Michigan’s Upper Peninsula and Northern Wisconsin
Zone 2

Transmission system limitations in Zone 2

There are several potential transmission system performance issues in Zone 2, including limited ability to import or export power, potential generator instability and low and high system voltages.  Potential overloads that are a result of multiple contingency planning events will continue to be monitored. The most severe limitations are expected to occur during both peak and off‑peak periods.

Electric system overview

Small increases expected in population, employment

Population in Zone 2 is projected to decrease by 0.1% per year between now and 2029, and employment is expected to grow about 0.3 percent each year in the same time period. Marquette County, Mich. is projected to realize the largest total increase in population and employment. Vilas County, Wis. is projected to have the highest annual growth rate in population, and Keweenaw County, Mich. is projected to have the highest annual growth rate in employment.

Electricity usage

Zone 2 typically experiences peak electric demand during both the summer and winter months. Ore mining and paper mills are the largest electricity users in the zone.

Electric load is forecasted to increase by 0.2 percent annually through 2029. Also, locally generated electricity is declining in the area with smaller, coal‑fired generators most at risk. This includes generation owned by industry, municipalities and utilities.

Transmission projects in Zone 2

The most notable planned, proposed, and provisional network / asset-renewal projects in Zone 2 are listed below – along with their projected year of completion and the factors driving the need for the projects.

The recent installation of inductor banks in the western U.P. have successfully mitigated issues with high voltages during lighter load periods. ATC completed Zone 2 projects that provided new interconnection facilities at Huron and Silver River substations for the new J703 and J704 generation. These new Reciprocating Internal Combustion Engine (RICE) generating plants are important power sources in the U.P. to ensure reliability after the recent retirement of the Presque Isle Power Plant.

Zone 2 includes the counties of:
  • Alger , Mich.
  • Baraga , Mich.
  • Chippewa , Mich.
  • Delta , Mich.
  • Dickinson , Mich.
  • Florence , Wis.
  • Forest (N) , Wis.
  • Gogebic (E) , Mich.
  • Houghton , Mich.
  • Iron , Mich.
  • Keweenaw , Mich.
  • Luce , Mich.
  • Mackinac , Mich.
  • Marinette (N) , Wis.
  • Marquette , Mich.
  • Menonminee (N) , Mich.
  • Ontonagon (E) , Mich.
  • Schoolcraft , Mich.
  • Vilas (N) , Wis.

Zone 2 Planned Projects

Project DescriptionProject #In-service yearNeed driver
J928–Garden Corners SS, GIC Network Upgrade 12020G-T Interconnection
Mackinac–McGulpin 138-kV line (9901 and 9903), submarine cable replacement 22021Condition and performance
J849, Chandler SS Generator Interconnection Facilities and Network Upgrades 32022G-T Interconnection
Atlantic SS, 138/69-kV Bus Reconfiguration and Transformer Addition 42022Operational Flexibility, Asset Renewal
NLKG31 Tap–Greenstone 138-kV Line, Construct New Transmission Line 52022Condition and T-D Interconnection
Presque Isle–Tilden 138-kV Line, Loop and Uprate 62022Reliability
Tilden SS, Control House Replacement and Breaker & Relay Asset Renewal 72023Condition and performance
Dead River SS–Control House and Breaker Replacement Asset Renewal 82024Condition and performance

Zone 2 Proposed Projects

Project DescriptionProject #In-service yearNeed driver
Winona–Atlantic 69-kV (Winona69), rebuild92024Reliability

Zone 2 Provisional Projects

Project DescriptionProject #In-service yearNeed driver
Empire SS, Control House Replacement and
Breaker & Relay Asset Renewal
102024Condition and performance