S.D. Codified Laws § 49-37-3.1
In order to provide electric power and energy to the people of this state at a more economical cost and with greater reliability, the board of directors of a consumers power district in providing for development of power plants, lines and systems or interest therein, for the generation, transmission, and transformation of electric power and energy, shall take into account, among other things, the reliability and availability of existing alternative supply sources and economies and exigencies to be achieved in developing large scale facilities for the generation and transmission of electric power and energy, whether or not such facilities have a capacity or capability in excess of the present or foreseeable needs of such district. A determination by a board of directors as to the size of the facility to be developed shall be made by resolution, and shall be final.
SDCL 49-37-3.1