Spring Hill’s large-scale battery to revolutionise renewable energy infrastructure
To support the increase of renewable energy in the electricity network, Ausconnex, part of the Endeavour Energy Group, plan to deliver large grid scale Battery Energy Storage Systems ( BESS ) in Spring Hill. This initiative will support the NSW.
Proposed Battery Energy Storage System in Unanderra
Ausconnex is proposing a high voltage ( HV ) BESS which will be co located on the site of the existing transmission substation at 191-195 Five Islands Rd, Unanderra (also known as the Spring Hill substation).
Building the BESS within the existing substation site, avoids the need for additional transmission lines, minimising environmental impact.
The proposed HV BESS at the Spring Hill substation will have a capacity to supply up to 100 megawatts of power and store 200MWh of energy.
Planning procedures and what to expect
As a State Significant Development (SSD), the proposed HV BESS will require NSW Planning Minister’s approval. This includes preparation of an Environmental Impact Statement (EIS) made up of a number of environmental studies to assess and mitigate any potential impacts during the HV BESS project’s construction and operation in line with EIS requirements.
Potential impacts on the existing site include noise, visual amenity and tree removal. The need for mitigation will be assessed as the issues are more thoroughly investigated via specialist studies associated at the EIS stage of the project.
Photo example of a noise logger used to measure background noise level
What are the benefits of a BESS?
- Grid reliability and stabilisation: The BESS can absorb or release electrical power almost instantly, efficiently providing valuable services in balancing power supply and demand.
- Renewable energy integration: A BESS can store excess energy generated from renewable sources like roof top solar and release it during peak demand times. This ensures a continuous and reliable supply of renewable energy – even when the sun isn’t shining.
- Flexibility to dispatch energy: During extreme weather events such as heat waves or storms when the electricity network is under stress, the BESS will be able to enhance reliability and resilience of the network 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 network upgrades 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.
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 BESS proposed at Penrith may be partially visible from the street, however, the surrounding industrial and other existing built structures and vegetation screening would limit visibility of the proposed infrastructure.
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 in Penrith?
Ausconnex, part of the Endeavour Energy Group, is planning to build a large BESS in Penrith as part of its commitment to renewable energy infrastructure. Ausconnex is proposing a High Voltage (HV) and a Medium Voltage (MV) BESS at the substation on Castlereagh Road, Penrith, leasing the land from Endeavour Energy. 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. Both the HV BESS and MV BESS will store energy for metropolitan Sydney and beyond, supplying the National Electricity Market (NEM) during peak demand times and support the local network around Penrith, when required.
When will it be built?
Both the MV and HV BESS have unique timelines and requirements for construction. They also need different planning approvals: the MV BESS will go through a Development Application (DA) with Penrith Council, while 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. Building both the MV and HV BESS will take about 18 months.
- HV BESS: Planning and design should be completed by mid-2025, with construction starting in 2026.
- MV BESS: Planning and design should be completed by mid to late-2025, with construction also starting in 2026.
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 risks for grid-scale batteries?
The design and installation of the BESS will follow Australian safety standards. 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. Fire & Rescue NSW are now engaged with Ausconnex as part of developing a fire safety study.
How much noise will the BESS generate once operational?
The local area around the project, including the Penrith Substation, railway, and nearby roads, already experience some level of noise.
Once operational, the BESS will adhere to industry noise regulations. A detailed noise and vibration study will be conducted as part of our Environmental Impact Statement (EIS). This study will assess potential noise impacts during both the construction and operational phases and propose measures to mitigate any identified noise issues.
Will there be a lot of noise and dust during construction?
During construction, work will take place on weekdays from 7am to 6pm and on Saturdays from 8am to 1pm.
A study on noise and vibrations will be included in our Environmental Impact Statement (EIS). This study will examine the noise and vibrations during both the construction and operation of the BESS. Based on the findings, we will recommend ways to reduce any noise and vibration issues in the area. The construction is expected to last around 18 months.
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 Penrith City 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).
As part of the Environmental Impact Statement (EIS) stage, a traffic and transport impact assessment will be done to understand the potential traffic, safety risks, and impacts during the project’s construction, operation, and decommissioning. This assessment will look at the capacity of key access roads, the impact of large vehicles, and how project traffic might affect road safety.
I have solar on my roof, how will the BESS affect my usage and what I give back to the grid?
If you have solar on your roof, any excess energy created will continue to feed back into the grid, which will include the medium voltage (MV) BESS at the Penrith substation. The energy stored at the MV BESS will be used to discharge energy back into the network when demand is needed.
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

Email: batteries@ausconnex.com.au
Phone: 1800 955 224.
ABN: 39 232 846 628