The aim of the part project AP5 „Economic assessment Bioenergy-Silphium“ is to determine the economic efficiency of cultivating Silphium perfoliatum L. as a renewable energy source. Results derived from field trials of different sites provide data for calculating annual gross margins. The different regions should guarantee statements about the economic competition ability with different soil conditions and climate. The results of the economic efficiency calculations are compared to other cultures typical for the selected site.