220 ILCS 5/16-126.1: Regional transmission organization memberships.

The State shall not directly or indirectly prohibit an electric utility that on December 31, 2005 provided electric service to at least 100,000 customers in Illinois from membership in a Federal Energy Regulatory Commission approved regional transmission organization of its choosing. Nothing in this Section limits any authority the Commission otherwise has to regulate that electric utility. This Section ceases to be effective on July 1, 2022 unless extended by the General Assembly by law.