It is, near cities where the energy has to be generated. And its hard to procure because of eminent domain fights, environmental impact statements and high costs.
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...