In an Australian first, this week we learned jet fuel made from used cooking oil will be introduced at Brisbane Airport. The fuel is made from organic waste, and will be stored, blended, and delivered to planes through the airport’s existing fuel system.

The project is being led by a company called Viva Energy, which pointed to the closure of the Strait of Hormuz and recent supply chain disruptions as major reasons for pushing ahead with the fuel now.

It’s a cool idea: the leftover oil from your pan-fried chicken schnitzel, filtered and refined until it’s powering an Airbus overhead. But the bigger question the announcement raises is whether fuel can ever really be “clean”. 

Let’s dive in.

According to the World Economic Forum, “a single long-haul flight can create more carbon emissions in a few hours than the average person in 56 different countries will generate in an entire year.”

The industry is under growing pressure to address its climate impact, which is where Sustainable Aviation Fuel (SAF) comes in. Instead of crude oil, SAF is jet fuel made from renewable sources like cooking oil or animal fats. The most common method, called HEFA, uses hydrogen to strip out impurities from these oils and rearrange their molecules until they match the structure of regular jet fuel.

The result is close enough to normal kerosene that it can be poured straight into existing planes and airport fuel systems, blended with normal jet fuel (currently up to a 50% mix), with no changes to aircraft or infrastructure needed. 

More than 90% of Australia’s fuel is currently imported. With the recent U.S-Iran conflict rattling global fuel supply chains, attention has shifted to domestic resources. 

For years, SAF was marketed almost entirely as a decarbonisation tool. Increasingly, it's now being sold as insurance against global instability, too. 

The Brisbane Airport SAF project is the first of its kind in Australia, but it didn’t arrive in isolation. A day after that announcement, Sydney-based investment firm Climate Tech Partners (CTP) announced fresh backing, with money also coming from Qantas and Airbus, for two waste-to-fuel companies: one in the Netherlands called Vertoro, and Wildfire Energy in Queensland.

Wildfire takes unsorted household waste (including rubbish from your red bin) and converts it into a synthetic gas that can be refined into methanol and SAF.

Vertoro converts industrial and forestry waste into a “bio-oil” that can be turned into fuel or plastic. At present, chemicals and plastics buyers are willing to pay more per litre for that bio-oil than aviation buyers are, so, by its own admission, that’s the market Vertoro is selling into first. Aviation contracts are positioned as a longer-term prospect.

When plastics pay more than jet fuel, the sustainable aviation industry can end up further down the queue.

There’s a big gap between what SAF can do in theory and how much of it actually exists.

Right now, SAF makes up less than 1% of all jet fuel used worldwide. Global SAF production today is roughly 2 million tonnes a year. The aviation industry needs roughly 500 million tonnes a year by 2050 to hit net zero. Even with output expected to grow to around 17 million tonnes by 2030, that’s still a fraction of what’s ultimately required. 

There’s also the cost. SAF is typically two to five times more expensive to produce than regular jet fuel, according to the International Council on Clean Transportation. 

Another problem is a “feedstock” bottleneck. Feedstock refers to the raw material a fuel is made from, in this case, used cooking oil or waste. The issue here is there just isn’t enough waste oil in the world to fuel every flight.

A recent national campaign in Japan enlisted supermarkets, convenience stores, and everyday households to donate used cooking oil, distributing thousands of plastic funnels to residents and businesses. Each funnel had a QR code printed on it, which participants could scan for links to instructions on how to collect the oil properly and where to donate it.  

Despite the effort (13,000 funnels distributed in Tokyo alone, the program’s results have been modest so far, according to a Reuters report. Even if Japan collected every last drop of used cooking oil, recycling industry group UCO Japan estimates that would cover only around a quarter of the SAF needed to hit a national 2030 target. 

Advocacy group Climate Integrity has challenged airlines over a gap between their sustainability messaging and business practices. It has formally asked Australia’s competition regulator to investigate Qantas’s sustainability marketing, arguing that the airline’s own numbers – with SAF making up roughly 0.2% of its total fuel use – sit awkwardly next to its description of the fuel as “central” to its net-zero strategy.

Climate Integrity also raises broader emissions concerns. CO₂ isn’t the only way flying warms the planet. Jet engines also produce nitrogen oxides (aka NOx, a group of gases that react in the atmosphere to trap heat) and condensation trails (aka contrails – those white streaks planes leave behind, which can spread out into thin, heat-trapping clouds).

A landmark 2021 study estimated these “non-CO₂” effects account for around two-thirds of aviation’s total warming impact. However, more recent research contests that figure, suggesting contrails’ share of the warming may be smaller than first thought. Either way, SAF does little to solve this part of the problem, because it’s a fuel fix, not an engine or flight-path fix.

Under best-case scenario modelling by the International Civil Aviation Organisation, if every drop of jet fuel were replaced with SAF by 2050, global aviation emissions would fall by around 56%. That’s a meaningful improvement, but not a silver bullet.

The answer is: sort of, and not at the scale the world needs… yet. 

SAF can still meaningfully cut emissions, and this week’s news shows real capital and infrastructure now backing it in Australia. But it’s not the whole answer, and more solutions are needed to address the warming effects that fuel swaps alone can’t touch.

As UNSW chemical engineer Dr Emma Lovell put it in 2025: “The fair assessment is that the transition to a sustainable aviation fuel market will not be driven by one source of one feedstock.”

Lovell says diverse technologies and approaches are needed for a variety of contexts. In other words: SAF is one piece of a much bigger puzzle.

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