1923
The incorporation of Northwestern Public Service brings together two electric energy companies in Nebraska and two in South Dakota.
Celebrating a Century: Explore Our Centennial Timeline
Discover the rich history of our company by exploring our centennial timeline. Follow our journey through the decades and see where we started and how we've grown.
Our Centennial Timeline
Our Powerful History is a tribute to the last 100 years of our company's journey and the people who have made it possible. From our humble beginnings to our present-day operations, we have come a long way in delivering reliable and affordable energy to our customers. As we look towards the future, we remain committed to providing sustainable energy solutions that will benefit our customers and the communities we serve. Join us as we celebrate our 100th anniversary and explore Our Powerful History - a testament to our past, present, and future.
1924-1941
Northwestern Public Service continues to purchase dozens of local and regional energy companies in South Dakota and Nebraska.
1927
The company donates one of its outdated 225-horsepower generators to Gutzom Borglum, the artist who, at the time, was carving Mount Rushmore with a jackhammer.
1930s
Street lighting improves dramatically. Mitchell’s main street is lit until midnight each night.
1931-1950
Northwestern Public Service promotes electricity use by selling and demonstrating electric appliances.
1941
Northwestern Public Service gives into public pressure and sells its electric utility holdings to the state of Nebraska for public ownership. Northwestern Public Service uses its payment from this sale to purchase natural gas operations in Kearney, North Platte and Grand Island, Nebraska.
1946
Northwestern Public Service becomes an independent investor-owned energy company.
Late 1940s
The economy booms after World War II and Northwestern Public Service focuses on growth and construction to keep up with demand for electricity.
1952
The power plant in Yankton is nearly destroyed by the flooding of the Missouri River, only to be saved by the hard work of the city and the line workers who submerge 18 automobiles to stem the tide of the river.
1953
Northwestern Public Service begins to purchase power from Missouri River dams built as part of the federal Flood Control Act of 1944 and passes along $358,000 in savings to its customers over the next two year thanks to the cheaper hydroelectric power.
1961
Northwestern Public Service purchases 10 electric franchises in South Dakota, expanding the company’s territory from Woonsocket to Chamberlain.
1961
The new 12,500-kilowatt Huron gas turbine is completed at a cost of $1.5 million, replacing the Mitchell Steam Plant as the largest power plant on the company’s system.
1965
Hubert Humphrey, a Northwestern Public Service customer, is elected vice president under Lyndon B. Johnson. Humphrey’s wife worked for the company as a billing clerk in the 1930s.
1969-1975
Northwestern Public Service and other ownership partners complete construction of Big Stone Plant, a 400-megawatt coal-fired electric generating plant near Milbank, South Dakota.
1979
The 75-megawatt Neal 4 coal-fired generation plant in Sioux City, Iowa, comes online.
1981
The 410,000-kilowatt Coyote I plant near Beulah, North Dakota, comes online.
1994
Northwestern Public Service expands into propane, technology, telecommunications and HVAC businesses nationwide.
1998
Northwestern Public Service changes its name to NorthWestern Corporation.
2002
NorthWestern Corporation purchases the Montana Power Company transmission and distribution system forming NorthWestern Energy. The company now provides electric and natural gas service to customers in Montana, Nebraska and South Dakota.
2003
NorthWestern Energy files for chapter 11 bankruptcy, which allowed us to restructure in order to reduce debt, improve capital structure and ensure the long-term financial health of the company.
2008
NorthWestern Energy became a part owner of the Colstrip Power Plant.
2011
NorthWestern Energy agrees to purchase power — up to 25 megawatts — from The Titan Wind Farm located west of Miller, South Dakota.
2012
NorthWestern Energy purchases the 40-megawatt Spion Kop windfarm in northcentral Montana.
2014
NorthWestern Energy purchases 12 hydroelectric facilities in Montana with a total generation capacity of 439 megawatts
2018
NorthWestern Energy purchases the 9.7-megawatt Two Dot windfarm near Two Dot, Montana.
2022
NorthWestern Energy’s new 58-megawatt Bob Glanzer Generating Station comes online, providing reliable, affordable energy to our South Dakota customers.
2023
NorthWestern celebrates 100 years of service in Nebraska and South Dakota.
Future projects
2023
The Yellowstone County Generating Station will come online to provide on‑demand resources to support the variability of wind and solar projects coming onto our system and help serve our customers during extended periods of peak demand.
2035
NorthWestern will add no new carbon-emitting resources to its portfolio after 2035.
2050
We plan to reach Net Zero carbon emissions by 2050.