(a) All purchases and contracts for supplies for services, except for personal services, made by the Authority, including contracts for the construction of facilities of the Authority, shall be made after advertisement for bids sufficiently in advance of opening bids for the Authority to secure appropriate notice and opportunity for competition; provided, that where the expense estimated to be necessary in connection with the purchase or work does not exceed two thousand five hundred (2,500) dollars the same may be carried out without advertisement for bids. Advertisement for bids shall not be required, however, when—
(1) an emergency requires immediate delivery of the materials, supplies, equipment, or performance of the services; or
(2) repair parts, accessories, or supplemental equipment or services are required for supplies or service previously furnished or contracted for; or
(3) professional, financial (including financial printing) or other expert services or work are required and the Authority shall deem it best in the interest of good administration that contracts therefor be made without such advertisement; or
(4) prices are noncompetitive because there is only one source of supply or because regulated under law; in such case the purchase of such materials, supplies, or equipment, or procurement of such services, may be made in the open market in the manner usual in commercial practice. In the comparison of bids and the making of awards, due consideration shall be given to such factors (in addition to whether the bidder has complied with the specifications) as the bidder's ability to perform construction work of the kind involved in the construction contract under consideration; the relative quality and adaptability of materials, supplies, equipment, or services; and the time of delivery or performance offered. The Authority may prescribe rules and regulations for the submission of bids.
(b) Any contract, purchase agreement or other instrument of sale accepted by the Authority for construction of a water or power plant shall contain an enforceable performance guarantee by the seller that the completed plant will produce as specified in the accepted contract, purchase agreement, or other instrument of sale. The seller shall provide, in addition to the guarantee, a detailed plan for engineering maintenance supervision and give assurances satisfactory to the Authority that such plan, if implemented will enable the plant to be operated as specified and during the life anticipated in the contract, purchase agreement or other instrument of sale.