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A major infrastructure project supporting decarbonisation in WA.

In line with the WA State Government’s decarbonisation strategy to be delivered by 2030, our Collie Battery Energy Storage System (CBESS) Project forms part of our own decarbonisation plan. In this project, coal-fired power generation is being replaced with renewable energy generation infrastructure and energy storage solutions.

CBESS is one of the renewable energy generation infrastructure projects which will help to improve system security and support increased renewable energy generation in the SWIS.


CBESS is located in the town of Collie, just over 200km south-east of Perth. The project site is near the Collie Power Station on Boys Home Road. The site is owned by Synergy and largely cleared. This makes it a ‘brownfields site’ which is being repurposed for this project.

The site is approximately 2.5 km south west of the Western Power owned 330 kV Schotts Terminal on the South West Interconnected System (or SWIS) and, once constructed, the CBESS will connect to this terminal.


Layout and size

Battery energy storage systems (BESS) can absorb excess energy generated by rooftop solar PV systems when the sun is shining and discharge when demand for electricity peaks usually in the evening. 

CBESS will be Synergy’s third BESS and one of the biggest in the world, providing around 500 Megawatts (MW) or 2000 Megawatt hours (MWh) of power when fully charged.

CBESS will use modularised batteries similar to KBESS1 and KBESS2. It is expected to be 40,000sqm which is approximately 2 full sized football ovals or 10 times the size of our KBESS1.


Project scope

  • CBESS will deliver 64% of the new energy storage capacity announced by the WA Government in June 2022 as part of Synergy’s decarbonisation program of works.
  • The project has submitted a Development Application (DA) to the Shire of Collie and is awaiting feedback.
  • Construction, testing and commissioning will result in a BESS and Power Conversion System with a notional facility size of 500MW / 2000 MWh in Collie with an estimated facility life of 30 years.
  • Our project team consulted with community members in May and August 2023 to get valuable insights and opinions from the local community about the project. More consultation sessions are planned as the project progresses.
  • The Shire of Collie have been extensively engaged throughout the process.
  • CBESS is proposed to be connected to the SWIS via the Western Power 330 kV Shotts Terminal through two 330kV overhead lines from the new CBESS site.
  • CBESS is being designed to operate completely independently from the existing Muja Power Station and the Collie Power Station.


Key project dates

May 2023 Premier announced CBESS project
September 2023 Development application submitted
Early 2024 Expected construction to commence 
End 2025 Expected comissioning (in October) 



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