Orbital solar starts to make sense when you need a collection area that's larger than what's feasible for Earth and currently Earth is not scarce as far as available surface area :)
Though, that said, existing urban rooftops are over a third of the required area to power the world, so you might as well stick some there while you are at it.
Was referring to NorNed, a 500km HVDC 700MW interconnect between the Netherlands and Norway https://en.wikipedia.org/wiki/NorNed,
and the Russian power grid IPS/UPS https://en.wikipedia.org/wiki/IPS/UPS
edit - the limits to how far you can push transmission are very high indeed. For instance, here's a study from 1984 that puts an upper limit on AC at 3000 - 4000km and for DC at 7000km. http://large.stanford.edu/courses/2014/ph240/sell1/docs/pari...