Brazil’s state-controlled energy giant built two blockchain tools with the Cardano Foundation and PUC-Rio to make its sustainable fuel data auditable. Petrobras , Brazil’s state-controlled energy company, has built two research-stage blockchain applications on Cardano to record the environmental claims tied to its sustainable aviation fuel and renewable diesel, the Cardano Foundation announced on Wednesday. Both came out of a research and development partnership between Petrobras, the Swiss not-for-profit Cardano Foundation and Rio de Janeiro’s Pontifical Catholic University ( PUC-Rio ). The goal is to make emissions and fuel lifecycle data easier to check, as airlines and passengers look for ways to verify green fuel claims. The first tool covers sustainable aviation fuel (SAF) , a lower-carbon jet fuel that works in existing aircraft and airport infrastructure. It runs on a Book-and-Claim model, which splits the fuel’s environmental benefit from the physical fuel so that the benefit can be credited to an airline, company or traveler even if the fuel was produced or used somewhere else. According to the foundation’s case study , each SAF attribute is issued on Cardano as a standardized token called CS-SAF , with metadata aligned to CORSIA, the carbon offsetting scheme for international aviation. The tokens can be minted, transferred and retired, which is meant to stop the same benefit from being counted twice. Passengers can type in their departure and arrival airports, work out the matching CS-SAF amount and receive a certificate showing their route, distance and allocation, linked to the original fuel certificate. The second tool targets Diesel R , Petrobras’ renewable diesel brand, and was built with PUC-Rio. The foundation described it as a proposed model that logs checkpoints as the fuel is produced, transported and used, building a single record of its lifecycle. That record is aimed at Scope 3 reporting, which covers indirect emissions across a company’s value chain and often depends on data held by suppliers and logistics firms. “The energy transition will depend as much on trust as it does on new fuels,” said Rafael Fraga , LATAM business development lead at the Cardano Foundation. “Public blockchain gives us the opportunity to make that trust part of the system by design.” The announcement did not give a timeline for commercial rollout of either tool. The work extends a relationship that started in December 2023, when the Cardano Foundation agreed to run blockchain education workshops for Petrobras staff through Petrobras University, a program open to more than 40,000 employees . In April 2025, the foundation announced a research collaboration with PUC-Rio’s Ledger Labs that would focus first on blockchain uses for renewable fuels, with Petrobras as an industry partner. Related Listen: How the Bitget Hack Reopened Crypto’s Fight Over Neutral Infrastructure AI-assisted content: This article was produced with the assistance of AI tools and was reviewed, edited, and fact-checked by a member of the Unchained editorial team before publication. Get the hottest takes from Laura, her guests, and The Chopping Block crew on all the news in crypto! Get daily news and insights — straight to your inbox