Dolgarrog — United Kingdom

Dolgarrog is a 32 MW hydro power plant in Wales, United Kingdom. It is operated by RWE. Based on its capacity (estimated), it can supply roughly 32k homes (estimated). It ranks #372 of 2,860 United Kingdom power plants by installed capacity. Commissioned in 1907, it is around 119 years old — an older, legacy facility. As a non-combustion source, it has no direct CO₂ emissions from generation. In context, hydro supplies about 1.9% of United Kingdom's electricity; the national grid averages 217 gCO₂/kWh (64.4% low-carbon) (2025).

Plant data: WRI Global Power Plant Database (CC BY 4.0), id GBR2001081.

Data provenance

Source of the capacity and fuel values:

capacity: GEM · 2026 · L100001054876; fuel: WRI GPPD

In context: how this plant compares

At 32 MW, Dolgarrog is well above the median hydro plant in United Kingdom (3 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 United Kingdom hydro capacity

0.5% of 5,950 MW across 118 plants in this dataset

Age among peers

0 of 20 dated hydro plants in United Kingdom 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 United Kingdom

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

Owner

Operated by RWE. All plants by this company →

Local climate & thermal context

This hydro plant converts the energy of falling or flowing water through hydro turbines. It sits in a temperate oceanic climate (Köppen Cfb) — Northern Hemisphere, latitude 53.2°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 43% 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: 76/100 — 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 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 #18 largest hydro power plant of 118 in United Kingdom by capacity.

United Kingdom has 118 hydro power plants in this dataset, together about 5,950 MW of capacity.

Nearby power plants

• Moel Maelogen A · Wind · 2.6 MW · Wales
• Moel Maelogen A Phase 2 · Wind · 11.7 MW · Wales
• Teyrdan · Solar · 9.3 MW · Wales
• Llandulas Landfill Scheme · Waste · 2.9 MW · Wales
• Dinorwig · Hydro · 1,800 MW · Wales
• Dinorwig · Hydro · 1,728 MW · Wales

Location

Coordinates 53.1912, -3.8426 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.

Frequently asked questions