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Sustainable aviation fuel: Why it matters and how you can help

Times are tough for travelers. But with the world preparing to reopen in 2021, we're here to keep you dreaming and planning for your next adventure - whether that's a staycation or flying off to parts unknown. Until then, we've got the latest COVID-19 travel advice and updates to keep you up to date and ready to go.

As we begin to venture out into the world again, it’s with a keen awareness of the environmental impact of travel — and we’re not the only ones. In a recent Skyscanner poll of 5,000 people across the US, UK, Australia, Germany and South Korea, 31% of US respondents said the pandemic has shifted their perspective on the importance of sustainable travel. The same poll also showed that 27% of US respondents would be willing to pay more for an eco-friendly flight option. This means more and more travelers will be prioritizing the environment when booking their next flight. You can read more about 2021’s emerging travel trends in our Horizons — The Return of Travel Report.

With the aviation industry committing to action on climate change, greener travel is well on its way to becoming a reality. Fuel and operational efficiencies, such as lightweight cabin equipment and single-engine taxiing, are just the beginning of an industry-wide shift to reduce CO2 emissions from flying. The air transport industry is now looking to sustainable aviation fuel to drive emission numbers down. But what is sustainable aviation fuel exactly? And how will it reduce the human impact on climate change? Let’s dive into the details.

Lone woman with a suitcase watches a plane take off.

What is sustainable aviation fuel?

Airplanes need a great source of energy to take us to see the people we love and the places we want to explore. Right now, that energy predominantly comes from liquid fuel refined from petroleum, a fossil fuel — but there are alternative liquid jet fuels.

Sustainable aviation fuel (SAF) is a term used to describe alternative aviation fuels made from sustainable and renewable sources. Those sources, or what the industry calls feedstocks, can be either “biological,” for example, using algae or cooking oil, or “synthetic,” using gases such as CO2 found in the air. In other words, sustainable aviation fuel is a cleaner, more environmentally friendly alternative.

SAF is what’s called a “drop-in fuel.” In order to be used commercially, it must currently be blended with traditional jet fuel, but with technological developments, the reliance on fossil jet fuel could be significantly reduced. But before that happens, the sustainable fuel — whether synthetic or biological — must be certified to the same quality and safety standards as fossil kerosene. This means that sustainable jet fuel has the same characteristics as fossil kerosene and is interchangeable.

Is sustainable fuel the same as biofuel?

The term biofuel is used to describe fuels produced from “biological” sources, such as plants or animal material. However, the term doesn’t encompass whether the material is sustainable. Likewise, the production of some biofuels can still contribute to deforestation, replace food production or pollute waters. Sustainable fuel, on the other hand, uses both sustainable feedstock as well as production and delivery methods to reduce the environmental impact of flying, on and off the ground. Moreover, the term biofuel doesn’t include the “synthetic” sources that can be used as alternatives to fossil-derived fuel. Those examples include gases such as hydrogen and even municipal waste.

The other accepted and most commonly used term for SAF is “sustainable jet fuel.”

What are the benefits of sustainable aviation fuel?

According to the United States Environmental Protection Agency (EPA), carbon dioxide from fossil fuels contributes to 65% of global greenhouse gas emissions. With a growing demand for travel, those numbers could go up. A 2015 Visa and Oxford Economics report identified two major factors contributing to the spike in travel. The first is a rising global middle class with disposable income that is spent on leisure activities such as traveling. The second is advancement in aviation technologies as well as industry competition making travel more affordable. The study predicts that by 2025, “nearly half of all households globally should be able to afford travel as part of the new traveling class.” 

In response to this growth, the aviation industry is committed to addressing its climate impact with ambitious goals and plans aimed at dramatically reducing greenhouse gas emissions. For example, United Airlines became the first major U.S. airline to back carbon capture technology (also called direct air capture), which takes existing carbon dioxide out of the air and either stores it deep in the ground or converts it to a clean energy source. Likewise, companies such as Airbus and Boeing are producing lighter and more fuel-efficient aircrafts that can travel longer distances on less fuel. While all of these efforts hold promise for the future, the global use of sustainable aviation fuel can have the most impact on our planet right now.

The biggest benefit of sustainable fuel is the reduction of greenhouse gases. We are talking up to an 80% decrease (!) according to SkyNRG. With that comes some serious improvement of local as well as global air quality.

The depletion of natural resources is another major problem for the environment and the economy when it comes to the use of standard fuel. Because a wide variety of sustainable resources are used to produce SAF, a diversified fuel supply won’t be subject to the price fluctuations of a single source. Better still, we will be putting to good use waste that would otherwise end up in landfills or be incinerated.

Most importantly, sustainable aviation fuel is easily integrated into existing structures, too. Because SAF is completely interchangeable with traditional fossil fuels once it’s been refined and able to be blended, there is no need for a new distribution network or aircraft modifications in order to use it. Making the switch really is a matter of investment in the production and distribution of sustainable aviation fuel.

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Is sustainable aviation fuel safe?

