Kite Gen is an Italian company that has some very innovative ideas about how to harness the power of wind. And the results are interesting from the point of view of aesthetics, a refreshing departure from the all too familiar three blade horizontal axis turbine.
The 3MW stem type generator works by letting up a single kite (assisted at first with integrated fans) which then sets sail to a height of 1000 meters or more. The action on the lift sequence runs a turbine at the base. When the kite reaches the end of the line, the system automatically pulls one end of the kite rope in quickly so that the air catch is dropped and then the whole thing is reeled in to a lower altitude at which the process is started over again (this time without the need of the assist fans). The reeling in energy is a very small fraction of the lift-out energy and the lift-out to reel-in time ratio is 9:1. The added benefit of high altitude wind generation is the consistency of the wind. The company claims that it could produce energy with these systems at fossil fuel (grid parity) costs and at minimum for 5,000 hours a year operation time.
Comparison diagram of forces:
In the carousel type 1GW installation, the kites also turn a larger turbine. Though the website does not state it quite this way, it seems that if the up and down time on the kites was coordinated in an automated program, the speed of the main carousel rotation could be controlled and potentially reach a very high rpm velocity at the main turbine.
Some images of the mock-up that was recently installed in Italy are in this clip: