Understanding the ISO
The ISO manages the flow of electricity across the high-voltage, long-distance power lines that make up 80 percent of California’s and a small part of Nevada’s power grid. The nonprofit public benefit corporation safeguards the economy and well-being of 30 million customers by "keeping the lights" on 24/7.
As the only independent grid operator in the western U.S., the ISO grants equal access to 26,000 circuit miles of power lines and reduces barriers to diverse resources competing to bring power to customers. It also facilitates a competitive wholesale power market designed to diversify resources and lower prices.
Every five minutes the ISO forecasts electrical demand, accounts for operating reserves and dispatches the lowest cost power plant unit to meet demand while ensuring enough transmission capacity is available to deliver the power.
The ISO opened its Northern and Southern California control centers in 1998 when the state restructured its wholesale electricity industry. While utilities still own transmission assets, the ISO acts as a traffic controller by routing electrons, maximizing the use of the transmission system and its generation resources, and supervising maintenance of the lines. As the nerve center for the power grid, the ISO matches buyers and sellers of electricity, facilitating over 28,000 market transactions every day to ensure enough power is on hand to meet demand.