NorthWestern Energy has requested a $10.9 million rate increase for its natural gas customers that, if approved, will raise an average customer’s bill about $4.81 per month.

The company filed the request with the Montana Public Service Commission on Friday. It is the company’s first natural gas rate case since 2012.

In addition to the $10.9 million rate increase, the company has asked that $5.59 million of the increase be approved on an interim basis to allow the company to begin recovering costs prior to the conclusion of the full rate case. NorthWestern also asked for the inclusion of two gas production assets into the company’s rate-base and an increase to the company’s return on equity for its natural gas consolidated utility from the current 9.8 percent, to 10.35 percent.

“As an impartial body, the Commission will be thorough and judicious throughout the proceeding.” Commission Chairman Brad Johnson said in a press release. “We will carefully weigh all aspects of the filing before rendering a decision, which we first and foremost hope will protect the long term interest of Montana ratepayers, while at the same time being equitable to the utility.”

Commissioner Roger Koopman said “commissioners must do their jobs, consistent with the requirements of law, so no one can predict the eventual outcome.

“But I cannot say I am not disappointed. This increase would be a bitter pill to swallow for many NorthWestern customers, especially those on low and fixed incomes,” Koopman added.

The Commission will also evaluate NorthWestern’s request to recover a portion of costs related to the company’s new, $26 million headquarters building that opened earlier this year in Butte, to determine the investment’s benefit to ratepayers.

The Public Service Commission has nine months to issue a final decision on NorthWestern Energy’s request.

To view the full rate filing, visit: http://bit.ly/2dyjBGp.