Sustainable Aviation Fuel (SAF)

Sustainable aviation fuel is the solution found by the aviation industry to the current environmental situation. This situation has become a big challenge for humanity, and many industries have been required to limit their carbon footprint by taking their carbon emissions to zero. And that is the primary purpose of sustainable aviation fuel.

International aviation has a significant impact on the global carbon footprint, an impact that grows quickly and will keep growing if an alternative to conventional jet fuel is not in place.

Air travel represents around 2-3% of the global carbon emissions generated by humanity at the moment. This could mean that, by the year 2050, aviation would have “spent” close to 22% of the global carbon budget if actions were not taken. So, reducing emissions is mandatory, which is why the aviation industry has committed to reducing net aviation carbon emissions to 50% below 2005 levels by 2050.

But how will the industry achieve this goal? Let’s see sustainable aviation fuel (SAF) in more detail.

What is the Sustainable Aviation Fuel?

Sustainable aviation fuel (SAF) can be classified in the group of biofuels, and it has the same characteristics as conventional jet fuel but with a much lower carbon footprint. Having a lower carbon intensity, SAF gives airlines an essential solution for minimizing aviation greenhouse gas emissions (GHGs) that account for 9 to 12 percent of all GHGs in the U.S.

Some emerging SAF pathways also share a net negative greenhouse emission footprint. Therefore, SAF is an effective solution to mitigate aviation GHG emissions.

Although it has a similar chemical composition to traditional fossil fuels, the raw materials used to make this sustainable jet fuel are very different from those used for traditional jet fuel. Let’s take a closer look.

What is sustainable aviation fuel made of?

There is a wide variety of raw materials that can be used to make sustainable jet fuel. As you may expect, the main characteristic of these materials is that they meet specific sustainability criteria to consider them sustainable feedstocks. Cooking oil and other non-palm waste oils from animals or plants are among the most common materials but not the only sustainable feedstocks used for SAF production.

Here’s a list of the most common sustainable materials used to produce SAF provided by the US Department of Energy:

• Corn grain
• Oilseeds
• Algae
• Other fats, oils, and greases
• Agricultural residues
• Forestry residues
• Wood mill waste
• Municipal solid waste streams
• Wet wastes (manures, wastewater treatment sludge)
• Dedicated energy crops.

Are sustainable aviation fuels actually sustainable?

The simplest definition explains that sustainability is the capacity to endure in a relatively ongoing way, generally referring to the capacity for the Earth’s biosphere to coexist with the human civilization. Let’s focus first on the part about endurance.

According to the US Department of Energy, “an estimated 1 billion dry tons of biomass can be collected each year sustainably in the United States, enough to produce 50–60 billion gallons of low-carbon biofuels. This vast resource contains enough feedstock to meet the projected fuel demand of the U.S. aviation industry, additional volumes of drop-in low carbon fuels for use in other modes of transportation, and produce high-value bioproducts and renewable chemicals.”

There is enough to endure on an ongoing basis for a long time. At least in the United States, and probably the same happens on a global level.

Now, to see how it will improve the capacity of the Earth’s biosphere to coexist with human civilization, we only need to take a look at the benefits of sustainable aviation fuel SAF.

What are the benefits of SAF for the aviation industry?

The clearest benefit of SAF for the leading industry players, such as airlines and airports, is the ability to reduce carbon emissions. According to British Petroleum (BP) data, SAF can reduce lifecycle emissions by around 80% compared to conventional jet fuel.

Moreover, other companies that supply SAF, like SkyNRG, claim that SAF can also reduce direct emissions: particulate matter (PM) with up to 90% and sulfur (SOX) with 100%, compared to traditional jet fuel.

Other benefits the airlines and airports obtain from using SAF over fossil jet fuel are:

• Improved aircraft performance as a result of cleaner combustion cycles in the engine.
• Lower local emissions of harmful compounds around airports during take-off and landing.
• No changes are required in the fueling infrastructure or the aircraft components to reduce emissions by using SAF.
• Improved energy efficiency obtained from a higher density than traditional jet fuel, resulting in higher payload conditions or extended range.

However, what could be more significant for all of us is that the benefits of choosing SAF over fossil jet fuel are not limited to aviation. It also has an impact on other stakeholders. Let’s see what other benefits we can find.

Other benefits of choosing SAF over conventional jet fuel

The current supplied SAF is produced from grown, renewable, and waste resources, providing other benefits apart from reducing the environmental impact generated by aircraft fuel consumption.

Some of these benefits include:

• Creating economic opportunities in farming communities that could provide the feedstocks required for SAF production.
• Extra revenue from growing feedstocks and biomass crops.
• Improved air quality, especially for the areas surrounding airfields.
• Job creation for renewable biomass technology research and development.
• Economic growth from operating SAF biorefineries and infrastructure that include local supply chains.

The future of SAF

Improving energy efficiency and sustainability has been commonplace in recent years across different industries. The environmental impact that has resulted in a pronounced climate change due to carbon emissions has made various industry partners look for alternatives to fossil fuels.

However, some energy sources like hydrogen and electricity are still in the early stages of development to alternative jet fuel. So, aircraft will still need alternative liquid fuel like SAF made from waste oils until any other jet technology is produced.

Therefore, we may see significant growth in the demand for SAF supply in the short term. Keep in mind that any aircraft with the corresponding fuel certification can use SAF. And although SAF is still more expensive than conventional fuel, it will become more efficient as the technology matures and prices will drop quickly.

Also, passengers are becoming aware of the value and benefits of taking a flight on aircraft using SAF instead of conventional fuel.

In short, we could dare to say that the future of SAF revolves around more research, development, and production, increased supply, and the deployment of more aircraft substituting fuel derived from petroleum for SAF for increased energy efficiency and a reduction of the carbon footprint and emissions.

SAF is only one step in the path to making any flight greener. With flight demand growing again after the pandemic, all stakeholders need to move quickly towards a broader solution.

Suppose you want to learn more about the environmental challenges and the initiatives taken in aviation to achieve the goal of carbon footprint reduction. In that case, you need to take a look at the course Aeroclass has prepared for you.

Learn about the possibility of electric and hybrid energy aircraft, together with SAF, to reduce the environmental impact now.