A pumped hydro system using groundwater in Bendigo’s disused mine shafts could galvanise other renewable projects in the region, and is a more logical idea than it might seem to some.
That’s the view of Bendigo Sustainability Group president Chris Weir, commenting on the results of a feasibility study which investigated whether the shafts have the capacity to power and store pumped hydro electricity.
The study concluded there was a strong prospect for cost-effective energy storage in a project, which could generate 30 megawatts and could store six hours, or 180 MWh, of energy for the local power grid, but would cost $50 million to create.
Mr Weir said pumped hydro, as opposed to large scale batteries, was the cheapest energy storage option because the infrastructure – the mine shafts – was already there.
He said Coliban Water had been pumping water out of the Central Deborah tourist mine at significant annual cost for a while, “so we know it works”.
The study concluded a pumped hydro electricity project could form part of a long-term groundwater management strategy and inherently take over dewatering of Central Deborah tourist mine, but Mr Weir was less sure.
“It won’t solve the groundwater problem, because we’re just recycling it,” he said.
Greater local solar and wind energy was required to power pumps and turbines needed to move the water around in a pumped hydro system, Mr Weir said.
It won’t solve the groundwater problem, because we’re just recycling itBendigo Sustainability Group president Chris Weir
The City of Greater Bendigo is believed to be investigating the possibility of large scale solar projects in the region, while the BSG is behind a push for community-owned solar farms.
A downside to the project, according to the feasibility study, was energy loss of around 30 per cent because the water was moved around.
Related:Pumped hydro – how does it work?
Promisingly, the project, if it goes ahead, would not take long to build, given most of the components were already in place, Mr Weir said.
The state government is calling for expressions of interest from industry and other parties over the next eight weeks to progress the work.
The next stage of the study, which could cost up to $1.5 million, will assess rock stability within the mine shafts and mine dewatering during construction, among others.
The technology is advanced in Australia with a company using a combination of solar and pumped hydro electricity in the old Kidston gold mine in Queensland, while in South Australia, British billionaire Sanjeev Gupta is looking to use an old iron ore mine to provide pumped hydro to power the local steel works with solar.
Full feasibility report into pumped hydro in Bendigo mine shafts