Long haul towards decarbonization for the aerospace industry
After coming under intense pressure to reduce its carbon footprint, the aviation industry has pledged to drastically reduce its greenhouse gas emissions, but the road to meeting these commitments is likely to be long.
What has the industry committed to do?
Even though the Covid-19 pandemic has shut down much of the industry, the number of air passengers is expected to double to 10 billion by 2050. Currently, aviation accounts for between 2-3% of global emissions of carbon dioxide, the main greenhouse gas. , according to the UN’s International Civil Aviation Organization.
So, without further action, emissions are expected to rise.
The International Air Transport Association, which brings together most airlines, and the aerospace industry have pledged to achieve net zero CO2 emissions by 2050.
In fact, 42 countries, including members of the EU, as well as Britain and the United States, have called on all governments to formally set the target at the next ICAO meeting in September.
However, no promises were made regarding aircraft vapor trails.
These have not yet been studied extensively, but a study by the European Union Aviation Safety Agency indicated that they could have as much impact on the environment as CO2.
How to go there?
The sector hopes that technological improvements such as more efficient engines, new materials and better air traffic management will do much of the work needed.
The engine manufacturer CFM, a joint venture between GE and Safran, hopes to have a new generation of engines by 2035 that will be more than 20% more efficient than those currently used.
According to the European aerospace industry, such improvements could help achieve around half of the necessary reduction in CO2 emissions.
The rest is expected to come from carbon capture and storage programs and emissions trading.
But most of these improvements will take time to implement and many non-governmental organizations say immediate action is needed and are calling for limitations or reductions in the number of flights.
What role for sustainable fuels?
The industry is looking to Sustainable Aviation Fuels (SAF) to play a major role in decarbonizing aviation.
SAFs must be made from sustainable biomass, recycled cooking oils, as well as captured CO2 or green hydrogen converted into synthetic fuels.
They would have the advantage of being able to be used by existing aircraft with little or no modifications and could lead to CO2 emission reductions of up to 80% over their entire service life.
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Airbus and Boeing have pledged that their planes can fly with 100% SAF by 2030, but these fuels currently account for less than 0.1% of jet fuel consumed and are two to four times more expensive.
To boost their production, the EU plans to impose the use of a certain percentage of SAF in jet fuel, while the United States favors tax credits.
What about hydrogen and electricity?
Electric propulsion is currently sought after for small planes and flying city taxis, but the weight of the batteries makes them impractical for commercial airliners.
It is also being explored as a hybrid option, with batteries providing additional power for takeoff, allowing the use of smaller, more efficient motors.
Hydrogen is also being explored to power fuel cells for electric motors, an option that results in zero emissions from the aircraft.
Here, the problem is not the weight, but the volume. It is almost four times larger than jet fuel, which also makes it impractical for medium and long-range passenger jets.
Nevertheless, Airbus is working on what will likely be a short-range regional jet capable of carrying less than 100 passengers which it hopes to fly by 2035.
By Mathieu Rabechault
© Agence France-Presse
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