On or before April 1, 1999, each electric utility owning an interest in, or having responsibility as a matter of contract or statute for decommissioning costs as defined in Section 8-508.1 of, one or more nuclear power plants shall file with the Commission a tariff or tariffs conforming to the provisions of Section 9-201.5 of this Act, to be applicable to each and every kilowatt-hour of electricity delivered or sold at retail in the electric utility’s service area, including, but not limited to, sales by the electric utility to tariffed services retail customers, sales by the electric utility to retail customers pursuant to special contracts or other negotiated arrangements, sales by alternative retail electric suppliers, and sales by an electric utility other than the electric utility in whose service area the retail customer is located; provided, however, that for a user that obtained electric power and energy from its own cogeneration or self-generation facilities on or before January 1, 1997, and subsequently takes services from an alternative retail electric supplier or an electric utility other than the electric utility in whose service area the user is located for any portion of its electric power and energy requirements formerly obtained from those facilities, the tariff required by this Section shall not be applicable in any year to that portion of the user’s electric power and energy requirements formerly obtained from those facilities, provided that for the purposes of this Section, such portion shall not exceed the average number of kilowatt-hours per year obtained from the cogeneration or self-generation facilities during the 3 years prior to the date on which the user became eligible for delivery services.
     The Commission shall determine whether the tariff meets the requirements of Sections 9-201 and 9-201.5 and of this Section, and shall permit the electric utility’s tariff together with any modifications made after hearing to become effective no later than October 1, 1999. In making its determination, the Commission shall retain the authority it possessed prior to the effective date of this amendatory Act of 1997 to make jurisdictional allocations of decommissioning expense recovery. The tariff filed pursuant to this Section shall be applicable to any user taking some or all of its electric power and energy requirements from an alternative retail electric supplier or from an electric utility other than the electric utility in whose service area the user is located on and after the date that the user becomes eligible for delivery services in accordance with Section 16-104. If the electric utility has in effect as of the effective date of this amendatory Act of 1997 a decommissioning rate as defined in Section 9-201.5 conforming to the requirements of that Section, the tariff or tariffs required by this Section shall if the electric utility requests be consistent with its decommissioning rate that is already in effect; provided, that the tariff or tariffs filed pursuant to this Section shall provide for the removal from base rates of any decommissioning costs that are included in the electric utility’s base rates and their inclusion in the tariff or tariffs required by this Section. The tariff required by this Section shall be included by the Commission in the reviews required by subsection (d) of Section 9-201.5.