Grid United: Uniting Regions of the US Power Grid With HVDC

By focusing on interregional transmission projects, Grid United is working to address one of the most significant challenges in the U.S. energy transition: bridging the east-west divide in the power grid. This approach aims to support the integration of renewable energy sources and help meet the growing demand for electricity across the country.

To achieve this aim, Grid United are currently involved in the development of three major HVDC projects in the US:

North Plains Connector

The North Plains Connector (NPC) is a proposed 3000 MW, 420-mile, 525kV HVDC transmission line, connecting Montana and North Dakota. The transmission system will extend from an existing AC substation in Colstrip, Montana, to two separate points in North Dakota: near the town of Center and near St. Anthony. This ambitious project will interconnect three regional U.S. electric energy markets: the Midcontinent Independent System Operator (MISO), the Western Interconnection, and the Southwest Power Pool (SPP).

Currently in the permitting phase and initiating regulatory filings, the North Plains Connector is expected to receive approvals by 2026, with construction commencing in 2028 and operations projected to begin in 2032. The project promises significant benefits, including facilitatiing the sharing of energy resources across multiple time zones, more than doubling the transfer capacity between eastern and western U.S. electric grids and easing congestion on existing western transmission systems.

The project will also support the integration of renewable energy sources and help mitigate the impact of extreme weather events.

The project has attracted several major energy companies and utilities as stakeholders. Grid United leads the development of the North Plains Connector, with ALLETE Inc. serving as a joint developer. Portland General Electric (PGE) has signed a Memorandum of Understanding (MOU) for 600 MW of transfer capacity, while BHE U.S. Transmission, Puget Sound Energy (PSE), NorthWestern Energy, and Avista Corporation have all signed MOUs for various ownership stakes in the project.

Pecos West Intertie

The Pecos West Intertie is a HVDC transmission line that's expected to span approximately 280-300 miles, with an initial capacity of 1,500 MW at ±525 kV, with potential for expansion up to 3,000 MW. The transmission line will connect Bakersfield in Pecos County, Texas (ERCOT region) to El Paso (Western Electricity Coordinating Council region). The Pecos West Intertie aims to connect the Electric Reliability Council of Texas (ERCOT) grid with the Western Interconnection, providing numerous benefits to the Texas power system.

This connection could help maintain power supply during severe weather events or other emergencies. The project is expected to reduce renewable energy curtailment and increase the integration of renewable resources by mitigating low-frequency and voltage oscillations. It will create new markets for power producers and facilitate power exchange between ERCOT and the Western Interconnection. The HVDC technology allows for independent control of active and reactive power, providing ERCOT operators with additional flexibility in day-to-day grid operations. Additionally, the converter stations can provide dynamic voltage response, similar to a 500 MVAR STATCOM, helping to stabilize the grid.

The project has faced some regulatory challenges. Grid United filed for a Certificate of Convenience and Necessity (CCN) with the Public Utility Commission of Texas (PUCT) on July 5, 2022. However, the PUCT rejected the CCN application, citing the state's right of first refusal law. Despite this setback, Grid United continues to pursue the project, emphasizing its potential benefits for Texas energy infrastructure.

Three Corners Connector

The Three Corners Connector is a HVDC transmission line that will connect the electric grids of the eastern and western United States. The project involves constructing a 290-mile, 525 kilovolt HVDC transmission line between Pueblo, Colorado and Guymon, Oklahoma. The primary goals of the Three Corners Connector are to alleviate transmission congestion, mitigate the impacts of extreme weather events, lower costs for consumers, and provide economic benefits to the regions it passes through. The project will have a transfer capacity of 3,000 MW ±525 kV, allowing power transfer between the Eastern and Western Interconnections.

As of January 2025, the Three Corners Connector is still in the planning and development phase. Key milestones include the route evaluation, stakeholder outreach, and initial engineering conducted in 2022-2023. The expected finalization of route analysis and initiation of regulatory filings is set for 2025. The projected start of transmission line construction is scheduled for 2027, with estimated completion and operational date between 2028-2031.

While the project has made significant progress, it still faces several challenges. These include obtaining final regulatory approvals, expected in 2025, securing remaining land rights, addressing potential environmental and community impacts, and coordinating with local, state, and federal permitting authorities.

Conclusion

As Grid United continues to forge partnerships with major utilities and secure federal support, these HVDC projects are set to substantially improve the grid infrastructure in the United States. The company's flagship project, the North Plains Connector, set to be operational by 2032, will be the first HVDC transmission link to connect three regional U.S. electric energy markets. Further, Grid United is collaborating with Hitachi Energy to develop multiple HVDC interconnections that will dramatically boost transmission capacity across the country

Grid United is an independent transmission company founded in 2021 with a mission to modernize and strengthen the United States power grid.The company focuses on developing utility-scale electric transmission projects to enhance grid resilience, improve reliability, and provide long-term economic benefits to communities.

Click here for more information on Grid United's projects

‍