Minnesota Electric Transmission Planning

Chapter 5 describes each of the Transmission Planning Zones in the state. The zones have not changed over the years so the description below for each zone is identical to what was provided in past reports, although any changes in the transmission system in a particular zone that occurred over the past two years are described in each section.

The discussion for each zone contains a list of the counties in the zone and the major population centers. The utilities that own high voltage transmission lines in the zone are also identified. A description of the major transmission lines in the zone is provided.

Transmission systems in one zone are highly interconnected with those in other zones and with regional transmission systems. A particular utility may own transmission facilities in a zone that is outside its exclusive service area, or where it has few or no retail customers. Different segments of the same transmission line may be owned or operated by different utilities. A transmission line may span more than one zone, and transmission projects may involve more than one zone.

Chapter 6 describes the needs for additional transmission facilities identified for each zone. Chapter 7 contains additional information about each of the utilities filing this report, including their existing transmission lines.

5.2 Northwest Zone

The Northwest Planning Zone is located in northwestern Minnesota and is bounded by the North Dakota border to the west and the Canadian border to the north. The Northwest Planning Zone includes the counties of Becker, Beltrami, Clay, Clearwater, Kittson, Lake of the Woods, Mahnomen, Marshall, Norman, Otter Tail, Pennington, Polk, Red Lake, Roseau, and Wilkin.

Primary population centers within the Northwest Planning Zone (population greater than 10,000) include the cities of Bemidji, Fergus Falls, and Moorhead.

The following utilities own transmission facilities in the Northwest Zone:

Great River Energy
Minnkota Power Cooperative
Missouri River Energy Services
Otter Tail Power Company
Xcel Energy

A major portion of the transmission system that serves the Northwest Planning Zone is located in eastern North Dakota. Four 230 kV lines and two 345 kV lines reach from western North Dakota to substations in Drayton, Grand Forks, Fargo, and Wahpeton, North Dakota, along with a 230 kV line from Manitoba and a 230 kV line from South Dakota. Five 230 kV lines run from eastern North Dakota into Audubon, Moorhead, Fergus Falls, and Winger, Minnesota. These five lines then proceed through northwestern Minnesota and continue on to substations in west-central and northeastern Minnesota. Additionally, a 230 kV line from Manitoba to the Northeast Zone crosses the northeastern corner of this zone and provides power to local loads. The 230 kV system supports an extensive 115 kV, 69 kV, and 41.6 kV transmission system to deliver power to local loads.

5.3 Northeast Zone

The Northeast Planning Zone covers the area north of the Twin Cities suburban area to the Canadian border and from Lake Superior west to the Walker and Verndale areas. The zone includes the counties of Aitkin, Carlton, Cass, Cook, Crow Wing, Hubbard, Isanti, Itasca, Kanabec, Koochiching, Lake, Mille Lacs, Morrison, Pine, St. Louis, Todd, and Wadena counties.

The primary population centers in the Northeast Planning Zone include the cities of Brainerd, Cambridge, Cloquet, Duluth, Ely, Grand Rapids, Hermantown, Hibbing, International Falls, Little Falls, Long Prairie, Milaca, Park Rapids, Pine City, Princeton, Verndale, Virginia, and Walker.

The following utilities own transmission facilities in the Northeast Zone:

American Transmission Company, LLC
Great River Energy
Minnkota Power Cooperative
Minnesota Power
Southern Minnesota Municipal Power Agency
Xcel Energy

The transmission system in the Northeast Planning Zone consists mainly of 230 kV, 138 kV and 115 kV lines that serve lower voltage systems comprised of 69 kV, 46 kV, 34.5 kV, 23 kV and 14 kV. Xcel Energy, Great River Energy, and Minnesota Power own a 500 kV interconnection coming from Manitoba Hydro with interconnections in Minnesota at Forbes and Chisago County. Minnesota Power owns a second 500 kV interconnection from Manitoba Hydro (the Great Northern Transmission Line), placed in service in 2020, which connects at the Iron Range Substation near Grand Rapids, Minnesota. American Transmission Company’s 345 kV line runs between Duluth, Minnesota, and Wausau, Wisconsin. Minnesota Power’s +/- 250 kV DC line runs from Center, North Dakota to Duluth, Minnesota. The CapX2020 230 kV line connects the Bemidji area in the Northwest Zone and the Grand Rapids area in the Northeast Zone (the CapX2020 Bemidji-Grand Rapids project). The 345 kV and 230 kV system is used as an outlet for generation and to deliver power to the major load centers within the zone. From the regional load centers, 115 kV lines carry power to lower voltage substations where it is distributed to outlying areas. In a few instances, 230 kV lines serve this purpose. Lastly, Minnesota Power and GRE plan to build the Northland Reliability Project, an approximately 180-mile, double-circuit 345 kV transmission line from northern Minnesota to central Minnesota. The project will support grid reliability and resilience in Minnesota and the Upper Midwest, and it was approved by MISO in 2022.

