NorthWestern Energy will appeal district court order vacating air quality permit for Yellowstone County Generating Station

BUTTE, Mont., April 07, 2023 (GLOBE NEWSWIRE) -- NorthWestern Corporation d/b/a NorthWestern Energy (Nasdaq: NWE) appreciates that Montana District Court Judge Michael Moses supported the majority of the Montana Department of Environmental Quality’s air quality permit, issued to NorthWestern Energy after significant review and analysis for construction of the Yellowstone County Generating Station in a lawsuit by the Montana Environmental Information Center and the Sierra Club.

Although the District Court found two limited issues with the Montana DEQ's analysis, the court unfortunately took the extreme step to vacate the air permit. NorthWestern Energy will fulfil its commitment to safe and reliable energy service for our Montana customers by seeking an immediate stay and will appeal the decision.

All NorthWestern Energy projects, including the Yellowstone County Generating Station, are designed to meet the best interests of our customers and the communities we serve.

“After significant review and analysis, the Montana Department of Environmental Quality issued NorthWestern Energy an air quality permit on Sept. 8, 2021 which allowed the company to initiate construction of this project,” said NorthWestern Energy Vice President of Supply and Montana Government Affairs John Hines, who oversees environmental compliance and stewardship. “This ruling, appears to require new criteria to be analyzed, and jeopardizes reliable service for our Montana customers during critical times when customer energy demand is high, the coldest nights and the hottest days, typically times when renewable resources are generating little or no energy. Our air permit was reviewed and approved by the DEQ using standards that have been in effect for many years. We began construction of this project with this in mind. We will work with the DEQ to determine the path forward.”

The Yellowstone County Generating Station will help meet NorthWestern Energy’s need for additional always-available, on-demand generation resources to serve our Montana customers reliably with the most affordable rates.

NorthWestern Energy relies on the energy market more than any of our peer energy companies in the region. The region faces an increasing probability of near-term deficits in its energy supply during peak load conditions, and the chance of shortages is expected to grow unless the region invests in new capacity, resources always-available to generate energy in all weather conditions.

If it was operating today, NorthWestern Energy’s Montana customers could have avoided at least $4.7 million in market purchases from Dec. 20 to 26, 2022 during the Arctic cold front when record low temperatures were set in several areas of Montana.

“The Yellowstone County Generating Station natural gas plant is a critical part of a balanced and affordable portfolio that includes renewables and generation that is available on-demand, 24/7,” said Hines. “A balanced portfolio is essential to support the responsible transition to cleaner generation resources without compromising energy service reliability.”

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NorthWestern Energy – Delivering a Bright Future
NorthWestern Corporation, doing business as NorthWestern Energy, provides essential energy infrastructure and valuable services that enrich lives and empower communities while serving as long-term partners to our customers and communities. We are working to deliver safe, reliable, and innovative energy solutions that create value for customers, communities, employees, and investors. This includes bridging our history as a regulated utility safely providing low-cost and reliable service with our future as a globally-aware company offering a broader array of services performed by highly-adaptable and skilled employees. We provide electricity and / or natural gas to approximately 764,200 customers in Montana, South Dakota, Nebraska and Yellowstone National Park. We have provided service in South Dakota and Nebraska since 1923 and in Montana since 2002. More information is available on the company's Web site at www.northwesternenergy.com.

Investor Relations Contact:	Media Contacts:
Travis Meyer	Jo Dee Black
605-978-2967	866-622-8081
travis.meyer@northwestern.com	jodee.black@northwestern.com