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Uenotai

Geothermal power plant in Akita, Japan. Approximate location 39.0012, 140.6039.

GeothermalAkitaJapan

Uenotai is a 28 MW geothermal power plant in Akita, Japan. It is operated by KYUSHU ELECTRIC POWER CO. Based on its capacity (estimated), it can supply roughly 51,621 homes (estimated). It ranks #362 of 659 Japan power plants by installed capacity. Commissioned in 1994, it is around 32 years old — long-established. As a non-combustion source, it has no direct CO₂ emissions from generation. In context, the national grid averages 477 gCO₂/kWh (32.7% low-carbon) (2025).

28MW installed capacity
51,621homes powered (est.)
1994commissioned (~32 yrs)

Plant data: WRI Global Power Plant Database (CC BY 4.0), id WRI1020127.

Capacity vs largest geothermal plants in Japan

Hatchobaru Otake: 110 MW110Hatchobaru…Kakkonda: 80 MW80KakkondaYanaizu-Nishiyama: 65 MW65Yanaizu-Ni…Mori: 50 MW50MoriSumikawa Akita: 50 MW50Sumikawa A…Ogiri: 35 MW35OgiriYamagawa: 30 MW30YamagawaUenotai: 28 MW28Uenotai

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

Owner

Operated by KYUSHU ELECTRIC POWER CO. All plants by this company →

Local climate & thermal context

This geothermal plant taps underground heat to raise steam that drives a turbine. It sits in a warm-summer humid continental climate (Köppen Dfb) — Northern Hemisphere, latitude 39.0°N — which shapes how much energy it can produce and how its output varies through the year.

7.5°Cannual mean temp
3,960heating degree-days (base 18°C)
135cooling degree-days (base 18°C)
727 melevation

Monthly mean temperature

J: -4 °CJF: -4 °CFM: -2 °CMA: 5 °CAM: 11 °CMJ: 15 °CJJ: 19 °CJA: 21 °CAS: 16 °CSO: 10 °CON: 4 °CND: -1 °CD21 °C

Heating degree-days here run 61% 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: 84/100 — this site sits in the top third of the power plants we cover by heating degree-days.

In colder climates, uninsulated hot equipment (boilers, turbines, valves, steam lines) loses proportionally more heat to ambient air — exactly the loss Inzonex modular insulation is designed to cut.

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.

How it compares & nearby plants

The #8 largest geothermal power plant of 14 in Japan by capacity.

Japan has 14 geothermal power plants in this dataset, together about 536 MW of capacity.

Nearby power plants

Location

Coordinates 39.0012, 140.6039 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.

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