If any existing electric generation plant within the state is offered for sale, the Public Utilities Regulatory Authority shall authorize the electric distribution companies to purchase and operate such plants if the authority, through a contested case proceeding, determines that such purchase and operation is in the public interest, provided any acquisition plan shall include provisions for payment of property taxes on the value of the purchased plant and provisions for employee protections. An electric distribution company purchasing such generation plants shall be entitled to recover the costs of such purchase in an annual retail generation rate contested case consistent with the principles set forth in sections 16-19, 16-19b and 16-19e, provided the return on equity associated with such purchase and operation shall be established in said contested case proceeding and updated at least once every four years. The authority shall review and approve the cost recovery provisions in the proceeding to determine that such purchase and operation are in the public interest.