Llechwedd had and I think still use theirs. Maenofferen also had a power station.
LLechwedd have recently installed a new generating set in their power station. However, they are going to export
all their power to the grid whilst buying in power for their own requirements. I still haven't got my head round the logic of that. I can understand exporting any surplus to the grid, but not all of it!
Croesor hydro station is still used also
The power station (at Blean y Cwm) was put out of use many years ago and the building converted to an outward bound centre (or similar). Recently, the pipe was renewed down from Llyn Croesor to the power station (the pipe is buried now, most of the original piping was above ground). The power station has ben re-equiped and now makes a modest contribution to our energy needs. This is
proper sustainable energy, not bloody windmills! I will try and find out it's current output.