The California ISO manages the flow of electricity across high-voltage, long-distance power lines. We operate a competitive wholesale energy market that promotes lower costs and renewable resources, as well as overseeing transmission planning to maximize efficiency and reliability.

Our vision

Operate the world's most reliable, cost-effective, and environmentally sustainable power system.

Our strategy

The 2022-2026 Strategic Plan serves as the central organizing principle and guides the priorities of our internal and external efforts over the coming years. Learn more

Our cultural values

Resilience, Accountability, Integrity, Service, Humility—our shared values. Learn more


million people served


circuit miles of transmission lines


million MWh of electricity delivered (2023)


market transactions per day (2023)


billion annual market (2022)

What we do

Grid operations

The ISO manages a transmission system that delivers wholesale electricity to local utilities for distribution to consumers.

Market administration

Our day-ahead and real-time markets ensure enough energy is procured, confirmed, and optimized to foster grid reliability.

Transmission planning

We identify regional grid reliability requirements and projects that yield economic benefits for consumers.

Who we work with

We work with other agencies and organizations to support policy, provide input, and share ideas.

Learn more


Governed by a Board of five members, Governor appointed, Senate confirmed

Joint authority shared with the WEIM Governing Body


Since our beginning in 1998, many great strides have been made by the ISO to operate a power system that serves over 30 million customers. From regional collaboration efforts to the integration of renewables such as solar and wind power, each milestone in our history leads us closer to our Vision of operating world’s most reliable, cost-effective, and environmentally sustainable power system.

In the past, the electricity industry operated as a monopoly with one local utility providing generation, transmission, and distribution services for its area. The 1992 Federal Energy Policy Act allowed for the creation of independent system operators such as the ISO and introduced competition to the wholesale side of the electricity business. 

Learn more about the ISO and its major milestones.

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