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 grid. The nonprofit public benefit corporation keeps power moving to homes and communities, and keeps the economy humming.
As the only independent grid operator in the western U.S., the ISO grants equal access to 26,000 circuit miles of transmission lines and coordinates competing and diverse energy resources into the grid where it is distributed to consumers. It also operates a competitive wholesale power market designed to promote a broad range of resources at lower prices.
Every five minutes, the ISO forecasts electrical demand and dispatches the lowest cost generator to meet demand while ensuring enough transmission capacity for delivery of power.
The ISO opened its two California control centers in 1998 as the state restructured its wholesale electricity industry. While utilities still own transmission assets, the ISO controls the routing of electrons, maximizing transmission system efficiency and 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.