A Greener Future for Aviation with New SAF Mandates in the UK, US and Elsewhere

Sustainable Aviation Fuel (SAF) is, undoubtedly, the key to a greener aviation future, with the industry being responsible for more than 2.5% of global CO2 emissions. Impressively, though, SAF can provide a reduction of up to 80% in carbon emissions. Its basic chemistry resembles that of fossil jet fuel, but the fundamental difference is its usage of sustainable feedstocks such as forestry waste, solid waste from homes and businesses, cooking oils and other non-palm waste oils. SAF is advantageous in that it can be blended with traditional jet fuel at up to 50%, quality tests can be completed as if it were normal jet fuel, and it can be used in any certified aircraft. Due to the availability of sustainable feedstocks and the production of the necessary technologies, SAF is more expensive and thus limited than traditional jet fuel – but it will become less costly as new technology develops.  

SAF Mandates in the UK: 

A consultation outcome by the Department for Transport has introduced a new mandate regarding the usage of SAF in the UK. The main objective of the mandate is to have at least 10% of jet fuel to be made from sustainable resources by 2030, which is equivalent to around 1.5 billion litres – it will operate as a greenhouse gas emission reduction scheme with tradable certificates. Eligible fuels will include waste-derived biofuels; recycled carbon fuels like un-recycled plastic and waste industrial gases; and power-to-liquid (PtL) fuels, and the mandate will begin in 2025 to ensure the target is reached by 2030. Notably, it will apply to jet fuel suppliers outside of the Renewable Transport Fuel Obligation (RTFO). This aims to decarbonise air transport by mandating that suppliers of transport fuel in the UK must show evidence that a proportion of their fuel is renewable and sustainable. Companies that own and supply over 450,000 litres of transport fuel are required to register under the RTFO. The consultation for this mandate aims to put a cap on hydro-tested esters and fatty acids, as well as seeking support on a potential buy-out price, which will ensure a maximum incentive for supplying SAF. 

SAF Mandates in the EU: 

The ReFuelEU Aviation proposal is an integral part of EU regulation which aims to boost the production and uptake of SAF. This came as a key component of the “Fit for 55” package, which is a package of legislative proposals published by the European Commission in July 2021. ReFuelEU Aviation is simply a mandate that starting from 2025, all flights from EU airports will use SAF, even if just a small proportion, and even if not an EU airline. The minimum share of SAF will begin at just 2% in 2025, gradually increasing year by year; the mandate expects it to reach 5% in 2030, and majorly, 63% in 2050. The ReFuelEU Aviation proposal is currently a provisional agreement that will undergo further approval processes and has faced a range of different reactions from industry experts, NGOs, and the European Parliament, as explained in the following article

SAF Mandates in the US: 


The US has also been particularly progressive in pushing for decarbonising aviation, with three key policies introduced to advance SAF. These are the California Low Carbon Fuel Standard (CA-LCFS); the US Renewable Fuel Standard (RFS); and the US Sustainable Skies Act.  



A low-carbon fuel standard, or LCFS, is an emissions trading mechanism designed to reduce the average carbon intensity in transportation fuels such as gasoline and diesel. This can typically be done by supplying electricity in electric vehicles, and in regular vehicles powered by fossil fuels, biofuels can be utilised by blending them into more renewable fuels. This regulation implemented originally by California was updated in 2019 to recognise SAF as a credible fuel too.  



The RFS is another notable fuel standard, an American federal program that requires a minimum amount of renewable fuels to be present in transportation fuel on an annual basis. Originally created in 2005 under the Energy Policy Act and updated through the Energy Independence and Security Act in 2007, this program does focus more on ground transportation but cleverly offers an “opt-in” approach for SAF. This allows SAF to generate Renewable Identification Numbers (RINs) without usual aviation fuel compliance obligations – currently, it aims for 1.6 RINs per gallon. Similarly, to the EU’s ReFuelEU proposal, the RFS mandated the renewable fuel blended into transport fuel would be in increasing amounts each year, having risen to 36 billion gallons in 2022.  


The Sustainable Skies Act 

Introduced in May 2021, this Act is effectively a tax credit that incentivises the use of SAF. Aviation fuel companies who blend with SAF can receive $1.50 per gallon that demonstrates 50% or higher greenhouse gas (GHG) savings, and even higher GHG savings can receive up to $2 per gallon. It generally defines SAF as a liquid fuel that consists of synthesised hydrocarbons. Alongside this, the Act has included a complementary proposal of $1 billion over five years to increase the number of facilities producing SAF in the US.

SAF Mandates in China:  

China produces notoriously high levels of carbon emissions and the Chinese aviation market is the second biggest in the world only to the US and emitted 13% of the world’s aviation CO2 emissions in 2019. The market for SAF in China has huge potential, with multiple possible feedstocks such as used cooking oil, forestry waste, and food waste from cities available. Despite this, the possibilities for Chinese SAF are limited as there are a number of obstacles involved in reaching a suitable SAF market. First and foremost, the enormous costs involved. The processes required for SAF production costs 2-6 times as much as that for traditional jet fuel – with 25-40% of airline costs consisting of fuel, this is an optimistic target. Further, the airline industry has already been in decline post-Covid, with China being one of the worst countries affected by the pandemic. Alongside this, another issue is the lack of specific SAF policies in China. The UK, US and EU all have set policies, regulations and Acts that set out specific blending mandates and incentives for using SAF. This is needed in China to act as a catalyst for booming the SAF industry; Dr Yang Fuqiang of Peking University, Beijing explained that even if they began with a requirement of 1% SAF in aviation fuel, this would be enough to get the industry moving. 

Concluding thoughts: 

Although aviation is inevitably a transportation sector with some of the highest carbon emissions, the introduction and implementation of SAF mandates around the world will invariably have a positive effect. The UK, the US, and the EU have all created clear regulations that have remained on target. Countries like China and others in the Global South must overcome certain obstacles to get their SAF industry on track, but research is highlighting the vast possibilities China has ahead of them. With a worldwide approach to advancing SAF, we may finally see a greener aviation future.