Battery-powered light aircraft and gilders with an electric auxiliary drive have been available for several years. But the problem, at least for the present and the near future, is the low energy density and heavy weight of (rechargeable) batteries. This means that electric drives cannot provide the power and range of combustion engines and, as a result, it has not been possible so far to use electric motors in larger aircraft. In terms of protecting the Earth’s atmosphere, it would be ideal if planes could run on electricity, as they would no longer emit gases and particles into the Earth’s sensitive upper atmosphere. If the planes’ batteries were recharged using electricity from renewable energies, then flying would even be carbon-free!
Research in this field is making headway. Apart from looking at how to run aircraft on electricity, scientists are also exploring other types of propulsion. The German Aerospace Center (DLR) has developed a motor glider called Antares DLR-H2, whose take-off is powered by a fuel cell and which can then fly for hours. A solar-powered plane called Solar Impulse is set to fly around the world in 2015, thus proving that flight is also possible using photovoltaic cells.
Dorothee Bürkle of the DLR Corporate Communications Department answered this question.