Yanai is a 1,578 MW gas power station in Yamaguchi, Japan. It is operated by Chugoku. Based on its capacity (estimated), it can supply roughly 1.8 million homes (estimated). It ranks #55 of 692 Japan power plants by installed capacity. Commissioned in 1992, it is around 34 years old — long-established. Its modelled annual emissions are 2,347,100 t CO₂/yr (Climate TRACE), equivalent to about 547k cars driven for a year. In context, gas supplies about 32.8% of Japan's electricity; the national grid averages 477 gCO₂/kWh (32.7% low-carbon) (2025).
Plant data: WRI Global Power Plant Database (CC BY 4.0), id WRI1000658.
Data status
Known data
Modelled source data
Calculated from dataset
Not available
Known, modelled and calculated values are kept separate. Missing fields are shown as unavailable.
Capacity provenance
The public capacity above is the current source-record value. A 2026 tracker candidate lists 1,578 MW for Yanai power station, but it is not used as the public primary value until scope is verified (unit vs operating vs installed/project total).
Data provenance
Source of the capacity and fuel values:
capacity: GEM · 2026 · L100000405194; fuel: WRI GPPD
In context: how this plant compares
At 1,578 MW, Yanai is well above the median gas plant in Japan (847.4 MW). Technically it is described as CCGT; combined-cycle with a heat-recovery steam generator (HRSG). Gas plants burn natural gas either in open-cycle turbines for fast peaking, or in combined-cycle units that recover exhaust heat in an HRSG to reach roughly 55–62% efficiency — the cleanest-burning fossil option.
Capacity comparison computed from the WRI Global Power Plant Database; fuel-type context is general engineering background.
~2,347,100 t CO₂/yr (modelled) — in everyday terms
This facility's annual emissions are roughly equivalent to:
Equivalencies via US EPA Greenhouse Gas Equivalencies; modelled emissions from Climate TRACE.
Key facts
- Share of Japan gas capacity
- 2.1% of 74,949 MW across 66 plants in this dataset
- Age among peers
- 17 of 58 dated gas plants in Japan are older
Calculated from the capacity and generation records in this dataset (WRI Global Power Plant Database (CC BY 4.0)).
Capacity vs largest gas plants in Japan
Installed capacity (MW), WRI Global Power Plant Database (CC BY 4.0).
Owner
Operated by Chugoku. All plants by this company →
Local climate & thermal context
This gas plant burns natural gas in a turbine — often in a combined-cycle setup — to generate electricity. It sits in a humid subtropical climate (Köppen Cfa) — Northern Hemisphere, latitude 34.0°N — which shapes how much energy it can produce and how its output varies through the year.
Monthly mean temperature
Heating degree-days here run 28% 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: 39/100 — this site sits in the mid third of the power plants we cover by heating degree-days.
A gas turbine here also runs ~0% below its ISO (15°C) rating at this annual mean (typical CCGT curve, 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
This site sits in a corrosive environment (estimated ISO 9223 class C4 — High), with humidity / wetness the leading environmental stress.
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 gas power plant of 66 in Japan by capacity.
Japan has 66 gas power plants in this dataset, together about 74,949 MW of capacity.
Nearby power plants
- Kaminoseki nuclear power plant · Nuclear · 2,746 MW · Yamaguchi Prefecture
- Hikari Works power station · Coal · 53 MW · Yamaguchi
- Iwakuni Thermal power station · Oil · 850 MW · Yamaguchi
- Kudamatsu Thermal power plant · Oil · 700 MW · Yamaguchi
- IWAKUNI MILL NPI · Oil · 159.1 MW · Yamaguchi
- MARIFU REFINERY · Oil · 202.9 MW · Yamaguchi
Location
Coordinates 33.953, 132.1248 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.
Frequently asked questions
What type of power plant is Yanai?
Yanai is a 1,578 MW gas power plant in Yamaguchi, Japan, commissioned in 1992.
Who operates Yanai?
Yanai is operated by Chugoku.
How much CO₂ does Yanai emit?
Yanai has modelled emissions of about 2,347,100 tonnes of CO₂ per year (Climate TRACE).