Tummel

Hydro power plant in Scotland, United Kingdom. Approximate location 56.7075, -4.021.

HydroScotlandUnited Kingdomconventional storage

Tummel is a 40 MW hydro power plant in Scotland, United Kingdom. It is operated by Scottish and Southern: Hydro Schemes - Tummel. Based on its capacity (estimated), it can supply roughly 40k homes (estimated). It ranks #317 of 2,860 United Kingdom power plants by installed capacity. Commissioned in 1955, it is around 71 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).

40Source-backed capacity
40,045homes powered (est.)
1955commissioned (~71 yrs)

Plant data: WRI Global Power Plant Database (CC BY 4.0), id GBR1000409.

Data status

Known data

FacilityTummel WRI
CountryUnited Kingdom · Scotland WRI
Coordinates56.7075, -4.021 WRI
FuelHydro WRI
MW installed capacity40 MW WRI source record; scope not independently normalised
OwnerScottish and Southern: Hydro Schemes - Tummel WRI
Commissioned1955 WRI
Technologyconventional storage WRI

Calculated from dataset

Capacity rank in country#317 of 2860 calculated
Fuel-specific rank in country#13 of 118 calculated
Capacity vs country/fuel peers13.33× · 3 MW median · 118 peers calculated
Homes-powered equivalent40,045 calculated
Climate6.3°C · HDD 4,266 derived from coordinates
Environmental severityC2 · 19/100 derived from coordinates

Not available

GWh reported / yrNot available not in dataset
CO₂ emissionsnot applicable not applicable

Known, modelled and calculated values are kept separate. Missing fields are shown as unavailable.

Capacity provenance

The public capacity above is a source-verified 2026 capacity claim: 40 MW for Tummel hydroelectric plant.

Source: GEM tracker raw 2026. Scope: operating/nameplate; source-backed GEM tracker 2026 plant record. Confidence: high_source_row_verified.

Data provenance

The capacity and/or fuel fields on this page include a source-backed provenance label from GEM, an official registry, Wikidata, OSM, or a cross-source match.

capacity: GEM tracker 2026 (location L100001054881); fuel: WRI source-record fuel

In context: how this plant compares

At 40 MW, Tummel 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.

Capacity vs largest hydro plants in United Kingdom

Dinorwig: 1,800 MW2kDinorwigDinorwig: 1,728 MW2kDinorwigCruachan: 440 MW440CruachanFfestiniog: 384 MW384FfestiniogFoyers: 300 MW300FoyersSloy: 153 MW153SloyGlendoe: 100 MW100GlendoeClunie: 61 MW61Clunie

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

Owner

Operated by Scottish and Southern: Hydro Schemes - Tummel.

Local climate & thermal context

This hydro plant converts the energy of falling or flowing water through hydro turbines. It sits in a subpolar oceanic climate (Köppen Cfc) — Northern Hemisphere, latitude 56.7°N — which shapes how much energy it can produce and how its output varies through the year.

6.3°Cannual mean temp
4,266heating degree-days (base 18°C)
0cooling degree-days (base 18°C)
416 melevation

Monthly mean temperature

J: 1 °CJF: 1 °CFM: 3 °CMA: 5 °CAM: 8 °CMJ: 11 °CJJ: 12 °CJA: 12 °CAS: 10 °CSO: 7 °CON: 4 °CND: 2 °CD12 °C

Heating degree-days here run 74% 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: 87/100 — 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

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 mild atmospheric environment (estimated ISO 9223 class C2 — Low), with humidity / wetness the leading environmental stress.

C2ISO 9223 corrosivity (indicative)
19/100environmental-severity index
11.2°Cseasonal temperature swing
167 kmdistance to coast

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.

How it compares & nearby plants

The #13 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

Location

Coordinates 56.7075, -4.021 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.

Frequently asked questions

What type of power plant is Tummel?

Tummel is a 40 MW source-record hydro power plant in Scotland, United Kingdom, commissioned in 1955.

How many homes can Tummel power?

Its output is enough to supply roughly 40,045 homes (estimated).

Who operates Tummel?

Tummel is operated by Scottish and Southern: Hydro Schemes - Tummel.

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