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Kumenan

Solar power plant in Okayama, Japan. Approximate location 34.941, 133.975.

SolarOkayamaJapan

Kumenan is a 32 MW solar power plant in Okayama, Japan. Based on its capacity (estimated), it can supply roughly 14k homes (estimated). It ranks #378 of 692 Japan power plants by installed capacity. As a non-combustion source, it has no direct CO₂ emissions from generation. In context, solar supplies about 9.8% of Japan's electricity; the national grid averages 477 gCO₂/kWh (32.7% low-carbon) (2025).

32Source-backed capacity
13,615homes powered (est.)

Plant data: WRI Global Power Plant Database (CC BY 4.0), id WKS0064166.

Data status

Known data

FacilityKumenan WRI
CountryJapan · Okayama WRI
Coordinates34.941, 133.975 WRI
FuelSolar WRI
MW installed capacity32 MW WRI source record; scope not independently normalised

Calculated from dataset

Capacity rank in country#378 of 692 calculated
Fuel-specific rank in country#46 of 324 calculated
Capacity vs country/fuel peers2.46× · 13 MW median · 324 peers calculated
Homes-powered equivalent13,615 calculated
Climate13.6°C · HDD 2,222 derived from coordinates
Environmental severityC4 · 45/100 derived from coordinates

Not available

OwnerNot available not in dataset
CommissionedNot available not in dataset
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: GEM tracker 2026 (location L100000801241); fuel: WRI source-record fuel

In context: how this plant compares

At 32 MW, Kumenan is well above the median solar plant in Japan (13 MW). Solar PV converts sunlight directly into electricity with no moving parts or fuel; output varies by time of day and weather, so it pairs with storage or flexible backup.

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

Capacity vs largest solar plants in Japan

Setouchi: 235 MW235SetouchiTomatoh Abira Solar Power Plant: 111 MW111Tomatoh Ab…Hosoe: 96 MW96HosoeOita - Marubeni Solar Power Plant: 82 MW82Oita - Mar…Kagoshima - Nanatsujima Solar Power Plant: 70 MW70Kagoshima …Rokkasho - Takahoko Solar Power Plant: 65 MW65Rokkasho -…Minamisoma: 60 MW60MinamisomaShin Mine CS: 56 MW56Shin Mine …

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

Local climate & thermal context

This solar plant converts sunlight directly into electricity with photovoltaic panels. It sits in a humid subtropical climate (Köppen Cfa) — Northern Hemisphere, latitude 34.9°N — which shapes how much energy it can produce and how its output varies through the year.

13.6°Cannual mean temp
2,222heating degree-days (base 18°C)
652cooling degree-days (base 18°C)
210 melevation

Monthly mean temperature

J: 3 °CJF: 3 °CFM: 6 °CMA: 12 °CAM: 16 °CMJ: 21 °CJJ: 25 °CJA: 26 °CAS: 22 °CSO: 16 °CON: 10 °CND: 5 °CD26 °C

Heating degree-days here run 10% 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: 46/100 — this site sits in the mid third of the power plants we cover by heating degree-days.

Solar PV loses ~0.35%/°C above 25°C cell temperature — roughly 0.3% at warm-season highs here (estimate).

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

C4ISO 9223 corrosivity (indicative)
45/100environmental-severity index
23.3°Cseasonal temperature swing
40 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 #46 largest solar power plant of 324 in Japan by capacity.

Japan has 324 solar power plants in this dataset, together about 5,680 MW of capacity.

Nearby power plants

Location

Coordinates 34.941, 133.975 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.

Frequently asked questions

What type of power plant is Kumenan?

Kumenan is a 32 MW source-record solar power plant in Okayama, Japan.

How many homes can Kumenan power?

Its output is enough to supply roughly 13,615 homes (estimated).

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