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Four Mile Hydropower Project

Hydro power plant in Michigan, United States of America. Approximate location 45.0933, -83.5025.

HydroMichiganUnited States of America

Four Mile Hydropower Project is a 2 MW hydro power plant in Michigan, United States of America. It is operated by Thunder Bay Power Co LLC. Based on reported annual generation of 13 GWh, it can supply roughly 3.6k homes. It ranks #8966 of 10,938 United States of America power plants by installed capacity. Commissioned in 1991, it is around 35 years old — long-established. As a non-combustion source, it has no direct CO₂ emissions from generation. In context, hydro supplies about 5.3% of United States of America's electricity; the national grid averages 384 gCO₂/kWh (43.0% low-carbon) (2025).

2Source-backed capacity
13GWh reported / yr
3,628homes powered
1991commissioned (~35 yrs)

Plant data: WRI Global Power Plant Database (CC BY 4.0), id USA0054341.

Data status

Known data

FacilityFour Mile Hydropower Project WRI
CountryUnited States of America · Michigan WRI
Coordinates45.0933, -83.5025 WRI
FuelHydro WRI
MW installed capacity2 MW WRI source record; scope not independently normalised
OwnerThunder Bay Power Co LLC WRI
Commissioned1991 WRI
GWh reported / yr13 GWh/yr WRI

Calculated from dataset

Capacity rank in country#8966 of 10938 calculated
Fuel-specific rank in country#1189 of 1449 calculated
Capacity vs country/fuel peers0.25× · 8 MW median · 1449 peers calculated
Homes-powered equivalent3,628 calculated from reported generation
Climate6.6°C · HDD 4,228 derived from coordinates
Environmental severityC3 · 38/100 derived from coordinates

Not available

TechnologyNot available not in dataset
GWh reported / yrNot available not in dataset
CO₂ emissionsnot applicable not applicable

Known, modelled and calculated values are kept separate. Missing fields are shown as unavailable.

Data provenance

The capacity and/or fuel fields on this page include a source-backed provenance label from GEM, an official registry, Wikidata, OSM, or a cross-source match.

capacity: Wikidata P2109 nameplate capacity; fuel: WRI source-record fuel

In context: how this plant compares

At 2 MW, Four Mile Hydropower Project is below the median hydro plant in United States of America (8 MW). Hydropower converts the energy of falling or flowing water into electricity; output depends on rainfall and reservoir level, and large dams also provide grid balancing and storage.

Capacity comparison computed from the WRI Global Power Plant Database; fuel-type context is general engineering background.

Reported generation trend

2013: 10 GWh20132014: 12 GWh20142015: 10 GWh20152016: 10 GWh20162017: 12 GWh20172018: 12 GWh20182019: 13 GWh201913 GWh

Annual generation (GWh), WRI Global Power Plant Database (CC BY 4.0).

Owner

Operated by Thunder Bay Power Co LLC.

Local climate & thermal context

This hydro plant converts the energy of falling or flowing water through hydro turbines. It sits in a warm-summer humid continental climate (Köppen Dfb) — Northern Hemisphere, latitude 45.1°N — which shapes how much energy it can produce and how its output varies through the year.

6.6°Cannual mean temp
4,228heating degree-days (base 18°C)
85cooling degree-days (base 18°C)
191 melevation

Monthly mean temperature

J: -7 °CJF: -6 °CFM: -2 °CMA: 5 °CAM: 12 °CMJ: 17 °CJJ: 20 °CJA: 19 °CAS: 15 °CSO: 9 °CON: 2 °CND: -4 °CD20 °C

Heating degree-days here run 72% above the median power plant in this dataset — a proxy for how much extra energy heated equipment must replace through its surfaces in winter.

Climate heat-demand index: 87/100 — this site sits in the top third of the power plants we cover by heating degree-days.

Climate normals: WorldClim 2.1 (1970–2000 monthly normals, 10 arc-min, CC BY 4.0); zone: Köppen-Geiger world climate classification (Kottek et al. 2006, 0.5° grid). Degree-days & heat-demand index computed by PowerAtlas — a modelled heat-demand proxy, not a measured site figure.

Site climate & environmental severity

For a plant’s outdoor hardware — heat-recovery steam generators (HRSG), expansion joints, valves, flanges and their insulation — the local climate sets how fast unprotected steel and coatings degrade. This site sits in a moderately corrosive environment (estimated ISO 9223 class C3 — Medium), with thermal cycling the leading environmental stress.

C3ISO 9223 corrosivity (indicative)
38/100environmental-severity index
26.9°Cseasonal temperature swing
23 kmdistance to coast

Higher environmental severity is exactly where protective removable insulation pays back most: a sheltered micro-climate slows corrosion, UV and thermal-cycling damage and extends outdoor hardware service life. This is an indicative site-climate context — not a condition assessment of any specific plant or operator.

Indicative estimate via the ISO 9223:2012 informative method (atmospheric corrosivity from temperature, time-of-wetness and airborne salinity), using WorldClim climate normals, the Köppen-Geiger class and coast distance. Indicative, not a measured corrosion rate.

How it compares & nearby plants

The #1189 largest hydro power plant of 1449 in United States of America by capacity.

United States of America has 1449 hydro power plants in this dataset, together about 102,513 MW of capacity.

Nearby power plants

Location

Coordinates 45.0933, -83.5025 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.

Frequently asked questions

What type of power plant is Four Mile Hydropower Project?

Four Mile Hydropower Project is a 2 MW source-record hydro power plant in Michigan, United States of America, commissioned in 1991.

How much electricity does Four Mile Hydropower Project generate?

Four Mile Hydropower Project generates about 13 GWh of electricity per year.

How many homes can Four Mile Hydropower Project power?

Its output is enough to supply roughly 3,628 homes.

Who operates Four Mile Hydropower Project?

Four Mile Hydropower Project is operated by Thunder Bay Power Co LLC.

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