Michigan’s Upper Peninsula and Northern Wisconsin Zone 2

Transmission system characteristics of Zone 2

ATC delivers power in Zone 2 with various transmission facilities including:

  • Morgan-Plains, Plains-Arnold and Plains-Dead River 345-kV lines,
  • Plains-Stiles 138-kV double-circuit line
  • Lakota Road-Plains 138-kV line,
  • Holmes-Old Mead Road 138-kV line, and
  • 138-kV facilities tying the Upper Peninsula of Michigan to the lower Michigan.
Transmission system limitations in Zone 2

There are a number of transmission system performance issues in Zone 2, including limited ability to import or export power, generator instability, overloaded lines and equipment, low and high system voltages and chronic limitations to transmission service. Primary drivers of these issues include a mismatch of load to generation in the Upper Peninsula and aging facilities in poor or deteriorated condition. In addition, other ongoing studies, including northern area studies performed by ATC and MISO, have identified several voltage and thermal limitations. The most severe limitations occur during both peak and off‑peak periods.

Electric system overview

Small increases expected in population, employment Population in Zone 2 is projected to grow about 0.2 percent annually between now and 2027, and employment is expected to grow about 0.8 percent each year in the same time period. Marquette County (Michigan) is projected to realize the largest increase in population and employment. Florence County (Wisconsin) is projected to have the highest growth rate in population while Keweenaw County (Michigan) is projected to have the highest growth rate in employment.

Electricity usage

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

In the recent past, there have been some load reductions in Zone 2. From these reduced levels, electric load is forecasted to increase by 0.4 percent annually through 2028. 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 projects and asset-renewal projects in Zone 2, along with their projected year of completion and the factors driving the need for the projects, are listed below.

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

Zone 2 Planned Projects

Project DescriptionIn-service yearNeed driver
J703: Huron Substation, new G‑T interconnection2019G‑T interconnection
J704: Silver River Substation, new G‑T interconnection2019G‑T interconnection
Munising‑Blaney Park 69‑kV line (Inland) rebuild2019Condition and performance
Plains – Arnold 138‑kV uprate2019Network integration transmission service request

Zone 2 Proposed Projects

Project DescriptionIn-service yearNeed driver
J711‑Silver River Substation, network upgrades2020G‑T interconnection

Zone 2 Provisional Projects

Project DescriptionIn-service yearNeed driver
Lakota - Winona 138-kV conversion2021Overloads and low voltages
Mackinac – McGulpin 138‑kV submarine cables
(9901, 9903), replacement
2021Condition
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