5.4 West Central Zone

The West Central Transmission Planning Zone extends from Sherburne and Wright counties on the east, to Traverse and Big Stone counties on the west, bordered by Grant and Douglas counties on the north and Renville County to the south. The West Central Planning Zone includes the counties of Traverse, Big Stone, Lac qui Parle, Swift, Stevens, Grant, Douglas, Pope, Chippewa, Renville, Kandiyohi, Stearns, Meeker, McLeod, Wright, Sherburne, and Benton.

The primary population centers in the zone include the cities of Alexandria, Buffalo, Elk River, Glencoe, Hutchinson, Litchfield, Sartell, Sauk Rapids, St. Cloud, St. Michael, and Willmar.

The following utilities own transmission facilities in the West Central Zone:

Central Minnesota Municipal Power Agency and Services (CMPAS)
Great River Energy
Missouri River Energy Services
Otter Tail Power Company
Southern Minnesota Municipal Power Agency
Xcel Energy

This transmission system in the West Central Planning Zone is characterized by a 115 kV loop connecting Grant County-Alexandria-West St. Cloud-Paynesville-Willmar-Morris and back to Grant County. These 115 kV transmission lines provide a hub from which 69 kV transmission lines provide service to loads in the zone.

A 345 kV line from Sherburne County to St. Cloud and 115 kV and 230 kV lines from Monticello to St. Cloud provide the primary transmission supply to St. Cloud and much of the eastern half of this zone. Two 230 kV lines from Granite Falls – one to the Black Dog generating plant in the Twin Cities and one to Willmar – provide the main source in the southern part of the zone.

Demand in the St. Cloud area continues to grow and several individual projects have been completed to address the need for more power into this area. The CapX2020 Quarry substation provides significant load-serving capability to the St. Cloud area system deficiencies. The CapX2020 Fargo-St. Cloud 345 kV project was completed in 2015 and transfers power between Fargo, North Dakota and the St. Cloud area. The CapX2020 Brookings, South Dakota-Twin Cities 345 kV project was also completed in 2015. The Riverview 345/115/69 kV substation was built in the St. Cloud Area along the CapX2020 Fargo-Monticello 345 kV line to address some of the area’s 69 kV issues. This is a Great River Energy substation connecting to Xcel Energy’s 69 kV system.

A pending major addition to the Southeast Planning Zone is the addition of the 345 kV MISO LRTP 2 Project. The planned 345 kV line will extend from the Big Stone, S.D. Substation to Alex Substation to the Big Oaks substation near the Sherco Power Plant. The Alex-Big Oaks portion of the 345 kV line will complete the CAPX Fargo-Monticello Project. The line was approved as part of MISO MTEP 21 Expansion Plan and is currently pending before the Commission.

5.5 Twin Cities Zone

The Twin Cities Planning Zone comprises the Twin Cities metropolitan area. It includes the counties of Anoka, Carver, Chisago, Dakota, Hennepin, Ramsey, Scott and Washington.

The following utilities own transmission facilities in the Twin Cities Zone:

CMPAS
Great River Energy
Missouri River Energy Services
Otter Tail Power
Xcel Energy

There are no major changes in the transmission facilities located in the Twin Cities Zone since 2013, although several projects are under review by the Commission.

The transmission system in the Twin Cities Planning Zone is characterized by a 345 kV double circuit loop around the core Twin Cities and first tier suburbs. Inside the 345 kV loop, a network of high capacity 115 kV lines serves the distribution substations. Outside the loop, a number of 115 kV lines extend outward from the Twin Cities with much of the local load serving accomplished via lower capacity, 69 kV transmission lines.

The GRE DC line and its outlet 345 kV circuits tie into the northwest side of the 345 kV loop and are dedicated to bringing generation to Twin Cities and Minnesota loads.

Tie lines extend from the Twin Cities 345 kV loop to three 345 kV lines: one to eastern Wisconsin, one to southeast Iowa and one to southwest Iowa. The other tie is the Xcel Energy 500 kV line from Canada tied into the northeast side of the 345 kV loop.

Major generating plants are interconnected to the 345 kV transmission loop at the Sherburne County generating plant and the Monticello generating plant in the northwest, the Allen S. King plant in the northeast, and Prairie Island in the southeast. On the 115 kV transmission system in the Twin Cities Planning Zone there are three intermediate generating plants: Riverside (located in northeast Minneapolis), High Bridge (located in St. Paul), and Black Dog (located in north Burnsville). There are also two peaking generating plants – Blue Lake and Inver Hills – interconnected on the southeast and the southwest, respectively.

The CapX2020 Brookings-Twin Cities 345 kV project was completed in 2015 and transfers power between the southwest corner of the Twin Cities and Brookings, South Dakota. The CapX2020 345 kV project between the southeast corner of the Twin Cities area, Rochester, and LaCrosse, Wisconsin, was also completed in 2015.

