Geograph - photograph every grid square

The great corrie of Cruachan was once a prized grazing, and hiding place, for cattle. It is now occupied by a loch, behind this dam.
This is a product of the nuclear power industry. Nuclear stations run continuously and constantly generate power, demand however is not constant. Storing electricity is a problem. This is the Cruachan pumped storage station. When demand for power is low, e.g during the night, the power is used to pump water up the hill into the corrie, at peaks its allowed to run back again generating electricity as its needed. Cruachan is in effect a giant battery, recharge at quiet times and run when power is wanted. Now that wind power stations are appearing, pumped storage offers a solution as to what to do when the wind does not blow.