sustainable aviation fuels

Jane Hupe, Deputy Director, Environment from the International Civil Aviation Organization (ICAO), shares her expertise on sustainable aviation fuels in this focus on transport and the environment

Electrification is being pursued as a possible solution for addressing the CO2 emissions from transportation, and many initiatives are also in place for its use in aviation. However, currently, a gallon of jet fuel contains about 15 to 30 times more energy as a lithium-ion battery of similar weight. This fundamental difference in energy density means that in the short to midterm, aviation will need to rely on liquid fuels for long haul flights.

This context explains the importance of taking advantage of the opportunity to develop liquid fuels that can deliver a reduced CO2 impact in the nearer term. In that regard, ICAO Member States agreed to include Sustainable Aviation Fuels (SAF) as an element of the basket of measures being pursued by them through ICAO to reduce aviation emissions and achieve the international aviation sector’s global goal of carbon-neutral growth from 2020. This basket of measures also includes other elements: technology and standards, operational improvements, and the Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA).

Significant progress has been achieved in SAF research, and today SAF production technologies are proven and safe to use in existing aircraft without the need for any modification. Six conversion processes have been approved by the ASTM International to produce SAF, and some SAF production pathways can generate up to 125% less CO2 emissions on a life cycle basis.

However, some challenges still exist as the world continues to try to take better advantage of the benefits of SAF for international aviation operations. Since 2009, ICAO has been seeking to help governments and industry to address these by performing a central role in facilitating the development and deployment of SAF.

ICAO’s actions are focused mainly on three pillars: the establishment of effective policies; the definition of global standards; and the organisation of events and outreach materials for information sharing and capacity building.

Establishing policies and measures to foster the use of sustainable aviation fuels

The second ICAO conference on Aviation and Alternative Fuels (CAAF/2) held in 2017 in Mexico agreed on the 2050 ICAO Vision for Sustainable Aviation Fuels, which calls on States, industry and other stakeholders for significant use of sustainable aviation fuels by 2050.

To understand progress towards the 2050 Vision, the development and deployment of sustainable aviation fuels is being monitored and assessed by ICAO through regular stocktaking events, the first of which was held in 2019. According to data gathered at the first ICAO Stocktaking Seminar toward the 2050 Vision for Sustainable Aviation Fuels (SAFS2019) commercial production of SAF increased from an average of 0.29 million litres per year (2013-2015) to 6.45 million litres per year (2016-2018).

To follow up on this process, in April 2020 an ICAO Stocktaking Seminar will be organised in Montréal to provide States and stakeholders an opportunity to continue the quantification of current and future SAF availability. Additionally, it will expand the scope of the stocktaking process by covering in-sector emissions reduction opportunities from aircraft technology and operational improvements.

Definition of global standards

As part of the Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA), ICAO has been working on globally accepted sustainability criteria and life cycle methodologies. These allow aeroplane operators to reduce its CORSIA offsetting requirements by claiming emissions reductions from the use of SAF. The result of this work is reflected in the four ICAO documents that are now available for download from the ICAO CORSIA Website.

The CORSIA sustainability criteria agreed for the implementation of the CORSIA pilot phase (2021 to 2023) defines that a SAF needs to achieve net greenhouse gas emissions reductions of at least 10%.

The default life cycle emission values for CORSIA sustainable aviation fuels currently includes sixteen distinct feedstocks available for SAF production. As an example, the use of SAF produced from miscanthus can generate up to 125% carbon emission reductions.

More feedstocks and conversion processes may become available to fuel producers as the industry evolves. ICAO is closely following up the development of promising technologies for SAF production, such as Power to Liquids (PtL), which uses renewable electricity, water and carbon dioxide to produce SAF. Additionally, work is ongoing to develop specific methodologies for CORSIA lower carbon aviation fuels, defined as a fossil-based aviation fuel that meets the CORSIA Sustainability Criteria.

Outreach and capacity building activities

The ICAO GFAAF is recognised as the online database for sharing information related to sustainable aviation fuels. It contains links to over 600 news articles dating back to 2005, details of past and ongoing initiatives, facts and figures, answers to frequently asked questions, and links to additional resources. It also includes a map with a live feed of flights using sustainable aviation fuels.

As part of the ICAO-UNDP-GEF assistance project “Transforming the Global Aviation Sector: Emissions Reductions from International Aviation”, a “Sustainable Aviation Fuels Guide” was developed to inform ICAO Member States on how sustainable aviation fuels can be deployed to reduce CO2 emissions from international aviation activities. The guide describes fuel production pathways, usage constraints, environmental and other benefits, and policy perspectives on the use and development of SAF. Four successful feasibility studies on the use of SAF were also developed as part of the ICAO-EU assistance project “Capacity building for CO2 mitigation from international aviation”. As a result, other ICAO States expressed their willingness to undertake similar SAF feasibility studies. ICAO is encouraging States to express such interest in their State Action Plans to reduce CO2 emissions, and to support the development of such feasibility studies.


Sustainable Aviation Fuels can play a major role in reducing international aviation emissions. ICAO’s efforts and activities supporting this work will continue steadily in the next triennium, in support of all applicable goals among our 193 Member States toward limiting or reducing the impact of aviation greenhouse gas emissions on the global climate.

Contributor Profile

Deputy Director
Environment International Civil Aviation Organization (ICAO)
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