What is hydro?
Hydroelectric energy (hydro) is a form of renewable energy that harnesses the power of moving water to generate electricity.
Types of hydro
There are three main techniques that we use at SSE to generate energy from hydro:
1. Storage hydroelectric
2. Pumped storage hydro
3. Run of river
Storage hydroelectric
Storage hydroelectric is sometimes also known as ‘impounded power’. A natural loch or man-made reservoir formed by draining a river collects water from the surrounding area, which can be hundreds or even thousands of square kilometres in size. What is created is a store of water situated at a higher altitude than the power station it supplies. The difference in height between the power station and the reservoir is called the ‘head’. The higher the head, the more energy there is in the water to drive the turbines and the more electricity it can produce. This is the same principle as the ‘header’ tanks in the lofts of houses that provide the water pressure for the hot water taps.
The amount of water the operator is allowed to extract from the reservoir is controlled, to prevent the water level from falling so low that the environment and wildlife are adversely affected.
Pumped storage hydro
Pumped storage schemes have two reservoirs to hold the water, with one higher than the other. Pumped storage works when water is released from the higher reservoir to drive the turbines in the power station below it before being passed into the lower reservoir. Traditionally, pumped storage has been used when there is high electricity demand and then at times when there is cheap surplus electricity available the electricity generators are switched to become massive motors, which pump water from the lower reservoir back up to the higher one, where it is stored until it is needed to meet the next peak in demand.
Run of river
In the simplest run of river schemes, some of the water from a naturally fast-flowing river is diverted via a tunnel to drive a water turbine in a nearby power station. The turbine spins as the water flows, driving a shaft that is connected to the electricity generator. The water is then allowed to flow back into the river.
The main disadvantage of run of river schemes is that the amount of electricity and when it can be generated is almost entirely governed by how much water there is in the river at any given time. When permission is granted to build run of river schemes, there is usually a requirement that a set minimum amount of water must always be allowed to remain in the river to protect wildlife and habitat. So when the river is low, due to lack of rain, the power station may be starved of water and unable to generate any electricity at all.
SSE's hydro portfolio
SSE's hydro locations
Filter sites
Cassley Power Station
The Cassley Power Station has a 10MW capacity and was completed in 1959. It is part of the SSE Renewables Shin Hydro Scheme.
Duchally Power Station
The Duchally Power Station was commissioned in 1959 and is part of the Shin Hydro Scheme
Shin Power Station
The Shin Power Station has a 18.6MW capacity and was completed in 1958. It is part of the SSE Renewables Shin Hydro Scheme.
Grudie Bridge Power Station
The Grudie Bridge Power Station has a 18.6MW capacity and was completed in 1950. It is part of the SSE Renewables Conon Hydro Scheme.
Achanalt Power Station
The Achanalt Power Station has a 3MW capacity and was completed in 1956. It is part of the SSE Renewables Conon Hydro Scheme.
Luichart Power Station
The Luichart Power Station has a 34MW capacity and was completed in 1954. It is part of the SSE Renewables Conon Hydro Scheme.
Lairg Power Station
The Lairg Power Station has a 3.5MW capacity and was completed in 1959. It is part of the SSE Renewables Shin Hydro Scheme.
Culligran Power Station
The Culligran Power Station has a 19MW capacity and was completed in 1962. It is part of the SSE Renewables Affric/Beauly Hydro Scheme.
Deanie Power Station
The Deanie Power Station has a 38MW capacity and was completed in 1963. It is a part of the SSE Renewables Affric/Beauly Hydro Scheme.
Aigas Power Station
The Aigas Power Station has a 20MW capacity and was completed in 1962. It is part of the SSE Renewables Affric/Beauly Hydro Scheme.
Kilmorack Power Station
The Kilmorack Power Station has a 20MW capacity and was completed in 1962. It is part of the SSE Renewables Affric/Beauly Hydro Scheme.
Mullardoch Power Station
The Mullardoch Power Station has a 2.4MW capacity and was completed in 1955. It is part of the SSE Renewables Affric/Beauly Hydro Scheme.
Fasnakyle Power Station
The Fasnakyle Power Station has a 69MW capacity and was completed in 1951. It is part of the SSE Renewables Affric/Beauly Hydro Scheme.
Quoich Power Station
The Quoich Power Station has a 18MW capacity and was completed in 1955. It is part of the SSE Renewables Great Glen Hydro Scheme.
Invergarry Power Station
The Invergarry Power Station has a 20MW capacity and was completed in 1956. It is part of the SSE Renewables Great Glen Hydro Scheme.
