The invention relates to a system for energy optimization in a plant for producing direct-reduced metal ores (3), in particular direct-reduced iron, wherein the plant (3) comprises at least one reduction unit (12), a device for separating gas mixtures (7, 7a, 7b) having an associated compressing device (4, 4a, 4b), and a gas-heating device (10) arranged upstream of the reduction unit (12). Furthermore, part of the process gases (2, 2a, 2b) is fed by means of a feed line from at least one plant for producing pig iron (1, 1a, 1b), in particular a smelting reduction plant, to the plant for producing direct-reduced metal ores (3). In the system according to the invention, a turbine (8, 8a, 8b), in particular an expansion turbine, is fit between the device for separating gas mixtures (7, 7a, 7b) and the gas-heating device (10) arranged upstream of the reduction unit (12) in such a way that a pressure drop between the device for separating gas mixtures (7, 7a, 7b) and the reduction unit (12) is converted into forms of energy that can be used to operate additional components (4, 4a, 4b, 15, 15a, 15b) of the plant for producing direct-reduced metal ores (3), in particular electrical energy and/or mechanical energy. By means of the invention, the energy consumption of the plant (3) is reduced and thus operating costs are lowered in a simple and advantageous manner, because the pressure drop between the device for separating gas mixtures (7, 7a, 7b) and the reduction unit (12) is used economically due to the use of the turbine (8, 8a, 8b).