Petrobras, Brazil’s state-controlled energy company, is exploring Cardano blockchain technology through two research projects designed to improve lower-carbon fuel tracking and prevent emissions benefits from being claimed more than once. The Cardano Foundation announced the projects Wednesday and shared the details with CoinDesk.

One initiative involves sustainable aviation fuel, a lower-carbon replacement for conventional jet fuel that can work with existing aircraft and airport infrastructure. The second focuses on Diesel R, a Petrobras diesel product that uses renewable materials such as vegetable oils and animal fats as part of its feedstock.

Frederik Gregaard, CEO of the Cardano Foundation, told CoinDesk that Brazil has been among the consistent users of Cardano, citing SERPRO in government and SENAI in the industrial sector. He said Petrobras’ participation reflects interest from a major regional company in blockchain-based provenance and traceability.

Gregaard also cited Cardano’s integration with x402 and Fireblocks’ support for Cardano Native Tokens as developments contributing to greater institutional interest. According to Gregaard, these additions give enterprises more opportunities to assess potential uses for the technology.

The aviation project focuses on the book-and-claim model used to separate an environmental benefit from the physical fuel. Under this arrangement, an airline can pay for the emissions benefit associated with sustainable aviation fuel even when the actual fuel is consumed at another location.

That separation creates a need for accurate records showing who owns each environmental benefit and when it has been claimed. The purpose is to ensure the same emissions reduction is not attributed to multiple parties.

The Cardano application would record the origin of each benefit, the recipient and the time it was claimed. The resulting history is intended to make duplicate claims easier to identify and prevent.

A passenger could potentially enter their departure and destination airports, calculate the corresponding fuel benefit and receive a certificate that links their allocation to the certificate for the original fuel.

The Diesel R project would track data throughout the fuel’s lifecycle. Information from production and transportation to final use would be connected to create a record showing how the fuel moved through the supply chain.

Such records could support Scope 3 emissions reporting, which covers indirect emissions associated with suppliers, customers and other parts of a company’s value chain. Companies often struggle to collect this information because it is held by other organizations.

Both projects are still being developed as research initiatives. The Diesel R system remains a proposed model, while Petrobras and the Cardano Foundation have not disclosed the fuel volumes that could be covered or provided a timeline for broader deployment.

Cardano’s work with x402 is another recent development. The payment standard allows applications and AI agents to pay for data or computing resources when they request them. Cardano’s initial payment-processing software has been tested on its pre-production network, but commercial operation on the live blockchain has yet to be demonstrated.