Below is the charge/discharge profile of Wivenhoe dam QLD. It soaks up daytime solar to sell into the morning and evening peaks. Marvel at how much rooftop solar is operating to drive this surplus. Also, coal power finds it more convenient to produce all day even at negative prices.
Remember, August is the middle of winter. What will the profile look like in high Summer?
As far as I know, there isn't a battery on the CAN-SYD interconnect, the biggest busiest part of the East Australian grid.
I heartily recommend IFN put one in. The order queue at the battery makers is very long as worldwide, grids have learned from the Tesla big battery in SA the benefits of batteries for frequency control, inertia and waste minimisation.
BESS should be operational any day now. More background and argument for the wonks from Giles Parkinson here:
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