The Royal Society’s new report questions as they look at the resource requirements and environmental impacts

54% of the carbon reductions available to the aviation industry are related to Sustainable aviation fuels (SAFs); the Royal Society suggests that this would require half of the UK’s agricultural land to provide the feedstocks.
March 8, 2023

Aviation’s net zero hopes are built on foundations made of sustainable aviation fuels

Even with technological advancements in aircraft, engines, and air traffic management, aviation still accounts for about 2% of global emissions. As more people travel, this percentage will likely climb over the next few decades. While battery- and hydrogen-powered flights are technically feasible, they are still many years away from becoming economically viable. Also, the aircraft entering service now have lifetimes of up to 30 years, which means that we will have long passed the net zero targets of 2050. . SAFs combine resources as varied as leftover cooking oil, animal fat wastes, and algae to make a fuel that minimises the lifecycle emissions by up to 80% rather than extracting carbon-intense fuels and burning them for propulsion.[i]

A worker at Neste Refinery, Rotterdam, experimenting with SAFs

Source: Business Traveller

A combination of actions is planned to produce a significant decrease in emissions from the aviation industry, including expanded use of SAFs, infrastructure and operational efficiency upgrades, fleet and technology renewal, out-of-sector emission reductions, and financial incentives. Technological advancements, which aim to improve propulsion and aerodynamic efficiency and achieve lightweight system architecture, make up one significant pillar of emissions reduction (34%). These advancements, according to PWC, are reaching their technical limits.[ii] With this in mind, the 54% of emissions reductions that will be met by the adoption of SAFs become even more important.[iii]

Available options for achieving aviation’s emissions reduction goals

Source: PWC

Major players in aviation clear SAFs for take-off

According to the Centre for Aviation Awards for Excellence 2022, Wizz Air is the fastest-growing airline in Europe and the greenest airline in the world. To that end, Wizz Air and Neste have signed a Memorandum of Understanding (MoU) for the supply of sustainable aviation fuel (SAF) beginning in 2025. The MoU allows Wizz Air to purchase 36,000 tonnes of SAF from Neste annually for the provision of the airline's routes throughout Europe and the United Kingdom.[iv] By 2030, Boeing promised to provide commercial aircraft that are 100% SAF-capable and certified. In order to support its commercial operations in the United States through 2023, Boeing announced arrangements to purchase 21.2 million litres of blended sustainable aviation fuel (SAF) made by Neste on February 15. The company's SAF purchases from these agreements more than doubled from the previous year.[v]

SAF output was expected to expand by 200% from 2021's production of 100 million litres to at least 300 million litres in 2022, according to the International Air Transport Association (IATA), in December of last year. More extreme predictions suggested that in 2022, overall production might reach 450 million litres. With the correct enabling policies, all scenarios put the SAF industry on the cusp of an exponential capacity and production ramp-up approaching an identified tipping point of 30 billion litres by 2030.[vi]

The Royal Society raise questions over how SAF production will impact our environment

The Royal Society’s report, Net zero aviation fuels: resource requirements and environmental impacts finds significant resource implications are associated with bio-based approaches to SAFs, particularly for energy crops, whose cultivation would necessitate using at least half of all agricultural land in the UK to supply all of the jet fuel consumed in the UK on an annual basis. As native agricultural produce is replaced with imports, this would result in major trade-offs for food production, increase the danger of carbon leakage, and have the potential to have a detrimental impact on the environment through soil erosion and pollution. What constitutes waste in terms of feedstocks and the effects of competition from other industries are both hotly contested topics. For instance, the use of agricultural, forestry, and sawmill residues in the manufacturing of aviation fuel may result in unintended ecological issues such as soil nutrient depletion, which prompts more fertiliser consumption and, ultimately, higher greenhouse gas emissions.[vii]

In response to the Royal Society's claim that providing the UK aviation industry with enough sustainable fuels would put pressure on food supplies. Airlines UK argued that the UK had enough feedstocks, that they would initially be derived from household, commercial, agricultural, and forestry waste as well as industrial waste gases, and that they did not compete with food crops.[viii]

Government should also encourage people to fly less, according to environmental activists.

Leo Murray, director of innovation at climate charity Possible, asserts that "Not all aspects of modern life in Western nations have an easy 'technofix' for the damage they do to the environment, and nowhere is this truer than for air travel."

"A Frequent Flyer Levy would target reduced demand amongst the group responsible for most of the environmental damage today while leaving the annual family holiday untouched."[ix]


[i] Business Traveller- Sustainable Aviation Fuel: In the pipeline

[ii] PWC- The real cost of green aviation

[iii] Ibid

[iv] Wizz Air- Wizz Air and Neste sign an agreement to supply sustainable aviation fuel

[v] Boeing- Boeing Doubles Sustainable Aviation Fuel Purchase for Commercial Operations, Buying 5.6 Million Gallons for 2023

[vi] IATA- 2022 SAF Production Increases 200% - More Incentives Needed to Reach Net Zero

[vii] Royal Society- Net zero aviation fuels: resource requirements and environmental impacts

[viii] BBC- Green flights not in easy reach, warn scientists

[ix] Ibid

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Oscar Pusey
Research Analyst

Oscar is a recent graduate with a background in earth science. He is currently studying an MSc focussing on disaster responses, emergency planning and community resilience. His postgraduate research project will assess the link between climate crisis risk perception and attitudes to green energy projects. “Adapting to the climate crisis through the pursuit of net zero requires community engagement and understanding. Zero Carbon Academy’s goals closely align with this approach and I’m excited to have the opportunity to research and communicate a variety of topics relating to our environment and sustainability”.

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