A 1,500W BFL Mini Rig SC costs $5.40 per day using the U.S. average residential rate of electricity around $0.15 per kWh.

So that is under $2K USD per year in electricity.  For an investment of $30K, $2K going to electricity isn't a particularly huge issue, though definitely operating one where electricity costs are $0.03 per kWh (like it is near Hydro electric generation) is going to be more profitable than running it where electricity costs are above average.

This compares to GPUs whose capital costs were low compared to the cost of the electricity to run them.

For comparison, a $1,100 GPU rig consuming 700W has electrical costs of $2.52 (using U.S. residential average of $0.15 per kWh) and $919 per year.

Of course, figure in the cost of capital per hash and this difference is even more pronounced.  Capital costs: GPU rig: $785 per Ghash/s.  ASIC rig: $30 per Ghash/s.

So ya, the cost of electricity is becoming much less of a factor than it used to be.