S.D. Codified Laws § 49-37-5
A consumers power district which is engaged in the generation and transmission of electrical energy shall sell electrical energy at wholesale directly to any municipality or political subdivision or rural electrical associations and electrical distribution cooperatives or any person, firm, association, or corporation which in turn generates, transmits, or distributes electricity on a nonprofit basis in the state which is engaged in the distribution and sale of electrical energy when any such person or organization makes application for the purchase of electrical energy, if the district has the requested amount of electrical energy available for sale, and the applicant agrees to make or pay for the necessary physical connection with the electrical facilities of the district.
SDCL 49-37-5