Peter Scott wrote:

There's a theme here. Huge hydro schemes are probably not going to be
built here, but maybe one important element of generation will be many
small scale schemes.

I didn't realise until the last year there is a small-scale hydro plant
at Beeston on the river Trent, there are several others in the sub-MW to
several-MW range

But they're all dwarfed by landfill gas, biogas and household waste
incinerators.

http://www.nfpa.co.uk/nffo3.html