A method for feeding electrical power into an electrical supply grid by means of at least one wind power installation at a grid connection point, wherein the at least one wind power installation has an aerodynamic rotor with rotor blades and the rotor has a moment of inertia and can be operated with variable rotor speed, the at least one wind power installation has a generator for generating a generator power, multiple energy generators feed power into the electrical supply grid and multiple consumers take power from the electrical supply grid, so that a power balance in the electrical supply grid between the power fed in and the power taken is produced and is positive if more power is fed in than is taken, and the method comprises the steps of: feeding in a basic electrical power in dependence on available wind power, specifying a supporting power to be additionally fed in and additionally feeding in the specified supporting power to be additionally fed in for supporting the electrical supply grid, an amount of supporting energy available for the supporting power to be fed in being determined and the specifying of the supporting power to be additionally fed in taking place in dependence on the available amount of supporting energy determined.