Unfortunately I think MT set us up for SNOWY 2.0 whether it made financial sense or not. Technically its fine, it will do the job and keep the lights on and ironically help the remaining coal power stations to run even more efficiently / profitable.Its the flattest, driest continent on earth and we're pumping water up and down because we have these silly unreliable energy sources. Pumped hydro is extremely inefficient - ScoMo should have cancelled it as soon as he got into office. Goes to show how bipartisan this carbon dioxide madness is.
I've stated before that SNOWY 2.0 is a financial hole in the bucket and I haven't changed.
However pumping water up hill (we don't pump it down), has been going on in the SNOWY and Wivenhoe, Qld for +40 years and in both cases it was successful as cheaper than high cost peaking coal plant which are probably not even a thing today. So in the right application is does work and technically and economically the best option in some cases. The issue that faces the grid today is that the peak is more "peaky" so ignoring RE, the problem wasn't getting any better, yes we have gas, but hardly cheaper either, around $100 MWh for peak gas.
On the dry bit, Dubai is building pumped hydro, it is being done on purely commercial grounds. https://gulfnews.com/uae/government/dubai-hydroelectric-power-station-to-cost-dh14b-dewa-awards-contract-for-hatta-project-1.1566032158700
On the side, Sept 2019 was the first month solar contributed >10% to the total generation for the NEM. SA 21%, Qld 13%, NSW 9%, Vic 8.7%, Tas 2.7%. So I'd expect Dec-Jan to see +15% for NEM, SA + 25%, Qld +20%.