Tesla tech already develop a PowerWall he can handle 5 to 7 kwh.
So u can charge it up on night to use it on day when electricity cost more, u can plug it to solar wall to add more juice and dont pay for charge.
Tesla "powerwall" can be chained by 10 device so u can grab 50 to 70 kwh with low cost electricity on day. Is expensive like 6-7k, but can be really interesting for big farm with big difference between day and night price.
Where i leave i have to pay for 0.148 per kwh, day or night. But mining is steel profitable since in run on little infra, i dont have cost for cooling easy etc ...