Additionally, remember that if you are profitable today with Bitcoin at $87500, it does not always guarantee you will be lucrative tomorrow if it collapses to $75000.  The same is true if Bitcoin rises; you might not be able to turn a profit today, but if it reaches $120,000, you might be well on your way to financial success.  Power is no different.  Profits may also be lost if you make the 25% rise from $0.04 kw to $0.05 kw.  Cost changes, even little ones, could have a significant impact.  Include any additional expenses, such as additional cooling required for the miner's location.  Dave