2021

10-Year
Assessment

South Central/Southwest Wisconsin and North Central Illinois
Zone 3

Transmission system limitations in Zone 3

In our analysis of Zone 3, we identified transmission facility overloads between Portage and Columbia substations. These overloads are the result of load modifications in the Portage area.

In addition, other emerging issues resulting in potential facility overloads could include steady growth in certain areas and different generation dispatches. The most severe limitations are expected to occur during both peak and off‑peak periods.

Electric system overview

Increases expected in population, employment –

Population in Zone 3 is projected to grow about 0.5 percent annually between now and 2029, and employment is projected to grow about 1.0 percent each year for the same time period. Dane County is projected to realize the largest total increase in population and employment. Dane County is also projected to have the highest annual growth rates in population and employment at 0.8% and 1.3%, respectively.

Electricity usage growing

Electric load is forecasted to grow approximately 0.7% annually through 2029 in Zone 3.

Transmission projects in Zone 3

The most notable planned, proposed and provisional network/asset renewal projects in Zone 3 are listed below along with their projected year of completion and the factors driving the need for the projects.

Zone 3 includes the counties of:
  • Columbia , Wis.
  • Crawford (S) , Wis.
  • Dane , Wis.
  • Dodge , Wis.
  • Grant , Wis.
  • Green , Wis.
  • Iowa , Wis.
  • Jefferson , Wis.
  • Lafayette , Wis.
  • Richland , Wis.
  • Rock , Wis.
  • Sauk , Wis.
  • Walworth , Wis.
  • Winnebago (N) , Ill.

Zone 3 Planned Projects

Project DescriptionProject #In-service yearNeed driver
J870/J871 MPFCA Highland Generator Network Upgrades12021G-T interconnection
J855 GIC Ebenezer SS Generator Interconnection Facilities and Network Upgrades22021G-T interconnection
J818 Jefferson SS Generation Interconnection Facilities and Network Upgrades32022G-T interconnection
J1188 Sheepskin SS Network Upgrades and Interconnection Facilities42022G-T interconnection
J850 North Creek SS, Generator Interconnection Facilities and Network Upgrades52022G-T interconnection
J864 Lone Rock SS Generator Interconnection Facilities and Network Upgrades62022G-T interconnection
Cardinal–Hickory Creek 345kV, line construction72023Reliability, Economic and Policy
J947 Tennyson SS, Generator Interconnection Facilities and Network Upgrades82023G-T interconnection
Barneveld SS, DIC, New Substation92023T‑D interconnection
J1000 Comet SS Network Upgrades and Interconnection Facilities102023G-T interconnection
J1003 North Beaver Dam SS Network Upgrades and Interconnection Facilities112023G-T interconnection
J1154 Crawfish River Solar Network Upgrades122023G-T interconnection
Nelson Dewey–Bloomington 69-kV (Y-184), rebuild & OPGW142025Asset Renewal
Darlington–Rock Branch 69-kV (Y-109), rebuild152025Asset Renewal

Zone 3 Proposed Projects

Project DescriptionProject #In-service yearNeed driver
None

Zone 3 Provisional Projects

Project DescriptionProject #In-service yearNeed driver
Rock County Reliability Project132024Reliability