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McCullys Gap Battery Energy Storage System

Join us in exploring  the McCullys Gap Battery Energy Storage System(BESS) project.

Situated on the ‘Spring Flat’ of Muswellbrook of the Upper Hunter Region of NSW, Australia, this advanced energy project will connect to the existing New South Wales (NSW) high-voltage transmission network. The project will deliver 400 megawatts (MW) of power for 4 hours that will contribute to a more reliable, secure and diverse energy system.

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The project

The project

Site concept schematic

Project details

·      Battery systems within shipping containers
·      Connecting to the existing transmission line via substation and overhead conductors
·      Storage area, internal access tracks, on-site parking, fire water, security fencing, lighting, noise walls and vegetation screening.

Location

The project is located six kilometres (km) northeast of Muswellbrook within the Muswellbrook Shire local government area (LGA). The project site is located immediately east and adjacent to the existing 330KV Muswellbrook substation.

Access

The site will be accessed off the Sandy Creek Road, designed to allow project traffic to enter and exit in a safe manner.

Operations

The project will be remotely operated for at least 30 years (24/7, 365 days of the year) with regular and routine maintenance performed on site. This automated approach would ensure efficient operation with minimal local traffic and disruption.

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Project STATUS

Project status

Currently the project team is preparing the Environmental Impact Statement (EIS) which will assess any potential impacts from the project.

Once completed, the EIS will be submitted and displayed to allow for review and determination.

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Project timeline

Project timeline

Our project team has undertaken preliminary flora and fauna surveys across the proposal site. Further studies are currently in progress to better understand the site characteristics, potential impacts and determine if mitigation strategies are required.

Ecology
Flooding
Heritage
Landscape
Noise
Transport
Feb 2025
Scoping Report submitted to the NSW Department of Planning and Environment
Mar 2025
SEARs Response from NSW Department of Planning and Environment
June 2026
EIS Development & Public Consultation
Q3 2026
SSD & EIS  submission to the NSW Department of Planning and Environment
Q4 2026
DPHI assessment and project Determination
2027
Construction Commencement (Subject to Approval)
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Why McCullys Gap

Site selection

Musswellbrook location image 1
Musswellbrook location image 2

Proximity

The location of the project was selected for its proximity to the existing Muswellbrook substation (330KV/132KV). The site's immediate proximity to existing infrastructure enables rapid deployment of essential storage capacity to the grid.

Regional profile

This project is positioned in the Hunter-Central Coast Renewable Energy Zone (HCC REZ). It strategically connects the NE REZ generation centre, the QNI (Queensland & NSW Interconnector), and the Sydney load centre.

Site characteristics

The project site has been chosen for its minimal planning constraints and suitability for visual impact mitigation.

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Why BESS

Why BESS

Large-scale battery systems contribute to the stability and reliability of our changing energy system. The energy stored in batteries is able to be used quickly and respond to changing conditions.

Typically, battery systems charge during the day when solar energy is plentiful and release the stored energy back into the grid at night.

Balancing supply icon

Balancing supply and demand

Battery systems help bridge the distance between where the electricity is generated and where it is needed most. By storing excess generation and delivering power during peak periods, batterieshelp optimise the flow of electricity across the national energy network.

Enhancing energy security icon

Enhancing Energy Security

Battery systems can adapt to changing energy network conditions within milliseconds which assists to provide a more stable and reliable system.

Supporting net 0 icon

Supporting Net Zero Ambitions

Recognised by the Australian Energy Market Operator (AEMO) as essential electrical infrastructure, battery storage plays a pivotal role in Australia's energy transformation. Our facility enables broader adoption of renewable generation across the network, supporting the nation's pathway to lower emissions and more affordable energy.

As a critical enabler of clean energy integration, battery storage supports the transformation of Australia's power infrastructure while ensuring reliable supply across the network.

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About Us

BW ESS is a global energy storage owner-operator, moving with speed to deliver market-leading projects.

The project is being delivered by BW ESS, a global energy storage developer, owner and operator.

BW ESS is a long-term utility-scale BESS developer, owner and operator. The company is headquartered in Zurich, with a presence in Sweden, the United Kingdom, Spain, Germany, Italy, Sweden and Australia.


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Contact

Share Your Thoughts

We warmly invite your valuable feedback, views and suggestions for our project. BW ESS is a long-term project owner, and we value building good relationships with neighbours in the local communities around the site in Muswellbrook NSW.

Please feel free to reach out to us:
• Complete the form below with your comments
• Call the consultation team: 1800 066 243
• Email us: contact@ghd.com

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