NorthWestern Energy to Join Western EIM

By Robert Mullin

NorthWestern Energy said Thursday that it will join the Western Energy Imbalance Market in spring 2021, making it the 14th utility to announce plans to sign on.

The Butte, Mont.-based company said joining CAISO’s real-time balancing market will result in more efficient use of renewables, increased grid reliability and lower costs to customers.

“The EIM will allow NorthWestern to make better use of our transmission and electric generation resources,” CEO Bob Rowe said in a statement. “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.”

NorthWestern serves about 718,000 electric and gas customers in Montana, Nebraska and South Dakota. But only its facilities in Montana — and Yellowstone National Park in Wyoming, where it has transmission — would participate in the EIM. The company’s Nebraska and South Dakota operations already trade in organized markets in the Eastern Interconnection.

NorthWestern’s Montana service territory covers about 73% of the state’s land area. It will bring an additional 6,700 miles of transmission into the EIM and increase the market’s access to a potentially wind-rich region that could serve West Coast load centers subject to increasingly ambitious renewable energy standards and tightened carbon-emission rules.

The utility owns about 442 MW of hydroelectric generation, nearly 50 MW of wind, a 222-MW share of the coal-fired Colstrip plant and 150 MW from the gas-fired Dave Gates Generating Station. It has power purchase agreements for an additional 135 MW of wind and will next year integrate another 80 MW of wind capacity from a Public Utility Regulatory Policies Act qualifying facility in south-central Montana.

“Participating in the EIM will help ensure that NorthWestern’s electric generating resources are used in the most economic manner possible,” said John Hines, the company’s vice president of supply.

“We welcome NorthWestern participating in our market and hope they will see the same benefits as the other participants,” CAISO CEO Steve Berberich said. “NorthWestern’s participation will only add to the market’s efficiency and resource diversity.”

CAISO said last month the EIM has produced more than $500 million in benefits for participants since its founding five years ago, including more than $100 million in the third quarter of 2018. (See Western EIM Reports Record Benefits.)

The EIM is steadily filling out the map of the Western Interconnection, with current participants APS, Idaho Power, NV Energy, PacifiCorp, Portland General Electric, Puget Sound Energy and Powerex. The Balancing Authority of Northern California and the Sacramento Municipal Utility District plan to begin participating in April 2019, while the Los Angeles Department of Water and Power, Arizona’s Salt River Project and Seattle City Light are scheduled to begin participating in April 2020.

Public Service Company of New Mexico is seeking permission from its regulators to join the EIM by 2021, officials announced in August. (See PNM Seeks to Join Energy Imbalance Market.)