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 Description | Project # | In-service year | Need driver |
|---|---|---|---|
| J870/J871 MPFCA Highland Generator Network Upgrades | 1 | 2021 | G-T interconnection |
| J855 GIC Ebenezer SS Generator Interconnection Facilities and Network Upgrades | 2 | 2021 | G-T interconnection |
| J818 Jefferson SS Generation Interconnection Facilities and Network Upgrades | 3 | 2022 | G-T interconnection |
| J1188 Sheepskin SS Network Upgrades and Interconnection Facilities | 4 | 2022 | G-T interconnection |
| J850 North Creek SS, Generator Interconnection Facilities and Network Upgrades | 5 | 2022 | G-T interconnection |
| J864 Lone Rock SS Generator Interconnection Facilities and Network Upgrades | 6 | 2022 | G-T interconnection |
| Cardinal–Hickory Creek 345kV, line construction | 7 | 2023 | Reliability, Economic and Policy |
| J947 Tennyson SS, Generator Interconnection Facilities and Network Upgrades | 8 | 2023 | G-T interconnection |
| Barneveld SS, DIC, New Substation | 9 | 2023 | T‑D interconnection |
| J1000 Comet SS Network Upgrades and Interconnection Facilities | 10 | 2023 | G-T interconnection |
| J1003 North Beaver Dam SS Network Upgrades and Interconnection Facilities | 11 | 2023 | G-T interconnection |
| J1154 Crawfish River Solar Network Upgrades | 12 | 2023 | G-T interconnection |
| Nelson Dewey–Bloomington 69-kV (Y-184), rebuild & OPGW | 14 | 2025 | Asset Renewal |
| Darlington–Rock Branch 69-kV (Y-109), rebuild | 15 | 2025 | Asset Renewal |
Zone 3 Proposed Projects
| Project Description | Project # | In-service year | Need driver |
|---|---|---|---|
| None |
Zone 3 Provisional Projects
| Project Description | Project # | In-service year | Need driver |
|---|---|---|---|
| Rock County Reliability Project | 13 | 2024 | Reliability |