Private Energy Partners has submitted plans for a 520-megawatt (MW) grid-scale battery energy storage system (BESS) in the Australian Capital Territory, designed to significantly improve regional energy security, grid reliability, and network resilience.
Dubbed the Flat Rock Energy Storage project, the proposed utility-scale installation was submitted for federal environmental approval under the Environment Protection and Biodiversity Conservation (EPBC) Act.
The facility sits on privately leased rural land, approximately 326 hectares, that has historically been used for sheep and cattle grazing.
The development features containerised lithium-ion battery technology and power conversion systems incorporating inverters and transformers, split across two distinct storage areas. The installation will be supported by two substations housing switchgear, circuit breakers, and protection systems: an on-site project substation and a dedicated Transgrid substation constructed near the connection point to the existing electricity transmission network.
Overhead transmission lines will connect the infrastructure, deliberately avoiding tree clearing and underground trenching across watercourses.
Operating 24 hours a day, seven days a week, the battery system will capture excess electricity when demand is low and release stored energy back into the grid when demand peaks.
Construction of the project is expected to take approximately 36 months, with the facility planned to operate for up to 50 years. Following its operational lifecycle, all infrastructure will be removed and the footprint rehabilitated.
To minimise direct ecological impacts, the project’s disturbance footprint is restricted to roughly 60 hectares of non-native and low-condition native grassland.
Construction activities will encompass site access establishment, earthworks, concrete pad placement, stormwater drainage networks, sediment ponds, security fencing, site offices, and temporary laydown areas.
The layout prioritises environmental protection by avoiding mature trees, requiring only a single ground-level road crossing over a modified drainage line to connect the two battery zones.
Internal tracks will match existing ground levels, while juvenile native trees will be planted along Uriarra Road and Mountain Creek Road boundaries.