AUSTIN, Texas — Southern Spirit Transmission, LLC (SST) has federal and Texas approval to build a transmission line connecting the Texas power grid to the southeastern U.S. power grid.
The power line would flow more electricity than the other four grid interconnections combined. The Electric Reliability Council of Texas (ERCOT) manages the power grid for the majority of the state.
Two direct current (DC) ties flow a combined 400 megawatts of power between ERCOT and Comision Federal de Electricidad (CFE) in Mexico. Two other DC ties flow a combined 820 megawatts between ERCOT and Southwest Power Pool (SPP) in the middle portion of the U.S. power grid.
In May 2014, Southern Spirit (formally Southern Cross) received federal clearance and preserved ERCOT’s independence from federal regulation. In 2017, the Public Utility Commission of Texas (PUC) issued a Certificate of Convenience and Necessity (CCN) and directed ERCOT to perform more than a dozen tasks to accommodate the DC tie.
In Sept. 2022, PUC approved ERCOT’s work. The company must still get easements from various landowners.
Typically, the cost to build transmission lines inside the ERCOT grid are directly passed to ratepayers as a line item on their power bill. However, the $2.6 billion Southern Spirit project is paid for privately by Pattern Energy.
In addition to transmission lines, Pattern Energy develops, builds and operates wind and solar projects in Texas and around the country. The company’s Texas portfolio includes a solar farm in Fannin County and wind farms in Kenedy County, Carson County and Comanche County.
In April 2023, Rainbow Energy Marketing Corporation (REMC) filed a request to ERCOT to revise the Planning Guide to treat DC ties as it does power plants for reliability planning. REMC is tied to oil and gas production as well as the wholesale buying and selling of natural gas and electricity.
In an ERCOT subcommittee meeting, commenters asked if the REMC request would impact the resolved directives concerning Southern Spirit. ERCOT filed a request to PUC asking for input. A Nov. 2023 filing by PUC staff raised concerns, such as the project could cost Texas ratepayers.
“Significant transmission upgrades may be required to support the full import deliverability capabilities of the proposed DC ties, and all other DC ties that are in existence today in the ERCOT system. Additionally, imports over DC ties may have the potential to divert generation from existing dispatchable generation within the ERCOT region, resulting in reduced incremental reliability benefits,” the filing shows.
Southern Spirit Transmission filed a response showing disagreement.
“... the SST project has been upgraded and reconfigured to meet new technical standards developed in response to other SST Directives and these project enhancements are expected to mitigate some of the issues identified in the study referenced by Staff,” the response shows.
In a PUC open meeting on Nov. 30, 2023, Commissioner Jimmy Glotfelty said if the Southern Spirit line was in place when ERCOT issued an Energy Emergency Alert (EEA) this year, then hypothetically there may not have been a need for the alert.
“Would we have had prices go through the roof? Probably not, because we would have had more generation in the north. It gives you options. It gives you flexibility, which is what we need,” Glotfelty said.
“Whatever the cost of such transmission upgrades might be, it will likely pale in comparison to the cost of another Uri-like event,” the company's response filing shows.
A Feb. 2021 deadly winter storm was named Winter Storm Uri by the Weather Channel. However, the National Weather Service does not recognize names for winter storms. The storm caused widespread power outages for days while temperatures remained in single digits. Hundreds of people died.
The costs associated with the storm totals billions.
It is unclear what impact Southern Spirit would have made if built and operating in 2021. However, the other DC ties connected to the U.S. power grid were sending power to Texas for grid reliability. Mexico was not able to send power to Texas as it was also dealing with electricity scarcity.
PUC Commissioners plan to weigh in on Rainbow Energy’s revision request during the Feb. 1 open meeting.
Until then, work continues for Southern Spirit. The company is awaiting approval of the route corridor in Louisiana and has updated its application in Mississippi. Once those are approved, the company will seek permits for the final route.
“Southern Spirit is coordinating with the U.S. Army Corps of Engineers and U.S. Fish and Wildlife Service, along with other federal and state permitting agencies, such as state game and fish departments, state historic offices, and local levee districts, as the project develops. Construction will commence after the project obtains the necessary regulatory approvals and secures all land rights,” Pattern Energy’s website shows.
The company plans to start construction by 2026 and be in service late 2029.