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The way of water: How pumped hydro works
06 October 2024
Powered by water
Pumped hydro is a form of long-duration energy storage based on the principles of traditional hydropower, one of the world’s oldest and most established energy technologies. Used for thousands of years in various forms, hydropower converts the movement of water into electricity. Today, there are more than 120 operating hydroelectric power stations across Australia. In Tasmania, hydro provides around 80 percent of the state’s electricity. There are also three major pumped hydro systems connected to the national electricity grid. As the energy system shifts towards cleaner sources, pumped hydro is expected to play an increasingly important role in supporting reliability. By complementing variable generation from technologies like wind and solar, it can help deliver a more stable and secure electricity supply.
In 2024, hydropower represented 5.5% of Australia's energy supply - Clean Energy Council.
HOW IT WORKS
Hydropower converts the energy of moving water into electricity.
There are four main kinds of hydro power:
Run-of-river
Storage
Pumped Hydro Energy Storage (PHES)
Offshore hydropower
Hydroelectricity is generated by channeling water – usually from a reservoir or dam – through a turbine, which acts as a powerful electricity generator. As the water rushes through the turbine's blades, it spins the generator, transforming that motion into clean electrical energy.
Pumped Hydro Energy Storage (PHES) takes this concept a step further, turning water reservoirs into massive energy banks. During times of low energy demand, surplus power from the grid or renewable sources like wind and solar can be used to pump water from a lower dam to a higher one. This creates a giant "battery" of stored energy, ready to be unleashed when demand peaks or renewable output dips.
What makes hydroelectricity so valuable is its ability to be generated instantly, whenever needed. This flexibility allows it to step in during surges, prevent blackouts, and meet sudden spikes in electricity demand. PHES, in particular, offers the advantage of producing large amounts of electricity over extended periods, providing a dependable and on-demand source of power.
Our flagship project
Cressbrook Pumped Hydro
Located at Lake Cressbrook, around 64 kilometres south of Stanwell’s Tarong power stations and 50 kilometres north-east of Toowoomba, the Cressbrook pumped hydro facility will be capable of generating 400 MW of electricity for up to 10 hours once operational in 2033.
The project will use Lake Cressbrook as the lower reservoir, with a new upper reservoir to be constructed on nearby land owned by Stanwell and its project partner, approximately 2.1 kilometres to the north-east.
During periods of high electricity demand or to firm the grid, up to 6.4 gigalitres of water will be released from the upper reservoir into Lake Cressbrook, driving two 200 MW turbines for up to 10 hours. Once the cycle is complete, water will be pumped back to the upper reservoir, ready for the next release.
Cressbrook Media Release
HYDRO INFORMATION HUB
View all Pumped Hydro newsThe way of water: How pumped hydro works Stanwell adds pumped hydro to its renewables mix 
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Stanwell adds pumped hydro to its renewables mix
04 October 2024
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