The present invention relates to a method for controlling a power plant for reducing spectral disturbances in an electrical grid being operative connected to the power plant, the power plant comprising a plant controller, at least one wind turbine and at least one auxiliary energy source, wherein the at least one wind turbine comprises a rotor adapted to drive a power generator via a shaft, wherein the generator is connectable with the electrical grid, and at least one damping controller configured to compensate structural oscillations of the wind turbine by controlling a torque on the shaft, wherein the at least one damping controller is capable of setting a limit of a control action on the shaft, the method comprising the steps of determining disturbance information for the power plant in the form of an electrical disturbance at a point of measurement electrically connected to the power plant, determining set-points for the at least one auxiliary energy source based on the determined disturbance information, and assigning the set-points to the at least one auxiliary energy source in order to counteract at least part of the electrical disturbance at the point of measurement using at least part of an available amount of energy from the at least one auxiliary energy source.