HELENA, Mont. — The Montana Public Service Commission has unanimously denied NorthWestern Energy’s recent application for a rate adjustment. It is the second denial this month.

The PSC published a notice of action from the Commission stating that NorthWestern’s response to the July 10 tariff request did not meet the Commission’s minimum submission requirements.

An official at the power company said the original request was made due to inflation and rising material costs.

If approved, the proposed interim rates would see an increase of $2.09 per month for electricity customers. Natural gas customers would see an increase of $4.81 per month.

“We understand there are other pressures,” Jo Dee Black, public relations specialist for NorthWestern Energy, said in an earlier interview with NBC Montana. “Just as our costs have gone up, our customers’ costs have gone up.”

The last rate increase took place in the fall of 2024.

But NorthWestern Energy faced some resistance Tuesday, with the Public Service Commission saying the application did not meet minimum standards.

The PSC previously identified multiple deficiencies in the August 6 submission, detailing nine issues that impeded its ability to assess the merits of the application. NorthWestern was given two weeks to address these concerns but failed to do so satisfactorily.

“Have we seen problems like this in previous applications or is this the first time?” PSC Commissioner Randy Pinocci asked.

“I believe this is the first time this has happened,” said Haylee Gobert, a utilities analyst for the Public Service Commission. “In previous filings, there were minor deficiencies and those are usually updated in discovery. While this met a higher threshold for deficiencies, this is the first time we’ve seen this.”

A PSC spokesperson said the final, but crucial, shortcoming in the application concerns details of service charges for residential, industrial and small and large commercial customers.

“I think this underlines the dedication of our staff. We don’t want anything to be taken for granted, but want to thoroughly check every application,” said Tony O’Donnell, commissioner at the PSC.

NorthWestern Energy now has an additional week to meet the minimum filing standards, otherwise the rate increase request will be denied.

“In order for the Commission to consider a rate case, the PSC requires very specific economic and business information from any monopoly utility applicant seeking to adjust the rates it charges to Montana ratepayers,” PSC Chairman James Brown said in a statement. “Compliance with these rules is essential for the PSC to do its regulatory work. To date, NorthWestern has failed to meet this critical information standard. Therefore, the Commission cannot proceed with considering Northwestern Energy’s combined gas and electric rate case until the company first complies with Montana law.”

If approved, the new electricity and natural gas rates would go into effect in April 2025. They could result in average electricity customers seeing an increase of $9.11, or 8.28%, compared to the July 2024 rates. Meanwhile, average natural gas customers would see an increase of $8.84, a 17.04% increase from the July 2024 rates.