(a) The billing period for net metering may be either a monthly period, a quarterly, semi-annual or annual period as determined by the billing cycle of the Utility.
(b) Except as otherwise provided in paragraph (3) of this subsection, the net energy measurement must be calculated in the following manner:
(1) The utility shall measure the net electricity produced or consumed during the billing period, in accordance with the established electric rate for that particular class of service.
(2) If the electricity supplied by the utility exceeds the electricity generated by the customer-generator which is fed back to the utility during the billing period, the customer-generator must be billed for the net electricity supplied by the utility.
(3) If the electricity generated by the customer-generator which is fed back to the utility exceeds the electricity supplied by the utility during the billing period, then the energy delivered by the customer-generator to the utility must be credited to the customer-generator's account at the retail cost of the utility producing the amount of energy. Any excess kwh generation by the customer is carried over as a credit from month to month. At the end of each calendar year, or after termination of service, any excess kwh credits are granted to the Authority by the customer without compensation to the customer.