Storing energy with hydro

The challenge

Australia's energy mix is becoming increasingly unreliable. Could pumped hydro be the answer?

In this article

  • Designing a pumped hydro plant - which has origins in one of our four year old research projects with Melbourne Energy Institute.
  • How pumped hydro works as a giant battery, that could provide South Australia with 100 megawatts of electricity.
  • Feasibility tests along the Northern end of Spencer Gulf.

We’re quite excited because one of our Arup Research projects from almost four years ago is on the verge of lighting up South Australia. The Cultana pumped hydro storage plant, proposed to be built along the Northern end of Spencer Gulf, is set not only to be the second ever seawater storage plant but also the largest in the world.

Unlike most hydroelectricity projects, pumped hydro does not rely on rivers or naturally flowing water. Instead, it acts as a giant battery. Water is pumped from a lower reservoir to a higher one when energy is cheap. Once there’s a surge in price or demand, it is then run back down and through a turbine. Since the water can be reused, it a relatively clean method of storage.

But how does it work? Let this handy seawater hydroelectricity schematic explain. Photo credit © Cultana pumped hydro project: Knowledge sharing report

Resilient Resources

We began researching the technology in partnership with the Melbourne Energy Institute in 2013. While fresh water pumped hydro has been used for decades in the United States, Japan and China, it is neither appropriate nor feasible for dry Australian summers when household energy demand is high.

Prior to Energy Australia announcing the Spencer Gulf project on February 21st, 2017, we worked with them on another 12 month investigation surrounding the use of seawater, once again in partnership with Melbourne Energy Institute. The Spencer Gulf site was selected because it offers 300 meters of elevation and is only 2km offshore, close to the high voltage transmission lines that run along the coast.

We are currently completing a feasibility study on the Spencer Gulf project. If the project is feasible, it could be providing peak power to the grid in another two and a half years. The plant is projected to have the capacity to produce around 100 megawatts of electricity with six-to-eight hours of storage capacity. It may not draw as much publicity as Elon Musk but it is the equivalent of roughly 60,000 home battery storage systems. It's also cleaner, more reliable and about one-third of that cost.

Outputs from the EnergyAustralia, Arup and the University of Melbourne’s Melbourne Energy Institute (MEI) feasibility study. Image Cultana pumped hydro project: Knowledge sharing report.


  • Pumped hydro is a viable method of energy production.
  • In February 2017, Energy Australia announced plans to go ahead with the Spencer Gulf pumped hydro storage plant - the outcome of a research project we conducted with the Melbourne Energy Institute in 2013.
  • The project has the projected capacity to produce 100 megawatts of electricity and could be supplying peak energy to the grid by late 2019.

This story was written by Jeff McAllister, as part of the Research Review. This series is produced by the Arup Australasia Research team; Alex Sinickas, Bree Trevena and Jeff McAllister with contributions from Sheda and Noel Smyth.

Lead Arup Researcher

David Dawson
David is an engineer with our Energy team in Melbourne.

Ask David about

  1. The details behind how pumped hydro works and what makes it a reliable energy storage solution
  2. The evolution of the project, from research into a technology to power plant
  3. Details around the economics and feasibility requirements for the building of Cultana


Research TEAM

David is our Australasia Energy Skills Leader based in Melbourne.
(Former) Leader of Agribusiness and Energy teams, Adelaide office - now external consultant
Matt is a senior consultant working with Business & Investor Advisory team at London.
Ben is an engineer with the Energy team.
Bas is a consultant working in our Economics and Business Investment Advisory teams.
Matt is a consultant working in our Infrastructure Advisory team in Melbourne.

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