A security deposit in an electricity bill is a payment made upfront to a retail electricity provider (REP) to secure a connection to the power grid and guarantee a reliable supply of power. The deposit is required for new customers who do not meet the requirements of the companys credit-score assessment or are unable to provide a letter of credit from another electric utility. Existing customers may also be required to pay a security deposit if they have not paid the total amount due for any given bill containing a previous balance. The full security deposit will appear on the initial bill and must be paid in full by the due date. The deposit amount varies depending on the company and its requirements, but it usually ranges from less than a hundred dollars to several hundred dollars depending on the customers credit history. The deposit is refundable, and the amount is credited to the customers account after a set number of payments or when the agreement ends.