Aviation generates about 2.5% of CO2 emissions. But it is growing and more than 20% in 2050. On the other hand, there should be zero emissions, according to the Paris Agreements. There is great hope for a fuel that does not produce emissions. On February 28, the British Royal Society published its latest study on green fuel issues. The main candidates are:
They are made from organic waste (cooking oil, agricultural residues, animal parts, manure, plants such as corn, algae, etc.). When burned, they produce CO2, which is however absorbed by plants and animals, which in turn produce them. This results in almost zero net emissions. It can now be manufactured and used in airplanes without changing the design. Its limitation is the immense amount of material. A study by the Royal Society concludes that Britain’s food with biofuel, half of the UK’s agricultural land should be dedicated to it. Removing plant material from rainforests, such as in Indonesia or Brazil, will have a devastating effect, warns Chris Lyle from the Royal Aeronautics Society. Waste is not enough. “A year of oil from French fries spent in Belgium would take Schipol two days to operate,” says Paul Peeters, professor of sustainable tourism at the University of Breda.
That’s what happened when CO2 bonded to hydrogen. Hydrogen must be generated with renewable energy (now almost entirely generated with gas). CO2 must be captured in places where it is emitted (eg cement works) or absorbed from the air. When burned, e-fuels generate CO2, which nevertheless has to be absorbed into the emissions grid almost zero. They could be used in the current developer. Porsche has announced that it wants to produce half a million liters by 2028, using a few thousand tons from aviation. The problem is they are grossly incompetent. “The capture of CO2 and the manufacturing of e-fuels are much more efficient than ending up in a gallon of fuel,” explains Bernard van Dijk, professor of aeronautics at the University of Applied Sciences in Amsterdam.
Hydrogen would be the whole world because it would not generate CO2 if it came from renewable sources, not almost entirely from gas, as is the case today. “Replacing the fuel of European flights with hydrogen would require 90,000 wind turbines, or the territory of a mill covered twice in Belgium,” observes van Dijk. In addition, the aircraft and a completely new infrastructure had to be designed for refueling. Hydrogen takes up a lot of volume and must be stored in the fuselage, taking up space for passengers . And it is very explosive, which the security system demanded. Airbus has promised a prototype hydrogen plane within the 2030s. Boeing is not interested and has just released the 747 to fly for decades on similar kerosene.