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“Book” the fuel and “claim” the benefits – a fundamental enabler for scaling up SAF deployment

6 May 2024

SAF offers great opportunity to decarbonise aviation. However, there are a few issues:

  • Sustainable fuels are still significantly more expensive than fossil fuels and are likely to remain so for the foreseeable future.

  • Considerable investment is needed to mature sustainable aviation and marine fuel technologies, production systems and supply chains.

  • Sustainable fuels are currently only created in limited volumes at only a few sites in Europe and North America, however corporations that are interested in using these decarbonised products are spread all over the world, and many would never purchase physical fuel.

  • Similar to renewable electricity, once produced, sustainable fuels, a drop-in fuel, are blended with fossil-based fuels in fuel tank farms and it becomes impossible to track exactly how much of it goes into a specific aircraft.

Until recently, the most feasible options for companies to reduce their net CO2 emissions is by either cutting back on travel and/ or purchasing high-integrity carbon credits to offset their CO2 footprint. SAF certificates, a crucial component of the Book and Claim model, now offer companies a new tool to access the environmental benefits of SAF through reducing their fossil fuel consumption and hence CO2 emissions.

The Book and Claim model turns the environmental benefits of using SAF into certificates (SAF certificates, SAFc) that can be traded, transparently and credibly, with the certificate cost being used to invest and scale SAF production. Corporate clients can purchase SAFc directly from SAF producers, or from air transport providers. The more SAF and SAFc purchased, the more producers can scale up production and reduce the cost of SAF. The system allows buyers to purchase any volume of SAF, e.g., towards complete carbon neutrality, without having to physically receive, store, blend and use the SAF purchased. This allows the environmental benefits of SAF to be realised without the operational challenges inherent in new fuel technologies.

Opportunities and impact of Book and Claim model

Book and Claim: what is it

Book and Claim is a flexible model for verified information of flow. It is a chain of custody model, “in which the administrative record flow does not necessarily connect to the physical flow of material or product throughout the supply chain” [1]. It allows fuel producers to “book” the emission savings of their products at one location, and customers to “claim” the emission benefits of the products in a different location, hence enabling a company to make a sustainability claim without actually using the sustainable products.

Book and Claim is based on the concept of carbon insetting – investing in innovation and projects aimed at reducing carbon emissions within a certain sector.

Comparison between carbon offsetting and carbon insetting

A key characteristic of the Book and Claim model is that the environmental benefits are de-coupled from the physical fuel. When materials and products move along the supply chain, their attributes, including the environmental benefits, are transferred, monitored, documented and verified as they move through each step in the supply chain.

Illustration of tracking SAF throughout the chain of custody [2]

A central component of the Book and Claim system is the SAF certificates (SAFc), which represent the certified emission reductions of SAF. This means that for example, an airline can purchase SAFc and claim its environmental attributes, but physically fuel their aircraft with conventional jet fuel at the local airport where only conventional fuels are available.

Book and Claim: how does it work

The flow of the Book and Claim system can be summarised in the following steps:

Step 1: Production and purchase. SAF producers produces SAF, which is purchased by corporate customers as SAFc.

Step 2: Supply. The purchased SAF (physical product) is blended with fossil fuels at tank farms, from which point it is treated as conventional fuel and enters the distribution network to the airport.

Step 3: Registry. The quantity and parameters of SAF produced are reported in the Registry. A Registry is an electronic data storage system that enables the registration, issuance, holding, transfer, and retirement of product units/certificates/credits. The SAF information from the producer is used to calculate the amount of GHG that will be avoided by using SAF.

The SAFc Registry creates two units for each tonne of voluntary SAF registered:

  • One unit represents Scope 1 emissions, which can be claimed by the airlines that actually burn the fuel, i.e., the emitters.

  • The other unit represents Scope 3 emissions, which can be claimed by the corporations whose employees and freight may travel on aircraft that burn fossil fuels, i.e., the consumers, hence providing flexibility in their climate disclosure needs and procurement models.

The SAFc Registry separates Scope 1 and Scope 3 claims [3]

Step 4: Climate disclosure: SAFc in the registry are ready to be traded. Any buyer can purchase the emission reduction certificates and use them for climate disclosure.

The SAFc Registry links procurement and disclosure [4]

Book and Claim: Emerging SAF Initiatives

Currently, various aviation stakeholders are developing Book and Claim initiatives, which are in different levels of maturity.

Three main elements are addressed by the ongoing SAF Book and Claim initiatives:

  • Guidance / Methodology: including principles, rules and protocols, which are designed by stakeholders consensus.

  • Registry: record of transactions and transfer of SAF molecules and environmental attributes.

  • Verification: to ensure compliance with the methodology.

A quick uptake on current various Book and Claim initiatives

ReFuelEU, with its main objective to increase both demand for and supply of SAF, contains a requirement for the Commission to report by 2024 on the feasibility of a Book and Claim system for airlines to manage the supply of SAF in flexible way across the EU [5].  


Realising the full potential of a high-integrity Book and Claim

Book and Claim is a virtual solution to a physical problem based on a one-atmosphere approach, i.e., all GHG emissions enter the same atmosphere and it does not matter where the fuels are burnt.

  • It allows buyers to purchase any volume of decarbonised products based on their needs without being geographically connected to a SAF supply site.

  • It provides low-cost entry for sustainable product buyers without the requirement for fuel handling infrastructure.

  • It enables SAF to be produced wherever it is cheapest and shipped “virtually” rather than physically.

  • It creates a market-based mechanism that allows suppliers, unable to carry the upfront cost of decarbonisation, to sell SAF certificates to customers that are willing to pay for emissions reductions upfront.

Nevertheless, creating a harmonised system for recording SAF transactions which is compatible with a rapidly expanding set of SAF environmental attribute definitions, regulations, and accounting, is an intensive and collaborative process that requires:

  • The focus on high-integrity SAF: SAF needs to be produced with high environmental integrity, instead of relying on raw materials and pathways that can harm the planet, for example through deforestation.  

  • Robust and accurate bookkeeping: including the tracking of specific emission reductions realised by using a particular batch of SAF, ensuring that only one SAF certificate is issued for each ton of SAF.

  • An independent, reliable and publicly accessible registry: a record of the retirement of SAF certificates, so 3rd parties can verify the emissions reduction claims made in corporate sustainability reports.

The SAFc Registry should be designed to enhance user trust

There are concerns and criticisms towards SAF certificates, given the historic and ongoing issues surrounding the quality of carbon credit schemes and limitations in other chain of custody schemes, for example palm oil. SAF certificates are however a necessary innovation to unlock SAF project development and increase global SAF production.

SAF Book and Claim market and stakeholder acceptance will rely on continuous development to address limitations and reduce risk. It has the potential to be a robust and globally accepted mechanism to realise the commercial and environmental potential of SAF as a route to aviation decarbonisation.



[2] Global Methodology for Sustainable Aviation Fuel Environmental Attribute Transactions, CoSAFA, May 2023,


[4] SAFc Registry, RMI, Dec 2023;


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