In gathering energy from the wind, the speed of the wind is crucial and has a large effect on how much energy is captured.
When moving higher up from the surface of the earth the average wind speed increases almost linearly. In the altitude of one kilometer the wind speed is over twice what it is in the altitude of 100 meters.
The energy contained in the wind increases by the cube of the wind speed.
Using kite energy technology, the kite is flying at a lying-eight orbit with high crosswind speed. In the energy generation phase the kite pulls the tether with maximal power out of the ground station where the tether is wound on a drum that rotates the generator. In retraction phase the tether is pulled back with less energy onto the drum.
Our group has shown that, for example, with a 100 sqm (5 m x 20 m) kite a power output of 1MW can be achieved in the energy generation phase.
The tethered wing system is similar except that instead of a kite, a more rigid airplane wing structure is used.