I doubt that anything like 450GWh of storage capacity will be needed with a good mix and spread of renewable energy but it shows what is available is vastly more than needed.
"The locations of these sites are shown below. Each site has between 1 gigawatt-hour (GWh) and 300GWh of storage potential. To put this in perspective, our earlier research showed that Australia needs just 450GWh of storage capacity (and 20GW of generation power) spread across a few dozen sites to support a 100% renewable electricity system.
In other words, Australia has so many good sites for PHES that only the best 0.1% of them will be needed. Developers can afford to be choosy with this significant oversupply of sites."
"PHES accounts for 97% of energy storage worldwide because it is the cheapest form of large-scale energy storage, with an operational lifetime of 50 years or more. Most existing PHES systems require dams located in river valleys. However, off-river PHES has vast potential.
Off-river PHES requires pairs of modestly sized reservoirs at different altitudes, typically with an area of 10 to 100 hectares.
The reservoirs are joined by a pipe with a pump and turbine. Water is pumped uphill when electricity generation is plentiful; then, when generation tails off, electricity can be dispatched on demand by releasing the stored water downhill through the turbine.
Off-river PHES typically delivers maximum power for between five and 25 hours, depending on the size of the reservoirs.
Most of the potential PHES sites we have identified in Australia are off-river. All 22,000 of them are outside national parks and urban areas."
