The 152.5MW Sloy Power Station and Dam is the largest conventional hydro power station in SSE’s existing hydro power fleet.

Construction on the scheme began in 1949 and was completed in 1951, becoming the first hydro scheme to be developed under the North of Scotland Hydro-Electric Board.

The scheme celebrated its 70th anniversary in 2021.

The existing power station is fed from Loch Sloy, just four kilometres away but, crucially, over 277 metres higher than the power station.

We recently announced plans to convert Sloy Power Station into a new pumped hydro storage facility.

Number of power stations
Total combined generation capacity
MW

Our plans for Sloy

An adapted pumped storage scheme would take excess energy from the grid and use it to pump water from Loch Lomond to the upper Loch Sloy where it would be stored before being released to power the grid when wind output is low and customer demand is high.

If progressed for development, the proposed pumped hydro storage project at Sloy would become SSE’s second such flexible electricity storage scheme in development, alongside the company’s plans for its proposed £1.5 billion Coire Glas scheme between Fort William and Inverness in the Scottish Highlands.

Find out more about the proposed project here.


Sloy Awe map

Power stations

Capacity (MW)

Gross head (metres)

Average annual output (million units)

Year started

Sloy

152.5

277

130

1950

Sron Mor

5

46

7

1957

Clachan

40

294

82

1955

Allt-na-Lairige

6

249

19

1956

Cruachan*

440

365

c700

1965

Nant

15

172

36

1963

Inverawe

25

36

106

1963

Kilmelford

2

111

12

1956

Loch Gair

6

109

19

1961

Striven

8

123

22

1951

Lussa

2.4

116

9

1952

*No longer owned by SSE Renewables

Major dams

Type

Length

Height

Completed

Sloy

Massive buttress

357

55

1951

Allt-na-Lairige

Pre-stressed gravity

425

24

1956

Shira (main)

Round headed buttress

725

45

1959

Shira (lower)

Concrete gravity and earth fill with concrete core

305

18

1956

Our Hydro Heritage

Visit Pitlochrydam.com

Our virtual 'Hydro Tour'

Join our virtual tour

Seeing Hydro through art

Cascades - A Virtual Exhibition