STATE OF CALIFORNIA
PUBLIC UTILITIES COMMISSION

Welcome to the California Public Utilities Commission (CPUC) website for the California Environmental Quality Act (CEQA) Review of the Ironwood Transmission Line Project (project) proposed by Horizon West Transmission, LLC (applicant or HWT). An application (A.25-09-008) for the project was submitted to the CPUC on September 22, 2025 and includes the Proponent’s Environmental Assessment (PEA) prepared pursuant to Rule 2.4 of the CPUC’s Rules of Practice and Procedure. Click here to access the Formal Proceeding website.

The CPUC is the CEQA Lead Agency for this project. This site provides access to public documents and information relevant to the CEQA review process. Additional project information and documentation will be posted as it becomes available. The U.S. Bureau of Land Management (BLM) is anticipated to be the Lead Agency for the National Environmental Policy Act (NEPA).

Horizon West Transmission, LLC proposes the construction and operation of an approximately 86-mile-long 500 kilovolt (kV) transmission line from Arizona Public Service Company’s (APS) North Gila substation to San Diego Gas & Electric Company’s (SDG&E) Imperial Valley substation. Approximately 80 miles of the project are in California. An overview of the proposed project is shown on Figure 1.1.

Approximately 80 miles of the 86-mile-long project located in California crosses unincorporated lands in Imperial County, the City of Calexico, and public lands under the jurisdiction or management of the BLM, U.S. Bureau of Reclamation, and California Department of Parks and Recreation. HWT would acquire a new 250-foot-wide right of way for the proposed project. To the extent possible, HWT proposes to use existing access roads and trails associated with the existing Southwest Powerlink transmission line, pipelines, highways, and county roads.

The proposed project is intended to mitigate delivery constraints as identified by the California Independent System Operator (CAISO). As described in CAISO’s 2022-2023 Transmission Plan, deliverability of energy resources east of the existing SDG&E Miguel substation, located in San Diego County, is limited by thermal overloading of existing lines and transformers. The proposed project was selected by CAISO as a preferred transmission upgrade to mitigate these deliverability constraints.

Review of Application and Proponent’s Environmental Assessment

• Application and Proponent’s Environmental Assessment submitted September 22, 2025
  • Application
  • Proponent’s Environmental Assessment
  • Appendix A Detailed Maps and Design Drawings
  • Appendix B Emissions Calculations
  • Appendix C Biological Resources
  • Appendix D Cultural Resources Study
  • Appendix E Native American Heritage Commission Sacred Lands File Search Contact List
  • Appendix F Environmental Data Resources Report
  • Appendix G Public Outreach Materials
  • Appendix H Wildfire Mitigation Plans
  • Appendix I Supporting Noise Information
  • Appendix J Visual Resources Technical Report
  • Appendix K Routing Study
  • Appendix L Weather Data
• Deficiency Letter #1 dated October 22, 2025
  • Deficiency Letter #1
  • Detailed Comments on Required Appendices and Supporting Materials
  • Detailed Comment on the Cover
  • Detailed Comment on Formatting and Basic PEA Data Needs
  • Detailed Comment on Section 1 Executive Summary
  • Detailed Comment on Section 2 Introduction
  • Detailed Comment on Section 3 Proposed Project Description
  • Detailed Comment on Section 4 Description of Alternatives
  • Detailed Comment on Section 5 Environmental Analysis General Requirements
  • Detailed Comment on Section 5.1 Aesthetics
  • Detailed Comment on Section 5.2 Agricultural and Forestry Resources
  • Detailed Comment on Section 5.3 Air Quality (submitted to HWT under separate cover on 11/17/25)
  • Detailed Comment on Section 5.4 Biological Resources
  • Detailed Comment on Section 5.5 Cultural Resources
  • Detailed Comment on Section 5.6 Energy
  • Detailed Comment on Section 5.7 Geology, Soils, and Paleontology
  • Detailed Comments on Section 5.8 Greenhouse Gas Emissions (submitted to HWT under separate cover on 11/17/25)
  • Detailed Comments on Section 5.9 Hazards, Hazardous Materials, and Public Safety (submitted to HWT under separate cover on 10/23/25)
  • Detailed Comments on Section 5.10 Hydrology and Water Quality
  • Detailed Comments on Section 5.11 Land Use and Planning
  • Detailed Comments on Section 5.12 Mineral Resources
  • Detailed Comments on Section 5.13 Noise (submitted to HWT under separate cover on 11/17/25)
  • Detailed Comments on Section 5.14 Population and Housing
  • Detailed Comments on Section 5.15 Public Services
  • Detailed Comments on Section 5.16 Recreation
  • Detailed Comments on Section 5.17 Transportation
  • Detailed Comments on Section 5.18 Tribal Cultural Resources
  • Detailed Comments on Section 5.19 Utilities and Service Systems
  • Detailed Comments on Section 5.20 Wildfire (submitted to HWT under separate cover on 10/23/25)
  • Detailed Comments on Section 5.21 Mandatory Findings of Significance
  • Detailed Comments on Section 6 Comparison of Alternatives
  • Detailed Comments on Section 7 Cumulative Impacts and Other CEQA Considerations
  • Detailed Comments on Section 8 List of Preparers
  • Detailed Comments on Section 9 References

For Additional Information

To request additional information or to be added to the mailing list, please contact CPUC's Project Manager:

Boris Sanchez
California Public Utilties Commission
505 Van Ness Avenue
San Francisco, CA 94102
Email: IronwoodTransmissionProject@kearnswest.com
Project phone #: (760) 359-8733