Sustainable Aviation Fuels (SAF)

​Sustainable Aviation Fuels (SAF) are considered one of the most promising measures to reduce CO₂ emissions from the aviation sector in the near- to mid-term using the existing global fleet and are expected to continue to play an important role in the future, after the introduction of alternative clean propulsion technologies.

EASA is involved in various activities to facilitate the uptake of SAF within the aviation industry.

What is the European Union (EU) doing to incentivise the use of Sustainable Aviation Fuels and which role will EASA play?

The ReFuelEU Aviation regulation is a pioneering policy for promoting the uptake of SAF and normalising its use in the main airports of the EU. EASA will play a key role, in coordination with the competent authorities of the Member States, in the monitoring and verification of the correct application of the regulation.

Background

In 2021, the European Commission presented the 'Fit for 55' package: a series of proposals to make the EU's climate, energy, land use, transport and taxation policies fit for reducing net greenhouse gas emissions by at least 55 % by 2030, compared with 1990 levels. 

The ‘Fit for 55’ will affect a range of sectors, including energy and transport. For aviation the most relevant future regulations are: 

• the revision of the EU Emissions Trading System for Aviation - a market-based measure to reduce CO₂ emissions;
• the ReFuelEU Aviation – a supply mandate accelerating the uptake of SAF, and;
• revision of the Alternative Fuels Infrastructure Regulation (AFIR) regulation – for the deployment of alternative fuels infrastructure.

• ReFuelEU Aviation
  

  In the draft regulation, the European Commission proposes obligations on fuel suppliers to provide a minimum share of SAF that increases over time. There is also a sub-mandate for synthetic aviation fuels. The main goal is to increase the uptake of SAF by aircraft operators and thereby reduce the overall emissions from aviation. Sustainable aviation fuels are technologically ready to play an important role in reducing emissions and are expected to account for a major part of the aviation fuel mix in the medium and long term. Through this regulation, the European Union intends to set out a framework to promote the uptake of SAF while preserving a level playing field in the air transport market.

• EU Emissions Trading System (EU ETS) rules on aviation
  

  The EU Emissions Trading System is the cornerstone of the EU’s policy to combat climate change. Through the inclusion of multiple economic sectors (e.g. power, heat, manufacturing industries, aviation), this cap and trade system incentivises CO2 reduction within each sector, or through trading of allowances with other sectors of the economy where emission reduction costs are lower.  CO2 emissions from aviation have been included in the EU ETS since 2012. Under the EU ETS, all airlines operating flights that depart and arrive within the European Economic Area (EEA) are required to monitor, report and verify their emissions, and to surrender allowances against those emissions.  EU ETS provides an incentive for airlines to use SAF certified as compliant with the sustainability criteria of the Renewable Energy Directive (RED), by attributing them zero emissions under the scheme, thus reducing airlines’ reported emissions and the ETS allowances they need to purchase. In April 2023, the EU agreed to key changes to the EU ETS aviation. These changes include:  A gradual phase out of the free emission allowances for the aviation sector and full auctioning from 2026.  Creation of a reserve of 20 million allowances until 31 December 2030 that will be reserved to incentivise the transition of aircraft operators from the use of fossil fuels. Setting up a monitoring, reporting and verification (MRV) framework for non-CO2 aviation effects. By 1 January 2028, building on the results of that framework, further proposals may be drafted on mitigation measures for non-CO2 aviation effects.

• EASA's role
  

  The proposal for the ReFuelEU Aviation Initiative would require EASA to play a key role by collecting various data related to the provision of SAF by fuel suppliers and use of SAF by the aircraft operators at the main EU airports. Subsequently, EASA will publish an annual report covering the collected data, as well as additional information concerning the aviation fuels and SAF market. Some of the information that EASA will be tracking through the report includes: The amount of SAF purchased by aircraft operators at Union level; The origin and the characteristics of all SAF purchased by aircraft operators for use on flights covered under the Regulation departing from Union airports; The compliance status of each aircraft operator and aviation fuel supplier having an obligation under the Regulation.   EU ETS EASA provides technical support to the European Commission on Market Based Measures (MBMs), including support in the implementation of the EU ETS. In addition, EASA provides modelling capabilities to assess the impact of market-based measures. The annual SAF report to be published by EASA is also expected to contribute to allocating free ETS allowances to those airlines that use SAF. Finally, EASA is engaging in research activities on the climate impact of non-CO2 emissions and the results of this activity are expected to contribute towards setting up a monitoring, reporting and verification (MRV) system for non-CO2 emissions as per the EU ETS Directive.

How are SAF approved and how much do they reduce emissions?

SAF technologies currently stand at different stages of commercial development and face various challenges. Their respective trajectories towards large-scale deployment follow different timelines ranging from short- to medium-term.

