Limestone Coast BESS

Project overview

The Limestone Coast BESS is a 250 MW / 500 MWh battery energy storage project supporting grid stability and energy transition in South Australia. GGC was engaged to deliver balance of plant works and HV infrastructure.

Technical Delivery

Scope of work includes comprehensive design and engineering, supply and installation of a 275/33kV substation (including primary plant, SCADA and control systems), and installation of client-supplied battery units and PCS systems.

Key Challenges

• Located in South Australia’s karstic, cave-prone Limestone Coast, the battery site required extensive geotechnical investigations to manage risks of ground instability and subsidence. GGC conducted thorough drilling, scanning and testing to identify voids and ensure stable foundation performance.
• Managing multiple work fronts on a complex, large-scale site required innovative logistics. GGC utilised a Combilift to flexibly mobilise and install large loads, including precast foundations, PCS units, battery units and auxiliary transformers, directly into position.

Recent progress and milestones

As at October 2026, the project has progressed from civil works into electrical installation and commissioning, with battery and inverter equipment now in place across the collector groups. The 33kV switchroom and control building have been installed, and commissioning partner Megavar has been on site testing and commissioning the switchgear and collector feeders.

Collector group works are well advanced. HV, LV and fibre optic terminations and testing are progressing across the site, while DC cabling continues on the final collector group.

Hot commissioning of the first collector group (CG1) commenced on 30 September with Trina, marking the first part of the battery system to be energised.

All harmonic filter foundations are complete and ready for the arrival of EnergySEA equipment.

At the 275kV substation, earthing, primary equipment and steel structures are being installed. The line circuit breaker is in place and fencing is underway. Internal roads, kerbing and pavements around the BESS perimeter are also being finished.

Solution

GGC applied a structured delivery approach integrating engineering, procurement and construction, ensuring seamless system integration and alignment with grid requirements.

Outcome

The project highlights GGC’s capability to deliver complex BESS infrastructure, supporting grid reliability and enabling large-scale renewable integration.