The commission may, upon its own initiative, or shall upon written application of any party in interest, order a public hearing with due notice to all interested parties, at which hearing the person proposing to create the development of water power or other plant or equipment, or extension of the same, shall be required to file with the commission, under oath, engineering plans and other information fully descriptive of the proposed development or such thereof as in the opinion of the commission can reasonably be furnished by such applicant, together with such other reasonable information as may be called for at the hearing or any adjournment of the same; and the commission shall have full power to issue or refuse the certificate of public necessity and convenience, or to qualify or withdraw the same as provided in §65-4-203.