Transmission facilities built under this chapter are exempt from property taxes for a period determined by the authority not to exceed the first five taxable years of operation; after this initial period, transmission lines of two hundred thirty kilovolts or larger and the transmission lines’ associated transmission substations remain exempt from property taxes but are subject to a per mile tax at the full per mile rate and subject to the same manner of imposition and allocation as the per mile tax imposed by section 57-33.2-02 without application of the discounts provided in that section.