In given article the nut driver's electric power consumption studies depending on the corresponding fixed threaded joint's assembly time are made. So far there are no recommendations from the tool manufactures for nut driver's optimal operating modes (the conclusion is made based on the attached instructions which provide instrument manufacturers), when evaluating this aspect taking into account the electrical power consumption and assembly time for different types of fixed threaded joints (wood, metal, plastic, etc.) and also taking into account obtainable tightening moments. In the examined literature sources which deal with the opportunities concerning the optimization of the automated assembly processes of fixed threaded joints, not enough attention is paid to the reduction of the instrument's energy consumption which is one of the main tasks in the industrial process because it directly impacts production costs.