The time for sustainable aviation fuel is now. The aviation industry currently produces more than 2% of global greenhouse emissions, and forecasts from the International Air Transport Association (IATA) predict that the number of air passengers will almost double by 2036.
While the air transport sector has made great strides in improving the efficiency of its operations, in order to meet its targets, it will need to continue innovating.
The International Civil Aviation Organization (ICAO) has agreed on a resolution aimed at stabilising the carbon emissions of the aviation industry by 2021. Under the CORSIA scheme, airlines will need to offset any increase in their carbon footprint beyond their 2020 levels by contributing to projects relating to the reduction of CO2 emissions. The goal is to reduce the carbon footprint of the industry to half the level recorded in 2005 by the year 2050.
One important element to achieving reduced carbon emissions is the development of sustainable aviation fuels (SAFs). When comparing the carbon life cycle of SAFs to conventional jet fuel, there is the potential to reduce CO2 emissions by 80%. Primary research in this field is focused on finding a suitable ‘drop-in’ bio fuel. Drop-in bio fuels are refined from biomass, that meet or exceed regulatory performance requirements for conventional jet fuel and are similar enough that they can simply be blended together without the need to adapt aircraft engines or refuelling equipment.
Sustainable aviation fuel development
The source material, or feedstock, of SAFs is varied and includes algae, municipal waste, various crops with a high oil content and even recycled cooking oil.
In 2008 Virgin Atlantic flew a Boeing 747 from London to Amsterdam as a proof of concept flight using a 20% blend of bio fuel in one of its engines. The bio fuel was refined from a babassu nut and coconut oil mix.
The US Navy, in 2010, flew a demonstration flight in a F/A-18 Super Hornet fighter jet using a 50/50 blend of bio fuel processed from the camelina plant and reported no change in the engine performance.
In fact, since 2008, thousands of flights have been made using blends of SAF by several airlines including Virgin Atlantic, KLM, Quantas, Continental and Finnair, and there are currently 5 airports around the world regularly offering supplies of SAF for refuelling.
Why hasn’t the use of sustainable aviation fuels taken off
Although the technology to produce aviation grade bio fuels is proven, with various new technologies in development, the International Renewable Energy Agency highlights a number of hurdles that still need to be overcome.
- Price – the refining and supply chain for conventional jet fuel is a mature industry with scaled efficiencies developed over years. SAFs, in comparison, are an emerging technology, populated in part by small to medium size businesses operating small scale and non-standardised refining techniques. Until production can be scaled up, the production cost of SAFs are likely to remain higher.
- Commercial scale– building a commercially viable refinery requires significant capital, and investors are wary of moving ahead without government support to offset the significant financial risks. In 2016 British Airways scrapped its ‘Greensky’ scheme due to falling oil prices and a lack of government support. The project would have used landfill materials to produce bio fuel at a refinery in Essex.
- Sustainability– concerns about the sustainability of feedstock include deforestation to plant bio fuel crops, the use of existing agricultural land competing with food crops and the carbon footprint of transporting biomass to a refinery. The feedstock also needs to be readily available in necessary quantities.
What does the future look like?
The government’s Future Fuels grant is aimed at helping innovative companies develop alternative fuels and predicts that bio fuels from waste materials alone could be worth £600 million annually by 2030. With the DfT’s Renewable Transport Fuel Obligation subsidy scheme now including SAFs, government support appears to be growing.
The potential goes beyond the front-line companies racing to develop commercial refining capabilities. In order to achieve sustainability, stakeholders throughout the life cycle of the product need to be involved, including farmers, processing, storage and transportation companies.
The advent of CORSIA in 2021 is likely to provide a financial incentive for airlines to increase their use of SAFs as they will be able to use this to offset their carbon footprint. In a climate where oil prices are once again rising, the gap in prices between SAFs and conventional jet fuel may not be such a barrier.
With increasing government support and developing industry partnerships, this may be a sign that the time for commercially scaled Sustainable Aviation Fuels has arrived.