Balancing authority
The ISO is the largest of about 38 balancing authorities in the western interconnection, handling an estimated 35 percent of the electric load in the West. A balancing authority is responsible for operating a transmission control area. It matches generation with load and maintains consistent electric frequency of the grid, even during extreme weather conditions or natural disasters.
![Wecc baamap](https://www.caiso.com/content/images/wecc-baamap.jpg)