Sustainable Aviation Fuel vs Conventional Jet Fuel
Sustainable aviation fuel (SAF) performs virtually identically to conventional jet fuel, it meets the same quality standards and is compatible with existing aircraft engines. However, when contrasted with traditional jet fuel, SAF provides notable environmental advantages. Conventional jet fuel is a fossil-based product that releases substantial amounts of CO₂, whereas SAF is specifically designed to have a lower carbon footprint across its entire lifecycle.
The real impact of SAF lies in this lifecycle; while burning SAF still produces emissions similar to those from fossil fuels, it primarily uses carbon that is already part of the current carbon cycle through various organic feedstocks or captured using technology like Direct Air Capture.
Moreover, SAF often leads to fewer particulates and sulphur emissions, thereby improving air quality around airports. Another advantage of SAF is that it has shown higher density in flights, which allows aeroplanes to fly further on less fuel.
Importantly, SAF matches conventional jet fuel in terms of key performance and safety specs, ensuring reliable operation under all conditions.
SAF and conventional jet fuel perform the same function in aircraft propulsion systems, but they differ in feedstock origin, production method, and lifecycle emissions. Here is an overview of these differences:
Feedstock Source
Conventional Jet Fuel
- Produced from crude oil extracted from underground fossil reserves.
- Refined through petroleum processing such as distillation and hydrocracking.
- Carbon originates from fossil sources that add new CO₂ to the atmosphere when burned.
Sustainable Aviation Fuel
- Produced from non-fossil carbon sources.
- Feedstocks include waste oils, biomass, captured CO₂ and green hydrogen.
- Carbon is part of the current carbon cycle rather than geological reserves.
Production Process
Conventional Jet Fuel
The production process is mature and widely deployed. It involves:
- Crude oil extraction
- Transport to refinery
- Fractional distillation
- Chemical upgrading to aviation fuel specification
SAF
Production depends on pathway and these processes are less widely deployed but are expanding.
- Hydroprocessed esters and fatty acids (HEFA) from waste oils
- Alcohol-to-jet processes from biomass-derived alcohols
- Fischer–Tropsch synthesis from biomass or captured CO₂ and hydrogen (eSAF)
Lifecycle Emissions
Conventional Jet Fuel
- Lifecycle emissions are high because fossil carbon is introduced into the atmosphere.
- Typical emissions are approximately 85–90 g CO₂e per MJ of fuel (lifecycle basis).
SAF
- Lifecycle emissions are lower because carbon is recycled.
- Reductions typically range from 60% to 90% depending on pathway and energy source.
- eSAF using low-carbon electricity has the highest potential reduction.
Environmental Impact Beyond CO₂
Compared with conventional jet fuel, SAF can result in reduced particulate emissions, lower soot formation and the potential reduction in contrail climate effects. These additional effects contribute to the overall climate impact reduction of SAF.
Cost and Availability
Conventional Jet Fuel
- Lower cost due to established supply chains and scale.
- Global production infrastructure already exists.
SAF
- Higher cost due to limited production capacity and newer technology.
- Costs are expected to decrease with scale, technology development, and policy incentives.
Summary Comparison Table: SAF vs Jet Fuel
| Parameter | Conventional Jet Fuel | SAF |
|---|---|---|
| Feedstock | Fossil crude oil | Waste, biomass, or captured CO₂ & green H₂ |
| Lifecycle emissions | High | Reduced (60–90%) |
| Engine compatibility | Full | Drop-in (approved blends) |
| Sulphur content | Higher | Lower |
| Production maturity | Established | Emerging |
| Cost | Lower | Higher currently |
For more:
- Sustainable Aviation Fuel
- How is Sustainable Aviation Fuel Made?
- How does SAF Reduce Emissions?
- Why Direct Air Capture is Critical to Sustainable Aviation Fuel Production
- SAF Regulations
- What is eFuel?
- What is eMethanol?