Tummel Power Station
The Tummel Power Station has a 34MW capacity and was completed in 1933. It is part of the SSE Renewables Tummel Valley Hydro Scheme.
Rannoch Power Station
The Rannoch Power Station has a 44MW capacity and was completed in 1930. It is part of the SSE Renewables Tummel Valley Hydro Scheme.
Pitlochry Power Station
The Pitlochry Power Station has a 15MW capacity and was completed in 1950. It is part of the SSE Renewables Tummel Valley Hydro Scheme and also home to the Pitlochry Dam Visitor Centre.
Clunie Power Station
The Clunie Power Station has a 61MW capacity and was completed in 1950. It is part of the SSE Renewables Tummel Valley Hydro Scheme.
Pitlochry Dam Visitor Centre
The Pitlochry Visitor Centre is located adjacent to the Pitlochry Hydro Power Station, part of the Tummel Valley Hydro Scheme.
Errochty Power Station
The Errochty Power Station has a 75MW capacity and was completed in 1957. It is part of the SSE Renewables Tummel Valley Hydro Scheme.
Trinafour Power Station
The Trinafour Power Station was completed in 1959 and is part of the SSE Renewables Tummel Valley Hydro Scheme.
Livishie Power Station
The Livishie Power Station has a capacity of 15MW and was completed in 1962, It is part of the SSE Renewables Great Glen Hydro Scheme.
Glenmoriston Hydro Station
The Glenmoriston Power Station has a capacity of 37MW and was completed in 1953. It is part of the SSE Renewables Great Glen Hydro Scheme.
Sloy Power Station
The Sloy Power Station has a capacity of 152.5MW and was completed in 1950. It is part of the SSE Renewables Sloy/Awe Hydro Scheme.
Inverawe Power Station
The Inverawe Power Station has a capacity of 25MW and was completed in 1963. It is part of the SSE Renewables Sloy/Awe Hydro Scheme.
Nant Power Station
The Nant Power Station has a capacity of 15MW and was completed in 1953. It is part of the SSE Renewables Sloy/Awe Power Station.
Lochay Power Station
The Lochay Power Station has a 45MW capacity and was completed in 1958. It is part of the SSE Renewables Breadalbane Hydro Scheme.
Cashlie Power Station
The Cashlie Power Station has a capacity of 11MW and was completed in 1959. It is part of the SSE Renewables Breadalbane Hydro Scheme.
Finlarig Power Station
The Finlarig Power Station has a capacity of 16.5MW and was completed in 1955. It is part of the SSE Renewables Breadalbane Hydro Scheme.
Sron Mor Power Station
The Sron Mor Power Station has a capacity of 5MW and was completed in 1957. It is part of the SSE Renewables Sloy/Awe Hydro Scheme.
Loch Ericht Power Station
The Loch Ericht Power Station has a capacity of 2.2MW and was completed in 1962. It is part of the SSE Renewables Tummel Valley Hydro Scheme.
Nostie Bridge Power Station
The Nostie Bridge Power Station has a capacity of 1.3MW and was commissioned in 1950. It is part of the SSE Renewables Great Glen Hydro Scheme.
Morar Power Station
The Morar Power Station was commissioned in 1950 and is part of the SSE Renewables Great Glen Hydro Scheme.
Kerry Falls Power Station
The Kerry Falls Power Station has a 1.25MW capacity and was commissioned in 1951. It is part of the SSE Renewables Conon Hydro Scheme.
Striven Power Station
The Striven Power Station has a 8MW capacity and was completed in 1951. It is part of the SSE RenewablesSloy/Awe Hydro Scheme.
Lussa Power Station
The Lussa Power Station has a 2.4MW capacity and was completed in 1952. It is part of the SSE Renewables Sloy/Awe Hydro Scheme.
Storr Lochs Power Station
The Storr Lochs Power Station has a 2.4MW capacity and was commissioned in 1952. It is part of the SSE Renewables Great Glen Hydro Scheme.
Gaur Power Station
The Gaur Power Station has a 7.5MW capacity and was completed in 1953. It is part of the SSE Renewables Tummel Valley Power Station.
Loch Dubh Power Station
The Loch Dubh Power Station has a 1.2MW capacity and was commissioned in 1954. It is part of the SSE Renewables Conon Hydro Scheme.
Ceannacroc Power Station
The Ceannacroc Power Station has a 20MW capacity and was completed in 1956. It is part of the SSE Renewables Great Glen Hydro Scheme.
Kilmelford Power Station
The Kilmelford Power Station has a 2MW capacity and was completed in 1956. It is part of the SSE Renewables Sloy/Awe Hydro Scheme.
