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Transmission Line Projects



The Office of Energy and Mineral Resources (OEMR) was created by Idaho Governor C. L. “Butch” Otter by executive order in part to help secure the state’s energy outlook. Toward that goal, the OEMR leads Idaho’s efforts to help facilitate the development of critical transmission projects as they emerge. There are numerous active transmission proposals that have expressed intent to locate within Idaho’s borders, such as the Gateway West Transmission line and the Boardman to Hemingway line.



The interconnected transmission system in the west is at or near capacity and many constrained paths have been identified. The existing bottlenecks in the power grid could create serious disruptions, just like a clot in an artery, resulting in an overall negative impact in the region that could also impair Idaho’s economic outlooks. New transmission facilities are essential to maintaining and enhancing economic opportunities that directly benefit Idaho and the region.

An additional consideration for new, needed transmission infrastructure is to develop Idaho’s renewable resources, such as wind, geothermal, solar, and bioenergy. Renewable resources are often located far from existing transmission lines, and accordingly, these resources are dependent upon new transmission projects. New transmission projects can provide the additional capacity necessary to assist in the development of renewable resources.

The expense associated with high capacity transmission projects ranges from $1.6 million to $2.6 million per mile. Delays or siting conflicts could add significant and perhaps unnecessary costs to projects. In some circumstances, financial considerations associated with these issues could ultimately stall a critical project.

The need for transmission to move power to growing loads and population centers becomes more and more critical as forecasted loads in the west continue to grow and the desire to develop more renewable resources increases. The region is preparing to embark on a period of significant transmission build out in order to meet these needs. Accordingly, Idaho must prepare itself for this requisite by establishing a harmonized effort with the federal, tribal, and state agencies, departments, divisions, and local governments for the purpose of insuring that Idaho’s energy needs are satisfied.

Transmission line corridors, some of which span hundreds of miles, cross many jurisdictional boundaries by definition. Both transmission and distribution substations serve arising electrical loads, regardless of these jurisdictional boundaries. Therefore, designation of corridors and substation sites in the utilities elements of the comprehensive plans in not just strictly a local matter. The placement of utility facilities is, in fact, both a local and interjurisdictional matter (and also a matter of state interest). Like a highway, transmission and distribution lines must run and connect across local boundaries. And like a regional or community park serving a cross-jurisdiction population, substations must be located to best serve loads crossing local boundaries.

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Map Courtesy of: U.S. Bureau of Land Management

The Gateway West Transmission line project is jointly proposed by Rocky Mountain Power and Idaho Power, who intend to build and operate approximately 1,000 miles of new high-voltage transmission lines between the Windstar Substation near Glenrock, Wyoming and the Hemingway Substation near Melba, Idaho. The project would include approximately 150 miles of 230 kilovolt (kV) lines in Wyoming and approximately 850 miles of 500 kV lines in Wyoming and Idaho.

The Bureau of Land Management (BLM) is the lead federal agency conducting the environmental review and analysis as part of the National Environmental Policy Act (NEPA) process. The BLM released its Record of Decision (ROD) on November 14, 2013, for segments 1 through 7 (Windstar to Populus, Populus to Midpoint and Populus to Cedar Hill) and segment 10 (Midpoint to Cedar Hill) of the project. It identifies the BLM authorized route on public land. The ROD is available on the BLM website at:

The BLM postponed the decision on segments 8 (Midpoint to Hemingway) and 9 (Cedar Hill to Hemingway) to resolve routing in this area. BLM released the Final EIS for Segments 8 and 9 in October, 2016.  The State of Idaho and local jurisdictions oppose the Agency Preferred Route BLM identified in the 2016 FEIS.  Read the State of Idaho’s Comments on the Draft EIS: 2016 State of Idaho Comments on the Gateway West Draft SEIS

The OER serves as the state of Idaho’s cooperating agency on the project.

Responsive imageMap Courtesy of: U.S. Bureau of Land Management

PacifiCorp, Bonneville Power Administration (BPA), and Idaho Power jointly propose to design, construct, operate and maintain a new 500 kilovolt, single-circuit electric transmission line from a proposed substation near Boardman, Oregon to the Hemingway Substation near Melba, Idaho. The project would include approximately 300 miles of 500 kV lines in Idaho and Oregon.

The Bureau of Land Management (BLM) is the lead federal agency conducting the environmental review and analysis as part of the National Environmental Policy Act (NEPA) process. The BLM released the Final Environmental Impact Statement on November 25, 2016.

The OER serves as the state of Idaho’s cooperating agency on the project.

For more information on the Boardman to Hemingway project, please visit the project website at:

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Map Courtesy of: Bonneville Power Administration


Bonneville Power Administration (BPA) proposes to build a new 115-kilovolt (kV) transmission line that would extend from BPA’s proposed Hooper Springs Substation near the city of Soda Springs, Idaho, to a new BPA connection facility that will connect the new line to Lower Valley Energy’s (LVE) existing transmission system in northeastern Caribou County. The project is needed to improve voltage stability on the transmission grid to meet future load growth in southeast Idaho and northwestern Wyoming.

BPA is a federal agency in the Pacific Northwest that owns and operates about three-fourths of the high-voltage transmission lines in its service territory.  LVE and Fall River Electric Cooperative are BPA customers who purchase all, or almost all, of the electric power required to serve their loads in Eastern Idaho from BPA.

BPA released the Record of Decision for the Hooper Springs project in March 2015, and is currently in the process of negotiating with landowners to secure the rights-of-way necessary to construct the transmission line and ancillary facilities.

The ROD is available on BPA’s website here: