The challenge for battery-powered aircraft

Aviation is facing one of its most difficult challenges ever: how to make mass air transport carbon neutral, even climate neutral. This industry is currently responsible for roughly 2.5 percent of the global man-caused CO₂ emission, a number that’s bound to go up as we continue to fly more and more. We also have to take into account non-CO₂ effects (due to NOx emission, contrails, high cirrus clouds), which are expected to increase the aviation-induced climate impact by a factor of 2-3. The continuous improvement of aircraft, however impressive by itself, can’t keep pace with the annual growth in passenger kilometers.

Tackling this huge challenge calls for a truly holistic approach, in which we address the energy carrier (getting rid of fossil fuel), the efficiency of aircraft and their propulsion systems and the flight path itself (shortening routes, optimizing flight altitudes to minimize cloud formation, continuous descent approaches). At first sight, one of the obvious choices is replacing fossil fuel with batteries, like we see happening in the automotive industry right now. The advantages are evident: sustainable electricity can be stored and retrieved with minimal losses, electric engines are extremely efficient, there’s no emission during flight and as the number of charging cycles increases, the environmental and climate impact related to battery production decreases. However, the situation for aircraft is a bit more complicated than for cars.