http://www.geni.org/globalenergy/issues/overview/grid.shtml

https://www.animatedsoftware.com/geni/rh2000ge.htm

A necessary corollary to such a global grid is islanding microgrids all over the place, areas or single buildings which have their own generating capacity that can link to the grid but detach from the grid when the grid is down.

PS:  Texas in USAmerica has a grid which does not connect with the rest of the USAmerican grid expressly because they do not want to be under the rules of the Federal Energy Regulatory Commission.  If they won't join the rest of USAmerica, think about how much less they'd join a global grid.

Solar IS Civil Defense