Advanced biofuels and Renewable Fuels of Non- Biological Origins (RFNBOs) have significant potential to increase the sustainability of the aviation sector. However, they currently exist only at demonstration level and still face industrial challenges, which means their emergence at commercial scale on the market could be expected in the coming years if specific incentives are in place. Crop-based biofuels are unlikely to play a role in the reduction of overall CO₂ emissions from aviation.

A wide spectrum of production pathways and feedstock with innovative, sustainable and cost-effective pathways will be necessary to contribute effectively to achieving the goals to reduce aviation CO₂ emissions. Several pathways are currently going through the approval process, and more should follow in the years to come. However, fuel approval is a lengthy and costly process that can be a barrier for fuel producers.

• Current specifications for conventional civil aviation fuel
  

  Today, the main specifications for conventional civil aviation fuel (Jet A-1) are the American Society for Testing and Materials (ASTM) specification D1655 and the UK specification DEF STAN 91-91. There are several other national and international jet fuel specifications, but as jet fuel is an internationally traded commodity these specifications are generally similar to and often follow the above requirements. To ensure compatibility with existing and future civil aircraft fleets, any new ‘drop-in’ aviation fuel such as SAF must meet similar strict fuel specifications as existing fossil-based ones, be mixable with them, have comparable behaviour and comply with global standards as well as have at least the same level of operational safety requirements as conventional fuels.  In 2009, ASTM International issued the ASTM D7566 Standard Specification for Aviation Turbine Fuel Containing Synthesized Hydrocarbons. It is currently the main reference within the aviation sector for new alternative fuel pathways (conversion process and associated feedstock) to be approved for safe use in aviation.  New pathways are assessed against the ASTM D4054 Standard Practice which defines the process by which a new blendstock (a fuel component that is either certified to be used as aviation fuel or is blended with other components to be certified) must be evaluated before approval. This includes extensive testing on the blendstock and final blends to ensure the fuel is fit for purpose and performs within expected norms.  Once approved, each suitable pathway is later included within ASTM D7566. Each Annex in ASTM D7566 is linked to a specific feedstock, process and blending requirements. As of today, seven pathways are included in ASTM D7566, which can be found in the table below. In addition, two pathways for the co-processing of renewable feedstocks in petroleum refineries are approved with a blending limit of 5%. Given the strict and technical safety requirements related to the use of aviation fuel, this stringent multi-tier approval process can take 3-5 years and requires significant financial investments (between €1 and €5 million).  The approval process can prove highly resource consuming in particular for small to medium-size fuel producers aiming to introduce new SAF pathways to the market. Such fuel producers may not always have the necessary human and financial resources to dedicate to the process, and significant volumes of fuel are also needed for testing purposes, which represent an additional strong constraint. Recognising the barrier posed by the difficult approval process, the United States set up a D4054 ‘Clearing House’ which provides advice and support on the approval process, carries out and/or coordinates the necessary tests required and funds Original Equipment Manufacturers (OEMs) to review the research reports produced based on the tests done (as required by the D4054 standard).

• Reducing emissions
  

  As the emissions from the combustion of drop-in SAF are comparable to fossil-based jet fuels, except for marginal efficiency gains, the majority of the reductions in Greenhouse gases (GHG) emissions originate from the production process. In order to assess the overall climate benefit from using SAF, a Life Cycle Analysis (LCA) is performed to account for all the stages in the life cycle of aviation fuels. It includes feedstock recovery and transportation, fuel production and transportation, and fuel consumption by aircraft. The GHG emissions of fuels are provided in terms of gCO2e/MJ, which can be compared to the relevant baseline emissions from fossil-based jet fuel in order to calculate the overall GHG emissions reduction.  The LCA of a fuel is a complex process and many variables (e.g., origin and type of feedstock, electricity mix, production method) can have a considerable impact on the total GHG emissions. Work is ongoing to approve GHG emissions reductions for Power-to-Liquid fuels, and with a fully decarbonised supply chain, emission reductions of up to 100% can be achieved compared to a fossil fuel reference Additional effects from use of SAF The SAF feedstock and production process typically results in very low levels of sulphur and aromatic content, which contribute to the formation of volatile and non-volatile particulate matter (PM) emissions. Studies on the use of SAF blended into fossil-based jet fuel have shown that PM emissions behind the aircraft at cruising altitudes are reduced by 50-97% compared to fossil-based jet fuel. The highest reductions can be observed at low engine power, typically applied when the aircraft is taxiing, and hence SAF can also improve local air quality and reduce health impacts. As such, due to their different physio-chemical composition, SAF drop-in fuels can have a positive impact on both air quality around airports as well as climate change through less CO2 emissions and the reduction in the formation of contrail-cirrus clouds. This is assuming that there are no increases in the aromatic and sulphur content of the fossil-based part of the blended fuel that negates the SAF benefits.  Land use impacts are a common concern surrounding some aviation biofuels. Direct land use changes (DLUC) occur when existing farmland is converted for the growth of feedstock for biofuel production, while indirect land use change (ILUC) occur when the increasing demand for biofuel lead to land expansion elsewhere, including the conversion of land with high carbon stock such as forests (e.g., deforestation and the release of CO2 stored in trees and soil). The impact of ILUC is estimated through complex modelling and the range of values can be wide. Studies have shown that the conversion of land with very high biodiversity, such as rainforest or peatlands, can release up to several hundred times more CO2-equivalent emissions than what the biomass subsequently grown on that land is able to reduce annually. For the above reasons, under RED II, the contribution of biofuels produced from food and feed crops towards EU Member States’ renewable energy targets for transport are capped, and the contribution of biofuels from food and feed crops for which a "significant expansion of the production area into land with high carbon stock" is observed is capped at 2019 level and phased-out by 2030. For the same reasons, biofuels produced from food and feed crops are not eligible under the proposed ReFuelEU Aviation.

