With SAF being constantly pushed as a panacea, a reality check is essential. The journey to achieve net zero by 2050 will in truth be long, arduous and terribly expensive. Success is by no means assured without urgent measures.
Airline strategy is now increasingly influenced by environmental sustainability. Both the International Civil Aviation Organization (ICAO) and the International Air Transport Association (IATA) have set impressive climate goals. In October 2022, ICAO member states agreed to a long-term aspirational goal (LTAG) of net zero emissions from aviation by 2050. This followed the aviation industry’s commitment to the same net zero objective, adopted by IATA in 2021. Net zero means the amount of greenhouse gases (GHG) removed from the atmosphere is equal to that emitted by that activity.
The quest for sustainability is driven by growing fears of irreversible climate change. In February 2024, for the first time, global warming exceeded 1.5 degrees C through a full year. “Why lose sleep over this?” climate sceptics demand, adding that ups and downs in the global temperature trend have been recorded throughout history. But an overwhelming majority of scientists believe that 1.5 degrees is a climate change “red line” and overshooting it even for a few years may trigger tipping points that cannot be uncrossed – such as the melting of permafrost that would, in turn, release huge amounts of trapped CO2 and intensify global warming. If proof were needed, the planet experienced record floods, droughts, heatwaves and wildfires in 2024. Another half degree temperature rise could greatly intensify these effects.
Where does aviation stand? Although flying is very carbon intensive it contributes just 2.5 per cent of global emissions. But thanks to non-CO2 emissions, soot and contrails, aviation’s total contribution to global warming is more than twice that figure. While engine manufacturers constantly strive to increase fuel efficiency, the gains are dwarfed by soaring demand for aviation services. Convinced of the need to act, the aviation industry has adopted a multi-pronged approach that banks mainly on sustainable aviation fuel (SAF). In fact, in IATA’s thinking, as much as 65 per cent of carbon mitigation required to achieve net zero by 2050 will come from SAF.
Yet, many major questions remain unanswered. Is the aviation industry’s commitment to sustainability strong and lasting? Can it afford the cost? Will it bear the pain? Even with the best of intentions, can SAF production be steeply ramped up in time to attain the 2050 net zero goal? Unfortunately, action so far – as opposed to mere aspiration – does not offer much hope. So what needs to be done?
SAF is a synthetic replacement for regular jet fuel, made from renewable sources like waste cooking oils, vegetable fats and agricultural waste, as well as captured CO2. While fossil fuel releases carbon that has been stored in the earth for millions of years, the carbon generated by SAF has only recently been removed, either by plants or by chemical processes. Therefore, SAF does not add to the overall amount of CO2 in the atmosphere. Apart from this direct CO2 benefit, SAF reduces the particulates and smoke that emerge from the engine and enhance contrails. Contrails are increasingly seen as deadly by climate scientists.
SAF is a “drop-in” fuel meaning that since its chemical composition is very similar to normal fossil fuel the two can be used interchangeably. Although current regulations only permit up to 50 per cent of SAF in jet fuel blends, efforts are on to clear even 100 per cent SAF. However, the process is slow. Both Airbus and Boeing have pledged to make their aircraft fully compatible with 100 per cent SAF by 2030.
Advocates of SAF claim that it can reduce emissions by up to 80 per cent across the lifecycle of the fuel, with a 100 per cent reduction possible in future. However, some recent studies have concluded that the emissions created in flight are considerable and that the benefits of SAF may be rather less than estimated. There are also concerns about secondary environmental impacts, including SAF feedstocks being grown as cash crops and usurping land used for food production. A 2023 report by the UK-based Royal Society said biofuels do reduce emissions, but that many estimates do not account for “land use changes”. Accounting for those changes “significantly” impacts estimated carbon output, and “few hit the renewable energy directive target”.
HOW IS SAF PRODUCED?
SAFs can be produced from a variety of feedstocks and through several different technologies. As of July 2023, 11 conversion processes for SAF production had been approved and seven other processes were under evaluation.
CHIEF CHALLENGES
According to the Geneva-based Air Transport Action Group (ATAG) over 7,75,000 commercial flights have been operated using SAF since 2011. Worldwide, 69 airports are currently regularly supplied with SAF. And 50 airlines have committed to 2030 SAF goals ranging from 5-30 per cent of their total fuel usage, with most committing to 10 per cent. It all looks rosy. However, formidable challenges lie ahead.
SEEKING SOLUTIONS
Accelerating production and reducing the cost of SAF is imperative and will best be achieved by a combination of urgent measures. Some of these are:
ACTIONS SPEAK LOUDER THAN WORDS!
Matt Finch, UK head of campaign group Transport & Environment says, “There are good SAFs, and there are bad SAFs, but the brutal truth is that right now there is not much of either. Conversely, right now there are thousands of new planes on order from airlines, and all of them will burn fossil fuels for at least 20 years. Actions speak louder than words, and it’s clear that the aviation sector has no plans to wean itself off its addiction to pollution.”
Finch’s opinion may seem unduly harsh since the aviation industry is indeed sincere in its desire to attain environmental sustainability. Yet, it is undeniable that traffic growth will far outstrip efficiency improvements for the foreseeable future, thus increasing carbon emissions. IATA’s strategy therefore rests heavily on SAF. Too heavily perhaps? Just a couple of high-profile accidents even partly attributable to the use of SAF could prove a severe setback.
The cost of SAF will surely fall with higher production levels and economies of scale. However, it is unlikely that it can ever match regular fuel costs. But if not SAF, what? In the near term, there is a woeful lack of alternatives. Battery-powered planes are suitable only for short flights of small aircraft. Hydrogen will probably take decades to overcome technological and infrastructural barriers, problems of scalability, and even environmental concerns.
Yet, with SAF being constantly pushed as a panacea, a reality check is essential. The journey to achieve net zero by 2050 will in truth be long, arduous and terribly expensive. Success is by no means assured without urgent measures. Will the aviation industry shoulder its responsibility to curb emissions, no matter what the cost, even reducing flying if necessary? If not, will planet Earth ever forgive us?