Aviation: Hydrogen instead of kerosene? - Kicke

We remember: Before Corona became a dominant topic, keyword climate change - the new aircraft has been subject of violent discussions. Even though the criticism of flying from the pandemic was pushed into the background, even though many aviators remain coronabaded on the ground: the problem is not out of the ground. A study under the direction of Manchester Metropolitan University, where the German Aerospace Center (DLR) was also involved, has found that the aviation industry has emitted around 32.6 billion tonnes of CO2 between 1940 and 2018 and about 3, 5 percent participated in man-made climate change.

Electric cargo plane

Lifting battery electrical: DHL has ordered twelve Cargo versions from the E-flyer "Alice". DHL

So there is a need for action, according to alternatives to the fossil fuel kerosene is therefore long ago. Battery electric drive, as it starts to establish itself on the ground, could also be in question for aircraft. An example is the Electric Jet "Alice" of the Israeli-American start-ups eviation, from which the logistics company DHL currently ordered twelve cargo versions, first deliveries should be done in 2024. The maximum range of the E-flyer is 815 kilometers - that's not little, long-distance compatibility but literally far away. The weighty problem seriously weighing rechargeable batteries is already known from electromobility with traction, battery-electric intercontinental flights are currently hardly conceivable.

Hydrogen for the long distance

Thus, also in the aviation of hydrogen (H2) comes into play, a fuel, with which long distances would be more feasible. Research approaches go in different directions. So it is possible to operate conventional engines directly with hydrogen instead of kerosene. An issue that employs Airbus in the context of his concept "Zero E" - both as a nozzle jets, but also turboprop aircraft and so-called treacher, which look like a skate and where the hull passes directly into the wings.

"Cleaner" Airbus Zero E Blended Wing Concept: Hydrogen jets could take on other forms than the usual. airbus

More useful, since with a better efficiency, is, of course, the solution fuel cell. Here, the prolonged hydrogen reacts with the oxygen from the air, thereby creating electricity, which in turn provides an electric powertrain. Research work in this regard, among other things, the DLR.

Fuel cell plus battery

His scientists are also involved in the research association enable, which also belong to the University of Ulm and companies such as Diehl Aerospace and MTU Aero Engines. Enable offers a third possibility around the topic of hydrogen: a hybrid drive system namely, the fuel cell and battery combined. How this works, explains Dr. Caroline Willich from the Institute for Energy Turning and Storage of the University of Ulm: "The fuel cell produces electricity from hydrogen and thus ensures the energetic base of the propeller drive. Lithium-ion batteries provide additional power during start or rising flux, which is needed to the Crossing height to reach. " The British-American developer Zeroavia has already sent a piper M with such battery fuel cell technology to a maiden flight, until 2023 the drive system should gain serial maturity.

Combined fuel cell and battery: Piper-M test airplane from Zero Avia. Zero Avia

Hydrogen instead of kerosene: which sounds so tempting plausible, however, also represents a great technical challenge. A question mark says, for example, behind the condenses, which are not caused by soot and nitrogen oxides in the case of a hydrogen flyer, but - at least in certain air heights -Trotz. From a lot of water vapor, they would consist, which can contribute in the unfavorable case - keyword cloud formation - also to heat the atmosphere and also influences the ozone budget.

Still staying question marks

It also applies to the problem of storing the volume-intensive hydrogen on board. Big and heavy tanks are counterproductive here. Instead of gaseous, Airbus relies on liquid hydrogen, which, however, must be stored at extremely low temperatures and in correspondingly well insulated tanks. The weight of the fuel cell systems as well as their integration and cooling is a challenge, as DLR scientist Björn Nagel says. In addition, at the airports, a H2 infrastructure together with functioning logistics must be established. And above all, flying with hydrogen is only CO2-neutral when it has been produced using regenerative energies.

Test flight over 30 years ago Incidentally, a Tupolew TU-155 has been lifted as a hydrogen test carrier over 30 years ago. Until you follow a "green" Airbus, it will take around 15 years - 2035 should it be ready.