I found this presentation by Matthew Stocks et al and asked the permission of Professor Andrew Blakers to extend it with a section on the potential in the UK. He agreed, and Dr Matthew Stocks kindly provided extracts for the UK.
This shows that there are 195 sites in the UK, with a total potential capacity of 6047 GWh.
As the requirement for 100% renewable electricity is only about 1400 GWh, it would be possible to select the best, near to existing grid power lines, and with the greatest height difference between the upper and lower reservoirs.
However, the UK has several interconnectors to neighbouring countries, some with time differences. These should allow 100% renewable electricity to be achieved with somewhat less pumped storage in the UK and the neighbouring countries.
This short presentation on Saving Electricity in Industry and Homes was given to an engineering society.
The data was valid at the time, but there have been considerable changes in some end-uses, especially lighting.
The on-site generation of electricity and heat from renewables – often called microgeneration - has been proposed in the U.K. for saving carbon – reducing carbon emissions – in the buildings sector.