Petrobras, Brazil’s state-controlled energy company, is testing the Cardano blockchain in two research projects aimed at tracking environmental claims tied to lower-carbon fuel, according to an announcement from the Cardano Foundation shared with CoinDesk on Wednesday.
One project covers sustainable aviation fuel, a lower-carbon alternative to conventional jet fuel that can be used in existing aircraft and airport infrastructure. The other centers on Diesel R, Petrobras’ diesel product made partly from renewable materials including vegetable oils or animal fats.
Both efforts are still in the research phase. The announcement did not disclose a timeline for broader deployment, and it also left out details on the fuel volumes covered by the trials.
The aviation project is built around book-and-claim accounting
The aviation initiative addresses a specific issue in the way green fuel benefits are marketed and assigned. Under a model known as book-and-claim, an airline can purchase the environmental benefit tied to sustainable fuel even when the physical fuel itself is used somewhere else.
That setup requires a clear record showing who owns the benefit and when it has already been claimed. Without that record, two companies could end up counting the same emissions reduction.
The Cardano-based application records where each benefit originated, who received it and when it was claimed. The stated purpose is to stop the same emissions benefit from being counted twice.
In the user flow described in the report, a passenger can enter a departure airport and destination airport, calculate the corresponding fuel benefit and receive a certificate that links the allocation back to the original fuel certificate.
The Diesel R project would log the fuel’s path from production to use
The second research effort is focused on Diesel R. It would capture data at each stage of the fuel’s production, transportation and use, then connect those entries into a continuous record of the fuel’s journey.
That record could help companies report Scope 3 emissions, which cover indirect emissions across suppliers and customers. The report notes that the information needed for those disclosures often sits with other businesses rather than the company making the report.
The diesel initiative is described as a proposed model, underscoring that it also remains research work rather than a live commercial deployment.
What Cardano Foundation said about adoption in Brazil
Frederik Gregaard, chief executive of the Cardano Foundation, told CoinDesk: "Brazil has been one of the most consistent adopters of Cardano, from SERPRO in government to SENAI in industry. It's great to see Petrobras, one of the largest firms in the region, continue to see value in on-chain provenance and traceability."
He added: "Institutional interest in Cardano keeps growing, especially with x402 arriving on Cardano and Fireblocks adding support for Cardano Native Tokens. It's never been a better time for enterprises to consider what this technology offers."
Cardano’s recent x402 development was also cited
The report also said Cardano joined x402 this month. The payment standard allows apps and AI agents to pay for data or computing services at the time they request them.
Its initial payment-processing software had been tested on Cardano’s pre-production network. Commercial use on the live blockchain, however, has yet to be demonstrated.