(a) The commission created pursuant to this subchapter shall have full power to operate and control the utilities system entrusted to its direction by the city ordinance creating the commission.
(b) Subject to such restrictions as may be prescribed in the ordinance creating the commission pertaining to the expenditure of surplus utility revenues, establishment of rates for service, and appointment of commission members, the commission shall have plenary powers with reference to the selection, supervision, and payment of compensation for all employees required in connection with the operation of the electrical distribution system, with reference to management, improvement, extension, and maintenance of the electrical distribution system, with reference to the purchase of such materials and supplies, or machinery as are necessary and proper, and with reference to necessary indebtedness to finance the extension, betterment, or improvement of the electrical distribution system.