If a state plan approved under this subchapter would result in a significant increase in the total electric or natural gas bill annually for any customer class as determined by the Arkansas Public Service Commission, the Division of Environmental Quality shall prepare a feasibility study to determine whether:
(1) An alternative approach is consistent with the Clean Air Act, 42 U.S.C. § 7401 et seq.; or
(2) The pursuit of implementing an alternative approach is likely to result in the imposition of a federal plan.