technology
Minnesota approves 150-megawatt battery storage project using Tesla units on 10 to 20 acres in Freeborn County
Spearmint Energy secured a site permit July 16 for a 150 MW / 600 MWh battery facility in Freeborn County. The project will use Tesla Megapack units at an estimated $457 million capital cost.
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Spearmint Energy received a site permit July 16 from the Minnesota Public Utilities Commission for its 150 MW / 600 MWh battery energy storage system in Freeborn County that will use Tesla Megapack 2XL lithium iron phosphate units. The facility, operating as Midwater BESS LLC, will occupy 10 to 20 acres of privately owned land next to the Glenworth Substation off Minnesota Highway 65.
Documents filed by the company place total installed capital cost at approximately $457 million with lifetime operating costs estimated at $246 million.
The project marks Spearmint’s second to clear Minnesota’s state permitting process after the 150 MW / 600 MWh Snowshoe Energy Storage Project in Olmsted County, approved in 2025. In June, Spearmint closed a $325 million expanded debt facility with Nuveen Energy Infrastructure Credit, Elda River Capital Management, Harrison Street Asset Management and Aiga Capital Partners.
The financing is intended to advance the company’s operating portfolio, including the Tierra Seca, Seven Flags and Revolution battery projects.
Spearmint had previously arranged roughly $450 million in project financing for the 300 MW / 600 MWh Red Egret battery facility now under construction in Texas City, Texas. In April the Minnesota commission approved a 200 MW expansion of Xcel Energy’s Capacity*Connect virtual power plant program, which requires regular status reports and an independent review.
