Final EIS available for Gallatin Canyon transmission line upgrade

Construction could start by May By Emily Stifler Explorebigsky.com Managing Editor</em BOZEMAN – NorthWestern Energy last fall started construction on a new 161-kilovolt transmission line between Four Corners and Big Sky. This summer the utility plans to continue the work, rebuilding the approximately 7.5-mile section of line between the Gallatin River Bridge north of Spanish Creek and Hell Roaring Creek. Of the project’s 37 miles, 16 are on National Forest land. The construction work could start as early as May – pending a 45-day appeal period that started March 29 – and is likely to cause traffic delays of approximately 15 minutes, according to Mariah Leuschen, Public Affairs Specialist for the Gallatin National Forest. Following a public meeting and comment period last fall, the Forest decided to use existing right-of-ways except for two alternative routes near Cave Creek and Cascade Creek. The new right-of-way removes the line from recreation residence tracts (although the distribution line will remain) and eliminates two transmission line crossings and a distribution line crossing of the Gallatin River. It “effectively meets the purpose and need to upgrade the existing transmission line while reducing visual and natural impacts surrounding the Cave and Cascade Recreational Residence Tracts, the Lava Lake Trailhead and the Gallatin River,” according to a press release from the Forest Service. The Gallatin is eligible for protection as a National Wild and Scenic River. Line construction will begin at the Castle Rock Campground, as the line will have to be relocated for the Montana Department of Transportation’s Highway Road Widening project, said Butch Larcombe, Corporate Communications with NorthWestern Energy. It will continue northbound and southbound from Castle Rock through this fall, and also again for the next two or three summers, Larcombe said. Timber clearing will start in June at the Hell Roaring Creek area and will conclude this fall at Meadow Village. The new line will be taller than the current one, and the insulators will be slightly larger. All of the new poles in the canyon will be single pole structures. The Gallatin Valley and Big Sky areas are among the fastest growing in NorthWestern Energy’s service territory, and usage exceeds capacity of the existing 69kV transmission line about 40 percent of the time, according to Claudia Rapkoch, a spokeswoman for the utility. “[The upgrade is] important for future growth, and for high-demand situations either brought on by extremely cold or hot weather, or during ski season,” Rapkoch said. The other transmission line feeding into Big Sky comes into the Lone Mountain substation from Ennis. As it stands now, Rapkoch said, if a fallen tree or a wildfire shut down one of the lines during the busy season, power delivery would be impacted. In addition, because NorthWestern’s grid is interconnected, all parts of the system must perform well for the utility to provide reliable power. The upgrade is part of a plan to increase capacity and reliability for Big Sky that’s already included the 2010 construction of a new substation in the Meadow Village. Because the Ennis line is rated at 161kV but energized at only 69kV, the utility will eventually install equipment to increase its capacity, as well. The entire Gallatin Canyon transmission line upgrade is expected to cost in the range of $35 million. The charges will be incorporated into the utility’s rate base, which is regulated by the Montana Public Service Commission and paid by all customers. The Forest Service Record of Decision and Final Environmental Impact Statement are available at fs.usda.gov/gallatin and at the Bozeman, Belgrade and Big Sky public libraries.

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