Hioki is a 29 MW solar power plant in Kagoshima, Japan. Based on its capacity (estimated), it can supply roughly 12k homes (estimated). It ranks #398 of 692 Japan power plants by installed capacity. As a non-combustion source, it has no direct CO₂ emissions from generation. In context, solar supplies about 9.8% 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 WKS0064386.
Known, modelled and calculated values are kept separate. Missing fields are shown as unavailable.
The capacity and/or fuel fields on this page include a source-backed provenance label from GEM, an official registry, Wikidata, OSM, or a cross-source match.
capacity: GEM tracker 2026 (location L100000800992); fuel: WRI source-record fuel
At 29 MW, Hioki is well above the median solar plant in Japan (13 MW). Solar PV converts sunlight directly into electricity with no moving parts or fuel; output varies by time of day and weather, so it pairs with storage or flexible backup.
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).
This solar plant converts sunlight directly into electricity with photovoltaic panels. It sits in a humid subtropical climate (Köppen Cfa) — Northern Hemisphere, latitude 31.7°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 42% 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: 33/100 — this site sits in the bottom third of the power plants we cover by heating degree-days.
Solar PV loses ~0.35%/°C above 25°C cell temperature — roughly 0.6% at warm-season highs here (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.
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 corrosive environment (estimated ISO 9223 class C4 — High), with humidity / wetness 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 #58 largest solar power plant of 324 in Japan by capacity.
Japan has 324 solar power plants in this dataset, together about 5,680 MW of capacity.
Coordinates 31.718, 130.406 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.
Hioki is a 29 MW source-record solar power plant in Kagoshima, Japan.
Its output is enough to supply roughly 12,339 homes (estimated).
