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Fuel for thought

Stephanie Taylor dips into sustainable aviation fuels at the Royal Aeronautical Society’s Sustainable Solutions conference. 

First thing’s first. What is sustainability? Robert Whitfield, a member of the Royal Aeronautical Society’s Greener by Design committee, defined it as meeting the needs of the present without compromising the needs of the future.

As a newcomer to the topic of sustainable aviation, I was surprised to learn from Keith Bushell, head of environmental affairs at Airbus, that sustainable fuels create approximately the same amount of carbon as Jet A1 or Kerosene and that the aforementioned substances can be considered biofuels.

I learned, however, that what makes aviation fuel sustainable is the process through which it’s created. While fossil fuels unlock carbon which has been buried for thousands of years underground and add it to the atmosphere, Bushell elaborated, the carbon generated by sustainable fuels has a short life cycle, because it’s using carbon which has recently been created by the existence of new plants.

Bushell claimed it’s in this way the aviation industry has managed to reduce its carbon output by 1.5% on average each year since IATA declared a deadline of 2020 for neutral carbon growth. Why the regulation? Aviation is perceived as a polluting industry, despite the fact it’s only responsible for 2% of carbon emissions in the atmosphere.

IATA’s resolution goes further. It decrees the industry must reduce its carbon emissions by 50% before 2050 (that’s 50% overall, not 50% of emission growth). Bushell stated that aviation fuel was responsible for between 18%-20% of this reduction strategy, but noted there’s currently still no framework (political or economical) to encourage the investment in and use of sustainable aviation fuel.

This seems odd when, if the industry did nothing in the way of offsetting carbon pollution, emissions would in fact grow to over double current levels by 2050. Odder still is that the ‘green’ technology is already available, as numerous new drop-in fuels (meaning no changes are required to the airframe or engine of an aircraft) are in the process of being certified, including lipid (or plant-based) fuels like HEFA and carbohydrate-based fuels like ISHC/SIP.

Perhaps the interest is lacking because there’s no one-size-fits-all solution. Bushell remarked that, in some cases, not only do crops being used for biofuels compete with food-based crops, but countries must select the right foodstock for the local environment. For example, whilst growing and processing corn for biofuel has noticeably lower emissions, doing the same in the USA creates a significantly larger amount of pollution in comparison.

Governments are interested, however, in new foodstocks using waste (known as an Indirect Land Use Change, or ILUC) such as landfill, forestry waste, agricultural waste and steel-making waste.
With these numerous possibilities for sustainable aviation fuel, all we need, Bushell argued, is long-term policy certainty. If Britain’s aviation industry had received some of the tax breaks and the investments which came as a result of the Renewable Energy Directive (RED) encouraging the EU to ensure 10% of transport operated on renewable resources (all of this went on roads, Bushell concedes), the UK could be responsible for producing 4.3% of the global aviation fuel demand by 2030. He estimated this would mean adding £265 million to Britain’s GDP, creating £220 million in export value and 4,400 jobs.

These notions are what makes Whitfield’s sentiment – that it’s not only technology, but also behaviour, which is the key to a sustainable future – sounds painstakingly obvious. Nonetheless, herein lies a second surprise.

Whitfield asked the audience which 15,000 km journey would burn less fuel, a single long-haul flight or one flight which stopped three times to re-fuel. I was one of the majority who voted in favour of the former being more sustainable. I’m sure I wasn’t the only one who was shocked when he revealed that the second option would burn 30% less fuel. Whitfield told the audience that on a long-haul flight 90% of the aircraft payload is the fuel; that by decreasing that significantly, the aircraft could save weight, reduce fuel burn and enable the airframe to be built with the need for less strength whilst carrying more passengers – a ‘virtuous circle’.

Whitfield then touched on the idea of air-to-air refuelling, saying that research on the feasibility and safety of the process seems encouraging. But the concept was first discussed 8 years ago and progress is slow. He cited another UK government goal, separate to those mentioned by Bushell, which is to reduce greenhouse gasses (GHGs) by 80% in comparison to their 1990 levels by 2050.
Although aviation has been allowed special treatment, having been set the target of reducing its GHG emissions by 80% in comparison to 2005 levels instead, Whitfield said the industry couldn’t accept the favour, as eventually it would be responsible for 30% of all UK GHG emissions.

This is why Whitfield believes that the industry must act quickly, with the solution not being to create and deploy new aircraft – which takes far too long and doesn’t necessarily save on GHG during the manufacturing process – but the further rollout of sustainable aviation fuel. Like Bushell, he agreed that the technology is ready and waiting to be used. He closed by exclaiming that we can do good, even while only 1% of psychopathology focuses on our potential, the rest being negative.

It seems there’s no alternative to liquid fuel for the time being (Bushell confessed electric power is still a long, long way off), but according to Whitfield, there may be room for other improvements to aviation fuel. According to a study completed in 2010, CO2 was the only gas about which scientists purported to have a high ‘level of scientific understanding’.

What about various oxides of nitrogen (NOx)? Once we further understand these gases, will we be able to make other previously unconsidered emissions savings across the aircraft? Whilst I’m still a beginner on the topic, I look forward to following the industry’s progress over the next four years and beyond.

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