Over the course of 12 months (12/1/15-11/30/16) in Vernon County, Wisconsin, the ground mount array pictured, at a 37.5 degree angle from the horizontal, facing due south with a clear view of the sky, produced exactly 9552.8 kwhrs of electricity. at 12 cents per kwhr that is $1,146 worth of electricity. This is actual measured data from my approx 6 kw peak output system pictured above I put together for a presentation to our county economic development group.

For the sake of discussion, here is a 6kw system (less ground mounting posts) for about $9000. Lets say it costs  $2000 to DYI install a ground mount framework (can be wood, pipe etc) and hire an electrician and run some wire to your main panel.  The payback of this system will be right around 10 years. Less if electricity rates go up. After that your electricity is essentially free for the remaining (15 year?) guaranteed life of the system.

Sac County, Iowa is about 100 mi south of Vernon county WI and I suspect has more hours of sun per year than I do to boot. You should be able to hit 10,000 kwhrs per year. Especially since the output of this size and model Solarworld (US made) panel is now 300 watts due to improvements in design rather than my 280 watt panels. Enphase microinverters have also improved and come down in price.