This past year I had a 20KW solar array put in.
For the month of July my electrical bill looked like this:
To translate this, my house uses a lot of juice, especially in the Summer months (air conditioning and such). I’m not proud of the power use. But in essence, the solar array covered 2,685KWh of electrical use.
Plus, I had an excess of 640KWh.
The DTE program (heavily subsidized by the government) pays me for the energy I produce so I end up with a negative electrical bill.
So does it pay off? Well, without the solar array, rather than getting about $360 back I’d have paid $286. That’s a difference of about $650 a month. Now, the summer months are better than the Winter months. So let’s assume about $6,000 per year. The array cost me (out of pocket) around $100,000 (a chunk of that being the clearing of the area and the necessary grading). So it’ll take a bit less than 20 years for it to pay off.