3.8. Fluctuations and storage http://www.ck12.org
TABLE3.11:
proposed location power (GW) head (m) volume (million
m^3 )energy stored
(GWh)
Bowydd 2.40 250 17.7 12.0
Croesor 1.35 310 8.0 6.7Alternative sites for pumped storage facilities in Snowdonia. At both these sites the lower lake would have been a
new artificial reservoir.
Pumped-storage facilities holding significantly more energy than Dinorwig could be built in Scotland by upgrading
existing hydroelectric facilities. Scanning a map of Scotland, one candidate location would use Loch Sloy as its
upper lake and Loch Lomond as its lower lake. There is already a small hydroelectric power station linking these
lakes. Figure 26.9 shows these lakes and the Dinorwig lakes on the same scale. The height difference between Loch
Sloy and Loch Lomond is about 270m. Sloy’s area is about 1. 5 km^2 , and it can already store an energy of 20 GWh.
If Loch Sloy’s dam were raised by another 40m then the extra energy that could be stored would be about 40 GWh.
The water level in Loch Lomond would change by at most 0.8m during a cycle. This is less than the normal range
of annual water level variations of Loch Lomond (2m).
Figure 26.9:Dinorwig, in the Snowdonia National Park, compared with Loch Sloy and Loch Lomond. The upper
maps show 10 km by 10 km areas. In the lower maps the blue grid is made of 1 km squares. Images produced from
Ordnance Survey’s Get-a-map service http://www.ordnancesurvey.co.uk/getamap. Images reproduced with permission of
Ordnance Survey. © Crown Copyright 2006.