1. Except as otherwise provided in subsection 2, the Commission may, in its discretion, investigate and ascertain the value of all property of every public utility actually used and useful for the convenience of the public. In making such an investigation, the Commission may avail itself of all information contained in the assessment rolls of the various counties and the public records and files of all state departments, offices and commissions, and any other information obtainable.
2. The provisions of subsection 1 do not apply to a competitive supplier.