Sustainable aviation fuel
illustration by pete ryan

Big Idea: Take Green Fuel to the Skies

Food waste, cooking oil and landfill debris will power our future air travel
Steve Burgess

June 26, 2024

My brother is getting married this summer. The wedding is in Peterborough, Ontario, and I live in Vancouver. So am I going? I want to be there for him, but these days I always think twice about jetting off. I’m the author of a new book about the environmental impacts of air travel. While researching, I came across some troubling facts: aviation fuel, which is refined from crude oil, makes up two to three per cent of global CO₂ emissions. Atmospheric interactions at high altitude mean its impact on global warming is higher still, accounting for about four per cent. In 2022, humanity burned through 4.8 million barrels of jet fuel per day; after the pandemic, when globetrotters ran wild, that number grew to around 5.6 million barrels. A person flying from London to San Francisco and back produces some 3.5 tonnes of CO₂. (A car, by comparison, releases 4.6 tonnes per year.) Particularly for shorter trips, it’s undeniable that flying is the most environmentally harmful way to travel.

In Europe and Japan, rail travel is a more feasible option—distances between cities are shorter, and rail infrastructures are vastly superior. By contrast, the distance covered in an overland trip from Vancouver to Toronto is roughly the same distance as London to Beirut. Air travel makes it practical. Almost 140 years since the last spike was driven to complete the Canadian transcontinental railway, flying is what connects this country from shore to shore to shore. In December of 2022 alone, major Canadian airlines consumed almost 3.5 million barrels of jet fuel. 

Urging people to fly less is a difficult sell. Many travellers hope that technological solutions will create more sustainable flight. And these changes are on the way. The question is not how, but when. The leading thrust toward greener air travel is sustainable aviation fuel, or SAF. It’s an umbrella term that covers many products. Biofuel is one of the most promising categories. It’s made from organic materials, like forestry byproducts, food waste and municipal waste, which can include detritus from landfills and wastewater-treatment plants. (It sounds unpleasant, but if it takes you to Paris relatively guilt-free, the smell will seem sweeter.) According to NASA, biofuels produce 50 to 70 per cent fewer emissions than regular jet fuel. Finnish oil refining company Neste leads the biofuel charge: its plants in Finland and Singapore can produce up to almost 8.2 million barrels per year. 

Although SAFs are slowly making their way into the market, no one is currently operating commercial flights purely on biofuels—they are still in a relatively early stage of development and not yet cheaply mass-produced. As a result, biofuels are currently between three to five times more expensive than conventional jet fuel. But some flights have already used a blend of SAF and regular jet fuel. Airlines like Lufthansa, KLM, Air France and Singapore Airlines use Neste’s SAF, which is comprised of palm oil refining residue and used cooking oil. Canadian SAF initiatives are also underway. Azure, a chemical manufacturing company, is set to open an SAF facility in Portage la Prairie, Manitoba, and use canola and soybean oil to produce an estimated billion litres of SAF annually. Calgary-based Cap Clean Energy is also seeking funding for a facility to produce SAF using agricultural byproducts, with plans to start production in 2027. 

Electrofuels, or e-fuels, made from CO₂ combined with clean hydrogen, are the other type of SAF in widespread development. At first blush, e-fuels seem to be the most exciting option for emissions-free air travel. A Brooklyn-based startup called Air Company has successfully flown a model jet using this kind of fuel.

But e-fuels are not as far along as biofuels. By its own admission, Air Company is nowhere near producing quantities that would be required for commercial flight. CEO Gregory Constantine told CNN that getting e-fuels to the mainstream would require a lot of time, money and effort, because the aviation industry is traditionally the hardest industry to decarbonize. To that end, S&P Global estimated that e-fuels will remain more expensive than biofuels until at least the 2030s.

Hydrogen on its own is considered an e-fuel, and a clean one, but there are still a number of practical difficulties surrounding its widespread adoption. Among them: hydrogen is not a “drop-in” fuel, the industry term for products that can safely substitute for, or blend with, the jet fuel used in current aircraft. This means we would still need to create fuel infrastructure and modify aircraft design to safely and efficiently store hydrogen. Biofuels, by contrast, are drop-in fuels and easily integrate with our current air technology.

Cost is another factor. While the global aviation industry has set a net-zero carbon emissions goal by 2050, costs for every kind of SAF will need to become more competitive. It would be nice if consumers were willing to pay a premium for eco-friendly flights. But since recent history suggests travellers are willing to contort their bodies like pretzels and forgo the effective use of their limbs, all to save 100 bucks on a flight to New York, the prospect seems unlikely.

SAF production will take time to ramp up and become more economical. The International Air Transport Association estimates that SAF production will triple to 1.5 million tonnes this year—but that would only make up 0.53 per cent of airlines’ fuel needs in 2024. The question then becomes whether we can reduce emissions as quickly as the climate crisis demands. The proverbial frog in the stovetop pot is probably too busy browsing TripAdvisor to notice the water heating up.

Governments might force airlines to make a change. Many countries are already implementing strict carbon reduction targets and policies that mandate SAF use. The U.K., for example, announced in April that, by 2030, 10 per cent of all fuel on flights will need to be sustainable. The EU voted to require two per cent of airline fuel be green by 2025, rising to 70 per cent by 2050. In the U.S., the Biden administration aims for domestic plants to produce 3 billion gallons of SAF by 2030 and for SAF to comprise 100 per cent of aviation fuel use by 2050. In response, companies are scaling up their capacity.

So am I flying to the wedding? You probably guessed. There is no universe in which I could plausibly tell my brother, “Sorry, I can’t come to your wedding because I am concerned about my carbon footprint. Can we do a Zoom?”

Unchecked airline emissions will continue to be a problem. So it becomes even more important to expedite and invest in sustainable alternatives to traditional fuel, options that can keep us in the air for decades to come. Flight still retains an aura of magic, and it’s hard to get that winged genie back into the bottle.

Steve Burgess is the author of Reservations: The Pleasures and Perils of Travel.