Battery size and the number of batteries you will need depends upon the level of energy independence you wish to achieve. This can range from being 100% independent, to peak time independence (avoid paying peak usage rates), to using a battery as emergency back up incase of a power failure. Cost increases with the level of independence but being fully independent from the grid may not always be your best option. Factors to consider are your budget, type of dwelling, energy consumption, peak usage times, and the size of your solar system (if you have one). Different types and sizes of batteries vary in price from a few thousand dollars up to tens of thousands of dollars. TWE will assess your power usage history and power usage forecast, to determine to right size battery for your home or business.