NorthWestern Energy Seeks to Buy More of Colstrip Coal Plant

The company says it does not expect customers' bills to increase

By Tristan Scott

BILLINGS — NorthWestern Energy said Tuesday it will seek regulatory permission to acquire Puget Sound Energy’s 25% share of Unit 4 of the Colstrip Power Plant for $1.

The agreement would include purchasing additional interest in the Colstrip Transmission System for an estimated cost of between $2.5 and $3.75 million.

NorthWestern says it will seek preapproval from the Montana Public Service Commission early next year to acquire 185 megawatts of coal-fired power generation capacity. It will also seek approval to sell 90 megawatts of that production to Puget Sound Energy for five years.

After the five years is up, NorthWestern will have the option of purchasing another 90 megawatts of capacity on the transmission line.

The company says it does not expect customers’ bills to increase. It will use the estimated $5 million in profit from selling power to Puget Sound Energy for environmental remediation and decommissioning costs when Unit 4 is retired.

The announcement came a day after NorthWestern Energy officials told regulators its 20-year power plan for the state leans toward building more natural gas-fired plants.

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