I imagine it is being primarily driven by the recent vast decline in the Canadian dollar. Just about all of the costs involved are going to be about 30% cheaper compared to a couple of years ago.
Not to mention that hydro quebec has some of the lowest electrical rates around and as a crown corporation (owned by provincial gov.), political considerations can bring the cost down substantially.
OVH is also near Montreal, in Beauharnois next to a large (1900 MW) run-of-the-river hydro plant.
Quebec has cheap hydro power and a cool climate which are probably more important factors.