3,600 * <Current Cost per Bitcoin> is probably a pretty good approximation of the daily cost.
Since Bitcoin is currently ~$500, that's ~$1.8mm per day.
Since Bitcoin is currently ~$500, that's ~$1.8mm per day.
Compared to that, there is a cost, if you will. n powerplants had to be built, or x tons coal had to be burnt to do all the calculations. Does that make sense?