However, if all the electric grids are connected that could leave them vulnerable to attack, unless they are arranged in such a way that knocking out one plant doesn't kill all the others. If it's more energy efficient to connect them, that would be a plus, especially if there's a way to provide power at good rates to more people.
Having all power grids in the United States connected puts the entire country at risk. A weather disaster or planned attack by hackers or terrorists could disrupt power for large sections of the country when all power grids are connected. Grids should be divided up in to more easily managed sections.
If Texas wants to have an electric grid that is separate from the rest of the country, they are well within their rights to do so. Having a national electric grid is not necessarily a good thing. A separate electric grid could make the grids less susceptible to terrorism and natural disasters.
The U .S . electrical power grid is a complicated environment of autonomously possessed, and also controlled, energy. America’s electrical power grid is primarily constructed from about three small to medium sized grids. They are generally hooked up to the substantially more conventional electrical power grid but nevertheless may be disconnected in an emergency.