The Electric Reliability Council of Texas board of directors has endorsed a plan that would make electric transmission service in the Lower Rio Grande Valley much more reliable.
The LRGV System Enhancement Project ” Tier 1″ plan, submitted to ERCOT by American Electric Power, calls for construction of three new substations and installation of roughly 352 miles of double-circuit 345-kilovolt (kV) transmission lines connecting them. ERCOT, which is under the Public Utilities Commission of Texas, deems the project “critical to reliability” in the region, essentially Cameron, Hidalgo, Starr and Willacy counties.
AEP and South Texas Electric Cooperative are the transmission service providers for the estimated $1.28 billion project. The cost would be shared by ERCOT’s 26 million customers statewide.
The Lower Valley largely relies on three major 345-kV long-distance transmissions lines connecting the region with the rest of the state’s grid, though two of the lines, which parallel the coast from near Corpus Christi to the Valley, are susceptible to damage from tropical storms and hurricanes, according to ERCOT. Existing conventional generating capacity in the Lower Valley is limited and no additional conventional generation is planned, ERCOT noted in its report on the project.
Conventional generation refers to power plants fueled by natural gas or coal for example as opposed to renewable energy such as wind or solar generation.
“Historically, the LRGV area has experienced reliability challenges, especially under transmission and/or generation outages, including those associated with extreme weather events, to serve the existing and projected electricity demand growth,” ERCOT said.
Demand for electricity in the Lower Valley “load center” is expected to grow steadily, while the potential for high-use industrial customers moving into the area is another reason why enhancing transmission service is necessary, according to the report, which noted that peak summer demand is expected to hit 3,200 and 3,300 megawatts (MW) by 2027 and 2030 respectively. One MW, which equals 1 million watts, is roughly the amount of power necessary to power 400 to 900 homes per year.
According to ERCOT, reliability issues will arise even with no outages at or above 3,200 MW, meaning the system improvements will have to be up and running by 2027. Factor in high-impact weather-related transmission or generation outages, and stability and reliability issues arise even below the 3,200 MW projects summer peak demand, the report said.
ERCOT said that the large volume of renewable resources — wind and solar farms — that have been built in and round the Lower Valley in recent years limits the capacity for importing and exporting power, which affects long-distance power transfer between the Lower Valley and the rest of the ERCOT grid. Wind and solar generation capacity in the Lower Valley was expected reach approximately 7 gigawatts by the end of 2021. A gigawatt is equal to 1 billion watts.
In addition to improving reliability and stability and improving system resiliency under high-impact weather conditions and increasing the capability for moving power into and out of the area, the improvements will ” provide a better operational flexibility during planned maintenance outage conditions,” according to ERCOT.
John Bruciak, general manager of the Brownsville Public Utilities Board, expressed gratitude that the problem is being addressed.
“The Valley has seen continued growth in its population and in the demands for electricity, but our transmission connections to the rest of the state’s electricity generation fleet has lagged behind our growth,” he said. ” We are grateful to the Public Utility Commission of Texas and to the ERCOT board of directors for taking decisive action toward improving our ability to bring in power from elsewhere in the state when we need it.
“Once this transmission project is completed sometime after 2027, we believe this should improve our ability to both provide reliable electricity service to our community and to recover more quickly after a major weather event like a hurricane. “
