NOVELTY - The biogas plant comprises a decomposition reaction section (ZRA) for the decomposition of a substrate, and a methane-forming reaction section for the formation of methane from the substrate decomposed in the decomposition reaction section. The decomposition reaction section and the methane-forming reaction section are parts of a continuous flow section. The decomposition reaction section is formed through a tubular decomposition reaction container (ZRB) and the methane-forming reaction section is formed through a tubular methane-forming reaction container (MRB).    USE - Biogas plant useful for producing gas from a substrate.    ADVANTAGE - The biogas plant ensures efficient production of gas from the substrate.    DETAILED DESCRIPTION - The biogas plant comprises a decomposition reaction section (ZRA) for the decomposition of a substrate, and a methane-forming reaction section for the formation of methane from the substrate decomposed in the decomposition reaction section. The decomposition reaction section and the methane-forming reaction section are parts of a continuous flow section. The decomposition reaction section is formed through a tubular decomposition reaction container (ZRB) and the methane-forming reaction section is formed through a tubular methane-forming reaction container (MRB). The flow section is formed from flow section with a slope of smaller than 10 degrees . The substrate is formed along the flow section in the methane-forming reaction section, through a backflow preventing means partially in a continuous forward movement. The decomposition reaction section is an ensiling section as part of the flow section that is formed through a channel-forming ensiling container. Ultrasound grinding means are arranged upstream in the ensiling section and/or in decomposition reaction section. The ensiling section is arranged upstream to a supply device for supplying grinded raw material. The supply device is formed through a conveyor tube (4) with a mixing screw for conveying the raw materials in the direction of a pump outlet of the supply device, and a recirculation pipe (8) for the recirculation of the raw materials to mixing screw, arranged between the mixing screw and the pump outlet. The pump outlet of the supply device is arranged to a solid material pump for defined transmission of the raw materials into the ensiling container. Gas separation means for partial separation of gas are arranged above the methane-forming reaction section at the end of the decomposition reaction section. Supply means for the supply of methane-forming bacteria in the form of liquid manure is arranged between the decomposition reaction section and the methane-forming reaction section. Means for increasing the temperature of the substrate are arranged in the methane-forming reaction section in counter flow through a heat pump. The methane-forming reaction section is arranged downstream to a gas separation section for pressure-controlled gas separation. The substrate separated in gas separation section from gas is pushed back through bacteria enriching tube partially to the substrate in methane-forming reaction section. An INDEPENDENT CLAIM is included for a method for the production of gas from a substrate by a biogas plant.    DESCRIPTION OF DRAWING(S) - The figure shows a cross-sectional view of a biogas plant (Drawing includes non-English language text).    Conveyor tube (4)    Recirculation pipe (8)    Methane-forming reaction container (MRB)    Decomposition reaction section (ZRA)    Decomposition reaction container. (ZRB)