Flying Wind Farms

I love this idea of the flying wind farms (which I found at Make). At last, the Twenty-first century gets a good science fictional idea to kick around. At first glance I thought this was going to include microwave transmission of the power back to the ground, but this plan has a tether that both controls position as well as serves as transmission conduit. I would assume there either has to be some remote control or onboard control that keeps it from becoming a flying lawnmower of death and mayhem should the tether be severed.