Wind is currently the most important sustainable energy source. Man has been using wind energy at least since the early Middle Ages to grind grain or pump water. Combined with a generator, a wind power plant can be used to produce electrical power. In 2019, the installed capacity in Germany was 54 Gigawatts, which covered about 20% of the electricity demand. Incidentally, the German wind energy industry employed around 135,000 people in 2017, compared to 21,000 in lignite mining.
The wind turbine exhibited here, with a rated output of 300 watts, is a vertical rotor, in which the rotor rotates around the vertical axis. Low noise emission and avoidance of cast shadows are some of the advantages compared to the horizontal rotors commonly used for power generation. However, vertical rotors cannot yet be built as large as horizontal rotors due to their design.
This wind turbine combines a wing-shaped Darrieus rotor with a barrel-shaped Savonius rotor. The Darrieus rotor uses the wing principle like an airplane. By turning the rotor, wind flows past its wings. The resulting lift forces make the Darrieus rotor particularly efficient. Unfortunately, it does not start by itself. The Savonius rotor is not a lift rotor, but works well even at low wind speeds. It is used to bring the wind turbine up to speed until the Darrieus rotor becomes effective.