Tomura is a 40 MW hydro power plant in Hokkaido, Japan. It is operated by HOKKAIDO ELECTRIC POWER CO INC. Based on its capacity (estimated), it can supply roughly 40k homes (estimated). It ranks #359 of 692 Japan power plants by installed capacity. Commissioned in 1978, it is around 48 years old — long-established. As a non-combustion source, it has no direct CO₂ emissions from generation. In context, hydro supplies about 7.2% 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 WRI1020230.
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 · 2026 · L100001054757; fuel: WRI GPPD
In context: how this plant compares
At 40 MW, Tomura is below the median hydro plant in Japan (350 MW). Technically it is described as conventional storage. Hydropower converts the energy of falling or flowing water into electricity; output depends on rainfall and reservoir level, and large dams also provide grid balancing and storage.
Capacity comparison computed from the WRI Global Power Plant Database; fuel-type context is general engineering background.
Key facts
- Share of Japan hydro capacity
- 0.1% of 27,749 MW across 55 plants in this dataset
- Age among peers
- 30 of 54 dated hydro 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 hydro plants in Japan
Installed capacity (MW), WRI Global Power Plant Database (CC BY 4.0).
Owner
Operated by HOKKAIDO ELECTRIC POWER CO INC. All plants by this company →
Local climate & thermal context
This hydro plant converts the energy of falling or flowing water through hydro turbines. It sits in a warm-summer humid continental climate (Köppen Dfb) — Northern Hemisphere, latitude 43.4°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 125% above 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: 96/100 — this site sits in the top 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 mild atmospheric environment (estimated ISO 9223 class C2 — Low), with thermal cycling 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 #54 largest hydro power plant of 55 in Japan by capacity.
Japan has 55 hydro power plants in this dataset, together about 27,749 MW of capacity.
Nearby power plants
- Tokachi · Hydro · 40 MW · Hokkaido
- Takisato · Hydro · 57 MW · Hokkaido
- Nokanan · Hydro · 30 MW · Hokkaido
- Sunagawa Daini power station · Coal · 250 MW · Hokkaido
- Naie power station · Coal · 350 MW · Hokkaido
- Okuniikappu · Hydro · 44 MW · Hokkaido
Location
Coordinates 43.4331, 142.884 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.
Frequently asked questions
What type of power plant is Tomura?
Tomura is a 40 MW hydro power plant in Hokkaido, Japan, commissioned in 1978.
Who operates Tomura?
Tomura is operated by HOKKAIDO ELECTRIC POWER CO INC.