The contiguous United States’ electrical power grid is separated into three parts: Two make up the Eastern Interconnection and the Western Interconnection, and their grids power both sides of the lower 48 states.

The third grid — called the Electric Reliability Council of Texas — is an electrical island that powers Texas, and it remains separate from the other two.

Texas has always operated on its own power grid, but the main motivator was the federal government, said ERCOT president and CEO Bill Magness.

Regional utilities in Texas created limited connections during World War II when the war effort demanded large amounts of power be sent to the Gulf Coast. The connections enabled power to flow from all over Texas to where it was needed most. That grid became the Texas Interconnected System.