View of the sun from under the water; View of the sun from under the water;

Cultana seawater pumped hydroelectricity energy storage, South Australia

World’s largest saltwater pumped hydro for South Australia

The Cultana Pumped Hydroelectric Scheme is a hydroelectric energy storage plant being planned for the Australian Defence Force’s Cultana Training Area, near the north-western tip of the Spencer Gulf in South Australia. 

When complete, the scheme will be able to store 3.5 gigalitres of water to flow through turbines allowing the generation of 225MW of electricity for up to 8 hours.

And, to ensure the scheme it is not a drain on vital fresh water resources, the plan is to utilise readily available seawater.

Project Summary


225MW of electricity generated for up to 8 hours

3.5gigalitres of water flow

When a catastrophic power grid failure plunged South Australia into darkness in September 2016, it caught many by surprise, creating debate about how we best provide for Australia’s future power needs.

While the causes of the failure were discussed, few knew that for the previous 3 years a talented team of Arup researchers, designers and engineers were already looking into South Australia’s future energy needs. Funded through Arup’s Global Research Challenge, the team analysed energy generation, need and capacity, identifying significant risks that could lead to uncertainty surrounding the ability to deliver power to the region’s homes and businesses.

From this research came the Cultana Pumped Hydroelectric Energy Project. 

Arup’s research identified significant opportunities for large-scale storage solutions to enable further renewable utilisation, whilst maintaining grid stability and certainty of delivery. ”

Mike Straughton Mike Straughton Australasia Environment and Resources Leader

It is being developed by Arup, EnergyAustralia and the Melbourne Energy Institute, with funding assistance from the Australian Renewable Energy Agency. 

Recently the project has moved a stage closer to helping boost South Australia’s renewable energy capacity, with a Project Development Agreement signed with EnergyAustralia. With this new agreement in place we are currently undertaking a front-end engineering design study, with a view to producing a reference design and progressing the project to a final investment decision.

With the agreement in place a 2-year build time is estimated, meaning that the project could be ready to power South Australia in the summer of 2020/21.


What is pumped hydro?

Pumped hydro works by linking two bodies of water, usually held within dams, one higher than the other, allowing water to flow through turbines between the two when energy is required. The higher dam acts like a battery, storing the potential energy of water that can be released on demand; meaning that, within minutes, electrical energy can be delivered to the grid.

During off-peak times, when energy is cheap to use, the system pumps water from the lower dam to the upper dam, recharging the battery.

How pumped hydro works How pumped hydro works

Why is this project different?

In an innovative, sustainable design, the Cultana Pumped Hydroelectric Energy Project will use seawater to drive the turbines. Unlike 97% of the world’s existing hydro systems this scheme will not consume precious fresh water resources, a key sustainability factor in Australia’s dry environment.

When complete the scheme will deliver the equivalent of 60,000 home battery storage systems, but at one-third of the cost. Power will be available on demand, so when South Australia swelters through summer, pressures on peak demand is mitigated.

And whilst freshwater schemes have been in operation globally for a number of years, this scheme will be the second example of a seawater pumped hydro storage plant anywhere is the world and it would also be the largest.

Arup’s research identified significant opportunities for large-scale storage solutions to enable further renewable utilisation, whilst maintaining grid stability and certainty of delivery. ”

Mike Straughton Mike Straughton Australasia Environment and Resources Leader