Notwithstanding comments above about "radar shadow"... Near my airfield there are several windfarms, and three show on our radar. One of these is located about 1-2 nms N of a private landing strip... and the returns from the turbines break through the MTI circuitry (i.e they show all the time)... snag is, when I'm vectoring traffic near these returns (not always possible to avoid) under RAS I have to be alert for a pop-up return from an aircraft departing this strip, which I may not spot immediately. SOP is to limit the service (which nicely covers the legalities?) but, frankly, this does little to prevent the increased possibility of incident.
PS... we object to EVERY new proposal (are you surprised?)