Although there is a 10-fold variation in electricity prices, mining will only be feasible for the top few percent.
I never understood the tendency to view mining cost projection in terms of a static equilibrium. It's dynamic and electricity prices are just one factor. Please enlighten me if you think mining doesn't fall into the realm of steady state systems (
http://en.wikipedia.org/wiki/Steady_state).
It really doesn't make much sense to mine with $0.2+/kwh.
Of course it makes sense - at least for the latest and more efficient equipment. You have to compare the opportunity cost of shipping and maintaining hardware at a remote location with the opportunity to keep it local. Relocation is a major effort and the timing is essential for the lifetime yield of new hardware.