Very interesting. The biggest problem with wind and solar is lack of storage. I would like to see what the efficiency is (1 kWh in equals whar fraction of a kWh out with transmission loss both ways, pumping loss and even evaporation loss) and what the estimated cost of storing and retransmitting each kWh is.
Based upon other reports, I would guess it to be 60~70% efficient.
We use some pumped storage in the US to supply daytime peaks with nightime generation.