Gabz wrote: ... ausgrid, endevour, ergon everyone who owns the poles and wires ban this sort of system. they only allow UPS style battery connections.
I don't see why it should bother them. Back in the days of the high feed-in tariff, they didn't (and still don't) want batteries anywhere near them. But with low feed-in tariffs, why would they care? From the grid's point of view, they just see lower electricity usage (both less importing, that they get paid for, and less exporting, on which they pay roughly average market rates for the energy). So far, they can't penalise us for using less electricity. (Maybe I shouldn't even suggest this... )
Energex also have some sort of zero export rule that was supposed to apply from now, but was postponed. Per this Solar Choice article, "Energex also notes that energy storage devices will be allowed provided none of their power is exported." This sounds like an over-reaction to me, but now that renewable generators are like the 6th largest generator (around 1 GW in Queensland), I guess they're running scared.
That sounds like something that either the Powerwall needs to enforce, or maybe the grid interactive inverter (with some sort of measurement of exported power) will have to provide. Since most existing grid interactive inverters presumably don't have zero export capability, either the Powerwall will have to do it, or there may be a market in third party gizmos to somehow make ordinary inverters force zero export. That doesn't sound trivial to me.