I don't recall it being in a C shape, it has the big skyscraper tower thing with all the comms towers, hell when I googled it there was a link that I saw that showed all the maps for these places and while trying to figure them out I never saw anything that matched the power grids for the other things I had found anywhere on the map.
Wait, why do I have to scan a comms tower to locate a power grid when all the others are visible with some driving, would have been nice if the mission had even pretended to allude to even doing that.