ERCOT and the Public Utility Commission of Texas have knocked down recent media reports that a proposed HVDC transmission link between Texas and its Louisiana and Mississippi neighbors will bring the state’s grid under FERC jurisdiction.
Speaking to the ISO’s Board of Directors Oct. 10, ERCOT CEO Pablo Vegas said news coverage of the U.S. Department of Energy’s plan to invest up to $1.5 billion in four transmission projects, including Pattern Energy’s Southern Spirit Transmission 525-kV link eastward, “made it sound like there had been some substantive change in the policy around interconnecting the ERCOT grid to other grids in the United States.” (See DOE Funding 4 Large Tx Projects, Releases National Tx Planning Study.)
“That’s not the case. That is not what has occurred with this recent announcement, nor with the underlying drivers for this project,” Vegas told directors.
Texas has long resisted federal oversight of the ERCOT grid by not mixing its electrons with those of the Eastern and Western Interconnections. It does have four DC ties with neighboring grids, two with SPP and two with the Mexican system, totaling about 1,220 MW of capacity.
One of the links to Mexico is through a variable frequency transformer with a control system that operates like a generator, but it is not a synchronous tie, Vegas said.
Several news stories following the DOE announcement implied that ERCOT soon would be connected to the Eastern Interconnection for the first time. A headline from the EV news site Electrek, “Hell froze over in Texas – the state will connect to the US grid for the first time via a fed grant,” drew most of the attention.
PUC Chair Thomas Gleeson said inquiries from a politician or two prompted him to issue a statement Oct. 4, the day after the DOE announcement.
“While the Southern Spirit Transmission line would cross multiple state lines, the Texas grid will remain independent from the national grid and would not be subject to any federal oversight,” he said.
Gleeson, like Vegas, noted ERCOT already has the four DC ties with its neighbors. “They do not have any impact on the independence of the Texas grid,” he said.
Southern Spirit, a merchant transmission line more than a decade in the making, would provide a 320-mile, HVDC link from Texas capable of carrying 3 GW of power either way. While it was originally designed to move renewable energy to the Southeast, some reports have framed the project as saving Texas should there ever be a repeat of the 2021 winter storm that almost brought down the ERCOT grid.
DC ties approved under Sections 210 and 211 of the Federal Power Act do not pose a risk to ERCOT’s independence, Vegas said. FERC says the Texas grid is not jurisdictional because it is not synchronously connected to the other two interconnections and thus its power sales are not considered interstate commerce and not subject to oversight.
Vegas said the 19 switchable units that can provide about 4 GW of power to either ERCOT or the Eastern Interconnection are “an incredible asset to us,” offering them as an alternative to DC ties.
“DC ties could [solve the reliability problem], but I think they need to be fairly evaluated from all of these factors to really understand what is the best investment for the ERCOT consumers when it comes to investing in reliability and the economic potential of more infrastructure,” he said.
FERC approved the Southern Spirit project, previously named Southern Cross, in 2014. The Texas PUC followed suit in 2017, approving Garland Power & Light’s application for a permit to build a 38-mile, 345-kV line connecting ERCOT to a Pattern Energy DC converter station in the Eastern Interconnection.
The PUC also established 14 tasks, or directives, for ERCOT to complete in accommodating Southern Spirit. The commission closed the project in 2022, saying it agreed with the ISO’s solutions.
The project got a major boost in August when the Louisiana Public Service Commission approved it, 3-2. However, that also opened an appeals window from landowners and lawmakers who have opposed the project. Mississippi regulators have not yet signed off on the project.
If Southern Spirit is fully approved, Pattern Energy says it would begin construction in 2026 and enter commercial operation in 2029. The company plans to invest $2.6 billion in Southern Spirit, which is eligible for up to $360 million in DOE financing support.
