Great Falls Transmission Line Replacement Project

Great Falls 100kV Generation Interconnection Replacement Project

Great Falls, Montana

PPL Montana’s $55-million Great Falls 100kV Generation Interconnection Replacement Project included the replacement of aging 100kV lines and wooden H-frame structures along a 10-mile corridor and supporting infrastructure. The 10-mile 100kV-line corridor interconnects four of Project 2188’s hydroelectric facilities, including Rainbow, Cochrane, Ryan, and Morony dams located on the Missouri River to NorthWestern Energy’s (NWE) substation for distribution.

New Wave staff provided oversight and management support services for the environmental regulatory compliance of all federal, state, and local regulatory requirements, as well as consultation with private landowners during the initial planning phase, through construction, and post-construction.

Project Activities

  • Relocation of the existing line termination from NorthWestern Energy’s (NWE) existing Rainbow substation to NWE’s new Crooked Falls substation
  • Replacement of the line terminations at Rainbow, Ryan, Cochrane, and Morony hydroelectric facilities
  • Replacement of the aging H-frame structures and 100kV lines along a 10-mile corridor
  • Replacement and relocation of the Morony substation from the dam structure to upland location
  • Maintenance and upgrades to the existing Cochrane substation located on the dam structure
  • Replacement and removal of 100kV lines over Section 10 waters

Environmental compliance services included identification and development of a schedule of proposed activities associated with the project, the construction schedule, and key milestones. From these pieces of information, an environmental matrix was created to identify a comprehensive list of regulatory requirements, including license compliance with FERC. The list identified the regulatory requirement, responsible parties, submittal dates, and agency review schedules.


  • Agency Consultation
  • Biological Evaluation
  • BNSF Right-of-Way and Regulatory Compliance
  • Consultation with Agencies
  • Erosion and Sediment Control Plan
  • FERC License Compliance
  • Major Facility Siting Act
  • NHPA Section 106 Compliance
  • Revegetation and Noxious Weed Plan and Monitoring
  • Section 10 of the Rivers and Harbors Act
  • Section 404 of the Clean Water Act
  • Threatened and Endangered Species Review