The Electric Reliability Council of Texas (ERCOT) manages the flow of electric power to 23 million Texas customers – representing 85 percent of the state’s electric load. As the independent system operator for the region, ERCOT schedules power on an electric grid that connects 40,500 miles of transmission lines and more than 550 generation units. ERCOT also performs financial settlement for the competitive wholesale bulk-power market and administers retail switching for 6.6 million premises in competitive choice areas.
ERCOT is a membership-based 501(c)(4) nonprofit corporation, governed by a board of directors and subject to oversight by the Public Utility Commission of Texas and the Texas Legislature. ERCOT’s members include consumers, cooperatives, generators, power marketers, retail electric providers, investor-owned electric utilities (transmission and distribution providers), and municipal-owned electric utilities.
Ancillary services are products used by ERCOT to maintain reliability minute-by-minute, 365 days per year. There are four main ancillary service products: Regulation Service – Up, Regulation Service – Down, Responsive Reserve Service, and Non-spinning Reserve Service.
Regulation up and down are used to balance the grid in a near-instantaneous fashion when supply and demand fluctuate due to a variety of factors, such as weather, generation outages, wind production intermitency, and transmission outages. ERCOT uses these regulation services every hour of the year. Resources providing regulation services must comply with ERCOT instructions in less than five minutes.
Responsive Reserves and Non-spinning Reserves are used by ERCOT when the grid is at, or near, a state of emergency due to inadequate generation. Resources providing Responsive Reserves must increase output in compliance with ERCOT instructions in less 10 minutes; those providing Non-spinning Reserves must comply in less than 30 minutes.
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The ERCOT market needs more electric generation to meet the demands of our nation’s fastest growing population and economy. Significant planned additions of renewables, creating volatility in supply through their intermittency, and the need for additional fast-responding, long-duration, dispatchable generation in ERCOT becomes even more clear.