Book-and-claim to de-risk European e-SAF production

Introduction

Europe’s aviation emissions are on the rise, with mitigative action trailing behind what is needed. In 2022, aviation accounted for 4% of the EU’s total greenhouse gas emissions, while the International Civil Aviation Organization (ICAO) estimated that by 2050, international aviation emissions could triple compared to 2015.

Central to cutting aviation emissions is replacing fossil kerosene with less emission-intensive sustainable aviation fuels (SAFs). However, among the different SAF feedstocks, only synthetic fuels (e-SAF) made from renewable hydrogen and sustainably sourced carbon is currently the only credible drop-in fuel that can decarbonise long-haul aviation. Despite e-SAF’s climate credentials, EU producers are struggling to get off the ground, with no large-scale projects having yet reached Final Investment Decision (FID). 

SAF uptake is mandated by the 2023 ReFuelEU Aviation regulation (RFEUA).  The targets mean that 6% of jet fuel in 2030, and 20% in 2035, must be SAF, with a corresponding sub-target of 1,2% of fuel from 2030, and 5% from 2035 being e-SAF. 

The RFEUA regulation currently includes a flexibility mechanism6F that is both too restrictive – in practice often enabling flexibility only within and not between Member States – and poorly targeted, failing to distinguish between e-SAF and biofuels. While other kinds of SAF are on track to meet 2030s targets, e-SAF projects face challenges the existing flexibility mechanism is not designed to help with.

Book-and-claim can help unlock e-SAF production and uptake in the EEA. However, to date book-and-claim proponents in the aviation and fossil fuel industries have advocated for systems with global scopes that cover all SAF. This approach would neither bridge the specific challenges e-SAF is facing, nor support EU industry. On the other hand, the European Commission objects to book-and-claim for SAF out of concern that it may stymy the development of physical supply infrastructure.

The SASHA Coalition proposes a third option, a well-regulated book-and-claim system designed to boost EU e-SAF production concurrently with the infrastructure development for long-term industrial resilience, by following these three criteria:

What is book-and-claim?

Book-and-claim allows market actors to buy ('claim') and sell the sustainability characteristics of a product independently from the physical product itself, in a traced and transparent chain of custody.

For e-SAF, this means an e-SAF producer could sell the physical fuel to one buyer nearby, and sell a certificate attesting to the fuel’s sustainability to another buyer. E-SAF producers benefit by not being restricted to buyers who are both geographically close and in need of e-SAF, and not seeing the price and the carbon intensity of the fuel increase because of transportation.

Buyers who purchase the certificate can claim the ETS zero rating on the e-SAF and do not surrender an ETS allowance for a fuel they don’t need to physically have access to and burn. This gives buyers access to a wider pool of potential fuel producers, important especially for airports in regions where there are currently insufficient nearby e-SAF projects planned, and that therefore have limited access to e-SAF.

Proposals for overly flexible book-and-claim mechanisms for SAF from aviation and fossil fuel industry actors have elicited substantial concerns. An unrestricted book-and-claim system may facilitate the development of unsustainable fuels with dubious certification, misleading consumers, while failing to stimulate production for sustainable e-SAF. This would undermine European industrial competitiveness, innovation, and climate action.

However, a book-and-claim system that is well-regulated can serve the clear purpose of driving high-integrity e-SAF in aid of EU climate and industrial goals, while avoiding the above risks.

What problems does book-and-claim resolve?

E-SAF projects are struggling to access finances – more than half of global e-SAF capacity is EU-based yet no large scale project has reached FID. This is partly due to high capital and operational expenditure, and the high price of e-SAF, increasing project risk and cost of capital. Other SAF types that enjoy lower prices today and more established value chains, do not face such challenges. A well-regulated book-and-claim system can therefore help de-risk e-SAF production but only if it works exclusively for e-SAF. Furthermore, an e-SAF exclusive accounting system would be far simpler to implement than one including all of the many biofuel production pathways. 

There is also a geographical discrepancy limiting e-SAF market development. E-SAF production largely occurs in places with high renewable electricity capacity, but which often are not close to significant airport hubs that are primary offtakers. The same discrepancy exists between Member States: our analysis demonstrates that Eastern and Southern Europe countries are set for an e-SAF deficit, while those in Northern Europe will initially enjoy a surplus.

Figure 1: Difference between projected annual e-SAF production and demand in 2030 for European countries (EU27, Norway and Iceland). Countries shaded in green are projected to have a surplus of e-SAF, while countries shaded in orange are projected to have a deficit. e-SAF projects are taken from Mutrelle et al. (2025), country boundaries are from World Bank (2025). Calculation methods and data sources for e-SAF surplus/deficit are detailed in the footnotes.

