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Tonstad

Hydro power plant in Vest-Agder, Norway. Approximate location 58.6648, 6.7084.

HydroVest-AgderNorwayconventional storage

Tonstad is a 960 MW hydro power station in Vest-Agder, Norway. It is operated by Lyse Produksjon AS [41%]; Statkraft [46%]; Agder [test] Energi [12%]. Based on its capacity (estimated), it can supply roughly 961k homes (estimated). It ranks #4 of 307 Norway power plants by installed capacity. Commissioned in 1968, it is around 58 years old — an older, legacy facility. As a non-combustion source, it has no direct CO₂ emissions from generation. In context, hydro supplies about 90.0% of Norway's electricity; the national grid averages 28 gCO₂/kWh (99.0% low-carbon) (2025).

960Source-backed capacity
961,097homes powered (est.)
1968commissioned (~58 yrs)

Plant data: WRI Global Power Plant Database (CC BY 4.0), id WRI1003576.

Data status

Known data

FacilityTonstad WRI
CountryNorway · Vest-Agder WRI
Coordinates58.6648, 6.7084 WRI
FuelHydro WRI
MW installed capacity960 MW WRI source record; scope not independently normalised
OwnerLyse Produksjon AS [41%]; Statkraft [46%]; Agder [test] Energi [12%] WRI
Commissioned1968 WRI
Technologyconventional storage WRI

Calculated from dataset

Capacity rank in country#4 of 307 calculated
Fuel-specific rank in country#3 of 291 calculated
Capacity vs country/fuel peers22.33× · 43 MW median · 291 peers calculated
Homes-powered equivalent961,097 calculated
Climate5.3°C · HDD 4,631 derived from coordinates
Environmental severityC4 · 31/100 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.

Capacity provenance

The public capacity above is a source-verified 2026 capacity claim: 960 MW for Tonstad hydroelectric plant.

Source: GEM tracker raw 2026. Scope: operating/nameplate; source-backed GEM tracker 2026 plant record. Confidence: high_source_row_verified_strict.

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 L100000602991); fuel: WRI source-record fuel

In context: how this plant compares

At 960 MW, Tonstad is well above the median hydro plant in Norway (43 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 Norway

Kvilldal: 1,444 MW1kKvilldalAurland5: 1,398 MW1kAurland5Tonstad: 960 MW960TonstadSy-Sima: 720 MW720Sy-SimaSaurdal: 640 MW640SaurdalSvartisen: 600 MW600SvartisenLang Sima: 580 MW580Lang SimaRana: 570 MW570Rana

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

Owner

Operated by Lyse Produksjon AS [41%]; Statkraft [46%]; Agder [test] Energi [12%].

Local climate & thermal context

This hydro plant converts the energy of falling or flowing water through hydro turbines. It sits in a subarctic (boreal) climate (Köppen Dfc) — Northern Hemisphere, latitude 58.7°N — which shapes how much energy it can produce and how its output varies through the year.

5.3°Cannual mean temp
4,631heating degree-days (base 18°C)
0cooling degree-days (base 18°C)
404 melevation

Monthly mean temperature

J: -2 °CJF: -2 °CFM: 0 °CMA: 3 °CAM: 8 °CMJ: 12 °CJJ: 13 °CJA: 13 °CAS: 10 °CSO: 6 °CON: 2 °CND: -1 °CD13 °C

Heating degree-days here run 88% 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: 92/100 — 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 corrosive environment (estimated ISO 9223 class C4 — High), with marine corrosion the leading environmental stress.

C4ISO 9223 corrosivity (indicative)
31/100environmental-severity index
15.5°Cseasonal temperature swing
12 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 #3 largest hydro power plant of 291 in Norway by capacity.

Norway has 291 hydro power plants in this dataset, together about 28,512 MW of capacity.

Nearby power plants

Location

Coordinates 58.6648, 6.7084 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.

Frequently asked questions

What type of power plant is Tonstad?

Tonstad is a 960 MW source-record hydro power plant in Vest-Agder, Norway, commissioned in 1968.

How many homes can Tonstad power?

Its output is enough to supply roughly 961,097 homes (estimated).

Who operates Tonstad?

Tonstad is operated by Lyse Produksjon AS [41%]; Statkraft [46%]; Agder [test] Energi [12%].

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