Geoff Maynard, a member of the Aviation Policy Group at the Chartered Institute of Logistics and Transport in the UK (CILT(UK)), has spent more than 25 years working across the aviation industry. His career has taken him through a wide range of technical, strategic and environmentally focused projects. A Natural Sciences graduate from Queen’s College, Cambridge, Geoff has held senior roles in both the public and private sectors and has contributed to major developments including Heathrow Terminal 5, Beijing’s Olympic Terminal and the new airport for Eswatini.
Drawing on this experience - and representing CILT (UK) in discussions with government and industry – Geoff sets out his view on Sustainable Aviation Fuel (SAF), its benefits, its challenges and why it must play a central part in aviation’s future.
What is SAF and why it matters
Sustainable Aviation Fuel is increasingly seen as a practical and immediate way of cutting aviation emissions. SAF is made from renewable or waste-derived sources and must meet strict CORSIA sustainability criteria under ICAO Annex 16. Although it still produces CO₂ when burned, its feedstocks are part of the existing carbon cycle, meaning it does not add new carbon to the atmosphere. It also avoids competing with food production. Crucially, approved SAF can be used as a direct replacement for conventional jet fuel without altering aircraft or engines.
A crucial step toward Net Zero
Reaching net-zero aviation is a significant challenge, and SAF is currently the only solution that can make a sizeable difference in the short term. It allows airlines to reduce emissions while continuing to use today’s aircraft and infrastructure.
Alternatives such as hydrogen and battery-electric aircraft are being explored, but they face major technical hurdles. Batteries are too heavy for long-distance flights, and liquid hydrogen demands much larger storage volumes than existing aircraft can provide. For now, these technologies are suited mainly to very small aircraft, leaving SAF as the most practical near-term route to cleaner flying.
The UK’s SAF mandate
To speed up the transition, the UK has introduced a SAF mandate requiring a fixed proportion of SAF to be blended into jet fuel. The requirement starts at 2% in 2025 and will gradually increase. Later stages of the policy also call for a small amount of SAF made from carbon captured directly from the air.
The mandate applies to all major aviation fuel suppliers, with only very small suppliers exempt. The targets have been set at levels that reflect current SAF availability; pushing for higher percentages too soon would risk shortages. The UK’s approach closely mirrors that of the European Union, which is also starting with a 2% requirement in 2025. So far, UK suppliers have met the target, although full end-of-year data is still being finalised.
Early impact and industry response
The first year of the mandate has had the intended effect. SAF producers have been able to supply the required volume using approved methods. Airlines, meanwhile, must demonstrate that the SAF they use complies with CORSIA rules - a process that has increased recordkeeping and verification requirements.
The main challenge will come as the mandated proportion increases. As more SAF is required, securing sufficient supply will become more difficult. However, as the percentage rises, so too will the environmental benefit, steadily reducing the sector’s overall carbon footprint.
Cost and financial support
At present, SAF is about twice as expensive as traditional jet fuel. This has only a small impact at low blend levels, but as the mandate grows, the cost difference will become more noticeable. Over time, production should become cheaper as facilities scale up, but SAF is still expected to remain more expensive than fossil fuel.
To help build the industry, the UK government has invested £63million in companies entering the SAF market. New legislation will also create a government-backed body that guarantees price support. If the cost of producing SAF exceeds the market price, this body will make up the difference, funded through a levy on aviation fuel suppliers. This is designed to give investors long-term confidence to build new plants and expand capacity.
Broader economic effects
The SAF mandate may have wider effects across the economy. Carbon-rich waste – one of the potential feedstocks for SAF - may become more valuable, increasing competition with waste-to-energy incineration. Over time, this could shift household and industrial waste toward fuel production rather than disposal.
The mandate may also support the economics of UK refineries. As demand for fossil fuels falls in other sectors, SAF production offers a way to keep refinery operations viable. Without it, refineries could face increased pressure as traditional fuel markets shrink.
Looking ahead
Meeting future SAF requirements will depend on continued investment and stable, long-term policy. With the right support, the UK is well placed to take a leading role in sustainable aviation.
SAF is not the complete answer to aviation’s climate challenge – but it is the most practical and effective tool available today. As Geoff Maynard and CILT (UK) consistently highlight, embracing SAF is essential if aviation is to cut emissions while remaining reliable and globally connected.