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United States. Federal Energy Regulatory Commission

Great Basin Transmission, LLC Seeks Expedited Approval for SWIP-North Transmission Line

Strategic Insights

— 2 min read

As part of the SWIP-North project, Great Basin Transmission, LLC is seeking expedited approval for the Southwest Intertie Project-North Transmission Line from the Federal Energy Regulatory Commission (FERC). The project involves the construction of a 500 MW transmission line in Idaho, which will provide a vital link between the western and eastern power grids. Great Basin has filed an amended tariff application that reduces its requested return on equity (ROE) and limits the equity portion of its capital structure. The company has also secured a federal backstop commitment from the U.S. Department of Energy (DOE) to ensure the project's viability, regardless of the outcome of the Idaho Power Company's (Idaho Power) Certificate of Public Convenience and Necessity (CPCN) application.

Key Takeaways:

  • Great Basin Transmission, LLC has submitted a motion to answer the protests of the Minidoka Pilgrimage Planning Committee and Hidden Valley Organic.
  • The company's amended tariff application reduces its requested return on equity (ROE) to 10.3% and limits the equity portion of its capital structure to 51%.
  • The U.S. Department of Energy (DOE) has executed a capacity reservation agreement with Great Basin, ensuring the project's viability and public-interest benefits.
  • The Idaho Power Company's (Idaho Power) CPCN application is immaterial to the Commission's consideration of the amended tariff and requested rate incentives.
  • The California Intervenors, including the California Public Utilities Commission, Northern California Power Agency, and California Department of Water Resources State Water Project, have withdrawn their protests and opposition to Great Basin's proposed TO Tariff and requests for incentive rate treatment.
  • Great Basin has requested expedited action on the application, citing the reduced rate request and withdrawal of protests.
  • The Minidoka Pilgrimage Planning Committee's Motion to Protest acknowledges that its objections are outside the scope of the Federal Power Act.

Statistics:

  • 500 MW: The capacity of the Southwest Intertie Project-North Transmission Line.
  • 77.169%: Great Basin's ownership percentage in the project, which will be retained by the company in exchange for operational control of its entitlements.
  • 22.831%: The remaining northbound capacity on SWIP-North, which is subject to the DOE backstop capacity commitments.
  • 250 MW: The amount of capacity that Idaho Power will seek to acquire in the CPCN proceeding.
  • 10.3%: Great Basin's reduced requested return on equity (ROE) under the amended tariff application.

Sources:

  • United States of America Before the Federal Energy Regulatory Commission (Great Basin Transmission, LLC, Docket No. ER25-2025-001)
  • Great Basin Transmission, LLC, Amendment to Tariff Filing, Docket No. ER25-2025-001 (June 19, 2025)
  • U.S. Department of Energy, Grid Deployment Office, "Transmission Facilitation Program," (last visited July 16, 2025)
  • Minidoka Pilgrimage Planning Committee, Motion for Leave to Protest, Docket No. ER25-2025-001 (July 11, 2025)

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