Abstract: The invention concerns a method for the operation of an underwater power plant with a water turbine to take up kinetic energy from a surrounding flow; and an electrical generator coupled directly to the water turbine; characterized in that the power regulation in the generator mode is done by a control or regulation of the load moment produced by the electrical generator for a freely adjusting rpm speed of the water turbine, wherein the setpoint value of the load moment in a first, power-optimized operating range is established by a state controller and/or a search mechanism for the power maximum; and in a second, power-limited operating range the assigned load moment is chosen so that an operating point distant from the power optimum results for the water turbine.