If you can generate your own electricity why bother with mining? I thought about adding solar Panels to my home too compensate for the mining rigs, then thought why not just add more panels and sell electricity back to the power company? No reason to bother with a mining rig right? turns out eh cost of a decently large solar installation, say 5Kw is a lot of money even if the tax rebate is included and the Florida incentives are added in.
Not all states allow for resale of electricity to the grid. There are some states that have a "zero-net" energy policy, they'll allow you to generate your own energy, consume and resell but you can't profit from it, the best you can do is a $0 energy bill.
But yeah, solar energy ain't cheap regardless. As I said, if alternatives were really competitive or superior, they'd have taken over traditional. There are other benefits however, so they aren't a totally dead idea.