AGL has acquired full ownership of two pumped hydro energy storage (PHES) projects at Glenbawn and Glennies Creek dams in the Upper Hunter, continuing development of the proposals originally initiated by Upper Hunter Hydro (UHH). Together, the projects could deliver up to 1,393 megawatts of generation with 10 hours of storage capacity, and have been identified as suitable sites for potential future integration with wind farms.
Both sites are located on existing WaterNSW infrastructure—Glenbawn Dam near Scone and Glennies Creek Dam north of Singleton—and form part of WaterNSW’s Renewable Energy and Storage Program. The program aims to use public water assets to support NSW’s energy transition and deliver regional benefits, through partnering with the private sector.
“It is crucial the future energy system is developed with a spectrum of storage and firming, encompassing short, medium, and long-term storage technologies”, AGL’s Chief Operating Officer Markus Brokhof said.
“Developing pumped hydro energy storage and other synchronous long duration storage is integral to ensuring reliability and affordability as Australia transitions to a renewable energy system.”
Pumped hydro storage involves moving water from a lower to an upper reservoir when demand is low and prices are cheaper, such as on sunny or windy days. The stored water can later be released to generate electricity during periods of higher demand, using gravity to drive turbines.
On current designs, the Glenbawn project would offer 770 MW of capacity with 10 hours of storage (7,700 MWh), while Glennies Creek would deliver 623 MW over the same duration (6,230 MWh). These energy volumes reflect the large size of the reservoirs and favourable elevation differences between upper and lower storage points.
The projects are in the early development phase, and AGL is preparing a provisional timeline covering environmental assessments, planning approvals, and construction stages. If both projects proceed, they are expected to support around 1,400 jobs during construction and 80 ongoing operational roles.
WaterNSW, who retain ownership of the dams, has been working with both the former developer UHH and now AGL to ensure the proposals meet environmental and operational requirements. The dams will continue to serve their current water management roles, and AGL has confirmed that dam operations or water security downstream will not be affected by the projects.
Turnbull Renewables, associated with the original proponent UHH, will continue to provide advisory support for the projects.
Outgoing UHH Chair, the Honourable Malcolm Turnbull AC, welcomed the transfer of ownership, saying, “Long duration storage will play a critical role in Australia’s future energy system, helping to keep the grid reliable by shifting renewable energy to match consumer demand. The Glenbawn and Glennies Creek projects are well placed to create jobs and drive investment in the Hunter which plays a pivotal role in the energy transition”.
