Section 23-18-607 - Monthly grid charge(a)(1) If an electric utility follows the rate structure in § 23-18-606(a)(2), the electric utility shall apply a monthly grid charge to:(A) Collect any of the fixed charges that are collected through volumetric charges, including without limitation any riders and surcharges; and(B) Exclude the cost of fuel and purchased energy.(2) The monthly grid charge shall be calculated based upon the: (A) Currently approved rates; and(B) Cost-of-service study underlying the electric utility's currently approved rates adjusted for any commission-approved:(i) Formula rate plan adjustments under the Formula Rate Review Act, § 23-4-1201 et seq.; or(ii) Adjustments under § 23-4-901 et seq.(b) The monthly grid charge under this section shall be calculated for each customer class as follows: (1)(A) Calculate the sum of all fixed costs collected through volumetric rates.(B) The fixed costs collected through volumetric rates shall be any demand-related or customer-related costs collected in rates stated in dollars per kilowatt hour; and(2)(A) Convert the fixed costs calculated in subdivision (b)(1) of this section into a rate, expressed in dollars per kilowatt hour, by dividing the total of the fixed costs under subdivision (b)(1) of this section for each customer class by the electric utility's sales during the test-year used to develop the retail rates approved by the commission in the electric utility's most recent application for a general change or modification in rates under § 23-4-401 et seq.(B) The monthly grid charge for each customer class shall be determined by multiplying the fixed costs expressed under subdivision (b)(2)(A) of this section by the expected monthly output of a one-kilowatt alternating current solar photovoltaic solar system determined under subsection (c) of this section.(c)(1) The expected monthly output of a one-kilowatt alternating current solar photovoltaic solar system shall be:(A) Expressed in kilowatt hours; and(B) Calculated by dividing the expected average annual output for a one-kilowatt alternating current solar photovoltaic solar system using the process described in subdivisions (c)(2) and (3) of this section by twelve (12).(2) For a fixed-tilt solar photovoltaic system, the average annual output for a one-kilowatt alternating current solar photovoltaic solar system shall be:(A) Expressed in kilowatt hours; and(B) Determined using the National Renewable Energy Laboratory PVWatts Calculator using a direct current to alternating current (DC/AC) ratio of one and one-tenth (1.1) using a single location central to the electric utility's service territory.(3) For a single-axis tracking solar photovoltaic solar system, the average annual output for a one-kilowatt alternating current solar photovoltaic solar system shall be: (A) Expressed in kilowatt hours; and(B) Determined using the National Renewable Energy Laboratory PVWatts Calculator using a direct current to alternating current (DC/AC) ratio of one and three-tenths (1.3) using a single location central to the electric utility's service territory.(d) The monthly grid charge shall not be less than the amount of any electric utility fixed costs that are collected through volumetric charges, including without limitation any riders, and excluding the cost of fuel and purchased energy that the net-metering customer avoids.Added by Act 2023, No. 278,§ 1, eff. 3/13/2023.