Ill. Admin. Code tit. 83, § 430.90 – Limitations

a) Nothing in this Part relieves the utility from carrying out its responsibilities as described in Section 201 and 210 of the Public Utility Regulatory Policies Act of 1978 (PURPA) or in the rules promulgated pursuant to said Act.
b) Nothing in this Part:
1. 1) limits the authority of the utility or a qualifying facility to agree to a rate for any purchase, or terms or conditions relating to any purchase, which differ from the rate or terms or conditions which would otherwise be provided by this Part provided such rate
  1. A) is just and reasonable to the electric customer of the electric utility and in the public interest, and
  2. B) does not discriminate against qualifying cogeneration and small power production facilities;
2. 2) affects the validity of any contract entered into between a qualifying facility and a utility for any purchase.