Sustainable Aviation Fuel: In the Pipeline, or a Pipe Dream?

Virgin Airways aircraft at Perth International Airport in Perth, Australia on April 29, 2020. AAP Image/Richard Wainwright

News Analysis

The international aviation industry has set an aspirational goal to reach net zero carbon by 2050 and backs sustainable aviation fuel (SAF) as “the best near-term opportunity to meet these goals.”

However, earlier this week, Air New Zealand dropped its 2030 emissions target, citing problems with SAF as one reason.

Consumption of the alternative fuel, made from renewable biomass and waste resources, is increasing.

U.S. Environmental Protection Agency (EPA) data shows that approximately 5 million gallons of SAF were consumed in 2021, 15.84 million gallons in 2022, and 24.5 million gallons in 2023.

According to the U.S. Department of Energy, it releases a fraction of the greenhouse gases associated with current jet fuel options. It’s touted as the aviation industry’s bridge from its current reliance on fossil fuels, to a future where commercial aircraft are powered by electric and hydrogen-powered engines.

While it’s usually added to jet fuel at a ratio of around five percent, several products are already approved at blends of up to 50 percent.

The feasibility of 100 percent SAF flights has already been demonstrated, including by a passenger-carrying United Airlines Boeing 737 MAX.

International Uptake Remains Low

While it sounds like the new fuel is the answer to reduce carbon footprints, why is SAF struggling to reach commercial viability?

Even though aviation is estimated to contribute 2.5 percent of greenhouse gas emissions annually, biofuel comprised less than 0.2 percent of total jet fuel used in 2022.

The most significant issues are production and cost.

While Europe and the United States already have subsidies in place, a detailed study by Bain & Co has found that SAF prices in 2050 will remain two to four times higher than the historical average of jet fuel, and that airlines’ efforts to decarbonise will increase their operating costs by 8 to 18 percent—think lower profit margins or higher ticket prices.

Is It as Efficient as Regular Jet Fuel?

And there’s another factor, revealed by commercial airline pilots who spoke to The Epoch Times—the energy-to-weight ratio of biofuel, which at least partly cancels out its benefits in real-world situations.

The pilots asked not to be named because they work for airlines that publicly promote the benefits of SAF.

“Basically, an aircraft has to generate enough thrust to carry its own weight, the weight of the passengers, luggage, etc., but also the weight of the fuel on board,” one explained.

“In the early stages of a long haul flight, that aircraft may be too heavy to reach its optimal cruise altitude and will level off for several hours to burn fuel. When it reaches a certain weight, it can climb higher.

“At higher altitudes, the air is thinner, so the engine burns less fuel. That saves money.

“The biofuel you ask about has less energy value than, say, Jet A1 fuel that most jet aircraft burn. So to produce the same amount of range and thrust, the aircraft needs to burn more fuel to achieve the same outcome, thereby negating the whole process.”

This factor seems to be overlooked—or at least not explicitly mentioned—in debate on the topic.

Bain & Co Says Net Zero by 2050 Unlikely

The Bain & Co report says any hope that zero-emission technologies will be ready to fill the gap is a fallacy. It also states that less than 5 percent of aviation emissions will be reduced by hydrogen and electric propulsion in 2050.

“As a result, the industry will likely fall substantially short of its ambitious 2050 goal—barring a sufficient reduction in air traffic,” Bain & Co says.

The consultancy further warns that industry and regulators may react to the inability to meet emissions reduction targets, by limiting air traffic growth to between 0.5 and 1 percent annually through 2050—increasing ticket prices as a result.

And that’s not the only bad news for airlines. The consulting firm predicts the cost of decarbonising will start increasing airfares by 2026. That will then trigger a fall in global demand of 3.5 percent by 2030.

Bain & Co says there are easier ways to achieve emissions reductions.

“Our research shows airlines can reduce CO₂ emissions by 43 percent through fuel efficiencies with current aircraft renewal cycles and operational improvements. A new generation of evolutionary engines and aircraft-frame design improvements would deliver 80 percent of these efficiency gains. Continued efforts to optimise flight and ground operations would deliver the rest,” the company says.

But buying these new aircraft rather than—as Air New Zealand signalled—keeping existing fleets in the air longer, comes at a cost that will inevitably fall on travellers.

So rather than a pipeline of low-emission fuel that will keep the airlines flying with little effect on ticket prices, sustainable aviation fuel may well be a pipe dream.

And Bain & Co concluded that commercial aviation’s transition to net zero will be “long and complex.”

“Many assumptions could change as technologies evolve and the path to full decarbonisation is likely to stretch beyond 2050. Regardless of the timing, commercial aviation companies are headed for unprecedented disruption. Some firms may struggle to survive.”

Perhaps Air New Zealand, for all its stated commitment to still meeting a 2050 target, can see the reality while other airlines remain committed. They are clearly hoping government support will get them over the line.