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Jozankei

Hydro power plant in Hokkaido, Japan. Approximate location 42.9871, 141.1562.

HydroHokkaidoJapan

Jozankei is a 120 MW hydro power station in Hokkaido, Japan. It is operated by Hydropower and Dams. Based on its capacity (estimated), it can supply roughly 120,137 homes (estimated). It ranks #201 of 659 Japan power plants by installed capacity. Commissioned in 1989, it is around 37 years old — long-established. As a non-combustion source, it has no direct CO₂ emissions from generation. In context, hydro supplies about 7.2% of Japan's electricity; the national grid averages 477 gCO₂/kWh (32.7% low-carbon) (2025).

120MW installed capacity
120,137homes powered (est.)
1989commissioned (~37 yrs)

Plant data: WRI Global Power Plant Database (CC BY 4.0), id WRI1020235.

Capacity vs largest hydro plants in Japan

Okutataragi: 1,932 MW2kOkutataragiOkumino: 1,500 MW2kOkuminoOkawachi: 1,280 MW1kOkawachiShin Takasegawa: 1,280 MW1kShin Takas…Okuyoshino: 1,206 MW1kOkuyoshinoMatanogawa: 1,200 MW1kMatanogawaTamahara: 1,200 MW1kTamaharaShin Toyone: 1,125 MW1kShin Toyone

Installed capacity (MW), WRI Global Power Plant Database (CC BY 4.0).

Owner

Operated by Hydropower and Dams.

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 43.0°N — which shapes how much energy it can produce and how its output varies through the year.

4.9°Cannual mean temp
4,763heating degree-days (base 18°C)
18cooling degree-days (base 18°C)
570 melevation

Monthly mean temperature

J: -8 °CJF: -8 °CFM: -4 °CMA: 3 °CAM: 8 °CMJ: 13 °CJJ: 17 °CJA: 19 °CAS: 14 °CSO: 8 °CON: 1 °CND: -4 °CD19 °C

Heating degree-days here run 94% 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: 93/100 — this site sits in the top 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 #41 largest hydro power plant of 55 in Japan by capacity.

Japan has 55 hydro power plants in this dataset, together about 27,439 MW of capacity.

Nearby power plants

Location

Coordinates 42.9871, 141.1562 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.

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