On May 1, 1975, we energized Big Stone Plant, a jointly-owned 475-megawatt coal-fired plant. On May 1, 2025, we proudly celebrated its 50th anniversary!
“The plant wouldn’t be what it is today without the hard work and dedication of our people, who consistently contribute to our communities,” said Brad Tollerson, Vice President, Energy Supply. “Thank you to the entire team for the ways you continue to provide safe, reliable electricity for our customers.”
Located near Big Stone City, South Dakota, we jointly own Big Stone Plant with NorthWestern Energy and Montana-Dakota Utilities Co. Approximately 80 of our employees operate the plant. It’s an important part of our energy generation mix to ensure we can provide our customers with reliable, low-cost electricity 24 hours a day, 7 days a week.
Big Stone Plant has successfully navigated both planned and unplanned outages, installed a state-of-the-art air-quality control system, and achieved numerous safety awards and recognition. It also plays a vital role in our communities by raising funds for local charities through events like the annual Golf and Give and partnering with the South Dakota Game, Fish, and Parks Department.
“Fifty years of safe and efficient operation is a significant milestone,” said Tollerson. “We’re proud of the plant’s contributions to providing power our customers can count on.”
Photo 1: Approximately 200 current and former plant employees, their families, our partner owners, and others involved in plant operations attended the celebration.
Photo 2: Big Stone Plant near Big Stone City, South Dakota.