How Does Sustainable Aviation Fuel Work?

The world is growing warmer. Today, aviation contributes about 3% of the world’s CO2 emissions. However, with the industry growth expected over the next few decades, that is set to increase substantially, causing an even greater impact on the climate. Unless, of course, emissions can be curbed significantly. Enter the promise of Sustainable Aviation Fuels. But how exactly do they work?

United 737-900ER
Airlines are betting big on advanced biofuels to help them reach their ambitious net-zero 2050 targets – or, in the case of United Airlines, 2040. Photo: Getty Images

When the International Air Transport Association (IATA) made its industry-wide net-zero-by-2050 declaration after its annual meeting in Boston last Monday, the organization put a lot of hope to the proliferation of sustainable aviation fuels (SAF) to reach the ambitious target.

According to one probable scenario, zero CO2 emissions from aviation would be achieved by as much as 65% from switching to SAFs. In Asia, the market for aviation biofuel is predicted to reach about $197 billion by mid-century. Today, SAFs are still in far too short supply. However, hopefully, with policy incentives and investments, that is set to change. But how does SAF work?

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Chemically similar

When it comes to chemistry, advanced biofuels are very similar to traditional fossil-based jet fuel. SAF, as used by airlines, is made by blending conventional kerosene with renewable hydrocarbon. The latter comes from various feedstocks, such as cooking oil (McDonald’s supplies Neste with leftover oil from french fries in the Netherlands), forestry waste, salt marsh grasses, and algae.

Because of their similar chemical composition to standard jet fuels, they are known as so-called ‘drop-in fuels’. This means that they can be incorporated directly into the refueling infrastructure present today. There is no need to alter or upgrade neither aircraft nor engines.

How Does Sustainable Aviation Fuel Work?
SAF is chemically similar to conventional jet fuel and can be used with existing infrastructure. Photo: Neste

More than just CO2

The ecological benefits from using SAF stem from replacing conventional jet fuel, but also due to the fact that the feedstock in many cases would have been left to decompose in landfills. This, in turn, contributes to the release of methane gas – which, in 2019, accounted for 10% of greenhouse gas emissions in the US (CO2 made up 80% of the total).

How Does Sustainable Aviation Fuel Work?
The feedstocks available for SAF today are certified for a 50% blend for commercial flights. Granted, it would still be too expensive for airlines to use half biofuel. Photo: Getty Images

100% blend certifications in the near future

You may already have heard that SAF produces up to 80% less CO2 during its lifecycle than traditional jet fuel. The exact number depends on the type of feedstock used, production methods, and delivery systems of the airports. Most of the thousands of commercial flights operating on SAF today do so with a blend of up to 10% SAF.

However, all of the approved feedstock production pathways have been validated for a blend of up to 50%, as have, for instance, all Airbus aircraft. However, the manufacturer is confident that it will soon achieve 100% certification for all its planes by the end of the decade.

Do you think Sustainable Aviation Fuels are the key to solving aviation’s sustainability quest? How much would you be willing to pay extra for your ticket, knowing that you are flying sustainably? Leave a comment below and let us know. 

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