NOVELTY - The method comprises preparing crushed biogenic raw materials in a mash tank comprising mixing tools under the supply of water in a flowable substrate (55), introducing the substrate together with a fermentation substrate into a first process chamber of a two stage anaerobic reactor, treating the substrate at a thermophilic temperature, introducing hydrogen, carbon gases and air into a second process chamber, processing the fermentation substrate in the second process chamber after a predetermined residence time, and treating the substrate at a mesophilic temperature.    USE - The method is useful for producing hydrogen and biogas (claimed), where the hydrogen is useful for electric drives of automobiles and fuel cells.    ADVANTAGE - The method is capable of efficiently producing the hydrogen with high yield and less production of wastage.    DETAILED DESCRIPTION - The method comprises preparing crushed biogenic raw materials in a mash tank comprising mixing tools under the supply of water in a flowable substrate (55), introducing the substrate together with a fermentation substrate into a first process chamber of a two stage anaerobic reactor, treating the substrate at a thermophilic temperature, introducing hydrogen, carbon gases and air into a second process chamber, processing the fermentation substrate in the second process chamber after a predetermined residence time, treating the substrate at a mesophilic temperature, exposing the fermentation substrate to electrical impulses in a zone and then treating by magnetic field, and producing biogas in the second process chamber. The biogenic substrate is treated by positive and negative electric pulses before introduced into the first process chamber. The fermentation substrate in the first process chamber has an upper level and a lower level. The biogas and the hydrogen are introduced before introducing air or oxygen. The biogenic substrate is mixed with the fermentation substrate in an injector and a spiral chamber before introduction of the fermentation substrate in the first and second chambers. The method further comprises adjusting pH of the fermentation substrate in the first process chamber by setting a gas pressure in a gas chamber, and arranging permanent magnets with a configuration in a Halbach array for generation of electrical voltage. An INDEPENDENT CLAIM is included for a biogas plant.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of a biogas plant.    Cylindrical air-lift pump (11)    Compressor (13)    Concentric reducer (21)    Hopper (46)    Biogenic substrate. (55)