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NorthWestern Energy Joins Western Energy Imbalance Market

June 22, 2021
The real-time wholesale energy market now includes a Montana-based utility.

The Western Energy Imbalance Market (EIM), operated by the California Independent System Operator (ISO), has expanded its footprint to Montana with the addition of NorthWestern Energy.

NorthWestern Energy's participation caps off a year of significant growth for the real-time energy market, with eight utilities joining already this year. The Western EIM now serves consumers in 10 states, including portions of Arizona, California, Idaho, Nevada, New Mexico, Oregon, Utah, Washington, Wyoming, and Montana. By 2023, 22 active Western EIM participants will represent more than 83% of the load in the Western Interconnection.

"We are very pleased to welcome NorthWestern Energy into the family of Western EIM entities," said ISO President and CEO Elliot Mainzer. "This new partnership with NorthWestern will add regional diversity and diverse resources into the real-time energy market and provide additional economic and environmental value to consumers in Montana and across the West."

Joe Stimatz, manager of asset optimization for NorthWestern Energy, agreed that joining the EIM will bring tangible benefits to the utility's customers.

"Our participation in the Western EIM will provide our customers with economically efficient energy to resolve imbalances and variations in load and generation on our Montana system," Stimatz said.

Since its launch in 2014, the Western EIM has been using advanced technology to find and deliver the lowest-cost energy to utilities, while enhancing reliability and reducing greenhouse gas emissions. The most recent quarterly results show the Western EIM has achieved US$1.28 billion in cumulative gross benefits for its participants.

NorthWestern Energy provides electricity and natural gas to more than 743,000 customers in Montana, South Dakota, and Nebraska. In Montana, the utility serves customers with an electric generation portfolio that is nearly 70% carbon-free and includes hydro, wind, and solar on 6809 miles of electric transmission lines and 18,068 miles of electric distribution lines. NorthWestern Energy is well on its way to meeting its goal of reducing its carbon intensity by 90% by 2045, with a 50% reduction to date.

Visit the Western EIM website for participant information and quarterly benefits reports.

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