The McCullys Gap BESS is a proposed 400-megawatt / 1.6-gigawatt hour Battery Energy Storage System, located eight kilometres northeast of Muswellbrook, NSW. The project would connect directly to the adjacent Transgrid Muswellbrook substation.
The proejct is proposed by BW ESS.
Key Dates
| Mar 2025 | Project Announcement |
| 2026 | Expected Construction Commencement |
| 2028 | Expected Construction Completion |
Procurement
| Procuring Agency: | BW ESS |
PROJECT HISTORY
| Mar 2025 | BW ESS submitted a Scoping Report to the NSW Government requesting the Secretary's Environmental Assessment Requirements (SEARs) for the project. The Scoping Report set out the proposed project's scope of a 400-MW / 1.6-GWh battery. The project was estimated to have a total estimated cost of $800 million, with construction scheduled to commence in 2026 and be completed in 2028. |
| Apr 2025 | The NSW Government issued the SEARs for the project. |
| Jan 2026 | The project was submitted to the EPBC Portal for environmental assessment. |
| Mar 2026 | The Federal Department of Climate Change, Energy, the Environment and Water declared that the project is a controlled action and will be assessed under the bilateral assessment agreement with New South Wales. |
Estimated Total Cost
(2025)
Sector
Energy
Procurement approach
Traditional Procurement |
Location
New South Wales |
Resources
