A turbomachinery plant comprising: a variable frequency drive electric unit comprising an electrical reversible machine capable of supplying power; a compressor, connected to the electrical reversible machine; a suction unit; a first line connecting the suction unit to the compressor; a first isolating valve arranged on the first line; a gas collection unit; a second line connecting the compressor to the gas collection unit; a second isolating valve arranged on the second line; an antisurge circuit comprising a third line, connecting the first line to the second line, and an antisurge valve arranged on the third line; characterized in that the turbomachinery plant further comprises: a gas depressurizing compressor having an inlet and an outlet and configured to suck an amount of gas through the inlet, to decrease the pressure of the amount of gas and to eject the amount of gas through the outlet; a fourth line connecting the second line to the inlet of the gas depressurizing compressor; a first on/off valve arranged on the fourth line movable between an open state, so as to allow the passage of an amount of gas toward the gas depressurizing compressor, and a closed state, so as to prevent the passage of an amount of gas toward the gas depressurizing compressor; a central control unit, connected to the first and second isolating valves (SV1, SV2), the antisurge valve, the first on/off valve, and configured to: close the first isolating valve and the second isolating valve and open the antisurge valve, so that an amount of gas flows substantially only in the antisurge circuit, and open the first on/off valve and activate the gas depressurizing compressor, so that an amount of gas sucked by the gas depressurizing compressor moves from the antisurge circuit to the gas depressurizing compressor, the compressor rotates encountering less resistance and absorbing less power and the power generated by the electrical reversible machine is maximized. a variable frequency drive electric unit comprising an electrical reversible machine capable of supplying power; a compressor, connected to the electrical reversible machine; a suction unit; a first line connecting the suction unit to the compressor; a first isolating valve arranged on the first line; a gas collection unit; a second line connecting the compressor to the gas collection unit; a second isolating valve arranged on the second line; an antisurge circuit comprising a third line, connecting the first line to the second line, and an antisurge valve arranged on the third line; characterized in that a gas depressurizing compressor having an inlet and an outlet and configured to suck an amount of gas through the inlet, to decrease the pressure of the amount of gas and to eject the amount of gas through the outlet; a fourth line connecting the second line to the inlet of the gas depressurizing compressor; a first on/off valve arranged on the fourth line movable between an open state, so as to allow the passage of an amount of gas toward the gas depressurizing compressor, and a closed state, so as to prevent the passage of an amount of gas toward the gas depressurizing compressor; a central control unit, connected to the first and second isolating valves (SV1, SV2), the antisurge valve, the first on/off valve, and configured to: close the first isolating valve and the second isolating valve and open the antisurge valve, so that an amount of gas flows substantially only in the antisurge circuit, and open the first on/off valve and activate the gas depressurizing compressor, so that an amount of gas sucked by the gas depressurizing compressor moves from the antisurge circuit to the gas depressurizing compressor, the compressor rotates encountering less resistance and absorbing less power and the power generated by the electrical reversible machine is maximized.