I found this site which goes into the size and capacities of wind farms,
Area Used by Wind Power Facilities [AWE

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I will hedge the numbers a bit and say the average is 50 acres per MW instead of the articles 60 acres per MW.
I also hear that the newer output factors are closer to 50%, up from the earlier 25 to 35%.
1 MW X 24 hours X 365 days= 8760 Mwh X 50%= 4380 Mwh per year for 50 acres, or 4.380 Gwh
Solar claims 2.8 acres per Gwh per year, so 50/2.8=17.857 Gwh per year per 50 acres.
So wind power is .0876 Gwh per acre per year,
and solar is .3571 Gwh per acre per year.
It looks like for energy density solar is about 4 times better than wind, but there would still be a question
of how useful the land under the panels would be compared to the land under the windmills.