Sodium Ion batteries are starting to come onto the market, and when these batteries reach full competitive market production, sodium carbonate costs $332 per tonne where lithium carbonate costs $20,000 per tonne, means batteries will become very competitively priced for 30 Kw/h batteries that can cover homes for the nights consumption, in 5 to 10 years it will be a no brainer to have 7 Kw of panels and a 30Kw/h sodium ion battery backup…I know because Aldi and Bunnings run their stores on the current technology and it runs their entire portfolio of shops across Australia [obviously they bought their assets at wholesale prices]