SECTION 48. PERIOD OF GRANTS.
   No such grant shall be exclusive, nor shall it be made for a longer period than twenty years. No such grant shall be renewed earlier than two years prior to its expiration unless the City Commission shall by vote of all of its members first declare by ordinance its intention of considering a renewal thereof. All grants of the rights to make extensions of any public utility shall be subject as far as practicable, to the terms of the original grant, and shall expire therewith.