And solar power panels are still too expensive their roi is even worse than the mining rigs and I doubt that anyone who writes here and claims free electricity has a high end solar system.
Then you are must not be aware that some countries are sponsoring solar systems with stipends, loans and tax brakes, for example 'green certificates' that pay for each 1k kWh produced and loans at 1.7% that pay back for the entire installation after 5 years. Basicly that means the entire install is paid for with a loan that is paid of with green certificates and that means 20 years garanteed production at EUR 0 cost. Beat that...