If the Commission shall be of the opinion from all the evidence before it that, in pursuance of the herein expressed policy of the Commonwealth to encourage water-power development, the plans of the applicant provide for the greatest practicable extent of utilization of the waters of the Commonwealth for which the application is made and that the applicant is financially able to construct and operate the proposed dam and works and that the general public interest will be promoted thereby, it shall grant the license to construct and operate the proposed dam and works.