Pumping up - renewably
Image source: ARENA
At present, the vast majority of existing large-scale energy storage comes from on-river hydroelectric dams, such as those in Tasmania and the Snowy Mountains. But there is limited potential for further large-scale hydroelectric systems in Australia.
However, there are hundreds of smaller locations across Australia that could potentially be used as short-term off-river pumped hydro energy storage (STORES) sites.
These consist of pairs of reservoirs that are separated by an altitude difference of between 300 – 900 metres.
Joined by pipes, water can circulate between the upper and lower reservoirs in a closed loop, which can be used to store surplus energy by pumping water to the uphill storage reservoir. Power is then generated on-demand when the water is flowing downhill into the lower reservoir.
According to Professor Andrew Blakers from the Australian National University, the low cost and technical maturity of STORES could allow solar photovoltaic and wind energy to reliably reach penetration levels above 50% and push towards 100% renewables.
Image source: ARENA
Professor Blakers leads the Atlas of Pumped Hydro Energy Storage Studya project, in which the Australian National University partners with ElectraNet and VTara Energy Group. The project, which is funded by the Australian Renewable Energy Agency, will map STORES sites across Australia, and develop a cost model to integrate the technology into Australia's electricity grid.
A current example for this is the disused Kidstone Gold Mine in North Queensland, where Genex Power Limited has just completed a feasibility study of the Kidston Pumped Storage Hydro Project.
Funded with up to $4 million from ARENA, the company aims to convert the former gold mine into a giant battery that potentially could feed up to 330 megawatt of power into the grid.
Some of the energy could be sourced from a 50 megawatt solar farm that Genex is developing at the Kidston site.
If Genex can reach financial close and construction is going ahead, the project could potentially provide a blueprint for other large pumped hydro storage projects at disused mines.