(a) In all proceedings before the commission, the parties to such proceeding shall consist of the affected applicant, any person who is permitted to intervene as provided in this Code section, and the Utility Finance Section established pursuant to Article 2A of this chapter.

(b) Any person on whom a statute confers an unconditional right to intervene may intervene by filing a notice of intervention with the commission or hearing officer, as appropriate.

(c) Any other person desiring to intervene must file an application for leave to intervene within 30 days following the first published notice of the proceeding. Any such application shall be in writing, shall be verified either by the party intervening or by his attorney on information and belief, shall identify the party requesting the intervention, and shall set forth with particularity the facts pertaining to his interest and the grounds upon which his application for intervention are based. Such application shall be served on all other parties in the proceeding, including those who have previously applied for leave to intervene. No untimely application for leave to intervene shall be granted by the presiding authority except for good cause shown.

(d) Any party or person who has previously applied for leave to intervene in a proceeding in which leave to intervene is sought by another person may file a response to the application for leave to intervene within 15 days after the application is served.

(e) The commission or hearing officer shall permit only the following persons to intervene:

(1) A person upon whom a statute confers an unconditional right to intervene;

(2) A person who demonstrates a legal, property, or other interest in the proceeding. In determining whether to permit intervention, the hearing officer may consider whether the person's interest is adequately represented by other parties and whether the intervention will unduly delay the proceedings or prejudice the rights of other parties;

(3) Any member of the General Assembly of the State of Georgia, who may without fee intervene on behalf of his constituents with the full rights and privileges of a designated party.

(f) The commission or hearing officer may condition any order permitting intervention so as to assure the orderly conduct of the proceeding.

(g) A person who is not a party may make a limited appearance by making an oral or written statement of his position on the issues within such limits and on such conditions as may be fixed by the hearing officer; but he may not otherwise participate in the proceeding.

(h) A party granted leave to intervene shall be present, absent good cause shown, during that portion of the proceedings for which that party has indicated a desire to be heard.

(i) An order by a hearing officer denying or conditioning an application for leave to intervene shall be immediately reviewable by the commission. An order by the commission denying or conditioning an application for leave to intervene shall be immediately reviewable as provided by law for the judicial review of final commission orders.

(j) Nothing in this Code section shall be construed to prohibit the commission from taking any action prior to the expiration of the 30 day period during which persons are permitted to file applications for leave to intervene.