220 ILCS 5/9-222
Whenever a tax is imposed upon a public utility engaged in the business of distributing, supplying, furnishing, or selling gas for use or consumption pursuant to Section 2 of the Gas Revenue Tax Act, or whenever a tax is required to be collected by a delivering supplier pursuant to Section 2-7 of the Electricity Excise Tax Act, or whenever a tax is imposed upon a public utility pursuant to Section 2-202 of this Act, such utility may charge its customers, other than customers who are high impact businesses under Section 5.5 of the Illinois Enterprise Zone Act, customers who are certified under Section 95 of the Reimagining Energy and Vehicles in Illinois Act, manufacturers under the Manufacturing Illinois Chips for Real Opportunity (MICRO) Act, customers who are tenants in a quantum computing campus under Section 605-1115 of the Department of Commerce and Economic Opportunity Law of the Civil Administrative Code of Illinois, or certified business enterprises under Section 9-222.1 of this Act, to the extent of such exemption and during the period in which such exemption is in effect, in addition to any rate authorized by this Act, an additional charge equal to the total amount of such taxes. The exemption of this Section relating to high impact businesses shall be subject to the provisions of subsections (a), (b), and (b-5) of Section 5.5 of the Illinois Enterprise Zone Act. This requirement shall not apply to taxes on invested capital imposed pursuant to the Messages Tax Act, the Gas Revenue Tax Act and the Public Utilities Revenue Act. Such utility shall file with the Commission a supplemental schedule which shall specify such additional charge and which shall become effective upon filing without further notice. Such additional charge shall be shown separately on the utility bill to each customer. The Commission shall have the power to investigate whether or not such supplemental schedule correctly specifies such additional charge, but shall have no power to suspend such supplemental schedule. If the Commission finds, after a hearing, that such supplemental schedule does not correctly specify such additional charge, it shall by order require a refund to the appropriate customers of the excess, if any, with interest, in such manner as it shall deem just and reasonable, and in and by such order shall require the utility to file an amended supplemental schedule corresponding to the finding and order of the Commission. Except with respect to taxes imposed on invested capital, such tax liabilities shall be recovered from customers solely by means of the additional charges authorized by this Section.
220 ILCS 5/9-222