The potential of wind turbines of any size depends primarily on the location and the predominant wind conditions there, because the energy generation increases exponentially with the speed of the wind: Double the wind speed brings eight times the yield - half only one-eighth. The height and diameter of the wind turbine also play a role, because for every metre that a wind turbine is built higher, the electricity yield increases by 1 percent, and by doubling the blade length, the yield increases fourfold (four times the "harvest area").
Mini wind turbines work on the same principle, but on a much smaller scale. After all, if the yield quadruples when the blade length is doubled, it also drops fourfold when the blade length is halved.
A small wind turbine only makes sense if the location is perfectly suitable. To find out for sure, you can have a wind measurement carried out beforehand to determine whether your location is suitable. However, in most cases this is not advisable because the costs for the wind measurement are not proportionate to the costs for the turbine and the expected energy yield.