The Texas Interconnection is an alternating current power grid - a wide area synchronous grid - that covers most of the state of Texas. The grid is managed by the Electric Reliability Council of Texas. The Texas Interconnection is one of the three minor grids in the continental U.S. power transmission grid. The other two minor interconnections are the Quebec Interconnection and the Alaska Interconnection. The two major interconnections are the Eastern Interconnection and the Western Interconnection. The Texas Interconnection is maintained as a separate grid for political, rather than technical reasons. In most respects, it is not subject to Federal Energy Regulatory Commission regulation. All of the electric utilities in the Texas Interconnection are electrically tied together during normal system conditions and operate at a synchronized frequency operating at an average of 60 Hz. Interconnections can be tied to each other via high-voltage direct currentpower transmission lines, or with variable-frequency transformers, which permit a controlled flow of energy while also functionally isolating the independent AC frequencies of each side. The Texas Interconnection is tied to the Eastern Interconnection with two DC ties, and has a DC tie and a VFT to non-NERC systems in Mexico. There is one AC tie switch in Dayton, Texas that has been used only one time in its history. On October 13, 2009, the Tres Amigas SuperStation was announced to connect the Eastern, Western and Texas Interconnections via three 5 GW superconductor links., the project was reduced in scope and only related infrastructure was constructed for nearby wind projects connecting to the Western Interconnection. Power demand is highest in summer, primarily due to air conditioning use in homes and businesses. On July 19, 2018 consumer demand hit 73,259 MW. A new peak of 74,820 MW was set between 4 p.m. and 5 p.m. Central Daylight Time on Monday, August 12, 2019 as high temperatures in Houston hit 100 degrees Fahrenheit. ERCOT had more than 78,000 MW of generating capacity available to meet demand in the summer of 2019, providing an adequate though not generous margin. For 2020, the forecasted peak demand is 76,696 MW. A megawatt of electricity can power about 200 Texas homes during periods of peak demand.
Electric Reliability Council of Texas
The Electric Reliability Council of Texas manages the flow of electric power on the Texas Interconnection that supplies power to 24 million Texas customers – representing 85 percent of the state's electric load. ERCOT is the first independent system operator in the United States and one of nine ISOs in North America. ERCOT works with the Texas Reliability Entity, one of eight regional entities within the North American Electric Reliability Corporation that coordinate to improve reliability of the bulk power grid. As the ISO for the region, ERCOT dispatches power on an electric grid that connects 46,500 miles of transmission lines and more than 550 generation units. ERCOT also performs financial settlements for the competitive wholesale bulk-power market and administers retail switching for 7 million premises in competitive choice areas. ERCOT is a membership-based 501 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, electric cooperatives, generators, power marketers, retail electric providers, investor-owned electric utilities, and municipally owned electric utilities. In an early morning period of low electricity demand, wind energy served more than 56% of total demand at 3:10 am Central Standard Time on Saturday, January 19, 2019. Two days later, ERCOT set a new wind output record of nearly 19.7 GW at 7:19 pm Central Standard Time on Monday, January 21, 2019.
