Presumably the Western Australia idea is for a barrage like in the Rance scheme in France? I believe that the Cook Strait idea is to capture the tidal current because in NZ the tidal ranges are too low.

I think they should have a look at the Kimberley idea but I doubt it is economic compared with abundant Gas in WA given the limited vision of most governments. The UK has not pursued anything with the river Severn even though their energy resources are much more sparse than Australia's.