US firm gets permission for 600 MWh Minnesota battery project that can support electrical grid

Spearmint Energy (Spearmint) has announced it has now secured a site for a planned 600 megawatt-hour battery energy storage facility in Freeborn County, Minnesota. This follows site permit approval from the Minnesota Public Utilities Commission (“PUC”) for the planned Midwater Energy Storage Project (“Midwater”). As Spearmint explains, this will see a 150 megawatt (600 MWh) standalone battery energy storage system (“BESS”) installed at the site. “Midwater will be sited on 10 to 20 acres of privately owned land adjacent to the Glenworth Substation off Minnesota Highway 65 in Freeborn County. The project is designed to support a more reliable, consistent, and affordable energy supply,” Spearmint explains in a press release. The new facility will essentially act as a large rechargeable battery for the state’s electrical grid. Once installed, the battery will be able to provide a maximum rate of 150 MW to the grid when needed. Spearmint secures permit for battery in Minnesota The 600 MWh figure effectively means the total amount of energy that the BEES can store. Taken together, these figures mean the system could, in theory, provide around 4 hours of 150 MW supply when fully charged. The concept behind it is essentially the same as a home storage battery in that it would be charged up when electricity is plentiful and relatively cheap. This could be when wind farms are at peak performance or when demand is low from consumers. It could also occur when power plants are producing more power than needed. Once charged, the battery can then be used to provide power when electricity demands rise or when supply falls (say, when renewables are offline/not performing at peak). Critically, the new facility will be on a multi-acre site alongside the Glenworth Substation. This will provide a practical connection to the high-voltage electricity network. According to Spearmint, the battery itself will sit inside a series of container-sized battery units with all the necessary electrical equipment, transformers, fire-safety systems, and control infrastructure. From there, it can charge from and discharge into the wider grid. The BEES will also be standalone, meaning it will not be reliant on any single electrical input source. Rather, it will be tied directly to the grid and charged that way when conditions allow. Standing out but standing alone “We appreciate the commitment of the Minnesota Public Utilities Commission and staff in reviewing this critical infrastructure project. The Midwater site permit represents a meaningful investment in Southern Minnesota’s energy future,” Andrew Waranch, Founder, President, and Chief Executive Officer of Spearmint, said. “Battery energy storage systems play a critical role in strengthening grid reliability, storing energy when supply exceeds demand and delivering it back to the grid when needed most,” said Peter Rood, Chief Development Officer of Spearmint Energy. “As electricity demand continues to grow, projects like Midwater provide flexible infrastructure that supports grid stability, enhances affordability, and enables the integration of diverse generation resources. We are pleased to have achieved this major milestone,” he added.This is an important announcement, but construction is yet to begin. The company will still need to jump other hurdles (such as grid interconnection agreements, financing, procurement, etc.) before the project can become a reality. Recommended ArticlesGet the latest in engineering, tech, space & science - delivered daily to your inbox.Christopher graduated from Cardiff University in 2004 with a Masters Degree in Geology. Since then, he has worked exclusively within the Built Environment, Occupational Health and Safety and Environmental Consultancy industries. He is a qualified and accredited Energy Consultant, Green Deal Assessor and Practitioner member of IEMA. Chris’s main interests range from Science and Engineering, Military and Ancient History to Politics and Philosophy.