MISO Northwest Exploratory Study Presented to National Wind Coordinating Committee Participants in study – MISO, Various utilities in Minnesota, North and South Dakota, Various wind and coal advocates through the UGPTC.

Study scope Identify the benefits of the best single line and two line transmission expansion given a projected 2000 MW wind and coal generation expansion in North Dakota and South Dakota marketed to the Twin Cities.

Assumed Generation Sites 500 MW coal plant in western North Dakota 250 MW wind in northern North Dakota 500 MW of wind in south central North Dakota 250 MW of wind in central South Dakota 500 MW of wind in southeast South Dakota and southwest Minnesota. - This amount is beyond the 825 MW level Total of 2000 MW’s under investigation

Assumed Generation Sites

Transmission Options Considered Minnesota only: –New or single line conversion North Dakota, South Dakota, and Minnesota combined: –Cross system 345 kV single line –Cross system 500 kV single line –Cross system 345 kV two line –Cross system 500 kV two line

Minnesota only single line options 1.Convert North MN 230 kV line to 345 kV 2.Convert Watertown-Granite Falls-Blue Lake to 345 kV 3.Convert Fargo-Granite Falls-Blue Lake 230 kV line to 345 kV 4.Build new Fargo-St.Cloud 345 kV line (North Line) 5.Build new Watertown-Blue Lake 345 kV line (South Line)

Minnesota only single line options # 1 # 4 # 3 # 2 & #5

Cross System 345 kV Single Line options 1.New Antelope Valley-Jamestown-Maple River- Alexandria-Benton Co 345 kV line (North Line) 2.New Antelope Valley-Jamestown-Maple River and convert north MN 230 kV line to 345 kV 3.New Hettinger-Ellendale-Watertown and convert Watertown-Granite Falls-Blue Lake to 345 kV 4.New Hettinger-Ellendale-Watertown-Granite Falls-Blue Lake to 345 kV(south line) 5.New Hettinger-Ellendale-Watertown and Maple River-Alexandria-Benton Co 345 kV lines

Cross System 345 kV single line options # 1 # 4 # 3 # 2 # 5

Cross System 500 kV Single Line options 1.New Antelope Valley-Jamestown-Maple River- Alexandria-Benton Co 345 kV line (North Line) 2.Convert Antelope Valley-Huron- Watertown- Granite Falls-Blue Lake to 345 kV 3.New Hettinger-Ellendale-Watertown-Granite Falls-Blue Lake to 345 kV(South Line)

Cross System 500 kV single line options # 1 # 2 # 3

Cross System Two Line Options (345 and 500 kV) 1.New Antelope Valley-Jamestown-Maple River- Alexandria-Benton Co and New Hettinger-Ellendale- Watertown-Granite Falls-Blue Lake to 345 kV lines 2.New Antelope Valley-Jamestown-Maple River- Alexandria-Benton Co and New Hettinger-Ellendale- Watertown-Granite Falls-Blue Lake to 345 kV lines 3.New Antelope Valley-Jamestown-Maple River- Alexandria-Benton Co and Convert Antelope Valley- Huron-Watertown with New Watertown-Blue Lake 500 kV

Cross System Two Line Options (345 kV and 500 kV) # 2 # 1 # 3 # 1 # 2

General Conclusions Line conversions didn’t add much capability A single circuit cross system addition at 345 kV should add around 800 MW of new transfer capability. A single 500 kV cross system line will not add a significant amount of additional capability above that of a 345 kV line –the underlying system can’t support the increased flows. A two line 345 or 500 kV cross system plan should be sufficient to add around 2000 MW of new thermal capability.

General Conclusions More analysis needs to be done to incorporate the Belfield area coal plant and the Ellendale wind farm into the bulk system. –Local Interconnection Issues To get two 500 kV lines to work better than 345 kV, there may need to be one or two North/South 500 kV ties between them to get them to unload the underlying system.

Concept Recommendations The following are not recommendations of specific projects but rather concepts of region to region transmission additions Actual projects will depend on many factors such as: –Available routing corridors –Actual location, size, and schedule of Generation development –Coordination with other Transmission plans and needs (Ex.CaPX) –Other

Recommended Transmission Concept Plan

Next Steps Finalize study with steering committee Investigate potential route corridors Draft addendum report for Midwest ISO Transmission Expansion Plan. Coordinate these next steps with the CapX study and process Begin process of establishing detailed plans. –Evaluate MISO queue, timing, utility resource plans, etc. –Review stability analysis, flowgate impacts, economics, etc.