Texas Electric Grids: Demand and Supply
The Electric Reliability Council of Texas (ERCOT) operates the electric grid for 75 percent of the state.
The Panhandle, South Plains and a corner of Northeast Texas are under the Southwest Power Pool (SPP).
El Paso and the far western corner of the Trans Pecos are under the Western Electric Coordinating Council (WECC).
The southeast corner of Texas is under the Southeastern Electric Reliability Corporation (SERC).
The councils were first formed in 1968 to ensure adequate bulk power supply.
In the chart below for summer use, note the slim margin of supply and demand in the hot summer of 2011 for the ERCOT area.