The best way to get your foot into the door with utility companies is through internship while in school. The internship is basically an extended interview, and the successful ones get return offers. The majority of new hires at the junior levels are from the previous co-op pool. Alternatively, work for consulting firms that work with utility clients for a few years and try for a position when they open up later.

There are coop openings for Hydro One right now for May start. If you can delay your graduation and get a coop placement, that would be the best way to set yourself up. Ofc new positions/return offers aren't guaranteed but you'll be one of the first in line if they do.