Summit Onahama power station is a 50 MW coal power plant in Ibaraki, Japan. It is operated by Summit Onahama S Power Corp. Based on its capacity (estimated), it can supply roughly 63k homes (estimated). It ranks #323 of 692 Japan power plants by installed capacity. Commissioned in 2004, it is around 22 years old — relatively modern. In context, coal supplies about 32.1% 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 CT-5380.
Data status
Known data
Calculated from dataset
Not available
Known, modelled and calculated values are kept separate. Missing fields are shown as unavailable.
Data provenance
Source of the capacity and fuel values:
capacity: GEM wiki unit-level table, historical/all-units fallback when no operating units, fetched 2026-07-05; fuel: Climate TRACE
In context: how this plant compares
At 50 MW, Summit Onahama power station is below the median coal plant in Japan (250 MW). Technically it is described as subcritical. Coal plants burn pulverised coal to raise high-pressure steam for a turbine; they run as baseload but are the most carbon-intensive mainstream source and the first targeted for retirement or efficiency retrofits.
Capacity comparison computed from the WRI Global Power Plant Database; fuel-type context is general engineering background.
Key facts
- Share of Japan coal capacity
- less than 0.1% of 53,431 MW across 94 plants in this dataset
- Age among peers
- 57 of 83 dated coal 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 coal plants in Japan
Installed capacity (MW), WRI Global Power Plant Database (CC BY 4.0).
Owner
Operated by Summit Onahama S Power Corp.
Local climate & thermal context
This coal plant burns coal to raise high-pressure steam that spins a turbine-generator. It sits in a humid subtropical climate (Köppen Cfa) — Northern Hemisphere, latitude 36.2°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 13% 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: 45/100 — 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
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 #87 largest coal power plant of 94 in Japan by capacity.
Japan has 94 coal power plants in this dataset, together about 53,431 MW of capacity.
Nearby power plants
Location
Coordinates 36.23, 140.28 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.
Frequently asked questions
What type of power plant is Summit Onahama power station?
Summit Onahama power station is a 50 MW coal power plant in Ibaraki, Japan, commissioned in 2004.
Who operates Summit Onahama power station?
Summit Onahama power station is operated by Summit Onahama S Power Corp.