A battery which is being constructed in Western Australia by a French renewable energy giant is set to be Australia’s largest battery after the company announced that it would proceed with a second stage of the battery’s construction that will more than double its overall size.

In its latest announcement, French renewable energy provider Neoen says that it will proceed with construction of the 341 MW/1,363 MWh second stage of its Collie Battery in Collie in the south-west of Western Australia.

The announcement comes after Neoen was awarded a second capacity services contract from the Australian Energy Market Operator to provide battery storage for Western Australia’s South-West Interconnected System (SWIS) – the electricity network that serves most of Western Australia’s population.

Under that contact, the second stage battery will provide 300MW of storage capacity.

This will be able to be discharged over a four-hour period during the peak energy demand in the evenings.

The latest development comes as Neoen is already constructing the 219 MW/877MWh Stage 1 of its Collie Battery.

Construction of Stage 1 commenced after Neoen was awarded an earlier contract last June to provide 197 MW of capacity over a similar four-hour peak-energy period.

When the first and second stage are combined, the Collie Battery will have a size of 560 MW and 2,240 MWh.

This will be larger than Synergy’s 500 MW, 2000 MWh battery that is under construction nearby in Collie along with the 275 MW/ 2,200 MWh eight-hour battery that Ark Energy will build at Myrtle Creek in NSW.

All up, the Collie Battery will have the ability to charge and discharge approximately 20 percent of average demand across the SWIS network.

As noted in Renew Economy, together, the two Collie batteries owned by Neoen and Synergy will be able to provide up to 40 per cent of the average demand in the SWIS.

As such these batteries – along with others at Kwinana and Wagerup, are playing a critical role in stabilising the grid which is increasingly penetrated by intermittent renewables by soaking up excess solar in the middle of the day and discharging into the evening peaks

Both stages of the battery are to be constructed with Tesla Megapack batteries.

Both will be constructed by CIMIC subsidiary UGL, which will act as the construction contractor.

Louis de Sambucy, CEO of Neoen Australia, welcomed the contract win.

“We are thrilled to have won this second NCESS contract and would like to thank AEMO, Western Power and the WA Government for their continued trust,” de Sambucy said.

“We are looking forward to the major contribution Collie Battery will make to supporting WA’s energy transition.

“I would also like to congratulate the team on reaching the milestone of 4 GW of capacity in Australia – it represents an extraordinary collective effort over the past 12 years.”