All such grants and renewals thereof shall reserve to the City the right to terminate the same, and to purchase or lease all the property of the utility in the streets and highways in the City and elsewhere, used in or useful for the operation of the utility, at a price fixed in the ordinance, or to be fixed in the manner provided by the ordinance making the grant or renewal of the grant. Nothing in such ordinance shall prevent the City from acquiring the property of any such utility by condemnation proceedings or in any other lawful mode; but all such methods of acquisition shall be alternative to the power to purchase, reserved in the grant or renewal as hereinbefore provided. Upon the acquisition by the City of the property of any utility, by purchase, condemnation, or otherwise, all grants or renewals shall at once terminate.