(last updated 22/04/2025)
In pursuit of Net Zero, the aerospace industry is on a mission to seek alternative solutions to help us reach the industry decarbonisation targets by 2050. With emerging avenues being explored, Sustainable Aviation Fuel (SAF) is considered one of the most promising pathways to reduce carbon emissions. Ahead of the Sustainable Skies World Summit, where SAF will be spotlighted as one of the event’s five key themes, let’s take a minute to dive into the 7 most talked about questions.
7. What is SAF?
Sustainable Aviation Fuel is an alternative to fossil fuels, typically made from plant and animal materials. Compared to traditional jet fuel, SAF reduces carbon emissions by up to 80%, depending on the source of material, method of production and the overall supply chain.
Other fuels being researched and tested include Lower Carbon Aviation Fuels (LCAF) and Zero Emission Fuels (ZEF)
Lower Carbon Aviation Fuels (LCAF)
- LCAFs are bio-jet fuels that could act as a complementary measure other sustainable fuels.
- The overall CO2 emissions savings vary. Currently, these fuels must be blended with kerosene for certification reasons but also because there is not enough production to meet fuel demand.
- Recommendations to accelerate this sector call on policy makers to support initiatives delivering at least a 50% reduction in CO2 emissions and have a significant supply of feedstock in order to create LCAF at a big enough scale.
Zero Emission Fuels (ZEF)
- ZEFs are also known as carbon-neutral fuels, meaning they produce no net-greenhouse gas emissions or carbon footprint.
- They are typically made using carbon dioxide (CO2) as a feedstock, which involves capturing and converting CO2 into a viable aviation fuel such as liquid methanol.
6. Is SAF the same as biofuel?
SAF is generally the preferred term in aviation as it encompasses the scope of materials used to produce it, including both biological and non-biological resources. Biofuels are not necessarily always produced sustainably, and therefore the term is avoided when discussing aviation-specific fuels. Biodiesel in particular is not suitable for use in aviation.
5. Who makes Sustainable Aviation Fuel?
Currently, some of the top producers include Neste, World Energy, Gevo, Alder Fuels and SkyNRG. In December 2022, the UK government announced funding for 5 UK-based projects to produce SAF, some focusing on converting household waste into sustainable fuel.
The UK government has recently announced the forthcoming implementation of the SAF Mandate, which took effect on January 1, 2025. Under this mandate, aviation fuel suppliers will be obligated to incorporate progressively larger proportions of SAF into the UK’s jet fuel supply, beginning with 2% in 2025, increasing to 10% by 2030, and ultimately reaching 22% by 2040.
4. How does Sustainable Aviation Fuel reduce emissions?
Compared to conventional fuels, burning SAF fuel reduces the amount of CO2 emissions across its lifecycle as well as other impurities such as sulphur dioxide.
‘One of things that really confuses people is that when we consume SAF in the engines we still produce a form of CO2, but it’s obviously made from biogenic sources or from captured CO2’ … ‘So in terms of increasing net CO2 in the atmosphere, SAF doesn’t do that. It’s the timeline over which we are recycling that carbon which is important’
Leigh Hudson, Environmental Manager – Carbon Management, British Airways (SSWS22 Webinar)
3. Is Sustainable Aviation Fuel actually sustainable?
SAF provides a significant reduction of CO2 emissions, but it is a drop-in solution meaning most current aircraft can only use a 50% blend of SAF and normal jet fuel. 100% SAF flights have been tested but they require technological modifications to the aircraft first.
2. Who uses Sustainable Aviation Fuel?
As of April 2025, over 50 airlines worldwide have integrated Sustainable Aviation Fuel into their operations to help reduce carbon emissions and achieve sustainability goals. More than 450,000 flights have used SAF blends, with a significant concentration in the U.S. and Europe.
1. Is Sustainable Aviation Fuel more expensive?
Generally, SAF is far more expensive that traditional fuels, often double the cost. This is the main reason why many airlines and carriers have been reluctant to adopt it. The cost of production partnered with the low demand is what is keeping the overall cost so high, with many citing the need for government incentives and investment as the solution.
‘SAFs are wonderful, they’re great, if you can get it. We wholeheartedly support any effort from government incentives and through the market to ramp up as fast as possible the production of these game changing sustainable aviation fuels.’
Sean Bradshaw, Technical Fellow – Sustainable Propulsion, Pratt & Whitney (SSWS22 Webinar)
“SAF is a key priority, as outlined by the Jet Zero Strategy. The SAF Mandate should be implemented by 1 January 2025 once passed as legislation.”
Claire Swadkin, Deputy Director Low Carbon Fuels, UK Department for Transport (SSWS24)
Latest News
- Global production reached 1 million tonnes (1.3 billion litres) in 2024, doubling the output from 2023 but falling short of the projected 1.5 million tonnes. (IATA)
- United Airlines has increased its SAF delivery locations, now incorporating blends into flights operating from London Heathrow (LHR) and San Francisco (SFO) airports. (United Airlines)
- A more than doubled its SAF usage compared to 2023, purchasing over 132,000 tonnes in 2024, accounting for 2.7% of its total fuel consumption. (British Airways)
- EasyJet signed a six-year agreement with Moeve for SAF supply on its Spanish routes from 2025 to 2030. Additionally, it secured access to up to 150,000 tonnes of SAF, including 75,000 tonnes of e-SAF, from 2030 onwards (EasyJet)
- In 2024, Air France utilised 43,953 tonnes of sustainable aviation fuel (SAF), reducing CO₂ emissions by over 150,000 tonnes. To support its long-term decarbonisation goals, the group has signed a 10-year agreement with TotalEnergies to secure the supply of up to 1.5 million tonnes of SAF.
The Bigger Debate: SSWS25 Agenda
To accommodate for the increased predicted numbers of flights and passengers in 2050, a huge amount of SAF will need to be produced. So, how does the industry do this?
Is SAF the right strategy? Is hydrogen or electric a better investment?
The discussion around SAF and the road to Net Zero more generally will be a key topic of conversation in a number of panel sessions planned for SSWS25. Explore the agenda.
