An introduction to sustainable aviation fuels | Article (2023)

In the middleTo manage an operational and economic recovery from COVID-19, the commercial aviation industry has set a long-term goal to reduce carbon dioxide (CO2) emissions. In October 2021 theInternational Air Transport Association (IATA), representing the global commercial aviation industry, andAirlines for America, a US industry trade group for all major US passenger and cargo airlines, announced its members' commitment to net zero carbon emissions by 2050. Achieving this goal, however, will be a difficult challenge.

Read the rest of the SAF series:

  • Part 2: Federal Legislation for SAF
  • Part 3: Cooperation in the private sector
  • Part 4: SAF and the global climate agenda

Aviation is a difficult sector to decarbonise. The tremendous power required to fly long distances in a heavy aircraft requires an energy-dense power source that provides liquid hydrocarbon fuel. Battery technology for electric flights is getting better and better. However, the batteries currently do not have an energy density close to that of liquid fuel and would be too heavy for large planes to fly long distances.hydrogen (H2)it is a potential liquid fuel that produces only water vapor and very small amounts of nitrogen oxides when burned. The transition to H2 as a fuel source brings with it a number of significant challenges in terms of production, storage and infrastructure, aircraft configuration, and engine modification requirements. Any electric or hydrogen-powered flight for large, long-distance aircraft could be decades away.

(Video) What is Sustainable Aviation Fuel?

The most promising strategy to significantly reduce the sector's carbon footprint in the short and medium term is to scale up the use ofsustainable aviation fuel (SAF). SAF is an alternative jet fuel made from renewable biomass or waste-based feedstocks and has a lower life cycle CO2 intensity than traditional petroleum-based fuel. SAF can be made from a variety of feedstocks, such as oilseed crops and energy grasses; agricultural and forest residues; municipal organic solid waste; fats, oils and fats from kitchen waste and meat production; algae; and industrial carbon monoxide exhaust.

Another type of sustainable aviation fuel is e-SAF orPower to Liquid (PtL). PtL is made by combining hydrogen, which can be separated from water (it's the "H" in H2o) Using renewable electricity in a process called electrolysis, which removes carbon from the atmosphere or from industrial exhaust gases. The obstacles to a wider use of this technology are theCostos PtL, which is well above the cost of other types of SAF, and the availability of renewable electricity for electrolysis. These high costs are expected to decline significantly over the next three decades and the global industrial trade groupAir Traffic Action Group (ATAG),in his 2021 reportwaypoint 2050, predicts PtL production of 42 to 57 percent of total SAF by 2050.

Benefits of sustainable aviation fuels

SAF is considered an "introductory" fuel and is approved for use with conventional fuel up to a maximum limit50 percent mix, which does not require modifying aircraft engines or refueling infrastructure. Currently thereseven SAF production processes (paths)Approved as safe for mixed use by civil jet aircraft.

(Video) Sustainable Aviation Fuel Animation

Plant-based SAF limits the release of carbon into the atmosphere as plants absorb CO2 through photosynthesis during growth. This creates a cycle: plants absorb carbon from the atmosphere and then convert to SAF, which releases the carbon back into the atmosphere when burned. In this way, SAF is "defossilized" using carbon already in the biosphere, not the fossil carbon used in petroleum-based jet fuel.

Using municipal solid waste as a feedstock for SAF also recycles carbon from waste and reduces emissions of methane, a potent greenhouse gas that can leak from landfills.

CO2 emissions from the life cycle of “clean” (unblended) SAF canuntil80 percent lowerthan that of conventional petroleum-based fuel. When blended with 50 percent conventional fuel, the reduction in CO2 emissions is still an impressive 40 percent.

SAF also generates lessconventional pollutantscontributing to local air quality concerns around airports. emits lessSulfur oxides and particulates, less carbon monoxide and fewer unburned hydrocarbons. With fewer particles in the aircraft exhaust, contrail formation is reduced.contrails and cirrus cloudsThey create a global warming impact that contributes significantlyEffects of aviation on climate change.

To ensure that SAF is truly more sustainable than oil, the UNInternational Civil Aviation Organization (ICAO)establish SAF standards that include the followingRequirementsto “achieve a reduction in greenhouse gas (GHG) emissions on a life cycle basis (compared to conventional fuel), contribute to local social and economic development” and avoid “competition with food and fuel”. water".

(Video) Introduction (Part 1: Sustainable Aviation)

According to the ATAG report, the cultivation of non-food crop feedstocks for SAF has the potential to use otherwise unproductive land, create employment opportunities in rural areas, increase farmers' incomes and enrich the soil when harvested. raw materials are used as cover crops between growing seasons. grown for conventional crops.

Challenges of sustainable aviation fuels

First approved for commercial aviation (when blended with petroleum jet fuel) in 2011, SAF is much more expensive than fossil fuel and generally costs at leastfour or five times more thanconventional kerosene.

