The cost of solar has dropped so much that you can cut the cost of energy out by adding solar power to mining. The profitability has to do with how much you spend on electricity. So in my mining farm right now is just one 4 GPU's I am setting into a wallet moneys to buy solar once the solar is added the return is better so I can set more aside for extra solar panels. Cost of solar from last year to this is almost half as much and $50 worth of bitcoin from Jan 2017 is now worth almost $1,000 So even if you pay a premium of electric to mine it you end up making more over time.
I think Bitcoin mining is going to fund a ton of solar and wind farms.
Just my 2 satoshi worth.