Carbon Tracker finds SAF faces material limits on scale, cost and sustainability. 

London, 30 October– SAF cannot deliver on its promise this decade.

A new report from Carbon Tracker, Fuel Disclosure, warns that alternative jet fuels (AJF), commonly known as SAF, are unlikely to make a significant dent in aviation emissions before 2030. Even if all existing, under development, and announced projects operate at full capacity, AJF production would only supply around 5% of global jet fuel demand and meet less than a half of the expected growth in total jet fuel consumption. 

The analysis finds that high costs, limited sustainable feedstocks and weak bankability will keep AJF’s impact this decade limited.  

Seven hurdles that limit scale 

The report identifies seven structural hurdles to scaling AJF, the first four concerning all types of alternative jet fuels and the last three concerning truly sustainable alternative jet fuels: 

1. Costs and price premiums – AJF costs materially more than fossil jet fuel, dampening demand and rollout. 
2. Regulatory uncertainty – fragmented regulation across jurisdictions limits demand  
3. Lack of long-term offtake commitments – low volumes of long-term offtake agreements gives little visibility on revenue for producers. 
4. Weak bankability – perceived technology, feedstock and policy risks constrain funding for new AJF capacity. 
5. Feedstock availability – wastes and residues that meet adequate sustainability standards are scarce and hard to aggregate.  
6. Feedstock sustainability – risks around lifecycle emissions, land-use and biodiversity constrain eligible supply. 
7. Opportunity costs – scarce sustainable feedstocks may cut more emissions in other sectors where abatement is cheaper or faster. 

Saidrasul Ashrafkhanov, Carbon Tracker analyst and report lead author, said: “On top of high costs, offtaker hesitation and financing constraints, most alternative jet fuels are also saddled with a handful of environmental downsides. These fuels may some day have a larger role in decarbonising aviation, but the burden of proof is on the industry to show that it can find a pathway that will deliver alternative jet fuel that’s at once sustainable, abundant, and feasible.”  

Policy coherence matters 

A proliferation of support schemes is not yet translating into clarity for investors or environmental outcomes. Rich Collett-White, Carbon Tracker energy analyst and report co-author, said: 

“A bewildering array of policies designed to scale up alternative jet fuels is causing confusion, with definitions and eligibility criteria differing from jurisdiction to jurisdiction. Consistent rules are needed to ensure fuels with high environmental integrity are prioritised, and unintended consequences avoided.”  

Short-haul is where faster wins are available 

Credible, earlier abatement is available on short-haul routes. Almost half of all flights are shorter than 270 nautical miles (500 km). Battery-electric and hybrid-electric aircraft carrying 5-100 passengers are approaching entry into service, offering a direct path to zero-emission operations on regional legs. Hydrogen-electric aircraft could open up medium-haul markets from the mid-2030s. This creates a clearer near-term investment case and preserves scarce sustainable AJF for long-haul. Despite this potential, new-propulsion aircraft remain underfunded relative to AJF. 

A portfolio approach – right-sizing AJF’s role 

AJF will be important for long-haul decarbonisation where battery solutions are unlikely to compete on range and payload – but the role is smaller than widely assumed. A pragmatic portfolio approach is recommended: 

• Right-size expectations for AJF – Prioritise pathways with robust sustainability credentials and clearer cost trajectories; avoid options with weak lifecycle performance or material nature/food security risks. 
• Back zero-emission short-haul – Redirect attention and capital towards battery-electric, hydrogen-electric and hybrid-electric aircraft on sub-500 km routes, where operational readiness is advancing fastest. 
• Design smarter policy and finance – Tighten sustainability guardrails in line with strong policies and implement revenue-certainty mechanisms that de-risk advanced projects and reward real emissions performance. 

Bottom line 

AJF is part of the solution but not the solution on its own. Treating it as the primary source of emission reductions risks misallocating capital and using finite feedstocks without bending the fossil jet fuel curve this decade. A balanced strategy that accelerates zero-emission aircraft on short-haul, preserves sustainable AJF for long-haul, and aligns policy with climate outcomes offers a potentially faster, cheaper and more credible path to aviation decarbonisation. 

 

Notes to editors 

• Terminology – The report treats AJF as the broad category and notes that while many fuels are labelled ‘SAF’, only some meet high sustainability standards – and this is stated explicitly where applicable.
• Scope – Analysis covers producer, supplier and operator market activity; global policy overview emphasises design differences between different mandates and targets around the world.  
• Publication – Analyst Report | October 2025. Authors: Saidrasul Ashrafkhanov and Rich Collett-White.  
• Download – Fuel Disclosure
  Sustainable. Abundant. Feasible – why SAF is unlikely to be all three at once — Download the report  

About Carbon Tracker 

Carbon Tracker is an independent financial think tank that carries out in-depth analysis on the impact of the energy transition on capital markets and the potential investment in high-cost, carbon-intensive fossil fuels.  

Media contact 

Alessandra Moscadelli, Media Relations – Carbon Tracker
[E] Alessandra.moscadelli@tracker-group.org | [T] +44 (0)7855837724