The hydroelectric or wind energy plant or plants and transmission lines constructed pursuant to Section 25730 may be leased for operation to, or the power generated may be sold to, a public utility or another public agency engaged in the distribution, use, or sale of electricity. The power generated may be used by the county for its own purposes, or for the production or transmission of water, but shall not be offered for sale directly by the county to customers other than to a public utility or another public agency. Any power sold to a public utility or another public agency engaged in the distribution or sale of electricity shall be marketed at the bus bar. For purposes of this section, “bus bar” means the high tension disconnect switch or switches of the hydroelectric or wind energy works.