At the current Bitcoin price level it is very hard to make a profit even with zero cost electricity. How is that possible? Depreciation of mining equipment.
But I read somewhere that it costs ~40 USD per bitcoin for large miners due to mass production and hence lower maintenance cost per unit. I dont think none of the large bitcoin firms would have run unless they made profit. Both Cex.io & KNC cloud are closed for customers, but they are mining on their own. Is not it obvious that they are mining because they are making profit ?