Sumikawa Akita is a 50 MW geothermal power plant in Akita, Japan. It is operated by J-POWER. Based on its capacity (estimated), it can supply roughly 94k homes (estimated). It ranks #308 of 692 Japan power plants by installed capacity. Commissioned in 1995, it is around 31 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).
Plant data: WRI Global Power Plant Database (CC BY 4.0), id WRI1020125.
Known, modelled and calculated values are kept separate. Missing fields are shown as unavailable.
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
At 50 MW, Sumikawa Akita is well above the median geothermal plant in Japan (30 MW). Geothermal plants tap underground heat to raise steam for a turbine; they provide steady, low-carbon baseload but are limited to geologically active regions.
Capacity comparison computed from the WRI Global Power Plant Database; fuel-type context is general engineering background.
Installed capacity (MW), WRI Global Power Plant Database (CC BY 4.0).
Operated by J-POWER.
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 40.0°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 93% 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: 93/100 — 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.
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 mild atmospheric environment (estimated ISO 9223 class C2 — Low), with thermal cycling the leading environmental stress.
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.
The #5 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.
Coordinates 39.9813, 140.7822 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.
Sumikawa Akita is a 50 MW source-record geothermal power plant in Akita, Japan, commissioned in 1995.
Its output is enough to supply roughly 93,857 homes (estimated).
Sumikawa Akita is operated by J-POWER.
