Idaho Power Co.’s plans to replace a transmission line that runs from Hagerman to Hailey moved another step forward Thursday, Oct. 8.
The Blaine County Planning and Zoning Commission unanimously approved a conditional use permit and site alterations for the project.
The power company needed the site alteration approval because it runs through Blaine County’s Mountain Overlay District, which sits above the developed parts of the Wood River Valley and covers steep slopes unsuitable for development.
The transmission line is one of two to connect the Wood River Valley with the utility’s electric grid. A second line to the east runs from Richfield, around Picabo and then north to Hailey.
The Hagerman-Hailey line is about 50 years old, and is at risk of intermittent failures, according to Idaho Power. The utility plans to start the replacement project in 2016 and finish by 2018.
The line has had six outages longer than five minutes, including one on Christmas 2009 that lasted almost 12 hours. Four have happened since 2004.
Jeff Maffuccio, Idaho Power’s facility siting coordinator, said the project is still awaiting authorization to cross federal land managed by the BLM, a decision that he expects by the end of this year. The transmission line has potential environmental impacts because it requires new roads, repairs and grading to existing roads, and some excavation and blasting.
Maffuccio said crews would have to use blasting to create holes if they encounter rock in their excavation work. The transmission line poles will be 80 feet tall, and trucks will pull the line taut on top of the poles after they are erected.
Maffuccio said the line runs through sage grouse habitat, which requires extensive review of each road and power pole that the project will use or install.
“We don’t want to create additional erosion,” he said. “We just want to make sure we use the access that’s best for everyone.”
Idaho Power Project Manager Tom Barber said it’s not certain how the Obama administration’s recent decision not to list the sage grouse as an endangered species will affect the project.
Thursday’s meeting before the county P&Z was comparatively lighter, but the commissioners still put the project under scrutiny. Many felt that the roadwork should include bringing county Road and Bridge Department staff along on site visits and fieldwork. That would ensure compliance with county road standards.
Commissioner Chip Bailey said it’s important to mask the roads and poles from public view as much as possible. The transmission line extends through part of Croy Canyon and along Carbonate Mountain before dropping down into Hailey.
The transmission pole structures will be 30 feet wide but 80 feet tall. That’s an increase of 13 feet in height compared to the current poles, but a decrease of 17 feet in width.
Maffuccio said Idaho Power will be responsible for replanting vegetation after the project is finished, as well as monitoring for noxious weeds and erosion.
Idaho Power is also seeking permits from Blaine County and the cities of Ketchum and Sun Valley on another project, a redundant transmission line between Hailey and Ketchum.