The California ISO is closely monitoring coronavirus (COVID-19) developments, and is taking proactive steps to protect our staff, our customers, the community, and the electric grid. Learn more.
ISO incorporation and policies
ISO market participant lists
Glossary of terms
Flex Alerts and conservation
Tours and speaking engagements
Contact us
As the only independent grid operator in the western U.S., the ISO grants equal access to nearly 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.
The role of the California ISOThe electricity industry includes traditional utilities, private power plant owners and state and federal agencies, each playing a distinct role...
How power flows in CaliforniaThe California ISO network is a long-distance, high-voltage transmission system that delivers wholesale electricity to local utilities for distribution...
Competition brings transparencyMore than 150 core transmission and generation companies participate in the ISO market, which is used to allocate transmission space...
The ISO gridThe ISO manages the flow of electricity for about 80 percent of California and a small part of Nevada, which encompasses all of the investor...
ISO historyBefore the establishment of independent transmission operators, electricity was a matter of local concern and was regulated strictly...
Opening accessThe California ISO is one of 9 independent system operators in North America. Collectively, they deliver over 2.2 million gigawatt-hours of electricity...
High-tech control centersGrid reliability is a 24-hour-a-day job requiring California ISO operators to assess the status of the transmission system at all times. The ISO...
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.
Why ISOs/RTOs are good for AmericaRegional markets promote efficiency through resource sharing. These organized markets are designed so that an area with surplus...
Grid planningThe ISO conducts an annual transmission planning process that uses engineering analysis to identify any grid expansions necessary...
Open-market grid welcomes diverse resourcesThe ISO market makes it easier for resources to compete to bring power to consumers. The key to reliably integrating renewable generation...
People powerWith advancements in automation and smart technology, consumers are becoming sellers, not just buyers of electricity. Customers who...
What we stand forWe strive to be a world-class transmission organization built around a globally-recognized and inspired...
Understanding electricityOne megawatt equals one million watts or 1,000 kilowatts, roughly enough electricity for the instantaneous instantaneous demand...