SIOUX FALLS, SOUTH DAKOTA – Several Upper Midwest energy companies filed plans Sept. 29 with the Minnesota Public Utilities Commission (PUC) to move forward with a critical transmission project in Minnesota and northeastern South Dakota that will deliver reliable energy to customers as older fossil fuel-based plants retire in the coming years and open new pathways for additional renewable energy proposed in the Upper Midwest.

The 345-kilovolt (kV) Big Stone South-Alexandria-Big Oaks project consists of two segments, with one running from Big Stone City, South Dakota, to Alexandria, Minnesota (western segment), and the other running from Alexandria to Becker, Minnesota (eastern segment). The transmission project will provide additional capacity to mitigate current capacity issues, maintain electric system reliability, relieve congestion on the grid, and allow more low-cost wind power from western Minnesota and the Dakotas to reach customers throughout the region. Renewable energy has no fuel costs and contributes to a diversified energy mix, which helps energy companies provide cost-effective electricity for customers.

“This project will allow us to continue to operate a reliable transmission grid, bring low-cost renewable energy to homes and businesses, further reduce carbon emissions, and focus on meeting our customers’ energy needs,” the utilities said. “We look forward to working with our state regulators, landowners and local officials to make this project a reality.”

The Big Stone South-Alexandria-Big Oaks project will help ensure continued electric reliability and improved system resilience in the Upper Midwest. In recent years, utilities have added new renewable energy, such as wind and solar, and several fossil fuel plants are expected to retire in the coming years as they reach the end of their expected useful lives. As plants are retired, new transmission is needed to deliver energy from where it is generated, particularly widespread renewable energy, to where it is consumed. The project also supports efforts to meet each energy company’s carbon-reduction goals and will help move toward meeting Minnesota’s carbon-free energy standard.

The eastern segment proposes stringing a new transmission circuit primarily on existing structures originally built as part of the CapX2020 Fargo-St. Cloud and St. Cloud-Monticello projects between Alexandria and a new substation on Xcel Energy property near the Sherco power plant in Becker. The western segment from Big Stone South to Alexandria proposes a new transmission line between Otter Tail Power’s (OTP) Big Stone South substation in South Dakota and the Alexandria substation owned by Missouri River Energy Services (MRES).

The utilities jointly filed a Certificate of Need application for both segments and a Route Permit application for the eastern segment. The western segment Route Permit application is expected to be filed in 2024 following a robust public outreach process, which is ongoing. Project participants include Great River Energy, Minnesota Power, MRES, OTP and Xcel Energy.

Planning for future transmission needs

Broad changes in the region’s generation fleet and the increasing frequency of extreme weather events have created the need for new transmission infrastructure across the region. To address the future need for continued reliable and resilient operations, the Midcontinent Independent System Operator, Inc. (MISO) collaborated with energy companies and other stakeholders to develop the Long-Range Transmission Planning (LRTP) process that resulted in the identification and recommendation of 18 new transmission projects across the Upper Midwest region. This first set of projects, approved in mid-2022 and including the Big Stone South-Alexandria-Big Oaks project, is the initial step to build the necessary transmission infrastructure that will enable energy companies to reliably integrate new resources and effectively operate the changing grid.

More than 95% of the eastern segment of the proposed project will not require changes to the existing transmission line, which began operation in 2015 as part of the CapX2020 project from Fargo to Monticello and a joint project with several other utilities. At that time, the PUC and the CapX2020 companies agreed there would likely be a need for new transmission in the future. As a result, the Fargo-St. Cloud and St. Cloud-Monticello projects were constructed as double-circuit capable, enabling the companies to meet customers’ energy needs at the time while anticipating growing demand in the future.

The PUC will review the energy companies’ proposal, which generally takes approximately one year and includes opportunities for input from customers, landowners and other interested stakeholders.

Learn more about the Big Stone South to Alexandria and Alexandria to Big Oaks projects on their websites at and Both websites include maps of the project areas and opportunities to provide feedback. 

“Transmission is the backbone of the electric grid, and it is essential for integrating renewable energy resources into the grid and maintaining reliable electricity service to homes and businesses in the region,” said Terry Wolf, vice president of power supply and operations at MRES. “By investing in these projects, we can create a more resilient electric grid for everyone, including our member municipals, while also making a significant step toward achieving our clean energy goals.”

For more information, contact MRES Vice President of Member Services and Communications Tim Blodgett at 605-338-4042 or