I guess you can have both positive and negative externalities.

I went back to re-read reflectorbital.com, indeed if you're only lighting a solar farm in the middle of nowhere maybe the light pollution is not so bad outside of the targeted zone.

Still fells like a complicated solution to me. Imo we need more storage innovation and investment, a lot more. We know we'll have more and more intermittent renewables electricity production, we just have to store it.