what's the economics like for installing a battery to store...

what's the economics like for installing a battery to store excess electricity produced during peak periods to continue to supply into the grid during low generating periods from renewables? Will batteries ever yield a positive economic return before they have to be replaced. I cannot justify the capital expenditure to install batteries in my own home, since they never pay for themselves, even though I'm paying around 28c/kWhr for power from the grid but only getting paid around 7c/kWhr for power supplied to the grid, so I'd be saving 21c/kWhr for every bit of energy I could draw from the batteries at night that's been stored from my solar panels during the day. And that's assuming the electricity retailers don't increase their daily supply charge to compensate for the loss of revenue from electricity sales if a significant number of consumers switch to home batteries. Maybe the economics for an industrial scale battery used in the wholesale market are completely different.