Baulkham Hills large-scale battery to revolutionise renewable energy infrastructure
To support the increase of renewable energy in the electricity network, Ausconnex, part of the Endeavour EnergyGroup, plans to deliver large grid scale Battery Energy Storage Systems (BESS) across Greater Western Sydney. This initiative will support the NSW Government’s objectives to achieve net zero emissions by 2050, providing safe, reliable and renewable power.
Aerial view of the Baulkham Hills Substation and proposed HV BESS site.
Planned Battery Energy Storage System in Baulkham Hills
Ausconnex is proposing a high voltage (HV) BESS which will be located adjacent to the existing substation at 191Z Old Windsor Road, Old Toongabbie. A BESS is a type of energy storage that captures energy from renewable and non-renewable sources and uses batteries to store and distribute electricity.
Having the BESS located adjacent to the existing transmission substation minimises environmental impacts by collocating energy transmission and energy storage infrastructure and maximises land use efficiency. The proposedHV BESS will have a capacity to supply up to 100 megawatts of power and store 200MWh of energy.
Planning procedures
As a State significant development (SSD), the proposed HV BESS will require NSW Planning Minister’s approval including the preparation of an Environmental Impact Statement (EIS). TheEIS will be prepared in line with the Secretary’s Environmental Assessment Requirements(SEARs).
As we progress through the development of theEIS, a number of environmental studies will be undertaken to assess potential impacts during the project’s construction and operation.
As part of these studies, the Ausconnex team will undertake site testing and surveying to measure background noise levels and analyse activities that might generate noise during construction and or operation of the project. To assess background noise and sensitivity in the surrounding area, we will use devices called noise loggers.
Pending approval of the project, construction is expected to begin in 2026 and will largely take place during standard construction hours (Monday to Friday from 7am to 6pm and Saturdays from 8am to 1pm). Standard construction noise mitigation measures will be implemented to minimise construction noise.
BESS stands for Battery Energy Storage System, as it consists of one or more batteries that store electrical energy for
use at a later time. This stored energy can then be drawn upon as needed, to meet various demands for power.
The proposed BESS will provide localised energy supply, support the growing demand in energy resources, and;
- Provide reliable power supply to customers now and in the future;
- Improve service reliability and provide grid support by reducing the risk of power disruptions;
- Support the energy network benefiting customers and enabling improved grid resiliency and;
- Enhance the energy sustainability ecosystem by storing excess solar generation.
A BESS, which generally looks like a set of shipping containers that are about three metres high, is comprised of four key components:
- Battery packs – a set of modules that turn chemical energy into electricity, which, in turn, make up the battery pack.
- Battery management system – BMS: Which ensures the safety of the battery system by monitoring and measuring the condition of the modules.
- Inverter or power conversion system – PCS: Which shifts the direct current ( DC ) generated by the batteries to alternating current ( AC ) that goes into the electricity grid and vice versa, allowing for charging and discharging.
- Balance of Plant – BoP: Which is the electrical equipment enabling connecting the BESS to the grid including transformers, switchgear and cables.
The HV BESS proposed at Baulkham Hills will be partially visible from Old Windsor Road, however there is an existing noise wall on the western side of Old Windsor Road that would provide visual screening and noise attenuation for residents and businesses west of the site. As we progress with the development of the Environmental Impact Statement and associated technical studies, further visual screening requirements will be assessed.
- Grid reliability and stabilisation – the BESS can absorb or release electrical power almost instantly, providing valuable services in balancing power supply and demand.
- Renewable energy integration – a BESS can store excess energy generated from renewable sources like solar during periods of low demand and release it during peak demand times. Ensuring a continuous and reliable supply of renewable energy even when the sun isn’t shining.
- Flexibility to dispatch energy – During natural disasters or heat waves when the grid is under stress, the BESS will be able to provide grid support, enhancing resilience to ensure the power stays on.
- Cost efficiencies – by discharging stored energy during peak demand periods, the BESS can help reduce the need for expensive peaking power plants, leading to potential cost savings for consumers on their power bills.
- Environmental benefits – by integrating renewable energy more effectively and decreasing dependence on fossil fuel-based peaking plants, BESS contributes to lower carbon emissions and a cleaner environment.
What is a BESS?
A Battery Energy Storage System – BESS – is an advanced technology that captures, stores and distributes energy from both renewable energy such as solar and wind, and non-renewable sources, making it available when needed. It supports the electricity grid by providing a reliable, efficient power supply.
