Construction has begun on the 500 MW/2,000 MWh Collie battery energy storage system in Western Australia’s (WA) southwest as the state moves towards emissions-free power generation in 2030.

Synergy said the four-hour battery energy storage system – scheduled for completion before the end of 2025 – will help to prepare the state’s power grid for the retirement of coal-fired power stations by improving system security and support increased renewable energy generation in the South West Interconnected System (SWIS).

Western Australian Energy Minister Reece Whitby said the battery will absorb excess energy generated by rooftop PV systems when the sun is shining and discharge when demand for electricity peaks, usually in the evening.

“This is an exciting milestone for Western Australia’s decarbonization journey,” he said. “When complete, this battery will support reliability and more renewable energy on WA’s main electricity grid.”

Synergy is building the AUD 1.6 billion ($1.05 billion) Collie big battery approximately 200 kilometers southwest of state capital Perth, just north of the existing coal-fired Collie Power Station that is to be retired by 2027. The facility will connect to the SWIS via Western Power’s existing 330 kV Schotts Terminal.

Collie-based earthworks specialists Cardinal Contractors has been awarded the contract to complete site preparation earthworks for the battery facility, with up to 500 jobs expected to be created at the peak of construction.

The Collie battery will be Synergy’s third large-scale battery energy storage system with the government-owned energy generator and retailer planning to build 3 GWh hours of storage by 2025.

Synergy said the 100 MW/200 MWh first stage of the Kwinana Battery Energy Storage System, built at the site of the decommissioned Kwinana Power Station about 30 kilometers south of Perth, has been providing power to the SWIS since it was completed in May 2023.

Work is continuing on the 200 MW/800 MWh second stage of that facility and is due to be completed in late 2024.

The WA government has estimated that the SWIS may need about 50 GW of new renewable electricity and storage infrastructure to support increased demand over the next 20 years.

Synergy’s big battery is one of two grid-scale energy storage systems being constructed at Collie.

French renewables giant Neoen is in the process of building the first stage of a planned 1 GW/4 GWh battery at Collie with the developer predicting the facility will be operational “by or before 2025.”