The UK would have to dedicate half its farmland or more than double its total renewable electricity supply to produce enough jet fuel to meet its “jet zero” ambitions, scientists said.
A report published Tuesday by the Royal Society argues that there is no single, clear and sustainable alternative to jet fuel that can support the current level of flight.
The scientists say that while the government and the aviation industry have set a 2050 target to balance emissions, huge challenges remain around the availability, costs and impacts of alternative fuels, as well as the need to new types of aircraft and airport infrastructure around the world. world to allow for the most likely long-term solutions.
Further research and significant investment would be needed, the scientists say, to address questions about four types of fuel: green hydrogen (made from water using renewable energy), biofuels (energy crops and waste), ammonia, and synthetic fuels, or e-fuels.
Producing enough biofuels would require about half of the UK’s farmland, while other feedstocks such as municipal waste could only contribute “a very small fraction” of jet fuel requirements, they report.
Producing enough green hydrogen or ammonia to power future aircraft would require more than double all of the UK’s current renewable electricity generating capacity. E-fuels or synthetic fuels, which are made by capturing and converting carbon dioxide from the air, would require five to eight times the UK’s current capacity.
The Royal Society said the findings underscored the challenges of decarbonising aviation, and that much work remains to be done on how such fuels are stored and managed, as well as their actual environmental impacts in production and when used in flight.
Aviation CO2 it accounted for 2.4% of global emissions in 2019. UK aviation (both international and domestic) caused 8% of the country’s greenhouse gas emissions.
Graham Hutchings, regius professor of chemistry at Cardiff University and chair of the report task force, said: “We need to be very clear about the strengths, limitations and challenges that need to be addressed and overcome if we are to scale up the new technologies required in a few short decades. ”
The report said more research was needed to understand how alternative fuels would affect contrails, which contribute significantly to the heating effect of aviation.
Sustainability would depend on how the fuel alternatives were produced, said Professor Marcelle McManus, director of the Institute for Sustainability at the University of Bath. “We need consistency, and we need to apply this globally, because the adoption of any of these new technologies will create demands and pressures for land, renewable energy, or other products that can have environmental or economic effects.”
As airlines search for sustainable fuels to reduce CO2 emissions by 70-80%, McManus said that for a number of different types of fuels labeled sustainable, that is “definitely not the case” that a change would result from.
Dr Guy Gratton, Associate Professor of Aviation and Environment at Cranfield University, said: “The term SAF (sustainable aviation fuel) is quite confusing… not everyone has the same environmental footprint.”
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The government has said it will force airlines to use SAF for at least 10% of their fuel needs by 2030. Gratton said while that target could be met, what the overall environmental benefits would be “a more complex question.”
He said creating radically different new aircraft fleets to run hydrogen airliners would be hugely expensive but doable, adding: “It seems reasonable to say that if we get the investment in research and infrastructure, we could get closer to a massive reduction in emissions.” . for the goal of 2050”.
A spokesman for industry body Airlines UK said the sector was committed to achieving net zero emissions by 2050. They said: “There is no magic bullet, but by modernizing airspace to make flying more efficient, by introducing new zero emissions like hydrogen planes and by increasing the use of sustainable aviation fuels in this decade, it can be achieved.”
The spokesman said the industry was working closely with the government to “maximise both the environmental opportunities and the huge economic opportunities of leading the jet zero transition.”
A Virgin Atlantic Boeing 787 will fly from London to New York later this year powered entirely by fuel made primarily from residual oils and fats, in what is billed as the first net-zero transatlantic flight.