In 2019 8% of the UK’s greenhouse gas emissions came from domestic and international flights.

The UK government have made a pledge to have net zero aviation in place by 2050.

Under the the Jet Zero plan commercial airlines will have to use a sustainable replacement for jet engines.

Reaching Jet Zero will be a challenge to say the least.

Electric engines are not a viable option due to the weight of the batteries needed to produce the power to get an aircraft off the ground.

So the sustainable options lie with non-fossil fuels, all of which are far from perfect.

A report on these alternatives has just been published by The Royal Society and it is sobering reading. The four non-fossil fuels outlined in the report are as follows:

• Bio fuels – these are made from crops such as rapeseed or poplar. However it “would require more than 50% of the UK’s available agricultural land to replace aviation fuels.”
• Hydrogen – Hydrogen gas can extracted from water using electric current. “Producing enough ‘green’ hydrogen to replace current fossil aviation fuel would require around 2.4 to 3.4 times the UK’s annual renewable electricity generation (2020)”
• Ammonia – ‘Green’ Ammonia production requires vast amounts of electricity – in fact “producing ‘green’ ammonia as a jet fuel would require 2.5 to 3.9 times the UK’s annual renewable electricity generation (2020).”
• Synthetic Fuels – “When done sustainably using renewable electricity, this would require 5 to 8 times the UK’s 2020 renewable electricity capacity.”

The report also points out that there is not a full understanding of the impact of non-CO₂ emissions from jet engines, and the formation of contrails, which currently contribute significantly to warming by aviation globally.

This should worry us all.