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Energy Currents
A Blog by Enerdynamics

Electric System Operators Perform Key Functions to Keep Us All in Power

by Bob Shively, Enerdynamics President and Lead Facilitator

The bulk electric grid is a large and complex machine that connects power plants with distribution systems across thousands of miles. To keep the grid functioning, system operators must continually balance customer demand with available supply and transmission capability. At the same time, operators must monitor and manage system quantities such as frequency and voltage. And they must always be ready to take action and respond to any system disturbances such as equipment failure or unexpected fluctuations in supply or load. These functions must be performed while also operating the grid at the lowest cost possible while maintaining acceptable levels of reliability. But many among us don’t really understand what a system operator does. Let’s take a quick look.

When we use the term system operator, we are technically referring to the bulk electric system operator, also known as a control area operator, transmission system operator (TSO), independent system operator (ISO), regional transmission organization (RTO), or a balancing authority (BA). This distinguishes the role from the distribution system operator, which we are not discussing here since the bulk electric system only includes the transmission grid and the power plants/storage facilities connected at transmission voltages. 

Who are system operators?

Given the unique physical characteristics of the electrical system, it is critical that a single entity takes charge of the regional bulk electrical grid. The system operator is this entity. In the U.S. there are two general categories of system operators – Independent System Operators (ISOs) in organized wholesale markets and utility-based system operators in non-competitive wholesale markets. This map shows areas in North America operated by utility-based system operators in gray, and areas operated by ISOs in color:

What do system operators do?

System operators schedule and dispatch power plants and operate the transmission system for a specific region of the electric grid. In regions with an independent system operator or ISO, they also facilitate wholesale markets and set market prices. To maintain reliability and acceptable levels of services, operators must ensure that system frequency and voltages at every busbar are within specified tolerances.

To do so, operators perform the following functions:

Almost always, we never notice!

System operators keep our system operating 24 hours a day, 365 days a year. Almost always we never even think about them; we just enjoy the benefits of the electricity they ensure reaches our distribution utility. But occasionally extreme weather, equipment failure, extreme demand, or other events result in system disturbances, and then we all wonder why our homes and businesses have gone dark. Luckily this doesn’t happen often. Bulk electric grids are designed with a reliability standard of one day of outage in 10 years. And most grids in the U.S. often exceed the design reliability. The actions of the system operator affect us all, so hopefully you now have a deeper understanding of what they do.

Does your organization need an easy option for employees to get a quick overview of system operators? Enerdynamics new online course Bulk Electric Grid Operations will be available soon to provide exactly this. The course can be purchased for individuals or at a discount for bulk orders. For more information email

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Electric Grid , Electric reliability , Electric system operator ,