It is known, that the main task of the electric power system (EPS) control is the power supply providing with the minimum expenses for the electric power production. In this case the requirement to the electric power quality, power supply reliability and the limitations on the energy resources cost must be observed. The power reserve presence into EPS is the necessary condition of the guaranteeing the normal operation from the point of view of the regime parameters values (frequency, the nodes voltage, the power flows along the transmition lines and others). In the proposed paper the problem of the developing the power reserve, presented to sale by the electric power producers, is examined. It is considered the procedure of the power reserve price determination.