This is asking the wrong question. The question is what is the cost per kWh of electricity delivered from that battery, which is not the cost per kWh of capacity installed (though it is related).
You have to charge the battery with electricity (which you could sell or have to buy), and then when you discharge it you are either offsetting electricity you would buy, or selling it. Throughout the process you're losing some of it (~8%), and the battery is degrading in capacity towards eventual replacement.
You also have black swan events - i.e. an early battery death due to manufacturing defects.
i.e. my rooftop solar array sells power at 7c / kWh. When I run the numbers on various offset scenarios, the cost per kWh delivered after all expenses and life time costs that I can find tends to be about 7 - 8 c / kWh. Which honestly makes perfect sense to me: the electricity company, at much more massive scale, can install and run batteries more cheaply then I can.
You have to charge the battery with electricity (which you could sell or have to buy), and then when you discharge it you are either offsetting electricity you would buy, or selling it. Throughout the process you're losing some of it (~8%), and the battery is degrading in capacity towards eventual replacement.
You also have black swan events - i.e. an early battery death due to manufacturing defects.
i.e. my rooftop solar array sells power at 7c / kWh. When I run the numbers on various offset scenarios, the cost per kWh delivered after all expenses and life time costs that I can find tends to be about 7 - 8 c / kWh. Which honestly makes perfect sense to me: the electricity company, at much more massive scale, can install and run batteries more cheaply then I can.