Grimsel 2 — Switzerland

Grimsel 2 is a 388 MW hydro power station in Piedmont, Switzerland. It is operated by Elektrizitätswerk Der Stadt Zürich (EWZ) [16%]; Energie Wasser Bern (EWB) [16%]. Based on its capacity (estimated), it can supply roughly 388k homes (estimated). It ranks #10 of 174 Switzerland power plants by installed capacity. Commissioned in 1981, it is around 45 years old — long-established. As a non-combustion source, it has no direct CO₂ emissions from generation. In context, hydro supplies about 52.3% 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 WRI1004211.

Capacity provenance

The public capacity above is the current source-record value. A 2026 tracker candidate lists 388 MW for Grimsel 2 hydroelectric plant, but it is not used as the public primary value until scope is verified (unit vs operating vs installed/project total).

Data provenance

Source of the capacity and fuel values:

capacity: GEM · 2026 · L100000603490; fuel: WRI GPPD

In context: how this plant compares

At 388 MW, Grimsel 2 is well above the median hydro plant in Switzerland (18.2 MW). Technically it is described as conventional storage. 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.

Key facts

Share of Switzerland hydro capacity

4.0% of 9,694 MW across 162 plants in this dataset

Age among peers

129 of 149 dated hydro plants in Switzerland are older

Calculated from the capacity and generation records in this dataset (WRI Global Power Plant Database (CC BY 4.0)).

Capacity vs largest hydro plants in Switzerland

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

Owner

Operated by Elektrizitätswerk Der Stadt Zürich (EWZ) [16%]; Energie Wasser Bern (EWB) [16%].

Local climate & thermal context

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 46.6°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 166% 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: 99/100 — 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 benign, low-corrosion environment (estimated ISO 9223 class C1 — Very 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 #4 largest hydro power plant of 162 in Switzerland by capacity.

Switzerland has 162 hydro power plants in this dataset, together about 9,694 MW of capacity.

Nearby power plants

• Grimsel 1 (Grimselsee) · Hydro · 32.5 MW · Piedmont
• Grimsel 1 (Oberaarsee) · Hydro · 35.3 MW · Piedmont
• Handeck 1 · Hydro · 100 MW · Bern
• Handeck 3 (Isogyre) · Hydro · 55 MW · Bern
• Reckingen · Hydro · 39.5 MW · Valais
• Innertkirchen 2 · Hydro · 62 MW · Bern

Location

Coordinates 46.5654, 8.3278 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.

Frequently asked questions