(a) In contested cases in which the agency has not presided at the reception of the evidence, the agency representative who presided shall initially decide the case or the agency shall require the entire record before the agency representative to be certified to it for initial decision. When the representative makes the initial decision, and in absence of an application to the agency within 30 days from the date of notice of the initial decision for review, or an order by the agency within such time for review on its motion, the initial decision shall, without further proceedings, become the decision of the agency. On review from the initial decision of the representative, the agency shall have all the powers it would have in making the initial decision and, if deemed advisable, the agency may take additional testimony or remand the case to the hearing representative for such purpose. When the agency makes the initial decision without having presided at the reception of evidence, the agency representative shall first recommend a decision, a copy of which shall be sent to each party and which shall be made a part of the record.

(b) A final decision or order adverse to a party, other than the agency, in a contested case shall be in writing or stated in the record. A final decision shall include findings of fact and conclusions of law, separately stated, and the effective date of the decision or order. Findings of fact shall be accompanied by a concise and explicit statement of the underlying facts supporting the findings. Each agency shall maintain a properly indexed file of all decisions in contested cases, which file shall be open for public inspection with the exceptions provided in paragraph (4) of subsection (a) of Code Section 50-13-3. A copy of the decision or order and accompanying findings and conclusions shall be delivered or mailed promptly to each party or to his attorney of record. Nothing in this Code section shall prevent agencies from entering summary decisions or orders for contested cases informally disposed of under paragraph (4) of subsection (a) of Code Section 50-13-13. Moreover, nothing in this Code section shall prevent the parties to a contested case before the Public Service Commission from waiving the requirements of this Code section relating to findings of fact and conclusions of law, nor preclude the commission from adopting a rule or rules prescribing the procedure whereby parties to a contested case before it may waive such requirements.

(c) Each agency shall render a final decision in contested cases within 30 days after the close of the record required by Code Section 50-13-13 except that any agency, by order, may extend such period in any case in which it shall find that the complexity of the issues and the length of the record require an extension of the period, in which event the agency shall render a decision at the earliest date practicable. Notwithstanding any other provisions of this law to the contrary, the procedures prescribed by Code Section 46-2-25, relating to procedure for utility rate changes, shall be applicable to and available to any person, firm, or corporation subject to the jurisdiction of the Public Service Commission; and nothing contained herein shall be deemed to abrogate or limit, in any manner, such Code section as it pertains to any rate, charge, classification, or service which may constitute the basis of a contested case, proceeding, hearing, or matter before the Public Service Commission.

(d) The Public Service Commission shall not be required to include findings of fact and conclusions of law in its orders and decisions in cases in which it presides at the reception of the evidence where no person appears in protest or opposition to the relief or authority sought; provided, however, that such cases shall not include those in which the relief sought is an increase or decrease in the rate or rates of any person subject to its jurisdiction; and provided, further, that, if an aggrieved person files a petition seeking judicial review pursuant to Code Section 50-13-19 with respect to such an order or decision, the Public Service Commission shall nevertheless prepare such findings of fact and conclusions of law and include the same in the record of the proceedings transmitted to the reviewing court pursuant to subsection (e) of Code Section 50-13-19.