Understanding the ISO

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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.

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 ISO The electricity industry includes traditional utilities, private power plant owners and state and federal agencies, each playing a distinct role...
	How power flows in California The California ISO network is a long-distance, high-voltage transmission system that delivers wholesale electricity to local utilities for distribution...
	Competition brings transparency More than 150 core transmission and generation companies participate in the ISO market, which is used to allocate transmission space...
	The ISO grid The 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 history Before the establishment of independent transmission operators, electricity was a matter of local concern and was regulated strictly...
	Opening access The 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 centers Grid 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 America Regional markets promote efficiency through resource sharing. These organized markets are designed so that an area with surplus...
	Grid planning The ISO conducts an annual transmission planning process that uses engineering analysis to identify any grid expansions necessary...
	Open-market grid welcomes diverse resources The ISO market makes it easier for resources to compete to bring power to consumers. The key to reliably integrating renewable generation...
	People power With advancements in automation and smart technology, consumers are becoming sellers, not just buyers of electricity. Customers who...
	What we stand for We strive to be a world-class transmission organization built around a globally-recognized and inspired...
	Understanding electricity One megawatt equals one million watts or 1,000 kilowatts, roughly enough electricity for the instantaneous instantaneous demand...