VERY VERY cheap (3c or under) maybe, though right now even at the way-too-late drop in S7 pricing it's still looking VERY iffy.
NOT 7.5c
I would agree on cheap being closer to 3C or so. The big guys can chase this electricity price and build where ever they find it. This is why they have a huge advantage. Some gear even at halving at 3C chances are they still can run.
Us more "regular" user's would be 8-10 cents or so I think. And above 10 get's tough unless your one of those who say's they use it for heat in winter... then it get's a little more complex.
i know that big farm run on 5 cent not 3 cent, and i doubt they changed their place with their mega farm
maybe they can afford to upgrade their contract in soem way?
No, they locate in places where electric is inherently cheap - like MegaBigPower in the Wenatchee area (normal electric rates of 3c/KWH or a little LESS even for small folks and residential).
Like real estate in general, it's all about location - but in this case it's all about locating where electric is VERY VERY cheap.
Real estate taxes aren't going to add a significant amount to their overhead if they own. A few thousand AT MOST to a farm running thousands of miners is a pittance.
And it's due to the scale they mine at. Even if they have a network engineer, someone to monitor miners 24x7, people to work on miners, etc. It is very small compared to what they bring in.
And in some countries they go to like China you would be surprised I think on pay. They are able to get people for not a ton of money.