Hi Pierre:
If there is a generator in the video, it is too small for the rotor size, and would burn out in a decent wind. The support stalks and guy wires will produce a lot of drag.
Belts are not used in wind turbines for a reason. Not reliable. I think it would burn out the generator and be blown to smithereens in productive winds. Other than that it does look like they at least have a decent grasp of the concept of a rotor. Looks cool.
People new to wind energy, of course, know nothing of any of this…