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NorthWestern Seeks to Join Western Energy Imbalance Market; Seeks Cost Savings, Improved Grid Reliability, Improved Renewable Integration

Nov 08, 2018

Butte, Mont. – Nov. 8, 2018 – NorthWestern Energy today announced its intent to join the Western Energy Imbalance Market (EIM), a real-time energy market that could mean lower cost energy for its Montana customers, more efficient use of renewable energy, and greater power grid reliability.

NorthWestern plans to join the EIM, operated by the California Independent System Operator (CAISO), by April 2021. NorthWestern has been studying the value and costs of the EIM for several years. Several other electric companies in the West and Pacific Northwest have joined the EIM since its creation in 2014.

The EIM uses state-of-the-art software to analyze regional power grid needs and make available low-cost generation to meet energy demand every five minutes. Participating electric companies have been able to provide value for customers by drawing automatically on the least-cost generating option available to meet short-term variations in their customers’ power use.

The EIM also gives participants the potential to optimize the use of renewable resources by making it easier to efficiently integrate variable renewable output with other resources, including hydro, coal and natural gas-fired generation that are available 24/7.

“The EIM will allow NorthWestern to make better use of our transmission and electric generation resources,” CEO Bob Rowe said. “Expanding our use of the regional electric grid through the EIM will help integrate variable renewable energy. We have seen significant growth in wind generation in Montana, which highlights the need to have access to other generation resources that are available on demand, 24/7. Being part of EIM will help with that need.”

“Participating in the EIM will help ensure that NorthWestern’s electric generating resources are used in the most economic manner possible,” said John Hines, vice president, Supply. “Participation will also allow NorthWestern customers to benefit from lower-cost generation owned by other utilities and power producers in the western region.”

“The energy imbalance market should provide much more flexibility and tools to balance the moment to moment fluctuations between energy demand and the generation resources available to meet this demand,” said Mike Cashell, vice president, Transmission. "The EIM will take us into a new era from a reliability perspective.”

NorthWestern Energy relies on a diversified portfolio of hydro, wind, coal, natural gas and solar generation to provide reliable and affordable electricity to its Montana customers. More than 60 percent of the electricity we provide in Montana comes from clean carbon-free hydro, wind and solar generation. That percentage will grow in the next few years as several large wind generation projects begin production.

Media Contact:
Butch Larcombe
(866) 622-8081

About NorthWestern Energy
NorthWestern Energy provides electricity and natural gas in the Upper Midwest and Northwest, serving approximately 701,000 customers in Montana, South Dakota and Nebraska.  More information on NorthWestern Energy is available on the company's website at
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