The California Independent System Operator (CAISO), established in 1998, is a nonprofit public benefit corporation that manages the flow of electricity across the high-voltage power lines comprising roughly 80 percent of California's electric grid. It operates a competitive wholesale energy market designed to lower costs and promote renewable resources, while also overseeing transmission planning to maximize grid efficiency and reliability. Through the Western Energy Imbalance Market (WEIM), CAISO extends real-time energy coordination across multiple western states to support a modern and reliable electric grid.
The scale of CAISO's operations is substantial: it manages approximately 26,000 circuit miles of transmission lines, delivers over 250 million megawatt-hours of electricity annually, and serves 32 million consumers. Its technical domains include grid operations, wholesale market administration, transmission planning, grid reliability, and regional energy coordination, with a geographic footprint spanning California and the broader Western United States.
