The flight lasted only one hour and 20 minutes, but it is a landmark in the race for sustainable aviation. When the ATR 72-600, Pratt and Whitney-powered prototype of Sweden’s Braathens Regional Airlines touched down at Bromma airport near Stockholm on 21 June, it was the first time a commercial regional aircraft had flown on 100% sustainable aviation fuel (SAF) in both engines.

The flight also took French aerospace manufacturer ATR, a specialist in turboprops, a big step closer to its self-imposed deadline of 2025 for full SAF certification. And it means that the partners in the project – Braathens, ATR and biofuel-refiner Neste – have cleared all the hurdles so far since embarking on the pursuit of SAF-powered aviation in late 2021.

Until now, all the tests have been conducted on the ground or in the air with one engine. But June’s flight represents a quantum leap. ‘After more than a century of commercial flights powered by kerosene, we are at the dawn of a new era,’ remarked ATR Chief Executive Stefano Bortoli, without exaggeration.

Although there’s a long way to go before all commercial aviation is SAF-powered, thereby slashing emissions by around 80%, there’s a ferment of activity in net zero fuel. In June alone, specialist SAF suppliers clocked a record number of deals that will account for their total production for years to come as airlines queue up for as many gallons as they can get.

US refiner Gevo has signed take-up contracts with Finnair among others as part of One World Alliance’s plan to buy up to 200mn gallons a year from the Colorado-based refiner when it starts production in 2025. Qantas and Airbus agreed to invest up to $200mn in establishing a SAF-producing industry in Australia. Until now Qantas, which has pledged to achieve a 10% SAF blend in its jet fuel by 2030, has had to source all supply from elsewhere.

Another US supplier, Aemetis, will sell millions of gallons of SAF to Finnair, Alaska Airlines and Qantas over a seven-year deal. Also in the US, SAFFIRE Renewables is a new joint project involving Southwest Airlines, the Department of Energy and cellulosic ethanol supplier D3MAX. Meanwhile, in Europe, Spanish oil and gas giant Repsol has started delivering SAF to Iberia on long-haul flights as part of a long-term cooperation. And all that happened in one month.

So far, so good.

Paltry volumes 
However, while the technology is ready, SAF being an energy-dense drop-in fuel that combines with jet fuel, the volumes are paltry. In early 2022, the percentage of SAF used in global jet fuel accounted for just 0.1% (25mn gallons) of the aviation industry’s total demand for kerosene. And it won’t even make 2% until 2025, according to the Swiss-based Roundtable for Sustainable Biomaterials.

This is despite a joint study by Deloitte and Shell finding virtual unanimity among 100 industry leaders that ‘SAF is the only viable solution [for low emission aviation] that can be implemented at scale before 2050.’

Dismayingly, the 2021 Deloitte study was less than optimistic, citing two big problems – price and availability. ‘SAF today is two to eight times more expensive than traditional jet fuel, depending on the feedstock,’ the consultant concludes. ‘If all the kerosene on a typical long-haul flight were replaced with SAF tomorrow, without any policy incentives, this would equal an increase of 30–200% of airline operating costs or ticket prices.’

This is a recurring refrain. Most SAF producers, including Big Oil, tell New Energy World that government subsidies are essential to bring down prices at the tarmac while the aviation industry awaits the essential economies of scale. Although the war in Ukraine could yet send the price of jet fuel through the roof, currently SAF remains at least twice as expensive.

As Deloitte explains, the cheapest SAF, known as bio-SAF, is made from plant or animal material such as crops, forestry or agricultural waste. But there’s not enough around and costs will probably increase as available feedstocks are exhausted. Synthetic SAF is produced mainly using CO₂ captured from the air and recycled. Industrial plants such as cement factories and steel works provide the feedstock. But the technology is young and expensive. And there’s huge emerging demand for it that will likely push up prices.

A bio-SAF refiner, Gevo harvests its raw material from carbohydrates extracted from sustainably grown corn while LanzaTech, another US company, bases its future on synthetic SAF and is licensing its technology all over the world, most recently to China.

‘LanzaTech’s carbon recycling technology is like retrofitting a brewery onto an emission source like a steel mill or a landfill site, but instead of using sugars and yeast to make beer, pollution is converted by bacteria to fuels and chemicals,’ the company explains. ‘Imagine a day when your plane is powered by recycled GHG [greenhouse gas] emissions… this future is possible today.’

Having been quietly developing its technology for a decade, LanzaTech has spun off its SAF-producing business, LanzaJet, which is aiming for a billion gallons by 2030.

