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 Badger Hollow Network Upgrade12021G-T interconnection
J584 GIC Jordan SS Generator Interconnection Facilities and Network Upgrades22021G-T interconnection
J855 GIC Ebenezer SS Generator Interconnection Facilities and Network Upgrades32021G-T interconnection
Northern Lights Substation, new T-D Interconnection42021T‑D interconnection
J947 Tennyson SS, Generator Interconnection Facilities and Network Upgrades52021G-T interconnection
J818 Jefferson SS Generation Interconnection Facilities and Network Upgrades62022G-T interconnection
J864 Lone Rock SS Generator Interconnection Facilities and Network Upgrades72022G-T interconnection
J850 North Creek SS, Generator Interconnection Facilities and Network Upgrades82022G-T interconnection
Cardinal - Hickory Creek 345-kV, line construction92023Reliability, Economic and Policy
Barneveld SS, DIC, New Substation102023T‑D interconnection
Portage – Columbia 138 kV (X-13/X-20), Rebuild Existing Double Circuit112024Reliability

Zone 3 Proposed Projects

Project DescriptionProject #In-service yearNeed driver
None

Zone 3 Provisional Projects

Project DescriptionProject #In-service yearNeed driver
None
Related Resources