Powered by ZigaForm version

The Last Mile Transmission Project

May 3, 2023 Public Open House

Innergex held a drop-in style Open House on May 3, 2023, in the Rock River Town Hall, from 5:30 to 7:30 PM. See here the panels that were on display.

Thanks to all who joined!

Innergex, through its affiliate Last Mile Transmission, LLC, is constructing a 34.5 mile 230 kilovolt generation-tie line running largely east-west between PacifiCorp’s existing Freezeout Substation in Carbon County, WY, northeast of Medicine Bow and the future Boswell Springs substation approximately 14 miles northeast of Rock River in Albany County. This Last Mile Transmission Line Project (“Last Mile”) will cross privately-owned lands in both Carbon and Albany Counties and lands administered by the Bureau of Land Management and the State of Wyoming.

Last Mile will use a combination of wooden H-frame and single steel pole transmission structures, spaced ~700-900 feet apart, with each structure being ~75-110 feet in height (150 feet maximum).

Purpose and need for the project

In 2020, PacifiCorp initiated an all-source Request for Proposals (“2020AS RFP”) to solicit competitively priced energy resources that can meet the region’s energy needs. Innergex’s Boswell Springs Wind Project was awarded a Power Purchase Agreement through the 2020AS RFP process and Last Mile is the line that will connect the Boswell Springs Wind Project with PacifiCorp’s electrical grid. The need for this type of transmission collector system had been identified by the Wyoming Infrastructure Authority (“WIA”) and PacifiCorp. The WIA identified this target area for a transmission collector system and transmission export hub as part of the Wyoming Collector and Transmission System Conceptual Design (WIA 2010). Together, the projects bring considerable benefits to the region.

Community Benefits

Innergex’s philosophy has always been to develop and operate reliable, high-quality projects while respecting the environment and balancing the best interests of communities and partners. Thus, when developing a project, Innergex believes in maximizing local benefits, such as giving preference to hiring local people, consultants, businesses, and contractors.

In addition to construction and employment expenditures, the Last Mile Project is expected to pay $763K in sales and use taxes, distributed to the State of Wyoming, Carbon County, and Albany County.

The Project will generate increased yearly tax revenue for state and local governments from property taxes based on the Project’s assessed value, starting at an estimated $119K in 2025, once the line is fully constructed. These revenues will directly benefit the State School Fund, the Carbon County General Fund, Carbon County School District #2, the Medicine Bow Health District, the Medicine Bow Conservation District and other county facilities and tax districts.


Siting considerations

Innergex evaluated nearly a dozen potential routes for the project, taking into account many significant constraints. This final design represents the shortest transmission line route possible to minimize physical and visual impacts, with several considerations including landowner interest, constructability, engineering and environment constraints, avoidance of subdivisions/towns, setbacks, etc.

The project area is relatively flat, characterized by rolling plains and primarily used for grazing. This Project is very compatible with existing and future ranching or agricultural operations which can continue throughout the life of the Project, including during construction. In addition, the post-construction right-of-way will be reclaimed to the minimum footprint needed for long-term operation and maintenance of the line, maximizing the amount of land available for ranching and agricultural activities.

Development of the Last Mile Project required environmental impact analyses and studies as part of the permitting process, especially with respect to the land managed by the Bureau of Land Management (“BLM”). No BLM Areas of Critical Environmental Concern, BLM Natural Areas, or designated wilderness areas are present in the project area. The Project also avoids the Como Bluff National Natural Landmark.


About Innergex

Founded in 1990, Innergex is an independent renewable power producer which develops, constructs, acquires, owns, and operates hydroelectric, wind, solar and energy storage facilities. Innergex is a long-term owner and operator of clean energy projects located in the United States, Canada, Chile, and France. Innergex is also the owner of the 330 MW Boswell Springs Wind Project in Albany County (www.boswellspringswind.com).


Project funding

Innergex will be responsible for 100% of the development, financing, construction, and start-up costs. After completion, Innergex will also be responsible for all operational and maintenance costs, as well as all decommissioning costs.


The Last Mile Project concluded a National Environmental Policy Act (NEPA) review with the BLM, obtained an easement for crossing a state parcel, and obtained a Conditional Use Permit with Carbon County in May 2022; as part of this process, public hearings were held with the Carbon County Planning and Zoning Commission and with the Board of County Commissioners.

Construction of the Last Mile Transmission Project begun in January 2023. Last Mile will interconnect the Boswell Springs Wind Project (also owned by Innergex) which has its own construction process. Major construction efforts on the Boswell Springs Wind Project have ramped-up in June 2023. The intention is to have both projects operational by October – December 2024.


December 7, 2022 Virtual Public Open House

  • Find the meeting slides here.
  • See the recording of the event here.


To download the Last Mile Project Brochure

To download the Application for Conditional Use Permit

Contact us

It is important to Innergex that we keep you informed as we go forward with this potential Project and to be a good community partner and neighbor. Please contact us if you have any questions or comments:


Last Mile, C/O Innergex Renewable Energy
3636 Nobel Drive, Suite 260,
San Diego, CA, 92122