The beginning of electric aviation has come to us, but it will take many years before the environment can fly free of guilt on a long-lasting fully electric jet.
Meanwhile, scientists are trying to make the commercial planes we already have more sustainable, and one of the best ways to do that is to change the fuel they use.
Instead of spitting carbon dioxide (CO2) in the atmosphere, researchers at Oxford University and Cambridge University in the UK have now found a way for planes to capture this gas from the air and burn it for fuel.
Instead of creating a new fleet of electric planes, which would require huge leaps in battery storage technology, this new approach would allow the world to reduce its carbon footprint from flying much earlier. That is, if it turns out to work on a larger scale.
In the laboratory, researchers were able to capture and transform CO gas2 directly into aircraft fuel using a cheap iron-based catalyst.
The amount of liquid fuel produced is still far too small to power a real aircraft, but if fossil fuels can be captured from the air in a sufficiently large volume, converted into energy at a sufficiently high efficiency and then re-emitted, an aircraft would could theoretically fly carbon neutral.
“This catalytic process provides an attractive way not only to reduce carbon dioxide emissions, but also to produce renewable and sustainable fuel for aircraft,” the authors write.
“Recycling carbon dioxide as a carbon source for both fuels and high-value chemicals offers considerable potential for both the aerospace and petrochemical industries.”
Normally, when fossil fuels burn, the hydrocarbons they contain are converted to carbon dioxide and water, releasing energy. The new system essentially reverses this natural process.
By adding heat to the system, the engineers were able to combine carbon dioxide with hydrogen, separated from the water, to produce a few grams of liquid fuel that the authors say could run on a jet engine.
The catalyst responsible for this impressive chemical reaction is composed of iron, manganese and potassium, which are abundant elements of the Earth, easier and cheaper to prepare than many similar candidates. The catalyst also combines easily with hydrogen and has a high selectivity for a range of jet fuel hydrocarbons.
The result is a bit of fuel, as well as more petrochemicals that can only be obtained from fossil fuels.
The new system is not the first nor will it be the last to convert our carbon emissions into the desired biofuel. In Canada, scientists have developed a huge industrial complex for CO capture2 just like the trees of a forest, using it to form hydrocarbon fuel.
But although a handful of studies have shown that it is possible to convert atmospheric CO2 in liquid fuel, it is extremely difficult and expensive to produce more than a small amount.
The new system looks promising, but whether it is practical or not is another matter.
“This looks different and looks like it might work,” said Joshua Heyne, a freelance engineer who was not involved in the study. Wired.
“Enlargement is always a problem and there are new surprises when going up larger scales. But when it comes to a longer-term solution, the idea of a circular carbon economy is definitely something that could be the future.”
Some, like Heyne, are hopeful, while others consider it “flying in the air” as a mere hype. Last year, when a European company announced that it was working on a way to capture CO2 from air to powering future planes, critics have pointed out that the fuel produced each day would only allow five minutes to fly.
Such tiny productions are not a solution to the climate crisis, and some environmentalists say that our only viable option is to fly less. Especially because the reality of a circular carbon economy is still far away and the climate change crisis has already reached us.
Ultimately, it all depends on how quickly we can expand this promising technology and the fact is that it may not happen fast enough.
Engineers want to eventually connect their new system to stable carbon emitters, such as coal-fired power plants, and this would, of course, require the continued production of fossil fuels. It is also very expensive and may not be attractive to companies, even if it works.
However, with the acceleration of climate change and aviation will increase only in the coming years, the team of engineers supports CO2 conversion and use as “an integral and important part of greenhouse gas control and sustainable development”.
Other sustainable plant-based biofuels require large amounts of cropland and do not address our emissions at the same time.
“This is therefore the vision for the path to net carbon emissions from aviation,” he concludes, “a fulcrum for the future global zero-carbon aviation sector.”
We will see.
The study was published in Communications about nature.