Alaska will be home to the highest-flying wind turbine, floating at 1,000 feet

That's an awesome idea.

If the tether was attached to a winch then they could lower or raise the turbines depending on the optimal altitude for wind speed.

Maintenance could also be much easier because it can be lowered rather than sending people up a turbine.

If you add a turbine behind the main turbine, how much less efficient would it be?

Wouldn't the tether be the most difficult part of this? Why is that not discussed more in the article or even shown in the picture?