When price is above this line, miners with the given conditions have positive cash flow (i.e. they make more money mining than their running costs), and when below the line, they would be better off turning their rigs off (if this simple model can be applied to their particular circumstance).
1. All costs are consolidated into one "electricity cost" variable, including things like rent and wages for mining farms.
2. 12.5 BTC/block emission schedule (update source code upon next halving).
It is likely that actual costs to miners varies in complex ways. This indicator only shows a cash flow calculation for a very simple set of parameters that will generally apply to miners, but not necessarily all of them. (For example, a miner may be locked into a prepaid contract for cheap electricity, or sell exhaust heat in the winter for extra revenue.)
Positive cash flow is also different from ROI , as this model does not take into account the cost of acquiring an ASIC mining rig.