Tummel — United Kingdom

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).

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

Capacity provenance

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

GEM · 2026 · operating plant capacity

Data provenance

Source of the capacity and fuel values:

capacity: GEM · 2026 · L100001054881; fuel: WRI GPPD

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.

Key facts

Share of United Kingdom hydro capacity

0.7% of 5,950 MW across 118 plants in this dataset

Age among peers

9 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 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.

Monthly mean temperature

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

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 #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

• Keltneyburn Hydro · Hydro · 2 MW · Scotland
• Calliachar · Wind · 32.2 MW · Scotland
• Innerhadden Burn Hydro · Hydro · 1.4 MW · Scotland
• Beinn Eagagach Hydro · Hydro · 1.1 MW · Scotland
• Invervar Hydro - resubmission · Hydro · 1.2 MW · Scotland
• Bruar Hydro Scheme · Hydro · 1.9 MW · Scotland

Location

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

Frequently asked questions