Utilities in Texas are planning almost $9 billion worth of transmission improvements over the next five years, according to the Electric Reliability Council of Texas' (ERCOT) annual transmission report.
ERCOT, the state's grid operator and manager of the wholesale electric market, filed its 2011 Electric System Constraints and Needs Report with the Public Utility Commission of Texas last week.
The report identifies existing and potential constraints in the transmission systems that pose reliability concerns or may increase costs of the electric power market and for Texas consumers. Proposed transmission projects are also highlighted in the report.
The planned projects are expected to improve or add nearly 7,000 circuit miles of transmission lines and more than 17,000 megavolt amperes (MVA) of autotransformer capacity to the grid, including the competitive renewable energy zones (CREZ) transmission additions that are scheduled to be in service by 2013.
Under the CREZ program, eight transmission service providers have been authorized to construct 46 new electric transmission lines (most at 345 kV) to deliver wind energy from rural areas to urban centers in Texas. CREZ projects are expected to increase the state's wind generation capacity to more than 18 GW.
ERCOT load forecasters considered a wide range of variables, such as population, weather, land usage, general business economy, governmental policy and societal trends in terms of both historical load data and the best predicted future indicators available.
CREZ projects
ERCOT's report identifies several proposed projects in areas categorized by weather zone. Many of these projects are being built to serve areas in order to move wind power to load centers.
The main cities in the Far West weather zone include Midland and Odessa. The largest planned improvements in this region involve CREZ projects, including the new Bakersfeld to Big Hill 345 kV line, the Sand Bluff to Long Draw to Scurry County South 345 kV lines and other new 345 kV lines. All of these transmission projects are designated to serve the CREZ areas and to move power – primarily wind energy – from west Texas to the population centers such as Dallas/Fort Worth, Austin and San Antonio.
Most of the congestion that is projected in the Far West weather zone is attributed primarily to the large growth in wind generation in west Texas. A majority of these projected constraints will be relieved by the implementation of the CREZ transmission upgrades. The congestion on the Fort Stockton Switching Station to Barrilla Junction 69 kV line will be alleviated with the CREZ upgrades coming into service in the McCamey area, thus facilitating power export from the area, ERCOT explains.
The North weather zone covers the northern counties of ERCOT's territory, including the cities of Wichita Falls and Paris. CREZ projects in this region include the Krum West to Riley (Oklaunion) to Edith Clarke 345 kV lines, Cottonwood to Dermott and Edith Clarke 345 kV lines and other new 345 kV lines. These projects are designed to move wind power from west Texas to the population centers such as Dallas/Fort Worth, Austin and San Antonio.
The Matador substation to Paducah Clare substation 69 kV line upgrade will allow for the exit of a Special Protection Scheme at a nearby wind generation plant and improve the reliability for customers served by this line.
The North Central weather zone consists of the Dallas/Fort Worth metroplex, Waco, Temple, Killeen and the eastern edge of Abilene. CREZ projects include the West Shackelford (Central C) to Sam Switch/Navarro 345 kV lines and substations, The Willow Creek to Clear Crossing to Dermott Switch 345 kV lines, Brown to Newton to Killeen Switch 345 kV line, and several other 345 kV and 138 kV lines.
The West weather zone includes Del Rio, Abilene, San Angelo and the western part of the Texas hill country. CREZ projects in this zone include new Big Hill to Kendall 345 kV line, the Scurry County to West Shackelford 345 kV line, the Dermott to Willow Creek 345 kV line and several other 345 transmission lines. This new construction will serve the purpose to move power – mainly wind energy – from west Texas to other zones such as the north central, south central and southern parts of the state. The Ballinger to Winters 69 kV line upgrade will improve reliability in the area.
While moderate load growth has contributed to some congestion, a majority of the constraints projected in the West weather zone is also mainly caused by the large increase in wind generation in the area. Some of the congestion is expected to be mitigated with the implementation of the CREZ transmission upgrades.
