Arenal Hydroelectric Power Plant Costa Rica

Arenal Hydroelectric Power Plant Costa Rica is a 157.5 MW hydro power station in Guanacaste, Costa Rica. It is operated by Instituto Costarricense de Electricidad [100%]. Based on its capacity (estimated), it can supply roughly 158k homes (estimated). It ranks #5 of 27 Costa Rica power plants by installed capacity. Commissioned in 1979, it is around 47 years old — long-established. As a non-combustion source, it has no direct CO₂ emissions from generation. In context, hydro supplies about 74.8% of Costa Rica's electricity; the national grid averages 24 gCO₂/kWh (100.0% low-carbon) (2025).

Plant data: WRI Global Power Plant Database (CC BY 4.0), id GEODB0002153.

Data provenance

Source of the capacity and fuel values:

capacity: GEM · 2026 · L100000601437; fuel: WRI GPPD

In context: how this plant compares

At 157.5 MW, Arenal Hydroelectric Power Plant Costa Rica is well above the median hydro plant in Costa Rica (50 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 Costa Rica hydro capacity

12.6% of 1,254 MW across 18 plants in this dataset

Age among peers

2 of 11 dated hydro plants in Costa Rica 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 Costa Rica

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

Owner

Operated by Instituto Costarricense de Electricidad [100%].

Local climate & thermal context

This hydro plant converts the energy of falling or flowing water through hydro turbines. It sits in a tropical savanna climate (Köppen Aw) — Northern Hemisphere, latitude 10.5°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.

Site climate & environmental severity

This site sits in a corrosive environment (estimated ISO 9223 class C4 — High), with humidity / wetness 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 #3 largest hydro power plant of 18 in Costa Rica by capacity.

Costa Rica has 18 hydro power plants in this dataset, together about 1,254 MW of capacity.

Nearby power plants

• Corobici (Miguel Pablo Dengo) Hydroelectric Power Plant Costa Rica · Hydro · 174 MW · Guanacaste
• Sandillal Hydroelectric Power Plant Costa Rica · Hydro · 32 MW · Guanacaste
• Miravalles V Geothermal Power Plant Costa Rica · Geothermal · 15.4 MW · Guanacaste
• Miravalles I and II Geothermal Power Plant Costa Rica · Geothermal · 115 MW · Guanacaste
• Boca de Pozo Geothermal Power Plant Costa Rica · Geothermal · 5 MW · Guanacaste
• Miravalles III Geothermal Power Plant Costa Rica · Geothermal · 27.5 MW · Guanacaste

Location

Coordinates 10.4755, -84.9989 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.

Frequently asked questions