HELENA, Mont. (AP) — One of the Colstrip power plant's four units is down and may take six months and $30 million to fix.
The outage is described in an internal Public Service Commission email Monday, from notes on a telephone conversation between a PSC staffer and a NorthWestern Energy official.
NorthWestern's Mike Barnes told the PSC that Unit 4 of the coal-fired plant was offline for maintenance in most of May and June. On July 1, days after restarting, the unit shut down due to a ground fault in the stator rotor of the unit's generator.
Officials found damaged core iron. Barnes told the PSC repairs could cost $30 million.
NorthWestern owns 30 percent of Unit 4. PSC spokesman Justin Post says the commission has not heard from the three other owners.