Black Start sounds like what happens after the coming micro-nova, when the material shed by the Sun causes three days of darkness.
My understanding is that Texas represents a third, minor, segment of the national grid.
One advantage that Texas has is that Tesla/SpaceX is consolidating there. IDK for sure, but the Tesla grid storage probably uses
Software Defined Power. This means that the DC power in their battery storage is used to fortify the phasing not the volume of power delivered.