Growing volumes 
On the bright side, although current production levels are a drop in a vast jet fuel bucket, volumes are forecast to increase steadily. According to projections by the International Air Transport Association (IATA), there should be 8bn litres of SAF available by 2025, nearly tripling to 23bn by 2030, and tripling again to 90bn by 2035. Thereafter volumes grow more slowly, up to 229bn by 2040, 346bn by 2045 and 449bn by 2050. At that point aviation is expected to hit net zero, assuming matching progress in airports.

And there is definitely a sense of urgency. One of the SAF pioneers, Netherlands-headquartered Neste, expects to boost production to 5.5mn tonnes by the end of 2023 while Gevo is already talking about building at least one more net zero plant on the back of surging demand.

Seeing the future, Big Oil is jumping aboard. Shell, for example, is working with Rolls-Royce on achieving certification for 100% SAF-fuelled engines. ‘We aim to produce around 2mn tonnes of SAF a year by 2025 globally,’ Shell says. That’s 10 times today’s total volumes. In the longer run the oil giant is aiming for ‘at least 10% of our global aviation fuel sales as SAF by 2030’.

Shell is throwing a lot of money into SAF. When its 820,000 t/y biofuels plant in Rotterdam is up and running in 2024, much of the production will be devoted to SAF. It has also invested in LanzaJet, with the idea of sub-licensing the refiner’s alcohol-to-jet technology.

Build back better 
Encouraged by US President Joe Biden’s tax credits for SAF under the Build Back Better policy, ExxonMobil is following suit with a $15bn budget that aims to produce 40,000 b/d of low emission fuels including SAF, by 2025. ExxonMobil is already selling SAF in France, Singapore and the UK.

Build Back Better may become a model for other countries. ‘You simply can’t get to net zero by 2050 without biofuels,’ Biden has said. The White House’s ambitions are high, in contrast to those of the former president. Biden has called for a 20% fall in aviation emissions by 2030, earlier than IATA predicts, through an increase in SAF production by at least 3bn gallons.

The National Renewable Energy Laboratory is on the case, with some of America’s top scientists tasked to develop different pathways to the creation of SAF. They are developing powerful cross-lab coalitions with other scientific agencies like the Chemical Catalysis for Bioenergy Consortium which boasts around 120 specialist researchers. This is not about pure science. The grand plan is to develop ready-made processes that can be bolted onto existing production facilities instead of having to build plants from scratch.

Financial pathway 
But the financial pathway is equally important in kick-starting production. A study by IATA shows that that the seemingly daunting financing of a $100mn plant can be overcome by subsidies provided in the early stages that ‘can make an otherwise unattractive project successful’. If the different stakeholders – project owner and operator, government, buyers in the form of airlines and debt financiers collaborate, there is a strong business case, IATA concludes. As production is scaled up, such a project would be ‘comfortably acceptable’, even at a discount rate of 9%.

The example of the rocketing sale of electric vehicles (EVs) augurs well for the price and availability of SAF. In 2000 in the US, which long boasted the most gas-guzzling vehicle fleet in the world, EV and hybrid electric vehicle (HEV) sales were almost zero. And now? The latest figures compiled by Reuters show that in January 2022, over 800,000 of the new vehicles hitting the road in America were hybrids and 435,000 were all-electric. Respectively, sales were up 76% and 83% on 2021 for that month.

While sales of internal combustion engine powered vehicles continue to dominate in the US, GM and Ford are switching to an all-electric strategy in common with other global manufacturers – an unthinkable step 20 years ago. It is inevitable that roles will be reversed.

The simultaneous race for electric, hydrogen or hybrid-powered flight is certain to affect demand for SAF. Scores of companies are developing aircraft that won’t need it at all – or, if so, not much of it. And most of them expect to have commercial flights in the air between 2025 and 2030.

Take Ampaire, the US-based start-up, which is confident that its hybrid-electric aircraft will be in widespread service by 2025, relying on SAF and batteries. As the latter become more powerful (and smaller), Ampaire’s aircraft will use less of the former.

This is not a daydream. In 2021, Ampaire’s Electric EEL, a six-seat Cessna, flew nearly 500 non-stop miles, the longest hop to date by an aircraft of that type.

Ampaire’s record-breaking hybrid-powered Cessna 
Photo: Ampaire

In the pursuit of low emissions flight, waste has become a valuable commodity. American Jim Lane, a world authority on sustainable fuels, tells New Energy World: ‘Many countries with a surplus of domestic waste residue, whether municipal, agricultural, forest or animal, have an advantage in converting it into fuels, chemicals or materials. That’s even if the manufacturing scale is smaller and the cost is therefore higher.’

In short, waste is the new gold.