Bendigo’s underground labyrinth of disused mine shafts could generate and store renewable energy under an ambitious proposal by the state government.
An investigation into whether the historic shafts have the capacity to power and store pumped hydro electricity will begin in June.
The state government and the City of Greater Bendigo are funding a $150,000 feasibility study, which will consider a number of suitable ‘mine voids’ across the local mine shaft network.
Pumped hydro electricity would involve connecting mine voids – areas of an excavation that remain after a mine has been filled in – to underground water sources through existing mine shafts.
It is believed a number of disused mines in Bendigo are full of groundwater that has seeped through the surface over the years.
Theoretically, solar panels would power water pumps, bringing underground water up mine shafts when peak demand and energy prices are low.
When energy prices are high, stored water would be released down the mine shafts through turbines, and the gravitational energy of the water would help generate electricity for peak demand.
Bendigo Sustainability Group calculations suggest one facility could generate enough power in an hour (784 kilowatt-hour) to sustain 160 households’ average daily electricity use.
The project could give Bendigo “around the clock energy supply” and could make the city a net exporter of renewable energy, the government says.
And the study will not interfere with operational arrangements in pumping and treating groundwater, or the Central Deborah gold mine tourist facility, according to the government.
Minister for Energy, Environment and Climate Change, Lily D’Ambrosio, said solar pumped hydro has the potential to store and generate significant amount of energy.
”This feasibility study is the first key step towards realising the benefits of solar pumped hydro for the Bendigo region,” she said.
However, an energy expert has adopted a more cautionary stance, while suggesting pumped hydro could, in the long-term, reduce Australia’s energy costs.
RMIT University Senior Industry Fellow, Alan Pears, said mines were a cost-effective way of creating an alternative energy supply.
“Up front costs are a real problem… and some rural communities have convenient old mines,” he said.
Mr Pears said the depth of the mine was particularly important, citing 200 metres as an ideal energy-making depth.
“The amount of energy you can store depends on the height difference between the two bodies of water,” he said.
“The higher the water is the more energy there is in it.”
If adapted successfully with the correct depth, a pumped hydro scheme could prove more economic than using energy storage batteries, said Mr Pears, who suggested the scheme could provide supplementary energy in times of need.
“It could help a rural community get through a high fire-risk situation. Or if power lines go down, it gives them a bit more independence,” he said.
“Getting electricity to rural communities is a lot more expensive than getting electricity to people in the big cities.
“It could in the long-term, reduce overall electricity costs.”
The investigation, results of which will be released by the end of 2017, follows a state government further investment of $20 million in Victoria’s large-scale energy storage.
Announced recently, the funding will help companies that specialise in battery, pumped hydro or solar thermal technology partner with network businesses to boost storage to 100 megawatts by the end of next year.
A 20 megawatt battery could power a town the size of Bendigo or Ballarat for up to four hours during a period of peak demand and avoid outages, the government said at the time.
Premier Daniel Andrews last month suggested improved energy storage levels would help avoid a scenario in February, where Bendigo was close to losing power for several hours to support NSW’s ailing power grid.
The federal government recently announced a $2 billion expansion of the Snowy Mountains hydro scheme in a bid to power up to 500,000 homes.
Prime Minister Malcolm Turnbull revealed the plan to increase the current 4000 megawatt output of the scheme by 50 per cent.
The state government on Wednesday announced $900,000 to establish a series of community power hubs in regional Victoria.
The two-year hubs, in Bendigo, Ballarat and the Latrobe Valley, will support the development of renewable energy projects by providing legal and technical expertise, as well as start-up funding.