Today I learned! Way way way lower than I expected. That said, according to this[1] the yields would be slightly worse than the major soar farms in Texas? But I guess Texas doesn't have to contend with the winter, although I was under the impression solar becomes considerably more efficient in the colder temperature ranges?
Texas seems to be 1500-1800, whereas Northern Canada (including all of Ontario and Quebec) seems to generally be 900-1200. So 20-50% worse, no? No clue about the cold factor, but the maps are lifetime kW per nominal kW panel, so presumably that’s factored in.
[1]https://solargis.com/maps-and-gis-data/download/usa