Olkiluoto 1 is a 1,760 MW nuclear power station in Satakunta, Finland. It is operated by Teollisuuden Voima Oyj. Based on its capacity (estimated), it can supply roughly 4.0 million homes (estimated). It ranks #1 of 203 Finland power plants by installed capacity. Commissioned in 1979, it is around 47 years old — long-established. As a non-combustion source, it has no direct CO₂ emissions from generation. In context, nuclear supplies about 39.9% of Finland's electricity; the national grid averages 57 gCO₂/kWh (96.3% low-carbon) (2025).
Plant data: WRI Global Power Plant Database (CC BY 4.0), id WRI1002473.
Data status
Known data
Calculated from dataset
Not available
Known, modelled and calculated values are kept separate. Missing fields are shown as unavailable.
Data provenance
Source of the capacity and fuel values:
capacity: GEM · 2026 · L100000500004; fuel: WRI GPPD
In context: how this plant compares
Technically it is described as boiling water reactor. Nuclear plants split uranium to raise steam with no direct CO₂; they run as steady baseload with very high capacity factors and the longest operating lifetimes of any thermal plant.
Capacity comparison computed from the WRI Global Power Plant Database; fuel-type context is general engineering background.
Key facts
- Share of Finland nuclear capacity
- 44.9% of 3,922 MW across 3 plants in this dataset
Calculated from the capacity and generation records in this dataset (WRI Global Power Plant Database (CC BY 4.0)).
Capacity vs largest nuclear plants in Finland
Installed capacity (MW), WRI Global Power Plant Database (CC BY 4.0).
Owner
Operated by Teollisuuden Voima Oyj.
Local climate & thermal context
This nuclear plant uses heat from nuclear fission to raise steam for a turbine-generator. 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.
Monthly mean temperature
Heating degree-days here run 97% 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: 93/100 — 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
This site sits in a corrosive environment (estimated ISO 9223 class C4 — High), with marine corrosion the leading environmental stress.
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 nuclear power plant of 3 in Finland by capacity.
Finland has 3 nuclear power plants in this dataset, together about 3,922 MW of capacity.
Nearby power plants
- Olkiluoto kt · Other · 100.5 MW · Satakunta
- Olkiluoto tv · Wind · 1 MW · Satakunta
- Olkiluoto Reserve power station · Oil · 100 MW ·
- Jalasjoki/Niiles · Hydro · 1 MW · Satakunta
- Rauma · Biomass · 71.5 MW · Satakunta
- Rauma · Biomass · 75 MW · Satakunta
Location
Coordinates 61.2371, 21.4433 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.
Frequently asked questions
What type of power plant is Olkiluoto 1?
Olkiluoto 1 is a 1,760 MW nuclear power plant in Satakunta, Finland, commissioned in 1979.
Who operates Olkiluoto 1?
Olkiluoto 1 is operated by Teollisuuden Voima Oyj.