Ann: Chairman's Address to Shareholders, page-28

I reckon as a grid connected domestic consumer, able to access a 20c feed in tariff, and spending 30c per kWh, I could save a maximum of $1 per day with a 10kWh battery. So for a 5 year payback, I need the fully installed price to be around $1500 including all inverters and installation before I even start to consider it. So it’s way off for any domestic consumer with a reliable grid. 

But the markets RFX are targeting have different parameters, and are massive in their own right, and will adopt at a much higher point. Price is not the primary factor.