At the end of each monthly billing period, where the electricity supplied during the period by the electric utility exceeds:
(1) The electricity generated by the eligible customer-generator during that same period; and
(2) Any unused credits for excess electricity from the eligible customer-generator carried over from prior months since the last twelve-month reconciliation period,
the eligible customer-generator is a net electricity consumer and the electric utility shall be owed compensation for the eligible customer-generator's net kilowatt-hour consumption over that same period. The compensation owed for the eligible customer-generator's net monthly kilowatt-hour consumption shall be calculated at the retail rate of the rate class the customer is normally assigned to.