With all these, let's just ask ourselves:
Is it still worth mining bitcoin right now ?
Is it still worth mining bitcoin right now ?
It depends on who (or where) you are.
Keeping with the numbers so far, if the network difficulty is 50B, 1GH/s can be expected to earn roughly BTC0.00000042 per hour. At $200 per coin, that's ~$0.000084 per hour.
Assuming we're using the newest mining tech @ ~0.2J/GH (supposedly coming to market soon), your electricity/hosting/cooling costs would need to be less than $0.42 per kWh to make a profit (which is just about everyone). So, yes, it's still worth mining Bitcoin.
But when will it no longer be worth it for grand-scale industrial miners? If we shoot for the best (er..worst?) case scenario using 0.2J/GH, $200/BTC, $0.01 / kWh, difficulty would need to be equal to or greater than 2 trillion (something like 14.5 EH/s ..or 14,500 PH/s) in order for them not to be profitable anymore. Assuming mining gear never becomes more efficient than 0.2J/GH and their expenses never go below $0.01 per kWh, the only other volatile variable is the price of Bitcoin. If the price goes up, the difficulty may still go up since miners can still make a profit.
