Is it worth noting that all hydro electric schemes require "surplus" power to pump the the water uphill, so is this surplus going to be available and where will it come from , given that we are running pretty tight in generation right now ?
A pumped storage scheme requires energy to pump water yes, ultimately it's a storage scheme, but I'll add that an on-river dam doesn't, it's energy positive as such.
Snowy 2.0 is in that regard a hybrid. It's a pumped scheme yes but the upper reservoir does also have natural inflow.
The existing Tumut 3 station is also a hybrid. It's primarily an on-river scheme but 3 of the 6 turbines do incorporate pumps to enable partial re-use of water, pumping it back from Jounama pondage (downstream) back up into Talbingo (upstream).
An attribute of SH2 is that it does have the ability to pump water discharged by Tumut 1 & 2. That is, it can take their discharge which ends up in Talbingo Reservoir, pump that up into Tantangara then, via the existing infrastructure, that can be sent back to Lake Eucumbene from where it came in the first place.
If, as a future project, a pump were to be installed from Blowering Reservoir to Jounama pondage, and if the 3 non-pumping turbines at Tumut 3 were equipped with pumps, then it would be possible to pump from Blowering > Jounama > Talbingo > Tantangara then natural flow to Eucumbene and thus recycle all water in the northern end of the scheme if desired. That's not proposed at present but it's a relatively straightforward add-on. Bearing in mind that the capacity of Blowering Reservoir is equal to just under 92% of its annual inflow or 101% of the annual discharge from Tumut 3. That being so, short term inflows become irrelevant in any scenario other than a truly massive flood.
Shoalhaven (NSW, Origin Energy) and Wivenhoe (Qld, CleanCo) are both "pure" pumped storage schemes without natural inflows.
The other Snowy stations (Tumut 1, Tumut 2, Blowering, Jounama, Guthega, Murray 1, Murray 2) are all on-river dams not pumped storage (though Murray 1 and 2 do involve some pumping, in one direction only, from Lake Jindabyne).
Barron Gorge and Kareeya (Qld), Lake Argyle (WA), the AGL hydro stations in Vic and all the Hydro Tasmania stations are on river. They're net energy positive with any pumping being a one-way diversion not pumped storage as such. Same with the various minor stations associated with irrigation or water supply dams.
A fact not well known to most Australians is that the Snowy scheme has never been completed to its full potential. SH2 as now proposed is simply a modernised version of a project first identified in the late 1950's. It's not the only one that could be added.