These kinds of studies usually go by the average emissions of the relevant country’s power generation.

Heres the relevant bit for this study though, it has both national and by province:

In addition, electric vehicles also benefit from the low-emissions intensity of electricity generation relative to gasoline in most parts of Canada. Comparing the lifecycle emissions of the two fuels on an equivalent energy basis, grid electricity emissions are 61% lower than those of gasoline at the national level and 20%-93% lower in the 8 provinces/territories whose grid electricity is cleaner than gasoline.6 A handful of provinces and territories have grids that are more emissions intensive than gasoline based on the 2023 domestic electricity generation profile (chart 2). That said, even in this latter group, most electric vehicles still have lower fuel-related emissions and lifetime emissions than comparable gasoline vehicles because they use less energy during operation. (See appendix for a breakdown of electricity generation by fuel type).

They go into detail. Most FF electricity will be 40%-60% effiency, though peaker plants can be as low as 25%. ICE to wheel efficiency is 18%, and natural gas is cleaner than oil to boot. Canada has a lot of hydro and nuclear.