Hydro power plant in Wales, United Kingdom. Approximate location 52.9438, -3.6712.
HydroWalesUnited Kingdom
Llyn Celyn is a 4 MW hydro power plant in Wales, United Kingdom. It is operated by Dwr Cymru Welsh Water. Based on its capacity (estimated), it can supply roughly 4.5k homes (estimated). It ranks #1853 of 2,860 United Kingdom power plants by installed capacity. 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 GBR0004909.
Known, modelled and calculated values are kept separate. Missing fields are shown as unavailable.
The capacity and fuel fields on this page are source-record values from the upstream open dataset. They are useful for identification and ranking, but they have not been upgraded to a 2026 registry/GEM-location verified value.
capacity: WRI Global Power Plant Database source-record (legacy); fuel: WRI source-record fuel
At 4 MW, Llyn Celyn is well above the median hydro plant in United Kingdom (3 MW). 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.
Installed capacity (MW), WRI Global Power Plant Database (CC BY 4.0).
Operated by Dwr Cymru Welsh Water.
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 52.9°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 50% 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: 80/100 — 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.
For a plant’s outdoor hardware — heat-recovery steam generators (HRSG), expansion joints, valves, flanges and their insulation — the local climate sets how fast unprotected steel and coatings degrade. This site sits in a corrosive environment (estimated ISO 9223 class C4 — High), with humidity / wetness the leading environmental stress.
Higher environmental severity is exactly where protective removable insulation pays back most: a sheltered micro-climate slows corrosion, UV and thermal-cycling damage and extends outdoor hardware service life. This is an indicative site-climate context — not a condition assessment of any specific plant or operator.
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.
The #46 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.
Coordinates 52.9438, -3.6712 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.
Llyn Celyn is a 4 MW source-record hydro power plant in Wales, United Kingdom.
Its output is enough to supply roughly 4,505 homes (estimated).
Llyn Celyn is operated by Dwr Cymru Welsh Water.
