Can airspace be 100% kerosene-free?
After talking about his experience flying the Solar Impulse, the first single-seat monoplane to circumnavigate the world with all-solar-powered electric motors, André Borschberg explained that this project's overarching goal was to focus the public's attention on the issue of CO2 emissions on the ground and in the sky. And the Solar Impulse project's success shows that clean technologies can be as efficient as legacy ones.
Stéphane Cueille pointed out that manufacturers need to embark on a path to develop solutions that will reduce the aviation industry's air emissions. While air traffic CO2 emissions only account for 2 to 3% of the world's total CO2 emissions, the former are increasing 4% a year, meaning that manufacturers need to continue to develop ever more innovative solutions, following on from the ones they have been rolling out since 2008 under the European Clean Sky initiative.
For André Borschberg, we need to realize that it is much simpler – and more important considering the relative quantities at stake – to tackle CO2 emissions on the ground than in the air, given the mass constraint to which aircraft are subjected. But the ambition of reducing aircraft emissions is extremely positive if we view this as an opportunity. This is the essence of the initiatives being promoted by André Borschberg in relation to onboard electric propulsion, starting with small planes.
In Stéphane Cueille's view, all-electric propulsion is not currently foreseeable for widebody commercial aircraft: for example, powering a recent-generation single-aisle aircraft with electric motors would entail cramming more than 170 tons of batteries into a plane that won't fly if it weighs more than 80! Large equipment manufacturers such as Safran need instead to adopt a "surgical strategy" of introducing electric propulsion for widebody commercial aircraft. Certain projects, such as electric taxiing, are already opening up prospects for very significant reductions in fuel consumption on the ground. At the same time, Safran is very interested in innovations in the field of small aircraft and unconventional VTOLs (aircraft designed for vertical takeoff and landing), which are made possible by hybrid electric propulsion – as illustrated by several startups at the Paris Air Lab. These innovations open up new uses for aviation and may offer a path for disruptive innovation in the future.
In their conclusions, both speakers reminded the audience that the objective that has been set to halve the aviation sector's CO2 emissions by 2050 represents both a constraint and a wonderful driver for innovation.