Streetlights are all over the place, lining roads and filling out car parks, while flood lights loom over ports, industrial parks and military bases alike.
A simple suggestion is to make it so that any lights within range of a generator or its powered network will also be considered to be powered and will turn on.
Besides being a neat cosmetic detail, it would make for a pretty immersive and distinctive way to visualise your presence on the map at a distance, with the added bonus of not requiring the player to go out of your way to place a bunch of decorative lights manually to enjoy it.
Image includes examples of various possible light sources, and an image of the Sentinel North bridge checkpoint which has active lighting effects ingame already, serving as a good example of how powered lights could look