Yes, that’s correct. Texas has 5 ties to the western/eastern US interconnections as well as with the Mexico grid. But none of that matters right now because those grids don’t have excess capacity to send to Texas anyway.
As per ERCOT's status page, both of the high-voltage DC ties between Texas are currently operating at >99% of their rated capacity, and they have been every time I've checked since yesterday. They're not being limited by the availability of power from the other side.
https://www.klfy.com/local/cleco-rolling-blackouts-to-be-use...
https://www.arkansasbusiness.com/article/134700/lr-based-tra...
Again, just because you have excess power in Missouri does not mean that power can magically transfer hundreds of miles away where it is needed. Energy transfer does not work like that.
> As per ERCOT's status page, both of the high-voltage DC ties between Texas are currently operating at >99% of their rated capacity
So as of that comment, either the amount of power available on the other side was equal to >99% of capacity, or it was greater than capacity.
The situation has changed now and neighboring states have had to drop the amount provided to interconnects, but as of the earlier comment, more interconnects would have helped.
Your turn to try again I suppose
Here's one: https://www.iso-ne.com/
Here's another: http://www.caiso.com/TodaysOutlook/Pages/default.aspx
But there's a limited capacity for Texas to bring in power over just 5 connections, combined with their choice that makes conversion to something compatible with the Texas grid much less efficient.
By isolating & not focusing on compatibility they have made it very difficult to have more robust redundancy in their grid.
https://www.misoenergy.org/markets-and-operations/real-time-...