The video report at the beginning of this article shows the first device in the world that can produce hydrocarbon fuels such as aviation kerosene, that is, kerosene, but also diesel from only the sun, carbon dioxide and water. The so-called multifunctional solar tower is the result of an international collaboration of scientists from Europe, mainly from Switzerland, Spain and Germany.
The technology and design is the responsibility of a team of researchers at the Federal University of Technology in Zurich. However, due to the local climate, the research institute IMDEA Energy in Madrid had it built.
And funding from the European Union was coordinated by the Bauhaus Luftfahrt technological institute from Bavaria, which itself contributed the most: a sixth of the total of 6.1 million euros, which means 150 million crowns. At the same time, the Swiss themselves put 1.75 million francs into the government fund for education, research and innovation, which translates to 44.2 million crowns.
How the world’s first device of its kind works
“We are the first to demonstrate a complete thermochemical chain of processes that produce jet fuel from water and carbon dioxide in a fully integrated solar tower system,” Professor Aldo Steinfeld of ETH Zurich explained to Science Daily.
The resulting gas factory consists of 169 glass panels, so-called heliostats, which turn their heads towards the sun and reflect and focus the radiation into a solar reactor at the top of the tower itself. It thus forms an energy flow in a volume of up to 3,000 kW per square meter at a target temperature of 1,450 degrees Celsius, which is directed through an opening with a diameter of 16 centimeters.
The reactor itself has a power of 50 kW, and the key thing is that its inner shell is covered with a very porous ceramic layer, or sponge, of cerium dioxide. Then, as a catalyst, triggers significant oxidation-reduction reactions in water and CO2, which are also injected into the reactor, and thermochemically decompose them into synthetic gas, or a mixture of hydrogen and carbon monoxide. This then travels to the condensing unit and in other processes, kerosene and diesel are produced in it at high temperature and pressure. And everything still runs on solar energy.
“This solar tower and gas plant operated in an environment corresponding to industrial use, set an important technological step towards the production of sustainable aviation fuel,” Professor Steinfeld added.
The pilot plant does not yet have a large capacity. Scientists want to improve it
Scientists have so far tested the device for nine days in 62 startup cycles lasting a total of 55 hours. During this time, the solar tower, reactor and factory in one produced almost 5200 liters of synthetic fuel. The study and results were published by the publisher of the prestigious scientific journal Cell Press. However, it does not indicate exactly how much kerosene and diesel it produces.
For comparison, a regular Boeing 787 Dreamliner can hold about 126,370 liters of fuel, which is enough for about 14,140 kilometers of flight, according to the New Atlas server. That’s a little more than a trip from Prague to New York and back.
However, the factory is still only in the pilot project phase, meaning a smaller test facility. And according to the study, the efficiency of the first solar tower is also only 4.1 percent, while the scientists will aim to exceed 20 percent. And this improves both heat recycling and the structure of the cerium oxide ceramic layer in the reactor, the advantage of which is that it does not burn in the process and can thus be used repeatedly.
A factory consumes as much CO2 as an airplane engine emits
In addition, kerosene produced with the help of solar energy does not necessarily replace aviation fuel from oil in the beginning. They say that it can also be mixed with it. It is fully compatible with existing aviation infrastructure, i.e. storage, distribution and use of the engine. “Solar gas tower represents a possible route to implement solar gas production on a global scale,” the study also says.
At the same time, the aviation sector emits about five percent of the world’s carbon dioxide emissions, responsible for the increasingly visible climate change. And according to the Swiss, every drop counts in the fight against him.
“The amount of CO2 the kerosene emitted when it burns in an airplane engine is the same as that used to produce it in a solar factory. Which makes it carbon neutral (gas), and especially if we use CO2 captured directly from the air – hopefully in the not too distant future,” Steinfeld added.
The Swiss also catch broadcasts directly from the air
The project of Swiss scientists began already in January 2016, when they tested the device only on a laboratory scale. A tower with a reactor and a factory in one began to be built in Spain a year later.
At the same time, the Synhelion startup was cut from the Federal University of Technology in Zurich due to the development and commercialization of the technology. However, it is not the only supporter of the university. The scientific academy has already awarded the company Climeworks, which develops, builds and tests the machine to capture carbon dioxide from the air already mentioned, and which the editors of SZ Tech have also previously written about.