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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 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

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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