St. Cloud Load Serving Study

1. St. Cloud Load Serving Study Xcel Energy Great River Energy

2. Overview: • Total load in the region is approximately 400 MW • Served through 12 distribution substations including GRE’s Sartell and Sauk River substations through 115 kV loop fed from Benton Co and Sherco. • Deficiencies include low voltages for loss of Benton – Granite City double circuit and approximately 105 MW of load served from the 6 mile radial line. • Planned upgrades include Sauk River – St. Cloud 115 kV line upgrade and Quarry 345/115 kV substation.

4. Option 1: • 10 mile 115 kV line from Sartell substation to Mayhew Lake substation. • 2 mile double circuit from West St. Cloud to Sartell tap. • Upgrade Quarry to West St. Cloud tap. • Convert Benton Co tap – Benton Co double circuit to single bifurcated line.

6. Option 2 (Preferred): • Upgrade Quarry – West St. Cloud 115 kV line. • Re-terminate Benton Co – Granite City line into Mayhew Lake (4 miles of new 115 kV line). • Convert – Benton Co – Benton Co tap to single circuit bifurcated line.

8. Questions?

9. Douglas Co Area(West Central Minnesota)

10. Overview: • Study area involves the 69 kV system served from Douglas Co and Paynesville 115/69 kV substations. • 50 MW of Load in the study area. • Poor reliability of lines in the area due to age.

11. Planned Projects: • Grove Lake switching station • Douglas Co 2nd 115/69 kV transformer. • Sauk Center – West Union 69 kV line upgrade.

12. Deficiencies: • Loss any section between Douglas Co and Villard will result in low voltages in the region. • Loss of Grove Lake – Sedan will result in low voltages in the region. Preferred Plan: • Rebuild 13 miles of 69 kV line from Grove Lake switching station to Glenwood substation.

14. Questions?

15. Maple Lake and Wakefield Areas(West Central Minnesota)

16. Overview: • Study area involves 69 kV lines between GRE-Maple Lake and Xcel Wakefield substations. • Recent improvements in the area include upgrading the 69 kV line between Wakefield and Watkins.

17. System deficiencies: • Loss of Wakefield – Fairhaven line causes low voltages in the region. • Loss of Watkins – Kimball line causes low voltages in the region. • Reliability problems due to the age of the conductor.

18. Option 1: • Rebuild 34.5 kV line between Paynesville – Eden valley and Watkins to 69 kV. Option 2 (Preferred): • Upgrade 69 kV line between GRE-Maple Lake and Watkins substations.

20. Questions?

21. Sioux Falls Area(South Dakota)

22. Overview: • Study area involves the transmission system for the city of Sioux Falls. • Load in the downtown area is fed primarily from a 69 kV system which is fed from the looped 115 kV system around the city. • Recent improvements are the addition of Lawrence #2, 115/69, 112 MVA transformer and the splitting of the 115 kV double circuit from Cherry Creek to Split Rock.

23. System deficiencies: • Lawrence #1 or #2 transformer in 2014 for loss of the other. • Lincoln Tap-South Sioux Falls in 2015 for loss of Lawrence to Sioux Falls Muni. • Lawrence-Sioux Falls Muni in 2016 for loss of Lawrence-Morill Tap. • West Sioux Falls-West Sioux Falls Tap-Sioux Falls Muni in 2016 for loss of Lawrence to Sioux Falls Muni.

24. Option 1: • Build a new 115 kV station from (old) Silver Creek location to Existing Sioux Falls substation at 115 kV. Add a new 115/69 kV transformer at Sioux Falls substation. Option 2: • Build a new 115 kV line from Lawrence to Sioux Falls substation. Add a new 115/69 kV transformer at Sioux Falls substation.

25. Sioux Falls: Option 1

26. Sioux Falls: Option 2

27. Questions?

28. Arden Hills Area North metro load serving

29. Branch Year Rating (Contingency) Contingency Goose Lake - Vadnias Tap 2011 208 MVA Terminal 8M15 breaker Apache Tap - Arden Hills 2011 306 MVA Goose Lake Multi Terminal Outage Lexington - Vadnias Tap 2012 208 MVA Terminal 8M15 breaker Apache Tap - Riverside 2020 214 MVA Outage of Apache Tap - Terminal Kohlman Lake 345/115 kV xfmrs 2020 515 MVA Double Circuit Between Kohlman Lake and Terminal split structure Arden Hills – TCAAP 2023 341 MVA Goose Lake Multi Terminal Outage Kohlman Lake and Goose Lake 115 kV equipment 2025 398 MVA Terminal 8M15 breaker Goose Lake - Kohlman Lake 2026 420 MVA Terminal 8M15 breaker Arden Hills Deficiencies

30. Option 1 (Rebuild or Re-conductor)

31. Option 2 (Preferred Option)

32. Questions / Comments

33. Red Rock area bulk supply Southeast Metro

34. Scenario Contingency Facility Rating % Loading 1 Stuck breaker 8P22 (Red Rock) Red Rock 345/115 kV # 9 515 96 1 Stuck Breaker K5 (Red Rock) Red Rock 345/115kV #10 515 94.2 1 Long Lake – Oakdale 115 kV Red Rock – Woodbury 214 126.7 2 Stuck breaker 5P2 (King) Afton – Red Rock 214 100.7 2 Stuck Breaker 8P22 (Red Rock) Red Rock TR 9 515 115.4 2 Stuck Breaker 8P23 (Red Rock) Red Rock TR 10 515 124.3 2 NSP 5 Long Lake - Oakdale 341 94.5 3 Stuck Breaker 5P2 (King) Afton – Red Rock 214 101 3 Stuck Breaker 8P32 (Kohlman Lake) King 345/115 kV TR 515 91.1 3 Stuck breaker 5P142 (Inver Hills) Inver Grove – Pilot Knob 239 93.9 3 Stuck breaker 8P22 (Red Rock) Red Rock TR 9 515 106.9 3 Stuck breaker 5P82 (Red Rock) Red Rock TR 10 515 103.2 Red Rock Deficiencies

35. Red Rock Opt. 1 (Preferred Opt)

36. Red Rock Opt 2 (new Afton Source)

37. Questions / Comments