Fasten Your Seatbelt – Here Are Your Future Airplanes
“Hydrogen has suddenly become a wonder fuel – although highly expensive. But it is the most likely fuel for planes. Airbus has unveiled concept planes, which probably won’t be flying until 2040. ”
Hydrogen – the new wonder fuel of the future – is being considered as a solution to the airline industry’s CO2 emissions challenge. Since hydrogen, when consumed, only emits water vapor, it is the cleanest fuel, assuming its technological challenges and economic hurdles can be overcome.
For all its environmental advantages, hydrogen is not an easy fuel to deal with. Compared to kerosene, it has three times the energy density, which is a big advantage over batteries, and it only weighs a third as much. The problem is that planes will need up to four times the volume of kerosene to remain airborne. For air transportation, space is notoriously scarce, and thus precious on any aircraft.
Another challenge is that hydrogen is a so-called cryogenic fuel, meaning that to liquefy the gas, it must be cooled to minus 253 degrees Celsius (minus 423 degrees Fahrenheit). But to be used for propulsion, the fuel must be compressed under high pressure, which necessitates a double-walled, cylindrical or spherical tank, adding a challenge to the aircraft’s design.
European plane manufacturer, Airbus, recently unveiled three concepts for its hydrogen planes of the future, acknowledging that these are only designs. The company’s plan is to have available a zero-emission plane by 2035. But which design?
Exhibit 16. The Longest Hauling Hydrogen Airplane SOURCE: Airbus
The first concept is a conventional-looking turbofan design, able to carry 120 to 200 passengers on routes of up to 3,700 kilometers (2,300 miles). This means it is unable to do long-haul or transcontinental flights. The concept aircraft is slightly smaller than the current base model A320neo, such as those operated by Lufthansa among others, but it achieves the same speed of over 800 kilometers (500 miles) per hour when operating on hydrogen.
The design is shown in Exhibit 16 (prior page). "In the aft part of the aircraft, behind the pressure bulkhead of the cabin, the hydrogen tank is located, and the nozzle on top of the stabilizer serves to let off gas in the case of a leak," explained Airbus Chief Technology Officer Grazia Vittadini at a recent presentation of the hydrogen-powered airplane designs.
Exhibit 17. A Turboprop Hydrogen Plane Concept SOURCE: Airbus
The second concept is a turboprop aircraft with propellers, taking up to a hundred passengers on short-haul routes. The plane can reach 600 kilometers (375 miles) per hour, making it about 20% faster than current turboprops. Both concepts feature modified gas turbines for propulsion, complemented by a hybrid electrical motor run by fuel cells.
Exhibit 18. A Flying Wing Hydrogen Plane Concept SOURCE: Airbus
The third concept is more disruptive. It is a hydrogen-powered Blended Wing Body design. The wings and fuselage form one continuous aerodynamic body. This design is deemed the preferred one for future aircraft. According to Airbus’ Ms. Vittadini, "The blended wing is aerodynamically the most advantageous model to integrate hydrogen tanks. But that doesn't mean that it is the ultimate solution for all other parameters." We have seen military versions of “flying wings,” but never a commercial aircraft with passengers.
Exhibit 19. The Dutch Flying V Hydrogen Concept Plane SOURCE: KLM
KLM and the Delft University of Technology in the Netherlands have shown their version of the Blended Wing Body concept - the Flying V – as a result of their study of possible hydrogen-powered aircraft. We wonder when we will see the first prototypes of these concept planes? Some experts say commercial versions may not be available for 20 years, beyond the target date. However, Dragan Kozulovic, professor for flight propulsion at the Hamburg University for Applied Sciences, said, "The world is ready for it and Airbus has seized the opportunity." He expects the turboprop to be the first commercial version, but then the airline industry will need to deal with readying the fueling system – the manufacture, transporting, storing and fueling of hydrogen - at airports before the next phase can begin.
Because hydrogen is only sustainable if produced from "green" energy, - solar or wind power – Dr. Kozulovic objects to Airbus billing its concepts, called ZEROe, as being entirely "emission free." Even if no CO2 is emitted, combusting hydrogen still produces water vapor, causing contrails in the skies that have a climate impact, as well as nitric oxide. "These aircraft will be significantly better, but not emission free," he explained. Hum. Will those emissions be acceptable under the Green New Deal?