Pumped Hydro Energy Storage (PHES) is Australia’s most established large-scale storage solution—and it’s poised to play a central role in a low-carbon grid.
How It Works
PHES stores energy by using excess electricity to pump water from a lower to a higher reservoir. When demand rises, the water is released back down through turbines to generate power—like a giant rechargeable battery.
The standout benefit? PHES can provide medium- to long-duration storage, delivering sustained electricity output for 8–24 hours or more.
Australia’s Potential
According to AEMO’s ISP 2024, PHES will help firm renewable energy and manage grid stress, particularly during evening demand peaks (AEMO ISP 2024, p. 25). It forms part of the “no-regret” investments in a renewable-ready NEM.
Projects like Snowy 2.0—a 2,000 MW PHES development—are expected to deliver 350,000 MWh of storage, enough to power 3 million homes for a week.
Beyond flagship projects, ANU’s PHES Atlas has identified over 20,000 viable sites across Australia, though most remain undeveloped due to long lead times and environmental approvals.
Pros and Pitfalls
Benefits:
- High efficiency (75–85%)
- Long lifespan (>50 years)
- Low operating costs after construction
Challenges:
- High upfront capital investment
- Multi-year permitting and construction
- Local environmental impacts (land use, waterway disruption)
Conclusion
Pumped hydro offers scale, stability, and strategic value to a grid increasingly dominated by intermittent renewables. While slower to deliver than batteries, it remains a foundational technology in Australia’s energy future.
