Have you tested this at a large scale to see how it affects ups?

No I have not, sorry. I am very new to Factorio modding and UPS analytics is not something I have come across yet.

If it helps, this mod basically spawns a hidden Electric Pole per tile. If you know how much Electric Poles affect UPS, then you could infer how much of an impact this mod will do.

Per this thread, which is very old honestly, power network UPS is only a thing when adding or removing networks. The number and size of power poles doesn't directly affect UPS. If you sat there and spammed a massive blueprint that took items on and off the power grid then it would do something.

https://www.reddit.com/r/factorio/comments/hsxglo/does_the_number_of_power_poles_affect_the_ups/

Cool, ty for infos