Sustainable Aviation Fuel Calculator

Sustainable Aviation Fuel: Taking Off towards a Green Future

Aviation, a pillar of globalization, is also one of the most challenging sectors in the transition to decarbonization. While cars are being electrified and homes are adopting solar panels, airplanes still largely depend on kerosene, a petroleum derivative with a high energy density. However, the path to more sustainable aviation has already begun, and its main driver is Sustainable Aviation Fuel (SAF). SAF is not a futuristic concept; it is a real solution that is produced from renewable sources, such as used cooking oils, agricultural waste, or algae, and that can reduce CO₂ emissions by up to 80% in its life cycle.

The adoption of SAF is crucial because, unlike electrification in other sectors, battery technology is not yet advanced enough to power long-haul flights. Therefore, improving the sustainability of the fuel used by current engines is the most effective short- and medium-term strategy to reduce the environmental impact of the sector. SAF does not require major changes in airport infrastructure or aircraft engines, as it can be mixed with conventional fuel, which makes it a viable and scalable path to a greener future for aviation.

The aviation industry has committed to achieving net-zero carbon emissions by 2050, and the widespread use of SAF is one of the most important levers to achieve this goal.

What is SAF and where does it come from?

SAF is a type of fuel that, at a chemical level, is almost identical to conventional kerosene, but is produced from sustainable and non-fossil raw materials. Throughout its life cycle, from the production of the raw material to combustion in the aircraft, SAF emits significantly fewer greenhouse gases. The main sources for producing SAF are:

1. Biomass and waste: Used cooking oils, animal fats, and agricultural waste are the most common sources for the production of SAF. This method does not compete with food production and takes advantage of resources that would otherwise be discarded.
2. Municipal solid waste: Household waste that cannot be recycled can be processed to produce synthetic fuel. This method addresses two problems at once: waste management and the decarbonization of aviation.
3. Energy plants: Plant species that are not suitable for human consumption, such as camelina or jatropha, are grown specifically to produce biomass that is used for the production of SAF.
4. Carbon capture technologies: Synthetic SAF (e-kerosene) is produced from green hydrogen and CO₂ captured from the atmosphere or from industrial sources. Although this technology is still in development, it has the potential to be the most sustainable long-term solution.

Despite its multiple sources, the main bottleneck for SAF is its limited production and high cost. In 2022, SAF accounted for less than 0.1% of global aviation fuel consumption, a figure that underscores the need for massive investment in new technologies and production plants. The EU has established a mandate that requires airlines to use a minimum of SAF on their flights, starting with 2% in 2025 and progressively increasing to 63% in 2050.

Environmental Impact and Emissions Reduction

The main benefit of SAF is its ability to reduce CO₂ emissions. The reduction in emissions is not because SAF emits less CO₂ when burned, as the amount of CO₂ released during combustion is similar to that of conventional kerosene. The magic of SAF lies in the fuel's life cycle:

1. The carbon cycle: The CO₂ that is released when burning SAF is the same CO₂ that was previously absorbed by the plants or algae during their growth through photosynthesis. This creates a closed carbon cycle, with a net CO₂ emission that is considered neutral.
2. Net emissions: The 80% or more reduction refers to the net CO₂ emissions throughout the entire life cycle. This includes the production of the raw material, transport, and processing of the fuel.
3. Non-CO₂ impact: Although SAF is excellent for reducing CO₂, its impact on non-CO₂ emissions, such as condensation trails and nitrogen oxides (NOx), is still under study. Some research suggests that SAF can reduce the formation of condensation trails, which would be a significant additional benefit for reducing the greenhouse effect.

Despite these benefits, the cost of SAF is the biggest obstacle to its adoption. Currently, SAF is between 3 and 5 times more expensive than conventional aviation fuel. This additional cost is the reason why SAF is used in small quantities, and the price difference is passed on to the consumer in the form of more expensive tickets. Government support policies and investment in new technologies are crucial to closing this cost gap and making SAF a viable large-scale option.

Diagram of how SAF is produced from used oils.

Challenges and the Future of SAF

The large-scale adoption of SAF is an ambitious goal that faces multiple challenges:

1. Cost and production: The current production of SAF is limited and expensive. Massive investment in new plants and technologies is needed for prices to come down and production to be scalable.
2. Raw materials: The availability of sustainable raw materials is a bottleneck. The industry must find a balance between the use of waste and the production of biomass to avoid deforestation and competition with food agriculture.
3. Infrastructure: Although SAF can be mixed with conventional fuel, an infrastructure for production, transport, and storage is needed that can handle the increase in demand.
4. Policies and regulations: Governments must implement support policies, such as tax incentives and SAF blending mandates, to stimulate demand and reduce the cost gap.

Despite these challenges, the future of SAF is promising. Research into advanced production technologies, such as e-kerosene, and the support of industry and governments, are signs that the sector is taking decarbonization seriously. SAF is not a magic solution, but it is a crucial and tangible step towards an aviation that does not compromise the health of our planet. The calculator you have used is an educational tool that allows you to see firsthand the potential of this technology and the impact it can have on the future of air travel.