Maison Dieu Battery Energy Storage System
A proposed grid-scale battery that will store clean energy when it is abundant and release it when the network needs it most — supporting a reliable, affordable and lower-emissions power system for New South Wales.
Storing clean energy for when it's needed
The Maison Dieu Battery Energy Storage System (BESS) is a proposed large-scale battery in the NSW Hunter Valley.
A battery of this kind charges up when there is plenty of low-cost renewable energy in the grid — for example on sunny or windy days — and discharges that stored energy back into the network during periods of high demand. This "firming" role helps keep electricity supply reliable as coal-fired generation retires and more renewables come online.
The facility would comprise around 100 batteries housed in individual, modular containers on hardstand footings, together with a control room, transformers and supporting equipment, connecting to the existing Transgrid 330 kV transmission network via a new switching station.
- 500 MW discharge capacity
- 3,000 MWh of energy storage
- Approx. 100 modular battery container units
- Connection to the Transgrid 330 kV network
- Located on established rural land in the Hunter Valley
- Site returned to prior use at end of life
Benefits for the grid and the region
Reliable power
Stored energy can be dispatched in seconds to help stabilise the grid and support supply as older generators retire.
More renewables
By soaking up surplus solar and wind and releasing it later, the battery helps the network carry more clean energy and cut emissions.
Downward price pressure
Additional storage adds competition and flexibility to the market, helping put downward pressure on electricity prices.
Local investment & jobs
Construction is expected to create employment and procurement opportunities for the Hunter region.
Roadmap-aligned
The project supports the NSW Electricity Infrastructure Roadmap and national goals for long-duration storage.
Responsible end of life
The facility is designed to be decommissioned and removed, with the land returned to its former use.
A well-connected site in the Hunter
Established rural land in the NSW Hunter Valley, adjacent to major electricity transmission infrastructure.
The site sits on established grazing land in the Hunter Valley, close to existing high-voltage transmission infrastructure. This proximity to the Transgrid 330 kV network is a key reason the location is well suited to a large battery — it can connect efficiently to the grid with minimal new transmission.
The Hunter Valley is a nationally significant energy region, and projects like this support its transition as it continues to power New South Wales.
How the project is being assessed
The project is being assessed as State Significant Development (SSD) under the NSW planning system, with specialist environmental and technical studies prepared by independent consultants. Community consultation forms part of this process.
Scoping & Secretary's Environmental Assessment Requirements (SEARs)
Environmental Impact Statement & technical studies, informed by community input
Public exhibition & assessment by the NSW Government
Determination, and — if approved — staged construction and operation
We are committed to genuine engagement with neighbours, the community and stakeholders throughout the assessment. If you have a question or would like to be kept informed, please get in touch below.
Sharing the benefits locally
We believe host communities should share in the benefits of the energy transition. The project will develop a benefit-sharing approach aligned with Clean Energy Council guidance, including meaningful engagement with First Nations groups.
Through the assessment process we will work with the community to understand local values and priorities, minimise impacts during construction, and identify opportunities that leave a positive, lasting legacy for the region.
- Benefit-sharing aligned with Clean Energy Council guidance
- Engagement with local First Nations groups
- Local employment and procurement during construction
- Ongoing, transparent community consultation
Get in touch
Questions about the Maison Dieu BESS, or want to stay informed as the project progresses? We'd be glad to hear from you.
Community & project enquiries