NO brake even, EVER even at zero electricity cost if difficulty rise continues like this and btc does not appreciate.
Do you know the
BTC/USD ratio for tomorrow, for example? No? So what can you tell about ROI?..
there is a no appreciation (increase in price) in what i posted.
Obviously, IF bitcoin goes up in $$ OR ruble terms, then you will make $$ or rubles.
however, if you rely on bitcoin appreciation, then the simplest way is to buy bitcoin with fiat, as you would not have to spend any electricity on it.