The invention relates to a measurement and evaluation method of energy consumption in an electrical drive having a control unit and an AC motor and an arrangement for realizing the method. The method has the following steps. Data of the state of the AC motor, such as power and frequency, is read at measurement points and saved. The energy consumption of the electrical drive is calculated in predetermined measurement intervals. The energy consumption of the virtual AC motor fed by constant-frequency input current is calculated and the energy consumption of an alternative control arrangement is defined in said measurement interval and they are added together. The energy consumption of the electrical drive is compared with the added total energy consumption of the virtual AC motor and the alternative control arrangement in order to evaluate the energy savings achieved by the electrical drive in the measurement time period in question.