• EASA's role
  

  The 2019 EASA study on a Sustainable Aviation Fuels ‘Facilitation Initiative’ recommended the creation of an European SAF Clearing House, modelled on the US Clearing House and carrying out similar activities.  EASA is currently managing a project that will set up and evaluate a European SAF Clearing House by following these primary objectives: Set up a new European capability to provide SAF approval solutions via an EU Clearing House for SAF. Define, validate and test the concept to be implemented in Europe by setting up the required European capabilities and tools. Based on the 2019 EASA study as well as a follow-up study commissioned in 2021, the following main activities can be identified for the European SAF Clearing House: Pre-screening of new fuel and production process projects, including advising fuel producers on their fuel and production process, to increase the likelihood of producing a sustainable, technically and commercially viable SAF. Navigate producers through the fuel approval process, including the partial funding of fuel testing and research report review costs. Assisting producers – including those following approved production processes – through all stages of product development, from early assessment to ongoing due diligence testing. This includes, where necessary and feasible, providing guidance on Sustainability Certification Schemes. Contributing to efforts to streamline the existing fuel approval process without compromising product performance and safety.

International Cooperation

The need for a safer and greener aviation sector doesn’t stop at national borders or continental boundaries. This is why International Cooperation is an essential activity for EASA to fulfil its mission. EASA partners with civil aviation authorities, regional and international organisations alike to address them in a cooperative effort. 

EASA’s International Cooperation activities are key in building the capacity to address the global environmental and sustainability challenges facing the aviation sector. EU funded actions are enhancing the relationship with partner states and provide sound technical understanding to facilitate their transition to sustainable aviation. The implementation of CORSIA, the update or first issuance of the State Action Plans for CO₂ reductions, and the support to scale-up the production and use of SAF, are the most prominent examples of EASA contribution to our partner countries. 

EASA is implementing several technical cooperation projects addressing sustainable aviation and climate change action around the world, such as in Africa, Caribbean, Latin America, South, South-East and North Asia. Concretely speaking EASA supports partner countries in developing a deeper understanding of what SAF means for their country, facilitating the definition of SAF Policies, performing studies on availability of feedstocks, assisting in the drafting of SAF Roadmaps and building capacity in SAF related matters, such as ASTM and sustainability certification schemes.

EASA facilitates partner countries in establishing partnerships with other states and organisations (e.g. industry, research or academia, international entities) or with other SAF initiatives (e.g. Clean Skies for Tomorrow, SAF Coalitions). At the same time EASA assists in creating a common understanding on SAF policies between different governmental departments (e.g. Aviation Authorities, Ministries of Transport, Energy, Environment, Finance) and helps to create synergies with other regional initiatives and/or other international organisations.  ​

• What is being done by EASA at the ICAO level on SAF?
  

  EASA is actively involved by providing technical expertise in some of the most relevant working groups at an international level, namely the Fuel Task Group of the ICAO Committee on Aviation Environmental Protection (CAEP) and the ECAC/EU Sustainable Aviation Fuels Task Group (SAF-TG) formed by experts from different European States and organisations.  Through the participation in these groups EASA has been supporting the development of guidance material on potential policies for the deployment of SAF, assessment of new technologies for SAF and Low Carbon aviation Fuel (LCAF) production, evaluation of SAF and LCAF availability through 2035 and the preparation of the ICAO Conference on Aviation and Alternative Fuels (CAAF/3) that will take place at the end of 2023. EASA will also actively participate is the “ICAO Assistance, Capacity-building and Training for Sustainable Aviation Fuels (ACT-SAF) programme”. This programme was launched in order to create opportunities for States to develop their full potential in SAF development and deployment, in line with the ICAO's No Country Left Behind initiative, the 2050 ICAO Vision for SAF, and the three main pillars of sustainable development recognised by the United Nations.