1. This section applies to an electrical corporation that has elected to exercise any option under section 393.1400 and that has more than two hundred thousand Missouri retail customers in 2018, and shall continue to apply to such electrical corporation until December 31, 2023.
2. Notwithstanding any other provision of law and except as otherwise provided for by this section, an electrical corporation's base rates shall be held constant for a period starting on the date new base rates were established in the electrical corporation's last general rate proceeding concluded prior to the date the electrical corporation gave notice under subsection 5 of section 393.1400 and ending on the third anniversary of that date, unless a force majeure event as determined by the commission occurs. Whether a force majeure event has occurred shall be subject to commission review and approval in a general rate proceeding, and shall not preclude the commission from reviewing the prudence of any revenue reductions or costs incurred during any proceeding to set rates. This subsection shall not affect the electrical corporation's ability to adjust its nonbase rates during the three-year period provided for in this subsection as authorized by its commission-approved rate adjustment mechanisms arising under section 386.266 , 393.1030 , or 393.1075 , or as authorized by any other rate adjustment mechanism authorized by law.
3. This subsection shall apply to electrical corporations that have a general rate proceeding pending before the commission as of the later of February 1, 2018, or August 28, 2018. If the difference between (a) the electrical corporation's average overall rate at any point in time while this section applies to the electrical corporation, and (b) the electrical corporation's average overall rate as of the date new base rates are set in the electrical corporation's most recent general rate proceeding concluded prior to the date the electrical corporation gave notice under section 393.1400 , reflects a compound annual growth rate of more than three percent, the electrical corporation shall not recover any amount in excess of such three percent as a performance penalty.
4. This section shall apply to electrical corporations that do not have a general rate proceeding pending before the commission as of the later of February 1, 2018, or August 28, 2018. If the difference between (a) the electrical corporation's average overall rate at any point in time while this section applies to the electrical corporation, and (b) the average of (i) the electrical corporation's average overall rate as of the date new base rates are set in the electrical corporation's most recent general rate proceeding concluded prior to the date the electrical corporation gave notice under section 393.1400 , and (ii) the electrical corporation's average overall rate set under section 393.137 , reflects a compound annual growth rate of more than two and eighty-five hundredths percent, the electrical corporation shall not recover any amount in excess of such two and eighty-five hundredths percent as a performance penalty.
5. If a change in any rates charged under a rate adjustment mechanism approved by the commission under sections 386.266 and 393.1030 would cause an electrical corporation's average overall rate to exceed the compound annual growth rate limitation set forth in subsection 3 or 4 of this section, the electrical corporation shall reduce the rates charged under that rate adjustment mechanism in an amount sufficient to ensure that the compound annual growth rate limitation set forth in subsection 3 or 4 of this section is not exceeded due to the application of the rate charged under such mechanism and the performance penalties under such subsections are not triggered. Sums not recovered under any such mechanism because of any reduction in rates under such a mechanism pursuant to this subsection shall be deferred to and included in the regulatory asset arising under section 393.1400 or, if applicable, under the regulatory and ratemaking treatment ordered by the commission under section 393.1400 , and recovered through an amortization in base rates in the same manner as deferrals under that section or order are recovered in base rates.
6. If the difference between (a) the electrical corporation's class average overall rate at any point in time while this section applies to the electrical corporation, and (b) the electrical corporation's class average overall rate as of the date rates are set in the electrical corporation's most recent general rate proceeding concluded prior to the date the electrical corporation gave notice under subsection 5 of section 393.1400 , reflects a compound annual growth rate of more than two percent for the large power service rate class, the class average overall rate shall increase by an amount so that the increase shall equal a compound annual growth rate of two percent over such period for such large power service rate class, with the reduced revenues arising from limiting the large power service class average overall rate increase to two percent to be allocated to all the electrical corporation's other customer classes through the application of a uniform percentage adjustment to the revenue requirement responsibility of all the other customer classes.
7. For purposes of this section, the following terms shall mean:
(1) "Average base rate" , a rate calculated by dividing the total retail revenue requirement for all the electrical corporation's rate classes by the total sales volumes stated in kilowatt-hours for all such rate classes used to set rates in the applicable general rate proceeding, exclusive of gross receipts tax, sales tax, and other similar pass-through taxes;
(2) "Average overall rate" , a rate equal to the sum of the average base rate and the average rider rate;
(3) "Average rider rate" , a rate calculated by dividing the total of the sums to be recovered from all customer classes under the electrical corporation's rate adjustment mechanisms in place other than a rate adjustment mechanism under section 393.1075 by the total sales volumes stated in kilowatt-hours for all of the electrical corporation's rate classes used to set rates under such rate adjustment mechanisms, exclusive of gross receipts tax, sales tax, and other similar pass-through taxes;
(4) "Class average base rate" , a rate calculated by dividing the retail revenue requirement from the applicable general rate proceeding that is allocated to the electrical corporation's large power service rate class in that general rate proceeding, by the total sales volumes stated in kilowatt-hours for that class used to set rates in that general rate proceeding, exclusive of gross receipts tax, sales tax, and other similar pass-through taxes;
(5) "Class average overall rate" , a rate equal to the sum of the class average base rate and the class average rider rate;
(6) "Class average rider rate" , a rate calculated by dividing the total of the sums allocated for recovery from the large power service rate class under the electrical corporation's rate adjustment mechanisms in place other than a rate adjustment mechanism under section 393.1075 by the total sales volumes stated in kilowatt-hours for that class used to set rates under such rate adjustment mechanisms, exclusive of gross receipts tax, sales tax, and other similar pass-through taxes;
(7) "Force majeure event" , an event or circumstance that occurs as a result of a weather event, an act of God, war, terrorism, or other event which threatens the financial integrity of the electrical corporation that causes a reduction in revenues, an increase in the cost of providing electrical service, or some combination thereof, and the event has an associated fiscal impact on the electrical corporation's operations equal to three percent or greater of the total revenue requirement established in the electrical corporation's last general rate proceeding after taking into account the financial impact specified in section 393.137 . Any force majeure event shall be subject to commission review and approval, and shall not preclude the commission from reviewing the prudence of any revenue reductions or costs incurred during any proceeding to set rates;
(8) "Large power service rate class" , the rate class of each corporation that requires the highest minimum monthly billing demand of all of the electrical corporation's rate classes in order to qualify as a member of such rate class, and that applies to qualifying customers only if they utilize the electrical corporation's distribution system.