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Aioi

Oil power plant in Hyogo, Japan. Approximate location 34.7742, 134.4568.

OilHyogoJapanSteamCO₂ modelled

Aioi is a 1,125 MW oil power station in Hyogo, Japan. It is operated by Kansai. Based on its capacity (estimated), it can supply roughly 845k homes (estimated). It ranks #88 of 692 Japan power plants by installed capacity. Commissioned in 1982, it is around 44 years old — long-established. Its modelled annual emissions are 892,440 t CO₂/yr (Climate TRACE), equivalent to about 208k cars driven for a year. In context, oil supplies about 2.5% of Japan's electricity; the national grid averages 477 gCO₂/kWh (32.7% low-carbon) (2025).

1,125Legacy source-record capacity
844,714homes powered (est.)
892,440t CO₂ / yr (Climate TRACE)
1982commissioned (~44 yrs)

Plant data: WRI Global Power Plant Database (CC BY 4.0), id WRI1000657.

Data status

Known data

FacilityAioi WRI
CountryJapan · Hyogo WRI
Coordinates34.7742, 134.4568 WRI
FuelOil WRI
MW installed capacity1,125 MW WRI source record; scope not independently normalised
OwnerKansai WRI
Commissioned1982 WRI
TechnologySteam WRI

Modelled source data

CO₂ emissions892,440 t CO₂/yr modelled · Climate TRACE

Calculated from dataset

Capacity rank in country#88 of 692 calculated
Fuel-specific rank in country#17 of 41 calculated
Capacity vs country/fuel peers1.12× · 1,000 MW median · 41 peers calculated
Homes-powered equivalent844,714 calculated
Climate15.2°C · HDD 1,829 derived from coordinates
Environmental severityC4 · 41/100 derived from coordinates

Not available

GWh reported / yrNot available not in dataset

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: WRI Global Power Plant Database source-record (legacy); fuel: WRI source-record fuel

In context: how this plant compares

At 1,125 MW, Aioi is well above the median oil plant in Japan (1,000 MW). Technically it is described as Steam. Oil-fired plants burn heavy fuel oil or diesel, usually as peaking or backup capacity on islands and grids without gas pipelines; high fuel cost keeps their utilisation low.

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

~892,440 t CO₂/yr (modelled) — in everyday terms

This facility's annual emissions are roughly equivalent to:

208kpassenger cars driven for a year
116khomes' yearly energy use
15 milliontree seedlings grown 10 years to absorb it

Equivalencies via US EPA Greenhouse Gas Equivalencies; modelled emissions from Climate TRACE.

Capacity vs largest oil plants in Japan

Hirono: 4,400 MW4kHironoKashima: 4,400 MW4kKashimaChita: 3,966 MW4kChitaAnegasaki: 3,150 MW3kAnegasakiYokohama: 3,016 MW3kYokohamaYokosuka: 2,274 MW2kYokosukaKainan: 2,100 MW2kKainanAtsumi: 1,900 MW2kAtsumi

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

Owner

Operated by Kansai. All plants by this company →

Local climate & thermal context

This oil plant burns oil or diesel to drive turbines or reciprocating engines. It sits in a humid subtropical climate (Köppen Cfa) — Northern Hemisphere, latitude 34.8°N — which shapes how much energy it can produce and how its output varies through the year.

15.2°Cannual mean temp
1,829heating degree-days (base 18°C)
818cooling degree-days (base 18°C)
30 melevation

Monthly mean temperature

J: 4 °CJF: 5 °CFM: 7 °CMA: 13 °CAM: 18 °CMJ: 22 °CJJ: 26 °CJA: 27 °CAS: 23 °CSO: 17 °CON: 12 °CND: 7 °CD27 °C

Heating degree-days here run 26% 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: 40/100 — this site sits in the mid third of the power plants we cover by heating degree-days.

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)
41/100environmental-severity index
23.0°Cseasonal temperature swing
83 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 #17 largest oil power plant of 41 in Japan by capacity.

Japan has 41 oil power plants in this dataset, together about 48,987 MW of capacity.

Nearby power plants

Location

Coordinates 34.7742, 134.4568 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.

Frequently asked questions

What type of power plant is Aioi?

Aioi is a 1,125 MW source-record oil power plant in Hyogo, Japan, commissioned in 1982.

How many homes can Aioi power?

Its output is enough to supply roughly 844,714 homes (estimated).

Who operates Aioi?

Aioi is operated by Kansai.

How much CO₂ does Aioi emit?

Aioi has modelled emissions of about 892,440 tonnes of CO₂ per year (Climate TRACE).

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