Members shall have a preference right to the purchase of all electric energy generated by an operating agency. As between members, the amount of electric energy to which each shall be entitled shall be computed annually and shall be based on the same percentage as the purchases of such member bore to the total generation of the operating agency for the preceding year. Surplus electric energy, that is energy not contracted for by the members, may be sold to any public utility authorized by law to distribute and sell electric energy.
RCW 43.52.380