NorthWestern Energy announces Big Sky substation site and design

Low-profile option to be constructed at Rainham site

By Sarah Gianelli EBS Senior Editor

BIG SKY – After a full year of dialogue between NorthWestern Energy and Big Sky residents, the utility company announced today that the controversial substation will be a low-profile design—a compromise between the traditional and gas-insulated options—built at the Rainham site, off of Ridgeback Road north of Lone Mountain Trail.

The site options had been narrowed down to two, Rainham, which is slightly more expensive but would impact fewer residents, and Midway, which received adamant community push-back from homeowners in the Antler Ridge and Sleeping Bear subdivisions.

During the facilitation process, led by Eric Austin of the Burton K. Wheeler Center for Public Policy, community members expressed concerns that the facility would be an eyesore, adversely affecting property values and viewsheds; be detrimental to wildlife, and create noise pollution.

NorthWestern was considering a traditional design similar to existing Big Sky substations, the cheapest and least aesthetically-pleasing option; the middle-of-the-road, low-profile option they ended up selecting; and the least intrusive, but most expensive gas-insulated option.

In a phone call with EBS, Austin said the low-profile design would reduce the height of the facility by 20 feet and have an exterior that would blend into the surrounding landscape. Austin added that NorthWestern will continue to work with nearby residents to finalize the last aesthetic details.

He added that the stand of trees at the Rainham site, and its distance from the road, would further reduce its visibility from Lone Mountain Trail.

With a growth rate of 8 percent, eight times the statewide average, Big Sky’s energy demand is expected to double in the next 10 years according to NorthWestern. A third substation would connect the Lone Mountain and Meadow Village substations, preempting future electrical needs and safeguarding against outages.

At the last official community meeting on June 20, NorthWestern’s vice president of transmission, Mike Cashell, said that he expected construction of the pad to begin in 2019, and that full completion of the station could be as far out as 2020.