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Imatra

Hydro power plant in South Karelia, Finland. Approximate location 61.1669, 28.7745.

HydroSouth KareliaFinlandconventional storage

Imatra is a 192 MW hydro power station in South Karelia, Finland. It is operated by Fortum Power & Heat OY. Based on its capacity (estimated), it can supply roughly 192k homes (estimated). It ranks #16 of 203 Finland power plants by installed capacity. Commissioned in 1929, it is around 97 years old — an older, legacy facility. As a non-combustion source, it has no direct CO₂ emissions from generation. In context, hydro supplies about 15.1% of Finland's electricity; the national grid averages 57 gCO₂/kWh (96.3% low-carbon) (2025).

192Source-backed capacity
192,219homes powered (est.)
1929commissioned (~97 yrs)

Plant data: WRI Global Power Plant Database (CC BY 4.0), id WRI1002350.

Data status

Known data

FacilityImatra WRI
CountryFinland · South Karelia WRI
Coordinates61.1669, 28.7745 WRI
FuelHydro WRI
MW installed capacity192 MW WRI source record; scope not independently normalised
OwnerFortum Power & Heat OY WRI
Commissioned1929 WRI
Technologyconventional storage WRI

Calculated from dataset

Capacity rank in country#16 of 203 calculated
Fuel-specific rank in country#1 of 95 calculated
Capacity vs country/fuel peers22.59× · 8 MW median · 95 peers calculated
Homes-powered equivalent192,219 calculated
Climate3.9°C · HDD 5,111 derived from coordinates
Environmental severityC2 · 29/100 derived from coordinates

Not available

GWh reported / yrNot available not in dataset
CO₂ emissionsnot applicable not applicable

Known, modelled and calculated values are kept separate. Missing fields are shown as unavailable.

Data provenance

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 L100000601606); fuel: WRI source-record fuel

In context: how this plant compares

At 192 MW, Imatra is well above the median hydro plant in Finland (8 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.

Capacity vs largest hydro plants in Finland

Imatra: 192 MW192ImatraTaivalkoski: 133 MW133TaivalkoskiPirttikoski: 131 MW131PirttikoskiSeitakorva: 130 MW130SeitakorvaOssauskoski: 121 MW121OssauskoskiIsohaara: 106 MW106IsohaaraValajaskoski: 101 MW101Valajaskos…Pamilo: 85 MW85Pamilo

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

Owner

Operated by Fortum Power & Heat OY.

Local climate & thermal context

This hydro plant converts the energy of falling or flowing water through hydro turbines. It sits in a warm-summer humid continental climate (Köppen Dfb) — Northern Hemisphere, latitude 61.2°N — which shapes how much energy it can produce and how its output varies through the year.

3.9°Cannual mean temp
5,111heating degree-days (base 18°C)
0cooling degree-days (base 18°C)
43 melevation

Monthly mean temperature

J: -8 °CJF: -8 °CFM: -3 °CMA: 3 °CAM: 10 °CMJ: 15 °CJJ: 17 °CJA: 15 °CAS: 10 °CSO: 4 °CON: -1 °CND: -6 °CD17 °C

Heating degree-days here run 108% 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: 95/100 — 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.

Site climate & environmental severity

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.

C2ISO 9223 corrosivity (indicative)
29/100environmental-severity index
25.4°Cseasonal temperature swing
54 kmdistance to coast

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.

How it compares & nearby plants

The #1 largest hydro power plant of 95 in Finland by capacity.

Finland has 95 hydro power plants in this dataset, together about 2,386 MW of capacity.

Nearby power plants

Location

Coordinates 61.1669, 28.7745 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.

Frequently asked questions

What type of power plant is Imatra?

Imatra is a 192 MW source-record hydro power plant in South Karelia, Finland, commissioned in 1929.

How many homes can Imatra power?

Its output is enough to supply roughly 192,219 homes (estimated).

Who operates Imatra?

Imatra is operated by Fortum Power & Heat OY.

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