Brazil formalizes book and claim for aviation fuel, completing a three-asset decarbonization architecture

Why it matters: Book and claim lets a buyer acquire verified emission reductions without being physically connected to the supply chain that produced the sustainable fuel. The model already works at scale for renewable electricity through I-RECs (operational in more than 70 countries) and was codified in January 2026 by ISO 22095-3:2026, which created the concept of Transferable Instrument with Entitlement to Claim (TIEC). Brazil now has three sector-specific environmental assets built on this logic, signaling that policymakers view book and claim as the default architecture for hard-to-abate sectors.

What changes for Brazilian companies

For SAF producers, the CS-SAF opens a revenue line that did not exist before: they can sell the physical fuel to one buyer and the sustainability attribute to another, potentially at a premium. This mirrors what already happens with I-RECs in the electricity market, where generators monetize the renewable attribute separately from the energy itself. Airlines operating in Brazil gain flexibility: instead of sourcing SAF physically (which depends on limited refinery capacity and logistics), they can purchase CS-SAF certificates to meet future blending mandates or voluntary commitments.

For traditional refineries that do not produce SAF, the signal is clear. Each new environmental asset raises the cost of inaction. The CBIO already penalizes fossil fuel distributors that fail to meet decarbonization targets under RenovaBio. The CS-SAF extends that pressure to aviation, a segment where refineries could lose market share to biofuel producers capable of generating both fuel and tradable certificates. Companies evaluating capital allocation now have one more reason to invest in SAF production capacity.

What is still undefined

The source describes the CS-SAF as a formalized instrument, but critical operational details remain open. There is no public information yet on which entity will operate the CS-SAF registry (the CBIO uses B3, the CGOB uses a system under ANP oversight), how certificates will be priced, or whether a secondary market will be allowed from the start. The CBIO was initially restricted to a primary market between biofuel producers and fossil fuel distributors; the CGOB and CS-SAF may follow a different path, but the rules have not been published.

Liquidity is the other open question. A book and claim system only delivers real price discovery when there are enough buyers and sellers. Brazil does not yet have mandatory SAF blending targets with defined percentages and timelines (comparable to the EU’s ReFuelEU mandates). Without a compliance obligation creating demand, the CS-SAF risks remaining a voluntary instrument with limited trading volume. Whether and when the government will set binding blending quotas will determine how quickly this market develops.

Who gains and who faces pressure

The Norden-Microsoft transaction reported by Reset illustrates who benefits most: companies that produce or trade sustainable fuel gain access to buyers anywhere in the world, not just those connected to their physical supply chain. In Brazil, ethanol and biodiesel producers with the technical capacity to pivot toward SAF are the most obvious winners, especially those already issuing CBIOs and familiar with environmental asset compliance.

On the other side, airlines face a new layer of climate governance. Even before mandatory blending targets arrive, investors and disclosure frameworks (CDP, GHG Protocol) increasingly expect scope 3 reduction strategies. The CS-SAF gives airlines a tool, but also removes the excuse that sustainable fuel was physically unavailable. Fossil fuel distributors that do not diversify face compounding pressure: CBIO obligations in road transport, potential CGOB obligations in gas, and now CS-SAF in aviation. The architecture is designed so that each new asset narrows the space for uncommitted players.

via Reset