Pumped hydro at Kanmantoo being investigated by copper mine operator Hillgrove Resources

Possibility: Hillgrove Resources is investigating whether it would be feasible to build a pumped hydroelectricity storage facility at its Kanmantoo copper mine when operations cease. Photo: Hillgrove Resources.

Possibility: Hillgrove Resources is investigating whether it would be feasible to build a pumped hydroelectricity storage facility at its Kanmantoo copper mine when operations cease. Photo: Hillgrove Resources.

A pumped hydro plant capable of storing electricity could be built at Kanmantoo when its copper mine is no longer viable, mine operator Hillgrove Resources has revealed.

In its half-yearly results, released on August 28, the company announced it was working with an engineering group to investigate whether the idea would be viable.

Pumped hydro involves using two dams, one at the top of a hill and one at the bottom, to store electricity.

Water is pumped up the hill when power is cheap, and allowed to flow downhill, powering a turbine, when prices rise or other power sources fail.

Hillgrove’s chief executive officer, Steven McClare, said it was early days yet, but the signs were promising.

“On the first glance it looks very viable,” he said.

“We’ll finish mining in the first half of 2019 and process out until 2020, but the work could be done simultaneously and it could be up and running within a three- or four-year period.”

The bottom of the pit could be filled with water even as underground mining continues nearby.

Nearby residents were mostly supportive of the idea when a survey was circulated, Mr McClare said.

“The main thing is people are going ‘how much water does it consume?’” he said.

“Sometimes they don’t understand the difference between pumped hydro and ordinary hydro … the only water you consume is evaporation.”

Pumped hydro facilities typically consist of two reservoirs of between nine and 100 hectares, according to the Australian National University (ANU), located in hilly terrain.

The area of the Kanmantoo mine’s main pit is around 30 hectares, and the distance between its projected floor and the top of the nearby tailings dam will be 427 metres.

ANU researcher Matthew Stocks said the ability of pumped hydro to store power could even allow South Australia to switch entirely to wind turbines and other renewable energy sources.

"About 400 hectares of reservoir is required to support a 100 per cent renewable energy grid for South Australia, which is four parts per million of the state's land mass," he said in June.

"Annual water requirement would be less than one per cent of South Australia's annual extraction from the Murray River."

Pumped hydro accounts for 97 per cent of electricity storage capability worldwide, according to the ANU.

South Australia is the only state which does not have a facility.

The state government has proposed a 100-megawatt battery as the answer to South Australia's energy storage needs.

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