TECHNOLOGY FOCUS - BIOTECHNOLOGY - Preferred Components: The methane content of the injected, purified biogas in the supplying network is at least 85 vol.%.    TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Components: The individual fermenter of the fermenter module is connected in series or parallel. The biogas pipeline emerging from the second purifying device is connected with the biogas pipeline emerging from the first fermenter via a suppressible bypass pipeline, where the integration of the bypass pipeline is carried out in a pipeline section directly in front of the block-type thermal power station. The block-type thermal power station is installed locally separated from the other modules. A controllable multi-port-valve is integrated into the biogas pipeline emerging from the second fermenter, through which the amount of the biogas supplied from the second fermenter to the block-type thermal power station is regulated depending on the load. The amount of biogas supplied to the block-type thermal power station for the electricity generation is measured in such a manner that it adjusts a ratio of the electrical energy to the sum of the generated heat energy and methane (respectively in kilowatt hour) to 1:3-1:12. A compressor for a maximum operating pressure of 100 mbar is integrated at least in the pipeline system for the first and the second biogas stream, between the first drying device and the block-type thermal power station and before the second biogas purifying device. A fermentation residue storage is connected with the pipeline carrying the second biogas stream via a pipeline carrying a third biogas stream (B3). A unit for regeneration of the contaminated wash solution resulting during the purification steps is integrated in the energy supplying unit. A pressure balancing pipeline is integrated in the pipeline downstream the second purifying device, where the pressure balancing pipeline is connected with either the pipeline carrying the biogas of the second fermenter or the fermentation residue storage. A desulfurization device is integrated immediately after the fermenters. A device for removing ammonia from the liquid fermenting substrate is integrated in the pipeline emerging from the fermentation residue storage to the fermenters.