Power available to a wind powered vehicle traveling directly downwind

[russ_watters]

What you describe is an overunity device like those electric generators powered by an electric motor and electric motor is supplied by the electric generator and on top of that you can also power a light bulb.
As I already mentioned not understanding energy conservation.

Incorrect. The power extracted never exceeds the power available per the equation. At this point I'm going to lock the thread since you seem to be uninterested in learning how these devices actually work and we're stuck in a loop where you just keep referring back to the wrong equation.