TL;DR: The Australian Labor party is fulfilling its 2022 election promise by installing a new community battery in Coorparoo. Community batteries, a relatively new concept in Australia, are shared resources that store excess rooftop solar-generated electricity for later use. They are about the size of a 4WD and can store the equivalent of around 25-45 average household batteries. This initiative benefits homeowners and renters without solar panels by offering access to renewable energy, reducing emissions, and easing pressure on the grid. Energex will receive $447,892 in the first round of grant funding for this installation. The Australian government plans to invest $200 million to install 400 such batteries nationwide. This initiative could save participants between $50 - $250 per year, depending on their solar exports and energy use patterns. The project in Coorparoo is expected to be completed by March 2025
Correct, I'm not certain but I suspect it will be all be done by calculation. Battery bank will have a digital meter and so will each of the participant houses. If your producing energy when the battery is charging your entitled to an equivalent amount for free from the battery in the other direction. When your actually consuming you can't tell where the exact power you are using is coming from but you can do calculations on the net energy movement and allocate from that.
I suspect the real benifit of the bank is actually network stability (ie preventing spikes/brownouts). A battery bank can respond to a drop in source or load in about 1ms while a generator typically takes around 100ms. This is really helpful for maintaining a healthy 240V supply when you have unstable supplies (like solar panels or wind turbines) or highly variable loads (like everyone turning on the kettle at once during state of origin half time). The whole cheaper electricity benifit is really just a way to sell it to the public.