Increased production will improve the economies of scale of these sustainable fuels that paid offless than 0.1 percentfrom96 billion gallonsof total global commercial aviation fuel consumption in 2019. In the United States, it was slightly more4.5 million gallons SAFproduced in 2020, a significant increase over 2019, but only a small fraction of18.3 billion gallonsJet fuel consumed by US scheduled airlines in 2019. Production capacity is limited but growing.

(Video) Sustainable Aviation Fuel AFKL

Fats, oils and fats (FOG) are the most commonly used raw materials for SAF today, but their availability is limited. A number of different feedstocks are required for a conventional jet fuel conversion. More thanbillionDry tons of biomass are potentially available annually in the contiguous United States as feedstock for bioenergy and chemicals.enough to excelForecast Domestic Demand for US Aviation Fuel

SAF competes with renewable diesel (RD) -used in road transport- for raw material resources and production capacity. DR benefits fromfavorable tax policy,make its production more profitable; it dwarfs the production of SAF nationally.

Momentum is building to encourage expanded production and use of SAF. Initiatives from the Biden-Harris administration, legislation passed in Congress, corporate partnerships with airlines, and a growing number of purchase agreements and airline commitments to purchase and use SAF are helping support growth in the fuels industry. sustainable aviation.

This first part of a four part article series covered the basics of SAF. Hesecond articleaddresses initiatives and legislation announced by the federal government in 2021 before Congress to support the development and encouragement of SAF production. The third article examines private sector strategies to encourage greater production of SAF at lower cost and the contractual arrangements for the purchase and production of SAF in the United States and internationally. The final article in the series will detail key SAF developments during the Glasgow 2021 international climate talks (COP26), including plans announced by the United States to boost the SAF industry.

Autor: Jeff Overton

(Video) Qantas: Introduction to Sustainable Aviation Fuel

Read all the articles in the Sustainable Aviation Fuel series.

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What is sustainable aviation fuels? ›

SAF is a biofuel used to power aircraft that has similar properties to conventional jet fuel but with a smaller carbon footprint. Depending on the feedstock and technologies used to produce it, SAF can reduce life cycle GHG emissions dramatically compared to conventional jet fuel.

How does sustainable aviation fuel work? ›

As Sustainable Aviation Fuel uses renewable feedstocks, it recycles carbon rather than adding carbon to the atmosphere, closing the carbon loop. This reduces emissions by 70%, significantly lowering the aviation industry's carbon footprint and dependency on fossil fuels.

What are 4 aviation fuels? ›

Overview of aviation fuels
DesignationAviation fuel type
Jet A-1 (USA: Jet A)Kerosene
Jet BKerosene-gasoline mixture
Avgas 100 LL MogasGasoline Super gasoline with additives
BiokeroseneKerosene-biofuel mixture

Who is making sustainable aviation fuel? ›

Together, Honeywell and United Airlines have invested in Alder Fuels, a clean tech pioneer, to produce renewable jet fuel from low-cost feedstocks such as woody biomass waste, cornstalks and other crop waste.

What is the benefit of sustainable aviation fuel? ›

Sustainable aviation fuel provides a cleaner alternative to fossil fuel, achieving up to an 80 percent reduction in greenhouse gas emissions over the fuel's lifecycle, compared to conventional fossil jet fuel. This enables airlines to lower their impact on the environment.

What are the 4 pillars of aviation sustainability? ›

The Four Pillars

Airports sustainability. Land use preservation and protection. Maintain System Capacity. Promote Safety.

How much does sustainable aviation fuel reduce emissions? ›

SAF is a liquid fuel currently used in commercial aviation which reduces CO2 emissions by up to 80%. It can be produced from a number of sources (feedstock) including waste oil and fats, green and municipal waste and non-food crops.

Does sustainable aviation fuel burn cleaner? ›

SAFs offer a 70% reduction in life-cycle carbon and a 90% reduction in particulates making them cleaner burning than petroleum-based jet fuel.

Can sustainable aviation fuel be made from solid waste? ›

Sustainable Aviation Fuels (SAFa) are aviation fuels that are produced largely from renewable bio-feedstocks (think corn, rapeseed, or palm oil) or waste from other production processes (used cooking oils, food waste, or other bio-based solid waste).

What are the 3 P's in aviation? ›

To help pilots better apply the principles of ADM, the FAA adopted the 3-P Model (Perceive — Process — Perform). This three-step process offers a simple, systematic approach to accomplishing each ADM task during all phases of flight.

What are the two most common types of aviation fuel? ›

There are two main types of aviation fuel used in general aviation: jet fuel and AVGAS. Jet fuel is a refined kerosene-based, clear or straw-colored liquid that is primarily used to power turbine engines, such as turboprop and jet engines.

How much does a gallon of sustainable aviation fuel cost? ›

For example, American Airlines recently announced it would purchase 100 million gallons of sustainable aviation fuel per year, starting in 2027, for around $5.50 per gallon.

When did sustainable aviation fuel start? ›

Since the first flight using sustainable aviation fuel (SAF) took off in 2008, a lot of progress has been made. Below is a snapshot of what is happening in the field of sustainable aviation fuel today.

How long has sustainable aviation fuel been around? ›

The first commercial flights using SAF took off in 2011, and it has since grown to become a key element in making air transport more sustainable.

