The Western Australia government owned energy utility Synergy is poised to become the first traditional generation company to boast more big battery capacity than coal, highlighting the rapid changes that are taking place in Australia’s main electricity grids.
Synergy this week confirmed that one of the country’s biggest battery storage projects – its 500 megawatt (MW) and 2,000 megawatt hour (MWh) Collie battery – is in the final stages of commissioning and is expected to be fully operational by the end of the year.
It will be the second biggest battery in terms of storage in the country, behind only the newly commissioned 560 MW, 2,240 MWh Collie battery owned by Neoen Australia, that is located in the same town.
The significance of the Synergy Collie battery is that it will take the company’s total big battery capacity to more than 800 MW (and nearly 3,200 MWh) – more than the 740 MW of coal fired power capacity that remains at its ageing Muja and Collie coal-fired power stations, also in the same town, that are due to shut by the end of the decade.
No other traditional generator in Australia comes close to the scale and speed of this transition. In the eastern states, AGL Energy, EnergyAustralia, Alinta and Origin are all investing in or contracting major battery projects, but are perhaps a decade away from closing the last of their coal plants.
Origin is likely the first to follow Synergy’s example, should it close the country’s biggest coal generator at Eraring (2.8 GW) as currently advised in August, 2027. It is currently building what will be the biggest battery – 700 MW and 2,800 MWh – at that same site.
Synergy’s plan is striking – not just for the speed of the transition away from “always on” baseload coal (when the machines are not broken) to highly flexible battery storage, but also because it is occurring in a unique grid, the South West Interconnected System, which is the biggest isolated grid in the world.
That means it has no links with other states or grid, and can’t trade power when needed. All its resources for bulk energy and firming must be sourced locally, and it has no hydro or geothermal options.
Dom Watson, the lead renewable engineer at Synergy, gave a fascinating insight into Synergy’s rapidly changing generation profile and the growth of battery storage at the Battery Asset Management summit in Sydney this week.
Watson noted that demand on the SWIS hit a new peak of 4.5 gigawatts in January this year, and last November – thanks to the fact that 40 per cent of all households have rooftop solar – it reached a new grid demand low of 511 MW.
Hence the need for new batteries, first identified, Watson says, in 2021 as the rooftop solar “duck curve” was in full flight, and the Australian Energy Market Operator grew concerned about its ability to handle such large amounts on the isolated grid.
“We’ve got about 40% of homes and businesses with rooftop PV installed,” Watson said. “And the run rate of that is not is not decreasing at all. And this is largely what’s driving the extremes in the WA mega market at extreme lows and extreme highs, and making it very challenging to meet the ramp rates to serve that evening peak.
“And that sort of underpins the essential need for battery technology.”
The first response to this soaring solar duck curve from authorities was developing a “big red button” to enable it to disable rooftop PV systems, although it seems that that is yet to be pushed in anger.
The second complication was the decision to close all the remaining state owned coal generators by 2030 and the coal supply problems caused by the financial collapse of mine owner Griffin Coal, which results in more than 50,000 tonnes of coal having to be shipped to W.A. from the eastern states.
All this prompted the push into big batteries, which began with the first 100 MW, 200 MWh facility at Kwinana, completed just last year in early 2024, followed by a 225 MW, 900 MWh stage two battery (K2) at the same site that was completed earlier this year.
K2, Watson noted, didn’t get built without some drama. Watson says supply problems – the brief closure of the Suez – meant that the company was forced to ship 18 Power Conversion Systems by air freight to ensure the battery was delivered on time.
“That was a pretty confronting decision to make, but was critical for the project’s success,” Watson said.
The Collie BESS, meanwhile, should be complete by the end of the year, taking total battery capacity in the SWIS to well beyond the 1.1 GW sought by AEMO, with more to come through the series of Capacity Investment Scheme auctions and incentives from the state’s capacity mechanism.
In five years time, W.A. will then become the second state, after South Australia, to close the last of its coal fired generators.
