Sustainable aviation fuel and the future of flying
Aviation holds a controversial position in the debate around climate change. Although the sector accounts for between two and three per cent of total global carbon emissions, flying is subject to far more discussion than, say, the production of cement, which accounts for eight per cent.
If the aviation industry was a country, it would be in the top ten of carbon-polluting nations.
There are many reasons for this increased profile. Flying is seen as luxury for some, while the impact is unbalanced, with a small number of frequent travellers making the largest contribution to emissions.
The aviation market also continues to grow and is showing no sign of slowing down. Indeed, the International Air Transport Association (IATA) predicts numbers could treble to ten billion journeys per annum by 2050.
Aware of both the continued focus on aviation in the wider climate battle and this anticipated growth, the industry has outlined ambitions to reach net zero by 2050. This means there is a need to find a way to decarbonise and cut emissions, without cutting flights.
However, there are a number of stumbling blocks.
For the aviation industry to meet this goal, the fleet of the future needs to be more fuel efficient than today
Aviation infrastructure is complex and built to last, which means that structural changes such as hydrogen cells or new propulsion technologies will require wholly new planes and structures.
With Airbus and Boeing controlling 90 per cent of aircraft manufacture, much-needed competition to deliver more efficient planes could potentially be stifled.
Waiting to see will simply take too long.
Sustainable aviation fuel
Today, the most promising avenue to deliver on net-zero targets is to increase and standardise the use of sustainable aviation fuel (SAF), which, according to IATA, has the potential to cut over 65 per cent of the carbon emissions needed to reach net zero.
SAFs are chemically similar to traditional fossil-based jet fuel but, crucially, emit up to 80 per cent less carbon. Such fuels are typically made from sustainable feedstocks of waste that would otherwise go to landfill, including excess cooking oil and algae.
While both fuels burn and release CO2, SAFs recycle the CO2 originally absorbed by the feedstock, whereas burning fossil fuel adds CO2 to the atmosphere. Similarly, SAF is compatible with existing plane components and aviation infrastructures, removing the need for modification, making it a viable short-term solution.
To date, over 450,000 commercial flights have been powered using some proportion of SAFs and this January Boeing piloted a 777 flight entirely powered by SAF.
However, SAF still constitutes less than one per cent of aviation fuel used today. Like many solutions to decarbonisation, sustainably scaling fast enough to meet demand is a huge challenge.
Today an estimated 450 million litres of SAF are produced each year, but to reach net zero by 2050, 450 billion litres must be produced annually.
SAFs are also expensive; they cost buyers an average of four times as much as kerosene, and producers have limited profit margins. This is a large factor in its limited production.
Many industry leaders, including Heathrow Airport chief executive John Holland-Kaye, are thus calling on governments to offer financial incentives and subsidies to drive production and uptake.
Earlier this month, the UK transport secretary and US secretary of transportation hosted a summit in Detroit, discussing a transatlantic collaboration to decarbonise the industry and stimulate economies of change. SAF was a major focus.
The UK government has mandated that at least ten per cent of jet fuel be from sustainable sources by 2030 and has allocated £145 million under the Advanced Fuel Fund to accelerate this process. At the same time, in the United States a tax-credit system has been proposed, promising to cut production costs and enhance the scalability of SAF production.
This transatlantic partnership could accelerate the widespread use and adoption of SAF.
While SAF is undoubtedly an important part of the path to net zero, it is not a total solution in and of itself. Research, investment and development into wider air technologies and the way we fly must be continued.
A lot more is needed – and quite possibly higher prices for flights. Not unreasonable you may say when the cost of a London-to-New York flight today is much the same as it was forty years ago.