated, who received it, and whether someone has already used it. The arrangement also illustrates how the Cardano network continues to support applications beyond token trading.

CS-SAF additionally includes an application that allows passengers to claim tokens and receive a certificate. Petrobras produces sustainable aviation fuel at its Duque de Caxias refinery in Rio de Janeiro state by co-processing petroleum inputs with renewable materials.

Certification Remains Central to SAF

Petrobras says its aviation fuel has received CORSIA sustainability certification. CORSIA, the International Civil Aviation Organization's Carbon Offsetting and Reduction Scheme for International Aviation, requires eligible fuels to come from producers approved through recognized certification systems, and auditors still need evidence covering feedstocks, production methods, and lifecycle emissions. While a blockchain record can help trace a certificate after it is issued, it does not replace fuel certification itself.

Recent U.S. guidance on blockchain records indicates that regulators can accept digital records when those records meet existing recordkeeping rules and remain reliable and accessible.

The public case study does not name airline customers, state fuel volumes, or report how many tokens users have retired. Those figures would indicate how widely Petrobras and its partners are using Cardano for sustainable aviation fuel accounting. Future reporting on claim volumes, audit times, and registry links would similarly show how the platform performs across fuel transactions.

The broader market is testing tokenized systems for assets and records, including tokenized stocks used as collateral. For its part, CS-SAF serves as a research system for tracking certified fuel attributes, not as proof that regulators accept Cardano for CORSIA reporting. Its records can support tracing, while certification rules still determine whether a sustainable aviation fuel claim qualifies.