Provided is a method for operating a wind farm having a plurality of wind energy installations or a wind energy installation for feeding electrical power into an electrical supply grid, comprising the steps of: feeding electrical power into the electrical supply grid, identifying a forecast power, which describes a power that can be fed in in a predetermined, future forecast period by the wind farm or the wind power installation, determining a reduction forecast power, which denotes, for the forecast period, a power by which the power fed in in the forecast period can be reduced, and supplying the reduction forecast power as negative control power, wherein the reduction forecast power is determined depending on the forecast power and depending on a controllable consumption power, wherein the controllable consumption power describes a power that can be consumed on demand in the forecast period by controllable consumers present in the wind farm or in the wind power installation.