5.6 Southwest Zone

The Southwest Transmission Planning Zone is located in southwestern Minnesota and is generally bounded by the Iowa border on the south, Mankato on the east, Granite Falls on the north and the South Dakota border on the west. It includes the counties of Brown, Cottonwood, Jackson, Lincoln, Lyon, Martin, Murray, Pipestone, Redwood, Rock, Watonwan, and Yellow Medicine.

The primary population centers in the Southwest Zone include the cities of Fairmont, Granite Falls, Jackson, Marshall, New Ulm, Pipestone, St. James, and Worthington.

The following utilities own transmission facilities in the Southwest Zone:

ITC Midwest LLC
East River Electric Power Cooperative
Great River Energy
L&O Power Cooperative
Missouri River Energy Services
Otter Tail Power Company
Southern Minnesota Municipal Power Agency
Xcel Energy

The transmission system in the Southwest Zone consists mainly of three 345 kV transmission lines, one beginning at Split Rock Substation near Sioux Falls and traveling to Lakefield Junction, the second traveling from Mankato, through Lakefield Junction and south into Iowa and a third line, completed in 2018 from Lakefield Junction, east to Huntley and then south into Iowa. Lakefield Junction also serves as a major hub for several 161 kV lines throughout the zone. A number of 115 kV lines also provide transmission service to loads in the area, particularly the large municipal load at Marshall. Much of the load in the southwestern zone is served by 69 kV transmission lines which have sources from 115/69 kV or 161/69 kV substations.

The 115 kV lines also provide transmission service for the wind generation along Buffalo Ridge. The transmission system in this zone has changed significantly in recent years with new transmission additions to enable additional generation delivery. Continuing these changes, the system was also enhanced by the addition of the 345 kV Multi-Value Project (MVP) Portfolio, including the Twin Cities-Brookings 345 kV transmission line in 2015 and the MVP 3 Project in 2018, providing additional outlet for the wind generation in the Southwest Zone. In addition to enabling additional delivery of wind generation, these lines provide opportunities for new transmission substations to improve the load serving capability of the underlying transmission system.
Two major planned transmission lines to the Southwest Planning Zone include the addition of (1) the 345 kV Minnesota Energy Connection, and (2) the Brookings-Lyon Co. and Hampton-Helena sections of the double circuit 345 kV line from the CAPX Brookings-TC project. The Minnesota Energy Connection would extend from the Sherco Power Plant in Sherburn County to somewhere in Lyon County. The planned line will carry renewable generation back Sherco Plant as part of the renewable repowering effort. The Brookings-Lyon Co. and Hampton-Helena double circuits are needed to help relieve congestion for renewable power coming from Southwest Minnesota and is a joint project between Xcel Energy, Great River Energy, Otter Tail Power, Missouri River Energy Services, and Central Municipal Power Agency and Services.

5.6 Southeast Zone

The Southeast Planning Zone includes Blue Earth, Dodge, Faribault, Fillmore, Freeborn, Goodhue, Houston, Le Sueur, Mower, Nicollet, Olmsted, Rice, Sibley, Steele, Wabasha, Waseca, and Winona Counties. The zone is bordered by the State of Iowa to the south, the Mississippi River to the east, the Twin Cities Planning Zone and West Central Planning Zone to the north, and the Southwest Planning Zone to the west.

The primary population centers in the zone include the cities of Albert Lea, Austin, Faribault, Mankato, North Mankato, Northfield, Owatonna, Red Wing, Rochester, and Winona.

The following utilities own transmission facilities in the Southeast Zone:

CMPAS
Dairyland Power Cooperative
Great River Energy
ITC Midwest LLC
Missouri River Energy Services
Otter Tail Power
Rochester Public Utilities
Southern Minnesota Municipal Power Agency
Xcel Energy

The transmission system in the Southeast Planning Zone consists of 345 kV, 161 kV, 115 kV and 69 kV lines that serve lower voltage distribution systems. The 345 kV system is used to import power from generation stations outside of the area to the Southeast Planning Zone for lower voltage load service. The 345 kV system also allows the seasonal and economic exchange of power from Minnesota to the east and south from large generation stations located within and outside of the zone. The 161 kV and 115 kV systems are used to carry power from the 345 kV system and from local generation sites to the major load centers within the zone. From the regional load centers and smaller local generation sites, 69 kV lines are used for load service to the outlying areas of the Southeast Planning Zone.

A recent major addition to the Southeast Planning Zone was the addition of the Huntley-Wilmarth 345 kV line which was completed in 2021. This line improves power flow across the transmission system. It was an economic project that connects part of Southern Minnesota to the Mankato area. The project was identified through the MISO Economic Planning effort.

A planned major transmission line addition to the Southeast Planning Zone is planned 345 kV MISO LRTP 4 Project. This planned 345 kV line will extend from the Wilmarth Substation to North Rochester to the Mississippi River. The line was approved as part of MISO MTEP 21 Expansion Plan and is expected to the filed the Commission in 2024.