There are two pumped storage stations in Wales that I know of. Dinorwig (where the power station is inside the mountain, as a student I got to go in there) and

There are two pumped storage stations in Wales that I know of. Dinorwig (where the power station is inside the mountain, as a student I got to go in there) and Ffestiniog. Wales has a long history of having dams built to provide water to English cities, see the Elan Valley, Llyn Vyrnwy, Llyn Clewedog and many more. The displacement of people and 'theft' of water even spurned a terrorist organisation to stop it called the Free Wales Army!