Completed Project Milestones

The following timeline includes completed project activities.


Project concept development
  • Worked with regional planning groups to analyze transmission needs
  • Preliminary line design informed by regional plans
  • Preliminary routing possibilities scoped using existing linear infrastructure as a requirement
  • Proof of concept technical studies


Early public meetings to share information and receive input on routing options
  • Public engagement to inform route development
  • Early meetings with residents, local governments, NGOs, agencies, transmission providers and other stakeholders to share information and receive input on potential routing alternatives


Initiation of National Environmental Policy Act (NEPA) Process
  • Bureau of Land Management (BLM) and Western Area Power Administration (WAPA) initiate the NEPA process
  • Public scoping meetings for NEPA
  • Scoping report released
  • Ongoing permitting with federal/state/local governments/agencies
  • Enter WECC Path Rating Phase 1


  • Prepare Administrative Draft of Environmental Impact Statement
  • BLM and WAPA release Draft Environmental Impact Statement (DEIS) and conduct public comment period
  • The Draft EIS is available on the BLM website. The Project Alternatives Map is available for download here. The posters displayed by the Southline Transmission Project team at the DEIS public hearings are available for download here.


  • WECC Path Rating Phase 2
  • WECC Path Rating Phase 3 Status Granted
  • FERC Granted PDO - On Sept. 17, 2015, the Federal Energy Regulatory Commission (FERC) granted a Petition for Declaratory Order (PDO), which was jointly filed in May 2015 by two entities related to the Project – Southline Transmission, L.L.C., and SU FERC, L.L.C. (SU FERC). Specifically, the PDO granted SU FERC’s request for negotiated rate authority and approved its proposed open solicitation process.


  • FEIS - The FEIS is available on the BLM project website.
  • BLM & WAPA ROD - The RODs represent the endpoint of the EIS process, stating the decisions of the agencies and providing background on the process. The RODs outline the options, as well as mitigation, enforcement, and monitoring commitments. The RODs are available on the BLM project and WAPA project websites.
  • BLM ROW - The BLM ROD approves the issuance of a right-of-way (ROW) grant for the construction, operation, maintenance, and eventual decommissioning of the Project.
  • Open Solicitation Information about the Southline Transmission Project's open solicitation process for capacity negotiations, can be found here.


  • ACC Approval - All documents related to the Southline Transmission Project’s application for a Certificate of Environmental Compatibility with the Arizona Corporation Commission are available on the ACC website. The docket number is: L-00000AAA-16-0370-00173.
  • NMPRC Approval - The Southline Transmission Project applied to the New Mexico Public Regulation Commission (NMPRC) for approval of project location and determination of right-of-way width. Approval was granted in August 2017 and the Final Order is available here.


  • New Mexico State Land Office Moves Southline Transmission Project Forward (December 2018)