Nira’s latest ERCOT scope models the region’s planned 765 kV expansion, offering a preview of how higher-voltage infrastructure could reshape generation and load interconnection outcomes.

ERCOT’s transmission system has long operated at 345 kV, a reliable foundation for decades of steady growth. But that system is now stretched thin. Texas is adding roughly 50 GW of new demand from data centers, industrial facilities, and electrification, while also managing a surge of renewable generation projects.

The result: rising congestion, limited transfer capability, and $1.97 billion in congestion costs in 2024 alone. The existing backbone is effectively at capacity, and new generation and load interconnections are increasingly difficult to accommodate.

ERCOT’s Regional Transmission Plan (RTP) for 2026–2030 evaluated multiple options to expand this backbone. Two primary solutions emerged:

• Enhanced 345 kV upgrades

• A new 765 kV high-voltage overlay

The studies found the 765 kV plan to be more cost-effective over time. Higher voltage means lower resistance, fewer losses, and greater transfer capacity, enabling bulk power to flow farther and more efficiently between generation and load centers.

Inside ERCOT’s 765 kV Plan

Following PUCT approval of the Permian Basin Reliability Plan in October 2024 and the voltage decision in April 2025, the Phase I 765 kV upgrade projects are advancing forward, targeting a 2030 in-service date.

• Elimination of 1,443 miles of existing upgrades and 434 fewer miles of new Right of Way (ROW) versus the alternative 345 kV projects

• Projected benefits:

  • $229 M in annual consumer savings

  • 560 GWh/year reduction in transmission losses

  • 600 – 3,000 MW increase in transfer capability

In short: ERCOT is building a new high-voltage spine to relieve congestion, improve reliability, and prepare for sustained load growth across Texas. Currently, these upgrades are not reflected in ERCOT’s base models. The 2029 SSWG cases do not yet include the 765 kV lines.

To bridge that gap, Nira created a new ERCOT prospecting scope that models the impact of the proposed 765 kV infrastructure using the Phase I RTP topology.

Our engineers extracted the 765 kV line and substation configurations from ERCOT’s most recent regional plan and integrated them into Nira’s generation and load interconnection models. This includes both the Permian Basin upgrades as well as the Eastern 765 kV lines. This enables users to assess how future transmission expansion could change available capacity and congestion patterns — years before these lines enter service.

While this scope focuses on system upgrades, it does not yet include future large-load projects such as proposed data centers beyond what is already implemented in the SSWG base cases. Nira is working closely with industry experts to develop a framework for incorporating more speculative load forecasts on top of current models, providing a clearer picture of how upcoming demand could interact with ERCOT’s planned 765 kV network.

Even without those speculative loads, the results from Nira’s current modeling show a dramatic increase in available load capacity under the 765 kV configuration, underscoring the importance of this new infrastructure in meeting Texas’s future demand.

Early Results

Generation Perspective

• Across 887 buses, approximately 14% of the system, shows an increase in available interconnection capacity.

• Areas with high renewable penetration, particularly solar in West Texas, see the greatest improvements in transfer margins.

• System-wide efficiency improves as higher voltage reduces resistive losses and line loading.

Load Perspective

• The new ERCOT 765 kV infrastructure enables substantial datacenter and load interconnection capacity across the system.

• Approximately 37% of ERCOT buses show significant capacity increases under current load forecasts, marking a notable improvement in system flexibility.

• Next steps include developing an additional forward-looking scope (in ERCOT, as well as other ISO/utility regions) that incorporates multiple GW of prospective datacenter deployments. In ERCOT, the inclusion of the 765 kV plan will help to ensure that this future datacenter load will be adequately served by the system.