If global aviation meets the goal it adopted last year, a flight halfway around the world in 2050 will result in “net zero” carbon dioxide in the atmosphere.
There is no guarantee that the industry will be able to achieve this, but, however it may be, the technologies that are being developed in pursuit of the goal will transform aviation.
Before the pandemic, aviation emitted about a billion tons of carbon dioxide a yearalmost as much as all of South America in 2021. The numbers are picking up as passengers fly again.
However, the big airlines have promised to reach carbon neutrality by 2050 at the latest. At a meeting of the United Nations agency dedicated to civil aviation in October, delegates from 184 countries adopted carbon neutrality as “a long-term global aspirational goal.”
There is currently no practical, market-ready technology that can drastically reduce aviation emissions. But new technologies are in the works.
Sustainable Aviation Fuel, or SAF, is a type of biofuel that is typically made from used cooking oil and similar biomass. During its life cycle, SAF can generate less carbon dioxide than conventional jet fuel, with which it can be combined.
Nevertheless, SAF production remains limited and expensiveSo airlines proceed slowly, mixing small amounts into their existing jet fuel supply at select locations.
However, there is not enough waste cooking oil and biomass to produce anywhere near the amount of fuel required by aviation, said Andreas Schäfer, director of the Air Transport Systems Laboratory at University College London.
Scientists are exploring alternative carbon sources for SAF, such as algae, yard waste, and food waste. But perhaps the most fascinating potential source is the air we breathe.
Researchers have developed the technology for an expensive process, known as “power to liquid.” It uses huge fans to pull carbon dioxide out of the atmosphere, then extract the carbon from the carbon dioxide molecule before combining it with hydrogen produced from renewable energy electrolysis of water.
The result is a hydrocarbon that can propel an airplane.
Another innovation, a hydrogen aircraft, has significant challenges. Hydrogen as a gas is too bulky to be stored in useful quantities on a plane, so it has to be cooled to minus 253 degrees Celsius, the temperature at which it condenses into a liquid.
Cryogenic infrastructure for recharging and storage at airports would also have to be built.
Electric-powered flights are another low-carbon option. Due to the current limitations of the batteries that power their engines, all-electric aircraft lack the power to propel large planes over long distances, but could offer a solution for smaller planes flying shorter routes.
By: PAIGE McCLANAHAN
BBC-NEWS-SRC: http://www.nytsyn.com/subscribed/stories/6551467, IMPORTING DATE: 2023-01-30 23:10:07
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