A generating power agency shall establish a physical connection of its transmission lines and associated facilities with the facilities of a distribution power agency or with the facilities of an intervening power agency when requested by the distribution power agency and shall make available any surplus capacity in its transmission lines and associated facilities and provide for the receipt, transmission, and delivery of power and energy for the account of the distribution power agency upon the payment of rates, tolls, and charges that are reasonable, fair, and nondiscriminatory for the use made of the transmission lines and associated facilities of the generating power agency.