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Kashiwazaki Kariwa

Nuclear power plant in Niigata, Japan. Approximate location 37.4259, 138.5941.

NuclearNiigataJapan

Kashiwazaki Kariwa is a 8,212 MW nuclear power station in Niigata, Japan. It is operated by Tokyo. Based on its capacity (estimated), it can supply roughly 18,498,116 homes (estimated). It ranks #1 of 659 Japan power plants by installed capacity. As a non-combustion source, it has no direct CO₂ emissions from generation. In context, nuclear supplies about 9.1% of Japan's electricity; the national grid averages 477 gCO₂/kWh (32.7% low-carbon) (2025).

8,212MW installed capacity
18,498,116homes powered (est.)

Plant data: WRI Global Power Plant Database (CC BY 4.0), id WRI1000679.

Capacity vs largest nuclear plants in Japan

Kashiwazaki Kariwa: 8,212 MW8kKashiwazak…Ohi: 4,710 MW5kOhiFukushima Daina: 4,400 MW4kFukushima …Hamaoka: 3,617 MW4kHamaokaGenkai: 3,478 MW3kGenkaiTakahama: 3,392 MW3kTakahamaOnagawa: 2,174 MW2kOnagawaIkata: 2,022 MW2kIkata

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

Owner

Operated by Tokyo. All plants by this company →

Local climate & thermal context

This nuclear plant uses heat from nuclear fission to raise steam for a turbine-generator. It sits in a humid subtropical climate (Köppen Cfa) — Northern Hemisphere, latitude 37.4°N — which shapes how much energy it can produce and how its output varies through the year.

12.2°Cannual mean temp
2,652heating degree-days (base 18°C)
560cooling degree-days (base 18°C)
91 melevation

Monthly mean temperature

J: 0 °CJF: 0 °CFM: 3 °CMA: 10 °CAM: 15 °CMJ: 20 °CJJ: 24 °CJA: 25 °CAS: 21 °CSO: 15 °CON: 9 °CND: 4 °CD25 °C

Heating degree-days here run 8% 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: 53/100 — 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 #1 largest nuclear power plant of 16 in Japan by capacity.

Japan has 16 nuclear power plants in this dataset, together about 42,537 MW of capacity.

Nearby power plants

Location

Coordinates 37.4259, 138.5941 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.

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