The Commission’s 2025 report on RFEUA expresses concern that this geographic disparity would be exacerbated by a virtual market (for all alternative fuels). This is because of a perceived risk that it would disincentivise development of the physical supply chain infrastructure that is needed for Union-wide alternative fuel access in the long run. But the incentive to scale infrastructure will not materialise until the e-SAF market scales. Book-and-claim would help spur the growth needed for infrastructure developers to make a business case, while a fixed end date would ensure the virtual market does not undermine long-term development.

The same report, however, ultimately concludes that book-and-claim would not have as great a de-risking effect as alternative measures. This conclusion rests on two questionable premises.

The first is the Commission’s reluctance to treat the range of alternative fuels under RFEUA with any considerable difference, a symptom of a “technology neutral” approach. The Commission correctly notes that synthetic e-SAF particularly needs support, but does not translate this recognition into bespoke regulatory support in lind with the greater sustainability and competitiveness premiums of e-SAF and the heightened barriers to scale it faces. One such barrier is competition with biofuels: the biofuel industry is already well-established and less in need of support, and the support it does receive reduces e-SAF’s relative competitiveness and bankability. Considering alternative fuels all together obscures the transformative benefits a book-and-claim mechanism could deliver when implemented specifically for e-SAF.

Secondly, the report considers book-and-claim as an isolated intervention. Book-and-claim is not a silver bullet and should be introduced in a package of policies, including a revenue certainty mechanism, in which each measure amplifies the impact of the other. Book-and-claim would greatly enhance, for instance, a contracts for difference (CfD) scheme with double-sided auctioning. It would increase the pool of buyers participating in the second auction, thereby not only increasing the chance of producers finding offtakers, but also potentially breaking some of the large bidders’ market power which would ensure a fair and competitive auctioning.

Similarly, book-and-claim’s de-risking effect would be optimised by accompanying measures. The Commission notes that virtual trading is not guaranteed to increase demand to fully offset price instability risk or secure offtakes of the length producers need. This holds only when book-and-claim is considered on its own – strategically deployed with other measures, these concerns fall away.

E-SAF only

• Energy security: Europe’s dependence on fossil fuels is not just a climate issue, but also a sovereignty issue. Import dependence subjects our industry to price surges, and our political decisions to geopolitical pressure. E-SAF is the only low-emission drop-in fuel that is scalable inside Europe and can offer long term energy security, while over-reliance on biofuels will merely substitute dependency on one import for another.

• Reducing emissions: E-SAF produced with renewable hydrogen is the only truly sustainable and scalable drop-in fuel alternative to kerosene. Not only do other SAF, including biofuels, have less potential to reduce lifecycle emissions than e-fuels, but they also risk impacting biodiversity.

• Industrial competitiveness: Biofuels are at a greater technical readiness level than e-SAF, and have more established value chains. Including them in a book-and-claim system and increasing their market access would set them up to outcompete e-SAF despite them offering a lower competitiveness premium, fewer emissions, and less resilient future supply chains due to feedstock limitations and projected price volatility. Therefore, investment does not need de-risking to the same degree.

EEA limited

• Energy security: Incentivising e-SAF development inside the EEA is key to seizing the energy security opportunity e-SAF offers.

• Industrial competitiveness: A book-and-claim system with extra-EEA scope may in the short term help European airlines comply with regulation, but in the long run it would allow non-EU companies with stronger state support to  outcompete European industry for the innovation, competitive manufacturing and economic opportunities.

• Supply chain transparency: Operating book-and-claim exclusively in the EEA, and excluding biomass feedstocks, makes it easier to ensure transparency in supply chains and robust certification to avoid greenwashing through double claiming or misrepresenting a fuel’s climate credentials.

Time bound

• Ensure investment: The purpose of book-and-claim is to de-risk investment in e-SAF production in its nascency, and prevent the current lack of infrastructure from hindering market development. But a set end-date is necessary to ensure actors are incentivised in the long run to invest in the physical supply chain infrastructure, or negotiate access to existing infrastructure currently controlled by fossil fuel incumbents, ultimately enabling distributed access to e-SAF across Member States.

Conclusion

A book-and-claim system could robustly support e-SAF producers de-risk investment and overcome the challenge of achieving FID. But this system must follow strict criteria if it is to truly boost e-SAF production, help meet aviation’s climate targets and cultivate competitive industry in Europe.

An unrestricted book-and-claim system, as some in the aviation and fossil fuel industries have proposed, risks boosting fuels that aid neither EU climate goals nor industrial competitiveness in the long run, and building manufacturing outside rather than within Europe.

But the Commission must not let these past proposals, that have had neither European industry nor the climate’s best interests at heart, blemish book-and-claim outright.

The SASHA Coalition urges the Commission to introduce a book-and-claim system that follows the criteria that it is exclusively for e-SAF, operates only within the EEA, and has a clear end-date.

Book-and-claim is not a silver bullet and should not be treated as such. Giving e-SAF production the support it needs demands a package of policies including book-and-claim but also a contracts for difference financial mechanism with double-sided auctions backed by a market intermediary, and extending the EU Emissions Trading System to extra-EEA flights as a starting point.