Loviisa Y1 — Finland

Loviisa Y1 is a 992 MW nuclear power station in Uusimaa, Finland. It is operated by Fortum Power & Heat Power. Based on reported annual generation of 8,171 GWh, it can supply roughly 2.3 million homes. It ranks #4 of 203 Finland power plants by installed capacity. Commissioned in 1977, it is around 49 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 WRI1002445.

Data provenance

Source of the capacity and fuel values:

capacity: GEM · 2026 · L100000500194; fuel: WRI GPPD

In context: how this plant compares

Technically it is described as pressurized 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

Load factor

94%, from 8,171 GWh of reported generation

Generation trend

7,948 GWh in 2015 and 8,171 GWh in 2017 (+3%)

Highest and lowest year

2017: 8,171 GWh; 2016: 7,915 GWh

Share of Finland nuclear capacity

25.3% 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)).

Reported generation trend

Annual generation (GWh), WRI Global Power Plant Database (CC BY 4.0).

Owner

Operated by Fortum Power & Heat Power.

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 60.4°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 98% 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 moderately corrosive environment (estimated ISO 9223 class C3 — Medium), with humidity / wetness 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 #3 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

• Loviisa kt · Other · 40 MW · Uusimaa
• Ahvenkoski · Hydro · 24 MW · Kymenlaakso
• Mussalo power station · Coal · 80 MW ·
• Kotka · Biomass · 72 MW · Kymenlaakso
• Porvoo Tolkkinen · Oil · 40 MW · Uusimaa
• Tolkkinen Biolaitos · Biomass · 11.3 MW · Uusimaa

Location

Coordinates 60.3708, 26.3468 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.

Frequently asked questions