Allt Na Lairige Power Station
The Allt Na Lairige Power Station has a 6MW capacity and was completed in 1956. It is part of the SSE Renewables Sloy/Awe Hydro Scheme.
Clachan Power Station
Clachan Power Station has a 40MW capacity and was completed in 1955. It is part of the SSE Renewables Sloy/Awe Hydro Scheme.
Mossford Power Station
Mossford Power Station has a 18.6MW capacity and was completed in 1957. It is part of the SSE Renewables Conon Hydro Scheme.
Vaich Power Station
Vaich Power Station was commissioned in 1956 and is part of the SSE Renewables Conon Hydro Scheme.
Dalchonzie Power Station
Dalchonzie Power Station has a 4MW capacity and was complete in 1958. It is part of the SSE Renewables Breadalbane Hydro Scheme.
Lubreoch Power Station
Lubreoch Power Station has a 4MW capacity and was completed in 1958. It is part of the SSE Renewables Breadalbane Hydro Scheme.
Lednock Power Station
Lednock Power Station has a 3MW capacity and was completed in 1961. It is part of the SSE Renewables Breadalbane Hydro Scheme.
St Fillans Power Station
St Fillans Power Station has a 16.8MW capacity and was completed in 1957. It is part of the SSE Renewables Breadalbane Hydro Scheme.
Chliostair Power Station
Chliostair Power Station was commissioned in 1960 and is part of the SSE Renewables Conon Hydro Scheme.
Loch Gair Power Station
Loch Gair Power Station has a capacity of 6MW and was completed in 1961. It is part of the SSE Renewables Sloy/Awe Hydro Scheme.
Mucomir Power Station
Mucomir Power Station was completed in 1962 and has a 1.7MW capacity. It is part of the SSE Renewables Great Glen Hydro Scheme.
Foyers Falls Power Station
Foyers Falls Power Station has a 5MW capacity and is part of the SSE Renewables Foyers Hydro Scheme. It was completed in 1968.
Foyers Pump Storage Power Station
The Foyers 300MW Pump Storage Power Station is part of the Foyers Hydro Scheme.
Claddoch Power Station
Claddoch Power Station was commissioned in 1949 and is part of the SSE Renewables Sloy/Awe Hydro Scheme.
Cuileig Power Station
Cuileig Power Station is part of the Shin Hydro Scheme.
Glendoe Power Station
Glendoe Power Station has a 100MW capacity and is part of the SSE Renewables Foyers Hydro Scheme. It was commissioned in 2008.
Kingairloch Power Station
Kingairloch Power Station is part of the SSE Renewables Great Glen Hydro Scheme. It has a 3.5MW capacity and was commissioned in 2005.
Orrin Power Station
Orrin Power Station has an 18MW capacity and was completed in 1959. It is part of the SSE Renewables Conon Hydro Scheme.
Torr Achilty Power Station
Torr Achilty Power Station has a 15MW capacity and was completed in 1954. It is a part of the SSE Renewables Conon Hydro Scheme.
Gisla Power Station
Gisla Power Station was commissioned in 1960 and is part of the SSE Renewables Conon Hydro Scheme.
Loyne Power Station
Loyne Power Station was commissioned in 1956 and is part of the SSE Renewables Great Glen Hydro Scheme.
Misgeach Power Station
Misgeach Power Station was commissioned in 1963 and is part of the SSE Renewables Affric/Beauly Hydro Scheme
Falls of Lochay Power Station
Falls of Lochay Power Station is part of SSE Renewables's Breadalbane Hydro Scheme. It has a capacity of 45MW and was completed in 1958.
Cuaich Power Station
Cuaich Power Station was completed in 1959 and has a 2.5MW capacity. It is part of the SSE Renewables Tummel Valley Hydro Scheme.
Coire Glas
SSE Renewables's Coire Glas is the first large-scale pumped hydro storage scheme to be developed in the UK for more than 40 years. It is located on the shores of Loch Lochy in the Scottish Highlands, between Fort William and Inverness and has a potential capacity of up to 1500MW. It will double Great Britain’s existing electricity storage capacity.
Innovation in hydro
We're currently developing two new pumped hydro storage projects to deliver the large-scale, long-duration electricity storage needed as part of Britain’s future energy mix and set out in 2022 in the UK Government’s ‘British Energy Security Strategy’.
These include plans to develop our fully consented 30GWh Coire Glas project in the Scottish Highlands, a potential £1.5bn-plus investment in what could be Britain’s biggest pumped hydro storage scheme in 40 years.
We've also announced plans to convert our 152.5MW Sloy Power Station, Britain’s largest conventional hydropower plant in central Scotland, into a new 25GWh pumped hydro storage facility.