Abstract
Nowadays wind farms do not provide frequency control in Germany. Because of the increasing wind energy generation, wind farms will have to provide this ancillary service in the future. Even though the provision of frequency control by wind farms has become a big research field, no work has yet been done concerning the proof of the provision. Thus in this paper a new concept is presented how wind farms can prove the provision of frequency control. Moreover a method for calculating the available amount of frequency control power based on probabilistic forecasts is described. An economic analysis is conducted for three different wind farms and a virtual power plant, consisting of these wind farms, participating at the market for negative tertiary control power in Germany.