To avoid the mentioned limitations of wind turbines (see Project Motivation), a wind power concept is currently under development, capable of harnessing the energy potential of high altitude wind using aerodynamic lift. On the other hand the absence of an “equivalent” wind tower or elevated nacelle renders installation and functioning much simpler and dramatically reduces cost.
A production cycle is executed, consisting of two phases. A power phase (rising phase) in which the Airborne Module increases its altitude pulling up the tether cable which drives the alternator at the ground station, producing electrical power.
As the maximum operating altitude is reached, the aerodynamic lift is reduced by changing the angle of attack of the module. Consequently, when the second phase of the cycle (recovery phase) starts, the pull on the cable is only a fraction of the force during the upwards phase. During this recovery phase, an electrical motor, installed at the winch, rewinds the cable to its original position, consuming power in order to do so but much less than that produced during the power phase due to the reduced pull force. As the minimum cycle altitude is reached the recovery phase ends and a new cycle can begin.
After cycle optimization the initial estimates indicate that as little as 25-30% of the energy produced during the power phase is consumed during the recovery phase.
