One can deduce a very good power coefficient of about 0.3 or 0.4 according to wind speed (comparable to that of a small conventional turbine) from data on Can you share your experience with your lifters? - #15 by Kitewinder and on Kiwee One – Kitewinder :
It delivers up to 100 W of continuous power at 25 km/h wind speed and can work up to 100 km/h.
Perhaps we should consider other architectures than a simple juxtaposition of small rope driven turbines possibly replacing (always stationary) flygen turbines.