Nesjavellir is a 120 MW geothermal power station in South, Iceland. It is operated by Orkuveita Reykjavíkur. Based on its capacity (estimated), it can supply roughly 225k homes (estimated). It ranks #8 of 20 Iceland power plants by installed capacity. Commissioned in 1998, it is around 28 years old — long-established. As a non-combustion source, it has no direct CO₂ emissions from generation. In context, geothermal supplies about 29.2% of Iceland's electricity; the national grid averages 28 gCO₂/kWh (100.0% low-carbon) (2024).
Plant data: WRI Global Power Plant Database (CC BY 4.0), id WRI1002805.
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: Wikidata P2109 nameplate capacity; fuel: WRI source-record fuel
At 120 MW, Nesjavellir is well above the median geothermal plant in Iceland (100 MW). Geothermal plants tap underground heat to raise steam for a turbine; they provide steady, low-carbon baseload but are limited to geologically active regions.
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 Orkuveita Reykjavíkur.
This geothermal plant taps underground heat to raise steam that drives a turbine. It sits in a polar tundra climate (Köppen ET) — Northern Hemisphere, latitude 64.1°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 122% 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: 96/100 — 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 moderately corrosive environment (estimated ISO 9223 class C3 — Medium), with marine corrosion 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 #2 largest geothermal power plant of 6 in Iceland by capacity.
Iceland has 6 geothermal power plants in this dataset, together about 560 MW of capacity.
Coordinates 64.1081, -21.2567 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.
Nesjavellir is a 120 MW source-record geothermal power plant in South, Iceland, commissioned in 1998.
Its output is enough to supply roughly 225,257 homes (estimated).
Nesjavellir is operated by Orkuveita Reykjavíkur.
