Petrobras tests Cardano to keep jet fuel emissions benefits from being claimed twice

Shell's figures are the nearest comparison. Avelia is the blockchain book-and-claim platform Shell launched in 2022 to track sustainable aviation fuel claims and prevent double counting ^[12]. By June 2026 it had contributed to more than 84 million gallons of that fuel entering the global network, according to a September Shell update reported by Cointelegraph ^[13]. Shell put the abatement over the same period at more than 780,000 tonnes of CO2e ^[13]. Divide the tonnes by the gallons and each gallon carries roughly 9.3 kilograms of claimed abatement ^[15]. That abatement is what an airline pays for under book-and-claim, even when the fuel itself burns somewhere else ^[5]. The Petrobras announcement disclosed neither the fuel volumes covered nor a timeline for wider use ^[4].

The announcement came from the Cardano Foundation ^[1]. Its chief executive, Frederik Gregaard, put Petrobras in a line of Brazilian users. "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 told CoinDesk ^[8]. He then moved to the foundation's wider pitch ^[9]. "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," Gregaard added ^[9]. The x402 payment software had so far been tested on Cardano's pre-production network, with commercial use on the live blockchain still to be demonstrated, CoinDesk reported ^[10].

If Petrobras assigns a volume of jet fuel to the aviation registry and starts issuing certificates to airlines, the Avelia ratio gives a first estimate of the abatement on offer ^[1][5][15]. The diesel ledger, still described as proposed ^[3], could matter more, or rather it could matter to more companies. Scope 3 reporting depends on data that often sits with other businesses ^[2]. A producer that hands its buyers a record from production to use supplies data they cannot collect on their own. Or both projects stay in research, the same footing as Viva Energy's January agreement with NoviqTech on digital book-and-claim ^[14], and the main gain goes to the Cardano Foundation's case to enterprises ^[9].

I'd expect the research outcome to hold for now. Since the collaboration began in 2023, Petrobras's visible commitment has been staff training and university research with PUC-Rio's Ledger Labs ^[11]. The case against that view is that a state-controlled producer ^[1] does not need a public launch date to issue certificates once a registry works. Shell's 84 million gallons also show the book-and-claim model can carry commercial volume ^[13]. An airline named as the buyer of a Petrobras fuel certificate would prove the view wrong ^[5].