Hydro may boost share of renewables in electricity grid

Hydro may boost share of renewables in electricity grid
Hydro may boost share of renewables in electricity grid

Hydro power could provide cost-effective large-scale energy storage that can support high levels of renewable energy in Australia’s electricity grid.

The Australian National University (ANU) is leading a study to map potential short-term off-river pumped hydro energy storage (STORES) sites, which would enable renewable energy to provide a larger share of generation to the national electricity grid.

Lead researcher Professor Andrew Blakers from ANU said the low cost and technical maturity of STORES could allow solar photovoltaic and wind energy to reliably reach penetration levels above 50 per cent and push towards 100 per cent renewables.

“Water is constantly flowing between the reservoirs to balance supply and demand, and STORES has the potential to support grid stability through inertial spinning reserve and very fast ramp rates from zero to 100 per cent in minutes,” he said.

STORES sites are pairs of reservoirs which are separated by an altitude difference of between 300 - 900 metres, in hilly terrain, and joined by a pipe. Water is circulated between the upper and lower reservoirs in a closed loop to store and generate power.

“South Australia has one possible STORES site with an altitude difference of up to 600 metres in the hills to the east of Spencer Gulf. This site could support the development of solar and wind resources in the area,” Professor Blakers said.

With $449,000 from the Australian Renewable Energy Agency (ARENA), ANU is partnering with ElectraNet and VTara Energy Group to conduct the Atlas of Pumped Hydro Energy Storage Study and develop a blueprint and cost model to integrate the technology into Australia’s electricity grid.

ARENA CEO Ivor Frischknecht said the study would help determine how cheap, efficient and effective pumped hydro systems can be in providing large-scale, reliable, clean energy storage that can feed into the grid on demand.

“The approach uses surplus energy to pump water uphill to a storage reservoir. This water can then be released downhill to generate electricity on demand,” he said.

“Whilst there been a recent focus on energy storage technologies such as batteries and solar thermal, the vast majority of existing large-scale energy storage comes from large on-river hydroelectric dams, such as those in Tasmania and the Snowy Mountains.

“There is limited potential for further large-scale hydroelectric systems to be installed in Australia; however there are potentially hundreds of smaller, environmentally suitable, off-river STORES scale sites.”

Chairman and CEO of VTara Energy Group Dr Clive Stephens said energy storage was increasing in importance as renewable energy penetration increases. 

“Pumped hydro is the cheapest form of large-scale storage. Off-river pumped hydro can support the electricity network and can be co-located with wind and solar for added benefits,” Dr Stephens said.

The study, which is due to finish in June 2018, will provide regular progress reports.

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