That same square mile has 2M plus m^2. So, you would need only 10W per m^2 peak solar power to beat that wind turbine.
Yes, there is lots of hand waiving here. For example, I am assuming equal duty cycle; that will vary with location. The crux still is that there is way less wind power than solar per m^2.
Also, the effect is important. At 1/4 mile distance, you can only place about 20 or so on a square mile of land. Looking at http://en.wikipedia.org/wiki/Wind_turbine#Horizontal_axis_wi..., that gives you less than 18MW peak power.
That same square mile has 2M plus m^2. So, you would need only 10W per m^2 peak solar power to beat that wind turbine.
Yes, there is lots of hand waiving here. For example, I am assuming equal duty cycle; that will vary with location. The crux still is that there is way less wind power than solar per m^2.