Is SAF Taking Flight? An Overview of the UK’s SAF Mandate and the Next Steps Needed to Decarbonise the Aviation Sector

Sustainable aviation fuel (SAF) has emerged as the cornerstone of aviation sector decarbonisation strategies, offering the only current scalable pathway to net zero for long-haul flight. With the UK’s SAF Mandate now in force, prescribing blending obligations from 2025 onwards, our Infrastructure, Energy and Natural Resources team has published a detailed briefing analysing the SAF Mandate’s primary features, its interactions with other decarbonisation measures, and its relationship to emerging revenue support mechanisms. 

In the article, our team examines the strategic role of SAF in the energy transition, assesses the challenges of scaling and enhancing investment in advanced fuels, and compares international regulatory divergences between the UK’s measures and SAF policies announced by other governments around the world. Through this, we situate the UK’s SAF Mandate not as an isolated intervention, but as a critical component of global energy transition and investment policies.

Key takeaways: 

• SAF is the aviation sector’s most investable decarbonisation pathway: With no viable alternatives for decarbonising long-haul aviation in the near term, SAF has transitioned from a speculative technology to an investable commodity class. Its ascent is underpinned by binding policy mandates, growing offtake commitments, and near-seamless compatibility with existing aviation infrastructure.
• The UK SAF Mandate delivers regulatory certainty: Legally binding blending obligations, rising from 2% in 2025 to 22% by 2040, provide long-term visibility over market demand. This durable policy framework enhances project bankability and aligns with investors’ requirements for stability, scalability, and predictable returns.
• Revenue support mechanisms are now being developed and need to be designed to de-risk SAF production: The UK’s proposed guaranteed strike price mechanism, modelled on the successful contracts for difference scheme, seeks to bridge the cost differential between SAF and conventional jet fuel. For investors, this offers a proven template for inflation-linked, long-term revenue streams (comparable to those underpinning renewables and hydrogen business projects).
• Advanced SAF technologies present a generational growth opportunity: As constraints on SAF derived from Hydroprocessed Esters and Fatty Acids increase, investment will pivot towards power-to-liquid and waste-based SAF pathways. These advanced technologies are critical to meeting future compliance thresholds, and offer the potential for differentiated returns to early capital positioned ahead of regulatory scaling.
• Lifecycle sustainability now underpins aviation investment strategies: SAF investment strategies must now integrate comprehensive lifecycle sustainability considerations. This encompasses mass-balance chain-of-custody data tracking models and lifecycle emissions eligibility criteria. Investors are increasingly expected to demonstrate alignment with sustainability criteria at every stage of the SAF lifecycle. Early adopters of holistic strategies stand to benefit from reputational advantages and regulatory arbitrage.

For a more comprehensive analysis, please read our publication here.

For more information on SAF, please speak to one of the authors, and/or your usual contact at Slaughter and May.