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Ohma nuclear power plant

Nuclear power plant in Aomori Prefecture, Japan. Approximate location 41.5099, 140.9131.

NuclearAomori PrefectureJapanABWRboiling water reactorConstruction

Ohma nuclear power plant is a 1,983 MW nuclear power station in Aomori Prefecture, Japan. It is operated by Electric Power Development Co Ltd [100%]. Based on its capacity (estimated), it can supply roughly 4.5 million homes (estimated). It ranks #38 of 692 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).

1,983MW installed capacity
4,466,849homes powered (est.)
2029Construction

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

Data status

Known data

FacilityOhma nuclear power plant GEM-nuclear
CountryJapan · Aomori Prefecture GEM-nuclear
Coordinates41.5099, 140.9131 GEM-nuclear
FuelNuclear GEM-nuclear
MW installed capacity1,983 MW GEM GNPT; source record
OwnerElectric Power Development Co Ltd [100%] GEM-nuclear
Commissioned2029 GEM-nuclear
Technologyboiling water reactor GEM-nuclear

Calculated from dataset

Capacity rank in country#38 / 692 calculated
Fuel-specific rank in country#14 / 24 calculated
Capacity vs country/fuel peers0.96× · 2,070 MW · n=24 calculated
Homes-powered equivalent4,466,849 calculated
Environmental severityC4 · 38/100 derived from coordinates

Not available

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 fuel fields on this page are source-record values from the upstream open dataset. They are useful for identification and ranking, but they have not been upgraded to a 2026 registry/GEM-location verified value.

capacity: GEM GNPT; fuel: GEM GNPT

In context: how this plant compares

At 1,983 MW, Ohma nuclear power plant is around the median nuclear plant in Japan (2,070 MW). Technically it is described as boiling water reactor. Its current lifecycle status is “Construction” — so it is not yet, or no longer, generating at full output. Nuclear plants split uranium to raise steam with no direct CO₂; they run as steady baseload with very high capacity factors and the longest operating lifetimes of any thermal plant.

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

Capacity vs largest nuclear plants in Japan

Kashiwazaki Kariwa: 7,965 MW8kKashiwazak…Fukushima Daiichi nuclear power plant: 7,456 MW7kFukushima …Ohi: 4,710 MW5kOhiFukushima Daina: 4,400 MW4kFukushima …Hamaoka: 3,504 MW4kHamaokaGenkai: 3,478 MW3kGenkaiTakahama: 3,392 MW3kTakahamaKaminoseki nuclear power plant: 2,746 MW3kKaminoseki…

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

Owner

Operated by Electric Power Development Co Ltd [100%].

Climate zone & how it works

This nuclear plant uses heat from nuclear fission to raise steam for a turbine-generator. It sits in a warm-summer humid continental climate (Köppen Dfb) — Northern Hemisphere, latitude 41.5°N — which shapes how much energy it can produce and how its output varies through the year.

~6°Ctypical annual mean
~19°Ctypical warm-season mean
Warm-summer humid continental: four distinct seasons — cold winters and warm summers

Climate zone & typical temperatures: Köppen-Geiger world climate classification (Kottek et al. 2006, 0.5° grid).

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 corrosive environment (estimated ISO 9223 class C4 — High), with humidity / wetness the leading environmental stress.

C4ISO 9223 corrosivity (indicative)
38/100environmental-severity index
24.5°Cseasonal temperature swing
38 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 #14 largest nuclear power plant of 24 in Japan by capacity.

Japan has 24 nuclear power plants in this dataset, together about 61,851 MW of capacity.

Nearby power plants

Location

Coordinates 41.5099, 140.9131 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.

Frequently asked questions

What type of power plant is Ohma nuclear power plant?

Ohma nuclear power plant is a 1,983 MW nuclear power plant in Aomori Prefecture, Japan, Construction 2029.

How many homes can Ohma nuclear power plant power?

Its output is enough to supply roughly 4,466,849 homes (estimated).

Who operates Ohma nuclear power plant?

Ohma nuclear power plant is operated by Electric Power Development Co Ltd [100%].

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