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Pumped hydro storage could be crucial for renewables in Australia, says study

A study from The Australian National University (ANU) has found that pumped hydro storage has the potential to build an electricity grid with 100 percent renewable energy.

According to a news release on Monday, the ANU's Andrew Blakers stated that the zero-emissions grid would be supported by pumped-hydro storage. It would rely, in the main, on wind and solar photovoltaic technology, negating the country's need for coal and gas-fired power.

"With Australia wrestling with how to secure its energy supply, we've found we can make the switch to affordable and reliable clean power," Blakers said.

Almost all new generation capacity in Australia was being provided by wind and solar, according to Blakers, but renewables accounted for just 15 percent of generation, with coal-fired power stations remaining dominant.

"Most existing coal and gas stations will retire over the next 15 years, and it will be cheaper to replace them with wind and solar PV," Blakers went on to add.

Finding and using an effective method of storage is crucial when it comes to renewables: while wind and solar may be good for cutting carbon emissions, they do not promise a constant stream of power.

"Pumped hydro energy storage is 97 per cent of all storage worldwide, and can be used to support high levels of solar PV and wind," Blakers said.

A 100 percent stabilized renewable energy electricity system would cost around 75 Australian dollars per megawatt hour, cheaper than power from coal and gas, the ANU said.

Pumped hydro storage uses turbines to push water uphill at night, filling a reservoir, the U.S. Energy Information Administration says. During the day, at times when demand for electricity is high, this water can be released to flow through turbines and generate electricity.

The ANU said it was studying the potential of short-term off-river pumped hydro energy storage, or STORES, sites. These are made up of a pair of reservoirs, separated by between 300 and 900 meters in altitude, connected by a pipe with a pump and turbine.

"This hydro power doesn't need a river and can go from zero to full power in minutes, providing an effective method to stabilize the grid," Matthew Stocks, from the ANU Research School of Engineering, said.

"The water is pumped up from the low reservoir to the high reservoir when the sun shines and wind blows and electricity is abundant, and then the water can run down through the turbine at night and when electricity is expensive."