Gronvollfoss is a 40 MW hydro power plant in Telemark, Norway. It is operated by Skagerak Kraft AS [100%]. Based on its capacity (estimated), it can supply roughly 40k homes (estimated). It ranks #166 of 307 Norway power plants by installed capacity. Commissioned in 1933, it is around 93 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).
Plant data: WRI Global Power Plant Database (CC BY 4.0), id WRI1003172.
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: GEM tracker 2026 (location L100001054790); fuel: WRI source-record fuel
At 40 MW, Gronvollfoss is around the median hydro plant in Norway (43 MW). Technically it is described as run-of-river. 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.
Installed capacity (MW), WRI Global Power Plant Database (CC BY 4.0).
Operated by Skagerak Kraft AS [100%].
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 59.7°N — which shapes how much energy it can produce and how its output varies through the year.
Monthly mean temperature
Heating degree-days here run 92% 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.
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.
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 #153 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.
Coordinates 59.6577, 9.2079 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.
Gronvollfoss is a 40 MW source-record hydro power plant in Telemark, Norway, commissioned in 1933.
Its output is enough to supply roughly 40,045 homes (estimated).
Gronvollfoss is operated by Skagerak Kraft AS [100%].
