Public Service Company of Colorado Submits Transmission to Transmission Interconnection System Impact Study Agreement

Strategic Insights -

Public Service Company of Colorado has submitted a document to the Federal Energy Regulatory Commission (FERC) regarding a transmission-to-transmission interconnection system impact study agreement with Three Corners Connector LLC (TCC), a project by Grid United LLC aiming to link the Eastern and Western U.S. electric grids. The $1.5 billion project aims to enhance grid reliability, enable the flow of clean and affordable energy across regions, and support economic growth through improved energy infrastructure and market access. The agreement provides the terms and conditions for a study of TCC's request for a transmission-to-transmission interconnection request for a proposed 1,800 MW bi-directional Voltage Source Converter (VSC) Bipole HVDC transmission line.

Key Takeaways:

  • The Public Service Company of Colorado (PSCo) has submitted a transmission-to-transmission interconnection system impact study agreement with Three Corners Connector LLC (TCC) for a proposed 1,800 MW bi-directional Voltage Source Converter (VSC) Bipole HVDC transmission line.
  • The project aims to link the Eastern and Western U.S. electric grids and enhance grid reliability, enable the flow of clean and affordable energy across regions, and support economic growth through improved energy infrastructure and market access.
  • The agreement is modeled upon the pro forma system impact study agreement in Attachment K of the Xcel Energy OATT for transmission service requests.
  • PSCo has begun the study work under the agreement and requests a waiver of prior notice requirements to allow expeditious completion of the study.
  • The agreement includes a clean version of Service Agreement No. 847-PSCo and a redline version of Service Agreement No. 847-PSCo against the conforming version of Attachment K-1.
  • Communications and correspondence related to this filing should be directed to Jessica A. Willey.

Statistics:

  • The project aims to cover a distance of approximately 300 miles.
  • The project has an estimated cost of $1.5 billion.
  • The proposed transmission line will have a capacity of 1,800 MW.
  • The transmission line will be a bi-directional Voltage Source Converter (VSC) Bipole HVDC transmission line.
  • The study will be conducted to assess the potential impact of the transmission line on the grid.

Sources:

  • Federal Energy Regulatory Commission (FERC), 16 U.S.C. SSS 824d (2018).
  • Xcel Energy Operating Companies Joint Open Access Transmission Tariff (Xcel Energy OATT), on file with and accepted by the Commission in Docket No. ER16-1422-000.
  • Three Corners Connector LLC (TCC) press release, dated June 18, 2025.