# Is there only one electron for each $k$ value allowed in the electronic band structure?

When we look at the electron band structure of a material we see the energy as a function of the wavevector k. But what I don't understand is if there is more than one electron in the same band with the same $k$ value, since according to pauli principle electrons are not allowed to have the same quantum number and $k$ is a well-defined number here.

If this is true i am not able to imagine two electrons in a material,one in one edge and the other one in the opposite edge, being force to have different wavevectors. Or maybe it is a consequence of the fact that electrons in the solid are delocalized??

You're allowed to have two electrons in the same band (one spin up, one spin down)$^*$. You're not allowed to have any more than that! The Pauli principle says that each state cannot be double occupied.
$^*$I am assuming the bands are not spin-polarized, in which case each band only holds on electron, but there are twice as many bands, so the counting still works out.