What are the benefits of a BESS?
- Delivers a reliable power supply
- Improves service reliability and delivers grid support by reducing the risk of power disruptions
- Enhances grid efficiency and provides support to the grid during peak demand
- Enhances energy sustainability by storing excess solar energy for use when it’s needed
Why are we proposing a BESS at this location?
Ausconnex, part of the Endeavour Energy Group, is planning to build BESS across Western Sydney and the Illawarra region as part of its commitment to renewable energy infrastructure. Ausconnex is proposing a High Voltage (HV) at the existing substation at this site. Having the BESS located adjacent to the existing transmission substation minimises environmental impacts by co-locating energy transmission and storage infrastructure while maximising land use. The HV BESS will store energy for metropolitan Sydney and beyond, supplying the National Electricity Market (NEM) during peak demand times and support the local network, when required.
When will it be built?
The HV BESS will follow a State Significant Development (SSD) process set by the NSW Department of Planning, Housing and Infrastructure (DPHI). This process requires an Environmental Impact Statement (EIS), which looks at environmental impacts and how to reduce them. Ausconnex is involving the community and other stakeholders throughout this process. Subject to project approval, construction is planned to start in 2027.
Will the BESS generate an electric and magnetic field?
Electromagnetic Fields (EMF) are created whenever there is a difference in voltage (which forms electric fields) or when electricity flows through wires or devices (which forms magnetic fields). Construction of the BESS will follow strict Australian safety standards and guidelines, ensuring it operates safely and effectively. The EMF levels are expected to be very low and within safe limits.
To further ensure safety, we will conduct detailed assessments of the potential impacts on nearby areas and sensitive locations as part of the Environmental Impact Statement (EIS). This assessment will help us understand and mitigate any possible risks related to EMF exposure.
What are the possible fire risk of grid-scale batteries?
The design and installation of the BESS will follow Australian safety standards and comply with the Work Health and Safety Regulation 2025. An advanced Battery Management System will ensure operation is within safe limits and will be supported by an array of sensors and fire suppression systems to reduce fire risks. Full scale fire testing will be completed to ensure adequate separation between the BESS and other infrastructure. Fire & Rescue NSW will be engaged as part of developing an appropriate emergency response plan to a fire.
How much noise will the BESS generate once operational?
Once the BESS is up and running, it will meet all industry noise standards. The sound you might hear will come from normal day-to-day operation and maintenance. We’ve undertaken a Noise and Vibration Assessment which includes recommendations to reduce noise, and we’ll put measures in place to reduce impacts to the community.
Will there be a lot of noise and dust during construction?
Construction will take place on weekdays from 7am to 6pm and on Saturdays from 8am to 1pm. We’re currently assessing the noise levels from equipment and activities during construction. If the assessment shows that noise reduction measures are needed, we’ll put measures in place to help minimise any impact in the area.
Will construction take place at night?
We’ll be working during regular hours (Monday to Friday from 7am to 6pm and Saturdays from 8am to 1pm) to build the BESS. During construction, we’ll keep noise levels down as much as possible.
Will there be many heavy vehicle movements during construction?
Building the BESS will involve some heavy vehicle movements around the site. Other materials, plants, and equipment might also need heavy vehicles for delivery. Once operational, the BESS will need very little maintenance, so traffic impacts will be minimal. Before construction starts, a traffic assessment report and an application to Council will be needed if there are plans for road closures or pathway closures. During construction, traffic impacts will be managed with a Construction Environmental Management Plan (CEMP) or a Traffic Management Plan (TMP).
The proposed HV BESS, a State Significant Development, requires NSW Government approval. A Scoping Report will be submitted to the Department of Planning, Housing and Infrastructure by the end of this year. Following this, an Environmental Impact Statement will be prepared and exhibited publicly, inviting community members and stakeholders to provide feedback, expected to be in late 2025.
For more information, please contact us at:
Email: batteries@ausconnex.com.au or Phone: 1800 955 224.
Acknowledgement of Country
Ausconnex acknowledges the Traditional Custodians of country where we work – the people of the Dharug, Wiradjuri, Dharawal, Gundungarra and Yuin nations – and recognises their continuing connection to the land, waters and community. We pay our respect to them, their cultures, and to the Elders past, present and emerging.Email: batteries@ausconnex.com.au
Phone: 1800 955 224.
ABN: 39 232 846 628
