Sounds like most studies point to a little over 20,000mi break even for cars based on the average US grid energy source mix. In my area it's an even higher mix of renewables than average, so probably 20,000 or less.

My EV is already a bit over 26,000mi, so it's most likely past it's break even and I plan on probably putting another 100,000+ miles on it before I sell it.