The first link I provided on Power to space use ratio now is dead.
So I provide the link of the concerned document, the pdf (only one page) being available and reproduced below, from AWEC2013:
https://repository.tudelft.nl/islandora/object/uuid%3Ae3e8aaa4-8ae1-498a-82ce-fdc7a149963f
59 Land and Space used.pdf (70.9 KB)
In my opinion the solution to the problem of the huge space used, is to maximize the frontal area of wind swept, going towards large AWES like the one envisaged on Advanced Kite Networks.