The Texas Public Utility Commission’s staff has recommended that the commission approve construction of three 765-kV transmission lines, rather than 345-kV lines, into the petroleum-rich Permian Basin to improve the region’s reliability (55718). 

Staff said in an April 17 memo that after “careful deliberation,” they found the 765-kV import paths’ long-term benefits justify an additional 22% increase in estimated capital costs.  

Based on confidential cost filings from transmission providers and updated estimates from ERCOT, staff said the 765-kV option’s expenses have increased from $9.06 billion to $10.11 billion. In comparison, the 345-kV option has increased from $7.69 billion to $8.28 billion. 

“Staff is convinced that the commission has a unique opportunity to timely address ERCOT’s current and expected rapid load growth by deploying an extra-high-voltage transmission network at a reasonable economic cost,” they wrote. “This decision balances forecast uncertainty, cost and reliability with establishing a forward-thinking policy decision that ably prepares the ERCOT region for the future.” 

The PUC is expected to discuss the recommendation at its April 24 meeting. The commissioners have promised a decision by May. 

Staff said 765-kV lines’ lower impedance than that of 345-kV lines increases power flows. They said ERCOT indicates the 345-kV plan has an incremental transfer capability of 1,340 MW while the 765-kV plan can transfer 2,105 MW. 

“The higher value for the 765-kV transfer indicates it can carry more power, and therefore serve additional load in the Permian,” staff said, noting the “uncertainty inherent in forecasting load out as far as 2038.” 

“The ability to serve more load could offer a buffer for the 2038 load forecast and may avoid or delay the need to build additional transfer paths in the near future,” they said. “Therefore, the increased capital cost of installing 765-kV infrastructure could function as a present investment that may save additional infrastructure costs in the future.” 

Staff also said the 765-kV option’s transfer capability will help ERCOT better manage the “uncertainty surrounding load and generation siting decisions” and the flexibility for power flows to shift due to changes in location and the nature of future load and generation. 

Because the 765-kV plan allows greater transfer capability, ERCOT designed the 765-kV plan using only three paths totaling about 1,255 miles of right-of-way, staff said. The 345-kV plan, with five paths, would require about 1,676 miles of ROW. 

The lines, if built, could be Texas’ first. SPP in December approved a transmission plan that included its first 765-kV project in Southwestern Public Service Co.’s West Texas and New Mexico region. (See SPP Board Approves $7.65B ITP, Delays Contentious Issue.) 

“765-kV technology may be new to Texas, but it is not a new technology,” staff said, pointing to American Electric Power’s “decades of experience” with EHV lines. AEP has offered other transmission providers access to its 765-kV standards and guidance, they said. 

ERCOT, at the PUC’s direction, filed its reliability plan for the Permian Basin in July 2024. The plan included the 345-kV and 765-kV import paths and a 2038 need date. The commission approved the plan in October 2024 but reserved a decision on the voltage level by May 2025. (See Texas PUC Approves Permian Reliability Plan.)