Mountain Island

Hydro power plant in North Carolina, United States of America. Approximate location 35.3339, -80.9867.

HydroNorth CarolinaUnited States of America

Mountain Island is a 60 MW hydro power plant in North Carolina, United States of America. It is operated by Duke Energy Carolinas LLC. Based on reported annual generation of 178 GWh, it can supply roughly 50,857 homes. It ranks #2534 of 9,833 United States of America power plants by installed capacity. Commissioned in 1924, it is around 102 years old — an older, legacy facility. 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).

60MW installed capacity
178GWh reported / yr
50,857homes powered
1924commissioned (~102 yrs)

Plant data: WRI Global Power Plant Database (CC BY 4.0), id USA0002728.

Reported generation trend

2013: 174 GWh20132014: 108 GWh20142015: 111 GWh20152016: 102 GWh20162017: 90 GWh20172018: 208 GWh20182019: 178 GWh2019208 GWh

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

Owner

Operated by Duke Energy Carolinas LLC. All plants by this company →

Local climate & thermal context

This hydro plant converts the energy of falling or flowing water through hydro turbines. It sits in a humid subtropical climate (Köppen Cfa) — Northern Hemisphere, latitude 35.3°N — which shapes how much energy it can produce and how its output varies through the year.

15.7°Cannual mean temp
1,661heating degree-days (base 18°C)
847cooling degree-days (base 18°C)
220 melevation

Monthly mean temperature

J: 5 °CJF: 7 °CFM: 11 °CMA: 16 °CAM: 20 °CMJ: 24 °CJJ: 26 °CJA: 25 °CAS: 22 °CSO: 16 °CON: 11 °CND: 6 °CD26 °C

Heating degree-days here run 32% below 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: 37/100 — this site sits in the mid third of the power plants we cover by heating degree-days.

In colder climates, uninsulated hot equipment (boilers, turbines, valves, steam lines) loses proportionally more heat to ambient air — exactly the loss Inzonex modular insulation is designed to cut.

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.

How it compares & nearby plants

The #265 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 101,657 MW of capacity.

Nearby power plants

Location

Coordinates 35.3339, -80.9867 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.

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