Sugarmill to Paine 161kV Transmission Line

01 April 21

Construction is currently underway to improve power transmission capacity and provide needed reliability investments to the power system serving the northern portion of the City of Idaho Falls and also benefitting all of eastern Idaho’s transmission grid.

Idaho Falls Power, along with PacifiCorp, is constructing a 14-mile 161kV Transmission line connecting the Sugarmill Substation along Hitt Road and extend across Lincoln and Yellowstone. The line will cross over U.S. Highway 20 near 25th then travel to the west and across the Snake River to the future Paine Substation, which is also under construction.

The transmission line and the Paine substation are expected to be completed in October 2021.

Sugarmill to Paine 161kV Transmission Line History

Idaho Falls Power (IFP) first built a 161kV transmission line, located on the southern portion of the city connecting the Westside Substation to the Sugarmill Substation, in the 1980s. The original design was for this to be a larger project that would also serve the northern portion of the city as well.

In 2008, IFP hired an engineering consultant and began public outreach to create a design for the future 161kV transmission line, which is currently called the Sugarmill to Paine 161kV Transmission line. Consultants in coordination with stakeholders began discussions on potential sites and routing options. The utility also began negotiations to acquire property, rights-of-way, and easements to construct the transmission line.

The project faced some legal challenges from concerned stakeholders in the region in 2011, but IFP continued to work on purchasing easements and rights-of-way from landowners. In 2017, IFP partnered with PacifiCorp (Rocky Mountain Power), as both utilities saw that this transmission line would benefit both utilities to better serve growth within the City and also outside of the City for Rocky Mountain Power customers in the area. The utilities entered into a Procurement and Construction Agreement wherein ownership and construction costs would be shared by each utility relative to their ownership/usage in the project.

Idaho Falls Power contracted with Summit Line Construction Inc. at the start of 2021 to begin construction on the power line portion of the project. The total cost of the line including property, right-of-way acquisition construction and materials will be roughly $14,500,000. The project will involve the installation of approximately 14 miles of steel structures and accompanying high voltage conductor and lower voltage under build circuits including communication lines.

In near future, Rocky Mountain Power will tap from the line to go to its Rigby Substation to the north and its Bonneville Substation to the west.

Paine Substation

The future Paine Substation, will be located to the northwest end the utility’s service area, is under construction for the cost of roughly $2,500,000. The contractor, Bodec, began work on the substation in February 2021.

The substation is named in honor of the utility’s former chief engineer, Jeff Paine. Mr. Paine was instrumental in the development of the utilities Bulb Turbine and Gem State hydroelectric projects along with countless other resources that our community enjoys today that enable us to provide some of the lowest cost, highest reliability electric service in the nation.