As the aviation industry prepares to cater to an estimated 10 billion passengers by mid-century, sustainable aviation fuels (SAFs) are increasingly viewed as the cornerstone to achieving net-zero emissions while accommodating growth.
Industry body IATA forecasts that to achieve carbon-neutral status across the sector by 2050, SAF will need to contribute up to 65% of the emissions reduction total.
But questions remain about SAF’s viability to decarbonise the sector at scale. For example, the Royal Society has calculated that the UK’s ambitions to achieve net-zero emissions from aviation will be hugely expensive, requiring enormous amounts of agricultural land or renewable electricity to produce clean fuels in sufficient quantities, rendering the plans unrealistic.
While its report raises important points, the challenges and technologies need to be fully examined when discussing potential hurdles.
For instance, the World Economic Forum argues that enough sustainable feedstock supplies – including municipal solid waste, agricultural residues, and cooking oil waste – exist to reach SAF production levels of 500 million tons annually by 2030, meeting projected fuel demand.
One of the key future production methods for SAF, Fischer-Tropsch (FT), converts a mixture of carbon monoxide and hydrogen (known as syngas) into synthetic crude – which can then be upgraded into SAF.
Syngas can be produced from a wide range of feedstocks, including biomass and municipal solid waste, making the FT technology largely feedstock agnostic.
Equally, other technologies exist to convert captured carbon dioxide and electrolytic hydrogen into syngas, which is then upgraded into synthetic crude. This provides a route to create renewable power-based SAF for fuel producers.
Currently, most SAF is produced using HEFA – hydrogenated esters and fatty acids – a feedstock that is very restricted in terms of supply.
By contrast, the feedstock flexibility associated with FT means its significance in the near future is assured. Additionally, greater renewable electricity production will facilitate increased production of electrolytic hydrogen-derived SAF.
This does not mean challenges will not exist when satisfying the projected 2050 SAF demand, however. Production capacity, for example, remains a key obstacle: currently planned plants in the UK will only yield 4 million tons of SAF annually by 2030, falling far short of the industry’s predicted requirements.
To make up this shortfall, governments must boost confidence in the SAF sector. This is beginning to happen: the USA, through the Inflation Reduction Act, has introduced tax credits that incentivise businesses to produce more SAF, while Europe’s ReFuelEU initiative proposes to penalise fuel suppliers if they do not provide enough SAF as a percentage of their overall supply.
But more can still be done. A key obstacle in the deployment of SAF projects is persuading financiers that SAF is a worthy investment. Since the technology and sector are still growing, more risk-averse banks are reluctant to invest in new projects. Consultations in the UK have flagged this reluctance to invest as a potential obstacle to future SAF deployment – suggesting that governments could partially underwrite costs, de-risking the sector.
SAF, as a sector, is still in its infancy. But it is a huge market on the cusp of growth – if the aviation sector wants to keep flying, it has got to become sustainable.
With solutions to SAF production in existence, in many ways it is a virtuous circle: the more they are deployed and proven, the more confidence will increase across fuel producers, and the more costs will drop, further encouraging take-up.
This may happen gradually over time, but if governments are serious about accelerating the industry’s green transition, then policy interventions will be vital.
Paul Ticehurst is a business development director with Johnson Matthey, based in London. He holds a Bachelor’s degree in Chemical Engineering with Minerals Engineering from the University of Birmingham and an MBA from Kingston University.
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