There seems to be an erroneous belief that wind and solar energy cannot be stored. This is not true. Nuclear power plants don’t shut down at night irrespective of whether power is required or not. Excess power is used in pumped storage schemes where two linked reservoirs are used. In times of low demand water is pumped from a reservoir at a low level to one high above. In times of high demand water is released from the top dam to drive turbines on its way down to the lower dam. Such schemes are in daily use for our National Grid in Wales and Scotland.