What is the most sustainable fuel source? ›

Wind energy is one of the most sustainable forms of energy currently available. It harnesses the power of naturally moving air to spin wind turbines, which in turn generate electricity. Not only is this great because it provides a regenerative form of energy, but it also does so without greenhouse gas emissions.

Which fuel is the most sustainable? ›

Gas burns cleanly with no soot or ash, and therefore produces lower emissions than oil for example. It is considered the most environmentally friendly fossil fuel. The advantages of using gas: Low investment costs.

What are the 5 C's in aviation? ›

Five C's:
  • Circle: If able, you want to minimize your travel so you can orient to the location without anything changing and not get any further off track.
  • Confess: Admit that you are lost and need some form of assistance. ...
  • Climb: "Climb to cope" ...
  • Conserve: ...
  • Communicate: ...
  • Comply:

What are the 3 E's of sustainability? ›

While many community dynamics are at work, three are particularly important to building healthy and prosperous communities over the long term: economy, ecology, and equity—the three E's.

Does aviation fuel contribute to global warming? ›

The global aviation industry produces around 2.1% of all human-induced carbon dioxide (CO2) emissions. Aviation is responsible for 12% of CO2 emissions from all transports sources, compared to 74% from road transport.

Is sustainable aviation fuel expensive? ›

Currently, SAFs are more expensive than traditional jet fuel. Estimates range from 2x for some waste-based sources to 6-10x for synthetic fuels using carbon capture. This is mainly due to the small production runs.

What is the freezing point of sustainable aviation fuel? ›

For freezing point, the standard requires -40 degrees C maximum for Jet A and -47 degrees C for Jet A-1,and Jet A-1 complies with -50 degrees C, while ATJ is -80 degrees C.

Does sustainable aviation fuel emit CO2? ›

ICAO also uses the term 'sustainable aviation fuel'. Relative to fossil fuels, sustainably-produced, unconventional, jet fuel results in a reduction in carbon dioxide (CO2) emissions across its life cycle.

Where is sustainable aviation fuel made? ›

Total will also be able to produce SAF as from 2024 at its zero-crude Grandpuits platform, southeast of Paris. All of these sustainable aviation fuels will be made from animal fat, used cooking oil and other waste and residue sourced from the circular economy.

What is the 123 rule in aviation? ›

It's called the 3-2-1 rule, and it's the easiest way to remember the regulation. To recap, if the weather at your destination isn't at least 3 SM of visibility and 2000' AGL ceilings from 1 hour before to 1 hour after your ETA, you need to file an alternate.

What is the 3/6 rule in aviation? ›

For larger aircraft, typically people use some form of the 3/6 Rule: 3 times the altitude (in thousands of feet) you have to lose is the distance back to start the descent; 6 times your groundspeed is your descent rate.

What is the 3 1 rule aviation? ›

A general rule of thumb for initial IFR descent planning in jets is the 3 to 1 formula. This means that it takes 3 NM to descend 1,000 feet. If an airplane is at FL 310 and the approach gate or initial approach fix is at 6,000 feet, the initial descent requirement equals 25,000 feet (31,000–6,000).

Is sustainable aviation fuel actually sustainable? ›

Chemically, it's nearly identical to normal fuel; it doesn't change how jet engines work. Rather, it does provide some sustainability because it balances the carbon emissions produced during flight with carbon absorbed during production.”

What is considered sustainable fuel? ›

Examples include: biofuels (e.g. Vegetable oil used as fuel, ethanol, methanol from clean energy and carbon dioxide or biomass, and biodiesel), Hydrogen fuel (when produced with renewable processes), and fully synthetic fuel (also known as electrofuel) produced from ambient carbon dioxide and water.

What does 100% sustainable fuel mean? ›

It means that the engines do not add anything to the carbon dioxide in the atmosphere.”

Is sustainable aviation fuel renewable? ›

Sustainable aviation fuels (SAF) are defined as renewable or waste-derived aviation fuels that meets sustainability criteria1. Technical analysis done at ICAO shows that SAF has the greatest potential to reduce CO2 emissions from International Aviation.

How clean is sustainable aviation fuel? ›

Sustainable aviation fuels (SAFs) offer a 70% reduction in lifecycle carbon and a 90% reduction in particulates, making them cleaner burning than petroleum-based jet fuel.

What are the 4 main types of sustainable energy? ›

Examples of renewable energy sources include wind power, solar power, bioenergy (organic matter burned as a fuel) and hydroelectric, including tidal energy.


1. Refueling aviation: The role and types of sustainable aviation fuels
2. Sustainable Aviation Fuels - 2021
(Bio360 Expo)
3. Sustainable Aviation Fuel/Biojet Technologies, Commercialisation Status, Opportunities & Challenges
(IEA Bioenergy)
4. Learn more about... Sustainable Aviation Fuels
(Air France-KLM Group)
5. Our&D UK - Sustainable Aviation Fuel
(UK Center for Applied Energy Research)
6. Airbus' roadmap for sustainable aviation fuels


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