A device for producing hydroelectric energy from an effluent stream, comprising: an open-loop main circuit comprising a main pipe in which fluids intended to be ejected, at the outlet, onto an electricity generating turbine/generator unit (61, 62), are circulated, with a first inlet of the main pipe receiving the effluent stream for siphoning fluids intended to circulate in the main circuit; characterized by - at least one feedback loop comprising a variable diameter nozzle whose inlet is connected to a second inlet of the main pipe, an ejector and a venturi throat so configured as to suck the effluents at the outlet of the ejector, with the feedback loop further comprising a tapping at the outlet of the venturi throat for supplying a variable frequency booster pump in order to establish a dynamic pressure of the circulating fluids, with said booster pump being followed by a tank whose outlet is connected to the inlet of the nozzle in order to maintain a chosen static pressure of the circulating fluids in continuous operation mode inside the main pipe; and - a control unit so configured as to establish a circulation of the fluids in the continuous operation mode in the main pipe, vary the frequency of the booster pump supply so as to increase/decrease the flow rate and the dynamic pressure of the circulating fluids, control the turning on/off of the device and control the operation of the turbine/generator unit (61, 62) in order to produce a controlled quantity of electricity. an open-loop main circuit comprising a main pipe in which fluids intended to be ejected, at the outlet, onto an electricity generating turbine/generator unit (61, 62), are circulated, with a first inlet of the main pipe receiving the effluent stream for siphoning fluids intended to circulate in the main circuit; characterized by - at least one feedback loop comprising a variable diameter nozzle whose inlet is connected to a second inlet of the main pipe, an ejector and a venturi throat so configured as to suck the effluents at the outlet of the ejector, with the feedback loop further comprising a tapping at the outlet of the venturi throat for supplying a variable frequency booster pump in order to establish a dynamic pressure of the circulating fluids, with said booster pump being followed by a tank whose outlet is connected to the inlet of the nozzle in order to maintain a chosen static pressure of the circulating fluids in continuous operation mode inside the main pipe; and - a control unit so configured as to establish a circulation of the fluids in the continuous operation mode in the main pipe, vary the frequency of the booster pump supply so as to increase/decrease the flow rate and the dynamic pressure of the circulating fluids, control the turning on/off of the device and control the operation of the turbine/generator unit (61, 62) in order to produce a controlled quantity of electricity. - at least one feedback loop comprising a variable diameter nozzle whose inlet is connected to a second inlet of the main pipe, an ejector and a venturi throat so configured as to suck the effluents at the outlet of the ejector, with the feedback loop further comprising a tapping at the outlet of the venturi throat for supplying a variable frequency booster pump in order to establish a dynamic pressure of the circulating fluids, with said booster pump being followed by a tank whose outlet is connected to the inlet of the nozzle in order to maintain a chosen static pressure of the circulating fluids in continuous operation mode inside the main pipe; and - a control unit so configured as to establish a circulation of the fluids in the continuous operation mode in the main pipe, vary the frequency of the booster pump supply so as to increase/decrease the flow rate and the dynamic pressure of the circulating fluids, control the turning on/off of the device and control the operation of the turbine/generator unit (61, 62) in order to produce a controlled quantity of electricity.