Kernkraftwerk Mühleberg — Switzerland

Kernkraftwerk Mühleberg is a 390 MW nuclear power station in Bern, Switzerland. It is operated by BWK FMB Energie AG. Based on its capacity (estimated), it can supply roughly 879k homes (estimated). It ranks #9 of 174 Switzerland power plants by installed capacity. Commissioned in 1972, it is around 54 years old — an older, legacy facility. As a non-combustion source, it has no direct CO₂ emissions from generation. In context, nuclear supplies about 29.9% of Switzerland's electricity; the national grid averages 39 gCO₂/kWh (97.7% low-carbon) (2025).

Plant data: WRI Global Power Plant Database (CC BY 4.0), id WRI1004274.

Data provenance

Capacity and fuel are the upstream open-dataset record, not yet matched to a 2026 registry or GEM entry.

capacity: WRI GPPD; fuel: WRI GPPD

In context: how this plant compares

At 390 MW, Kernkraftwerk Mühleberg is below the median nuclear plant in Switzerland (950 MW). 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 Switzerland nuclear capacity

7.0% of 5,582 MW across 7 plants in this dataset

Age among peers

1 of 5 dated nuclear plants in Switzerland is older

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 Switzerland

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

Owner

Operated by BWK FMB Energie AG.

Local climate & thermal context

This nuclear plant uses heat from nuclear fission to raise steam for a turbine-generator. It sits in a temperate oceanic climate (Köppen Cfb) — Northern Hemisphere, latitude 47.0°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 41% 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: 75/100 — 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 mild atmospheric environment (estimated ISO 9223 class C2 — Low), 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 #6 largest nuclear power plant of 7 in Switzerland by capacity.

Switzerland has 7 nuclear power plants in this dataset, together about 5,582 MW of capacity.

Nearby power plants

• Niederried · Hydro · 15 MW · Bern
• Kallnach · Hydro · 8 MW · Bern
• Aarberg · Hydro · 15.2 MW · Bern
• Felsenau · Hydro · 11.3 MW · Bern
• Matte · Hydro · 1.2 MW · Bern
• Hagneck 1 (M3 M4 u. M5) · Hydro · 12.7 MW · Bern

Location

Coordinates 46.9689, 7.2684 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.

Frequently asked questions