A: No, you do not need Solar to enjoy battery storage. Although battery storage was designed to work alongside Solar initially, you can now use battery storage to store cheap energy tariffs and use this cheap stored energy when the tariffs are much higher.
For Example: you store cheap energy rates of 7.5p per Kw through the night, You then use this 7.5p energy through the day when you should be paying peak tariff rates of around 35p to 55p per Kwh, therefore you are saving from 27.5p to 47.5p per Kwh.