The IATA has estimated that more than 250,000 flights have already flown using a blend of sustainable aviation fuel. The alternative fuel market is still small, but any new SAF must pass rigorous testing by aircraft engine manufacturers such as Boeing, Airbus and Rolls-Royce to make sure it meets a whole range of technical and chemical qualities. Then, before it can be blended with traditional fuel, it must be approved by ASTM International, an important international standards organization formerly known as the American Society for Testing and Materials (ASTM).

So, yes — flying with SAF is completely safe for you and better for the environment!

How are my flight’s carbon emissions reduced by flying with SAF?

When we talk about reducing carbon emissions, we are talking about reducing its lifecycle numbers — that is, how long carbon stays trapped in the atmosphere. When coming up with numbers, every step of the supply chain to produce fuel — from feedstock, production and shipping — is taken into account.

Reducing carbon emissions means relying less and less on fossil fuels to power aircraft engines. Burning fossil fuel releases CO2 into the atmosphere. Since it took millions of years to form this carbon, it takes a really long time for it to return to the ground. In the meantime, CO2 stays in the atmosphere, contributing to the greenhouse gases causing global warming. That is why fossil fuels have a “long carbon lifecycle.”

It’s not that SAF does not use carbon — it actually recycles the carbon that’s already in the atmosphere. Because no fossil fuels are used, and sustainable methods are applied, alternative fuels have a “short carbon lifecycle,” which significantly reduces CO2 emissions. As such, the carbon that’s released takes less time to return to the earth to be absorbed by plants and trees.

A hand grabbing at the setting sun over mountains.

How can the travel community contribute to sustainable aviation fuel efforts?

Air travel will continue to grow. And, sustainable aviation fuel is our most viable option for now. We are still years away from commercial aircrafts that run solely on alternative energy sources, such as solar. Carbon capture technology is still very new, and figuring out how to run these power plants with renewable energy is a major hurdle. The future of travel is green, but it will take time to get there, so investing in immediate and easily integrated solutions such as sustainable aviation fuel must be prioritized.

Skyscanner remains committed to building environmental awareness for a more sustainable future. We’ve partnered with SkyNRG, a global leader in the SAF space, to purchase sustainable aviation fuel to offset our corporate travel. As a founding member of SkyNRG’s Board Now program, we are now directly contributing to developing a new European sustainable aviation fuel production facility.

Moreover, we are helping travelers like you do their part by making informed, greener choices when booking their next adventure. While at the moment you can’t choose flights powered by SAF, you can search for and book greener flights. Look for a small green and white leaf highlighting flights that, based on our calculations, have less-than-average CO₂ emissions for that route.

Greener choices shows travelers flights with less than average CO2 emissions.

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You can choose to fly with airlines that have committed to investing in and using sustainable fuel. The airlines on the growing list include American Airlines, Alaskan Airlines, United, Jet Blue, KLM, Qantas and Lufthansa, among others.

Finally, thanks to our partnership with CHOOOSE, an organization dedicated to combating climate change, you can offset your next adventure by contributing to carbon-reducing projects.

Our decisions matter! No action or role is too small in the demand for greener and more sustainable travel.

A few final words

With safer travel protocols and the global COVID-19 vaccine rollout, we can finally start planning to get back out there again. If this pause in travel has taught us anything, it’s that travel is one of life’s greatest pleasures — and it’s up to us to preserve this beautiful planet for generations to come. It is our hope that the demand and transition to sustainable aviation fuel is just the start of a lifelong path to sustainable travel.


What are the current limitations of alternative aviation fuels?

Alternative fuels are still relatively new and production costs are higher and availability is limited. However, as demand continues to grow, and governments and industries worldwide continue to address climate change, investment in production facility infrastructure will make sustainable aviation fuel available on a global scale, thus lowering costs.

What is sustainable aviation fuel made of?

The list is quite long and very diverse. The feedstock, which is the raw material from which sustainable fuel is produced, ranges from gases already present in the atmosphere (called waste gases) to cooking oils, plant oils, residential and commercial waste, algae, salt marsh grass, agricultural or forestry residue and tallow, which is rendered animal fat and a byproduct of the meat industry.

Can I offset my flights with contributions to sustainable aviation fuel?

Absolutely! In fact, United Airlines is now giving passengers the opportunity to make financial contributions that will either purchase sustainable jet fuel (which is more expensive than fossil jet fuel) or go to companies developing sustainable jet fuel. Another example is Lufthansa’s Compensaid platform, which enables passengers to track their CO2 emissions and offset them by buying sustainable aviation fuel.

The return to travel

A new year of travel is upon us and we are ready! Discover what travelers like you are looking forward to and prioritizing as they plan to explore the world again in Skyscanner’s Horizons — The Return of Travel Report.

Where can I go?

Making plans to get back out there? Find out which borders are open with our interactive global map, and sign up to receive email updates when your top destinations reopen.

Interactive travel advice map that lets you know where and when you can get back out there.

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