A recent study by the Australian National University has identified 22,000 potential pumped hydro energy storage (PHES) sites across Australia for the on-demand delivery of electricity from renewable energy sources.
Being able to reliably dispatch power generated from variable renewable energy sources such as wind or solar will be critical for gradually reducing the use of coal or gas in our energy mix.
The recent success of Tesla's 100MW lithium-ion battery installed in South Australia - the to date largest in the world - made international news.
But potentially low-cost alternatives to batteries for the storage of large-scale renewable energy plants are emerging.
This includes a technology that is based on a principle of power generation we have exploited throughout history and is readily available in nature.
It's water running down the hill, driven by gravitation.
But whether we use it for running mills or to generate elecricity at large-scale river dams such as in Tasmania and the Snowy Mountains, we usually rely on solar power stored in evaporated water.
By contrast, pumped hydro technology requires input from power harnessed, for example, in a solar energy plant, to pump water from a lower reservoir up into a higher reservoir.
Separated by an altitude difference of between 300 – 900 metres, the reservoirs are joined by pipes, through which the water can circulate in a closed loop.
Power is then generated on-demand and fed into an electricity grid when the water is flowing downhill into the lower reservoir.
Several feasibility studies testing the technology are on the way, including in the Spencer Gulf in South Australia, in Kidston in Queensland and in Tasmania.
But the number of potential opportunities in Australia could be vast, according to results from the ANU's Atlas of Pumped Hydro Energy Storage Study.
Supported with around $0.5 million from the Australian Renewable Energy Agency (ARENA), the research identified more than 12,000 potential sites in Victoria and NSW, which together could provide energy storage capacity of around 40,000 Gigawatt-hours (GWh). Across the country, 22,000 potential STORES were mapped with a combined potential energy storage capacity of 67 GWh.
According to lead researcher Professor Andrew Blakes, Australia is estimated to need around 450 GWh of storage to support a 100% renewable electricity system.
"We have found so many good potential sites that only the best 0.1% would need to be developed."
Pumped hydro has a lifetime of 50 years, and is the lowest cost large-scale energy storage technology, according to Professor Blakers.
ARENA's chief executive officer Ivor Frischknecht said that the findings of this study prove there are opportunities across Australia worthy of further investigation.