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Kymmen

Hydro power plant in Vaermland, Sweden. Approximate location 59.95, 12.75.

HydroVaermlandSwedenpumped storage

Kymmen is a 55 MW hydro power plant in Vaermland, Sweden. It is operated by Fortum. Based on its capacity (estimated), it can supply roughly 55k homes (estimated). It ranks #82 of 178 Sweden power plants by installed capacity. Commissioned in 1987, it is around 39 years old — long-established. As a non-combustion source, it has no direct CO₂ emissions from generation. In context, hydro supplies about 40.0% of Sweden's electricity; the national grid averages 35 gCO₂/kWh (98.8% low-carbon) (2025).

55Source-backed capacity
55,062homes powered (est.)
1987commissioned (~39 yrs)

Plant data: WRI Global Power Plant Database (CC BY 4.0), id WRI1019433.

Data status

Known data

FacilityKymmen WRI
CountrySweden · Vaermland WRI
Coordinates59.95, 12.75 WRI
FuelHydro WRI
MW installed capacity55 MW WRI source record; scope not independently normalised
OwnerFortum WRI
Commissioned1987 WRI
Technologypumped storage WRI

Calculated from dataset

Capacity rank in country#82 of 178 calculated
Fuel-specific rank in country#57 of 142 calculated
Capacity vs country/fuel peers1.57× · 35 MW median · 142 peers calculated
Homes-powered equivalent55,062 calculated
Climate4.2°C · HDD 5,003 derived from coordinates
Environmental severityC2 · 23/100 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 L100001023252); fuel: WRI source-record fuel

In context: how this plant compares

At 55 MW, Kymmen is well above the median hydro plant in Sweden (35 MW). Technically it is described as pumped 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 Sweden

Karlshamn: 1,020 MW1kKarlshamnHarspranget: 818 MW818HarsprangetStornorrfors: 599 MW599Stornorrfo…Letsi: 483 MW483LetsiMessaure: 463 MW463MessaurePorjus: 417 MW417PorjusLigga: 342 MW342LiggaTrängslet: 329 MW329Trängslet

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

Owner

Operated by Fortum. All plants by this company →

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 60.0°N — which shapes how much energy it can produce and how its output varies through the year.

4.2°Cannual mean temp
5,003heating degree-days (base 18°C)
0cooling degree-days (base 18°C)
265 melevation

Monthly mean temperature

J: -6 °CJF: -6 °CFM: -2 °CMA: 3 °CAM: 9 °CMJ: 14 °CJJ: 15 °CJA: 14 °CAS: 9 °CSO: 5 °CON: -1 °CND: -5 °CD15 °C

Heating degree-days here run 104% 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: 94/100 — 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 humidity / wetness the leading environmental stress.

C2ISO 9223 corrosivity (indicative)
23/100environmental-severity index
21.1°Cseasonal temperature swing
158 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 #57 largest hydro power plant of 142 in Sweden by capacity.

Sweden has 142 hydro power plants in this dataset, together about 12,709 MW of capacity.

Nearby power plants

Location

Coordinates 59.95, 12.75 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.

Frequently asked questions

What type of power plant is Kymmen?

Kymmen is a 55 MW source-record hydro power plant in Vaermland, Sweden, commissioned in 1987.

How many homes can Kymmen power?

Its output is enough to supply roughly 55,062 homes (estimated).

Who operates Kymmen?

Kymmen is operated by Fortum.

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