Any municipality establishing or purchasing a plant as provided by this chapter, reconstructing, extending or enlarging the same, as provided in section 7-218, or paying or liquidating obligations incurred pursuant to any power purchase contract entered into by or on behalf of such municipality, may pay for the same by an issue of bonds, payable in a term not exceeding thirty years, which shall not be disposed of at less than par, but such bonds shall not be issued until a vote authorizing the same has been passed by the town or borough or the common council of the city. No indebtedness shall be incurred by any municipality in connection with such plant except as provided in this section, provided money may be borrowed temporarily to pay the running expenses thereof and may be borrowed in accordance with section 7-217a. All receipts from the sale of gas or electricity shall be paid over to the treasurer of such municipality. The gross expenses of running such plant and conducting such business of supplying gas or electricity, including interest on such bonds and the requirements of the sinking fund, if such a fund has been provided for the payment of such bonds, shall be included in the appropriations made annually or from time to time by such municipality and shall be paid out of the treasury thereof. For the purposes of this chapter, the proceeds of any notes issued pursuant to section 7-217a for the purpose of purchasing capacity or energy shall be considered income of the plant operated pursuant to this chapter by the municipality issuing such notes and shall be applicable against the expenses related to such plant.