Crosswind Kite Power with Tower

Abstract

Crosswind kite power replaces the tower and the support structure of a conventional wind turbine by a lightweight tether leading to a potentially lower levelized cost of electricity. However, in this chapter it is shown that tethering the kite to the top of a tower instead of to the ground can have advantages: Most notably, the ``cosine loss” is reduced, i.e. the misalignment of the wind velocity vector and the direction of the traction power transfer. Hence, a tower can increase the power and energy yield up to about the double. Even for small tower heights compared to the kite’s operation altitude, a significant efficiency increase can be obtained. Further advantages of a tower are highlighted e.g. for the autonomous start and landing and for the wind velocity measurement. Possible tower concepts are illustrated.