According to CoinMeta, Brazil's state-owned energy company Petrobras is testing Cardano, which involves two low-carbon fuel projects aimed at addressing the issue of duplicate claims for the same environmental benefits. The company is collaborating with Cardano Foundation and PUC-Rio's Ledger Labs to develop sustainable aviation fuel (SAF) and renewable diesel R research applications. The SAF project utilizes Cardano to record the ownership and retirement of verified environmental attributes, while diesel R is managed through information linking during production, transportation, and use. Both projects are still in the research phase, and no commercial deployment timeline or fuel volume has been announced yet. The prototype of Petrobras represents the SAF attributes as CS-SAF tokens, in compliance with the International Civil Aviation Organization's CORSIA framework. The goal of this project is to create an auditable chain of environmental declarations to ensure independent ownership and reporting of environmental benefits.