Interconnection (Eastern, Western, ERCOT, Quebec)

North America's power grid is actually divided into separate synchronous interconnections that operate largely independently of each other, connected only by limited direct-current ties rather than being one single grid. The Eastern Interconnection covers the area east of the Rocky Mountains (and part of northern Texas), spanning dozens of balancing authorities. The Western Interconnection covers the area from the Rockies west, including part of Mexico. ERCOT (the Electric Reliability Council of Texas) covers most of Texas and is unique in that it is simultaneously the balancing authority, the interconnection, and the regional transmission organization all in one, which is also why it largely operates outside FERC's interstate jurisdiction. Quebec forms its own separate interconnection as well.