Answer: Texas

The power distribution grid of the contiguous United States is distributed into three distinct grids: the Western Interconnection, the Eastern Interconnection, and Texas Interconnection.

While the electrical distribution in the Eastern and Western interconnection portions of the United States are controlled by multiple smaller entities that all work together to produce and distribute electricity around their respective halves of the country, the state of Texas is isolated and serviced by the Electric Reliability Council of Texas.

How did this geographic peculiarity come about? After all there are other large states, like California, that seem like candidates for such an arrangement. It’s a combination of both Texan spirit and practical considerations coupled up with the large supply of natural resources in Texas. While part of the isolation can be attributed to the strong desire of Texans to maintain a degree of autonomy on all levels from larger national efforts, a good part of it can be chalked up to practical reasons rooted in national security and the fact that they don’t actually need to plug into the national grid.

Right around the time the national power grid was really growing and becoming increasingly intermeshed, Texas was home to many large factories involved in World War II production war efforts. The grid planners were very anxious about the potential for problems in the greater national electrical grid (be they acts of sabotage or simple overloading of the system) to bring the factories to a halt. As a result, they designed the expansion of the power grid in Texas to be completely internal and without interconnection to the east and west national grids.

As time went on, there simply wasn’t a call to connect Texas to the grid as Texans neither needed the connection (abundant coal and natural gas in the region made it easy for them to produce all the power they needed) nor were they interested in connecting and, in the process, becoming subject to numerous federal regulations regarding power production and distribution.

To this date, Texas remains off the national grid and continues chugging along, electrically speaking, with energy produced right in its own backyard.