I doesn't, at all. Energy production and energy distribution are entirely different things. There is enough unused (i.e. wasted) hydro power in Quebec to power the entire Bitcoin network. If energy is produced too far from where it is demanded such that transmission is prohibitively expensive, there is no downside to having highly mobile miners to make use of it. In fact the extra revenue generated can be used to subsidise the rest of the grid.
Here's a writeup on how that's a misleading statement, and how the best use of that hydro power for offsetting carbon would be for it to be used to offset neighboring province's much worse coal-based power.
