In North Queensland, Australia, an old gold mine is being transformed into a giant water battery. Two former gold-mine pits near Charters Towers are being transformed into a water battery that can store 2,000 MWh of electricity.
The project forms part of the Kidston Clean Energy Hub.
Water flows from an upper reservoir into a lower one when electricity is needed. The flow creates pressure that causes the turbine blades to turn, producing electricity.
When electricity demand drops or renewable generation exceeds grid needs, the flow reverses.
Water is pumped back up to the upper reservoir to recharge the system for when power is needed.
An abandoned mine eliminated the need for new reservoirs
The Kidston Pumped Hydro Project is located adjacent to the former Kidston Gold Mine in North Queensland. Instead of constructing new reservoirs, two of the original gold-mining pits have been converted into separate reservoirs.
The upper pit serves as the source for water flowing down to the lower pit.
Using existing pits greatly reduced the cost and time required to complete the project. Existing infrastructure also helped developers avoid some of the biggest hurdles associated with pumped-hydro projects.
Both reservoirs were built into existing gold-mining pits. This meant that roads, accommodations, air strips, and even much of the existing water infrastructure were already in place.
Saving money was not the only advantage
According to Genex Power, reusing existing assets helped lower costs and shorten development time.
Another important aspect contributing to the success of this particular project is the difference in elevation between the two reservoirs. The vertical drop between them is approximately 183 meters.
This allows the facility to generate substantial amounts of electricity from falling water.
Electricity demand peaks at the wrong time
Renewable energy sources like wind and solar do not always produce power when it is needed most. Wind farms require suitable weather conditions to generate electricity, while solar farms rely on sunlight.
On top of that, people tend to use the most electricity in the evenings when renewable generation is decreasing. This presents problems with matching supply and demand, particularly if we do not have sufficient storage mechanisms available.
According to the Australian Renewable Energy Agency (ARENA), pumped-hydro storage will become increasingly important as renewable generation expands across Australia.
Many storage technologies operate over relatively short periods. Pumped hydro can store energy for longer and help maintain grid reliability as more renewable generation comes online.
The project’s role extends beyond energy storage
Kidston will produce 250 MW of power for up to eight hours at full capacity, according to Genex Power. It has a total storage capability of 2,000 MWh, making it one of Australia’s largest electrical storage facilities.
Kidston is also significant for another reason. It is Australia’s first new pumped-hydro project in over 40 years and the first to be developed by the private sector.
The hub includes large-scale renewable-energy generation and long-duration energy storage.
Mining left behind exactly what the project needed
It is described as the world’s first-ever pumped-storage hydroelectric project utilizing abandoned gold mines.
Extensive tunneling work was required for the project. That included numerous shafts and a large powerhouse cavern connecting the two reservoirs.
The wider setup ties right into the 50-MW solar farm that’s already up and running to help power the local area. Looking ahead, developers are planning to add a standalone battery system to give the whole site even more capacity.
For decades, the primary use for this location was extracting minerals below ground level.
From now on, its value will come from moving water between the two reservoirs.
Gold may no longer be extracted here, but two enormous holes left by mining will now serve as reservoirs.
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