I WAS grateful to etymologist Dirk Campbell for giving us a brief note on the word idiot, its derivation and shades of meaning, so take your choice. From my point of view, I guess ‘idiot’ like ‘beauty’ is in the eye of the beholder.
In the same spirit I investigated the Dinorvic system for storing electric power mentioned in Peter Gardiner’s letter.
There was no Dinorvic but Dinorwic is an installation that stores power by using a loch in Snowdonia high near Elidir Mountain called Marchly Mawr that had been dammed to form a reservoir.
The method uses the loch as the header for water that is driven by a pumping station in the mountain, Dinorwic, using not-needed power to pump water up to the loch. When the power can be used the water from the loch drives the reversible pumps to generate power to the grid.
It involved increasing the reservoir capacity 1.5 million cubic metres of rock,16 kilometres of underground tunnels,12 million tonnes of excavated rock,1.2 million tonnes of concrete 4,500 tonnes of steel and transmission lines to the grid.
If you want to store electricity from a very large group of wind farms you need a mountain with a loch or reservoir high enough and, although I couldn’t find any cost details, a hell of a lot of money.