Hydro power plant in Hawaii, United States of America. Approximate location 19.7203, -155.1189.
HydroHawaiiUnited States of America
Waiau Hydro is a 1 MW hydro power plant in Hawaii, United States of America. It is operated by Hawaii Electric Light Co Inc. Based on its capacity (estimated), it can supply roughly 1.0k homes (estimated). It ranks #10906 of 10,938 United States of America power plants by installed capacity. Commissioned in 1924, it is around 102 years old — an older, legacy facility. As a non-combustion source, it has no direct CO₂ emissions from generation. In context, hydro supplies about 5.3% of United States of America's electricity; the national grid averages 384 gCO₂/kWh (43.0% low-carbon) (2025).
Plant data: WRI Global Power Plant Database (CC BY 4.0), id USA0000774.
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: Wikidata P2109 nameplate capacity; fuel: WRI source-record fuel
At 1 MW, Waiau Hydro is below the median hydro plant in United States of America (8 MW). 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.
Annual generation (GWh), WRI Global Power Plant Database (CC BY 4.0).
Operated by Hawaii Electric Light Co Inc.
This hydro plant converts the energy of falling or flowing water through hydro turbines. It sits in a temperate oceanic climate (Köppen Cfb) — Northern Hemisphere, latitude 19.7°N — which shapes how much energy it can produce and how its output varies through the year.
Monthly mean temperature
This site has effectively no heating season (tropical/equatorial climate), so winter heat loss is not the driver here. The thermal concern shifts to year-round process heat and humidity/heat-driven corrosion of hot equipment.
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 an aggressive, high-corrosion environment (estimated ISO 9223 class C5 — Very high), with marine salt corrosion 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 #1445 largest hydro power plant of 1449 in United States of America by capacity.
United States of America has 1449 hydro power plants in this dataset, together about 102,513 MW of capacity.
Coordinates 19.7203, -155.1189 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.
Waiau Hydro is a 1 MW source-record hydro power plant in Hawaii, United States of America, commissioned in 1924.
Its output is enough to supply roughly 1,001 homes (estimated).
Waiau Hydro is operated by Hawaii Electric Light Co Inc.
