Excellent info - thank you.

Yes, I've been through solarquotes.com.au a few times but haven't looked in earnest for some time. This is encouraging information.

I know my usage can easily be 15-20kWh in a day, and I can get a week of overcast though it's not common.

The 'free' electricity offers presumably are in return for a guarantee to feed-in to them outside sunlight peak, I suppose?

I assume the power providers have come up with ToU and FiT tariffs based on a LOT of data, so we here with our spreadsheets and one or two datapoints aren't likely to come out far ahead, but it sounds like break-even within a few years is feasible.

They don't require that we feed in at any specific time, but they do price their peak rates quite high so you have to ensure you have enough storage to not consume at those times.

No doubt their models and prices will be updated once more large homes BESS are installed.