NOVELTY - The biogas plant comprises a biogas fermenter that guides an organic substrate, and a microorganism-feeding device, where the biogas fermenter is mounted as fermentation module in a compact power plant together with a substrate-loading- and input module upstream and with a diesel generation module downstream towards the fermentation module and/or an output module containing a diesel-tank, a heat accumulator and a fertilizer tank, and an analytical- and control module for monitoring the diesel-quality and for controlling the module into a container.    USE - Used as a biogas plant.    ADVANTAGE - The biogas plant is simple and cost-effective.    DETAILED DESCRIPTION - The biogas plant comprises a biogas fermenter that guides an organic substrate, and a microorganism-feeding device, where the biogas fermenter is mounted as fermentation module in a compact power plant together with a substrate-loading- and input module upstream and with a diesel generation module downstream towards the fermentation module and/or an output module containing a diesel-tank, a heat accumulator and a fertilizer tank, and an analytical- and control module for monitoring the diesel-quality and for controlling the module into a container, which is equipped for a surface- or underground installation. The loading- and the input module comprise a conveyor device for transporting the substrate to the fermentation module to a drier into the diesel generation module, which comprises a mixer for mixing of dried substrate and fermentation swamp. The fermentation module comprises a conveyor system for delivering of the fermentation swamp to the mixer in the diesel generation module and/or to the fertilizer container in the output module, and comprises a gas tank for producing biogas. A biogas-gas turbine is connected with the gas tank for power generation. The diesel generation module is provided in a low-temperature gasifier for the production of tar-bearing low-temperature carbonization gas and biomass cokes and/or a high-temperature gasifier for the production of synthetic raw gas and a fischer-tropsch vessel downstream the diesel generation module for the production of diesel. The fischer-tropsch vessel of a barrel is looked for producing paraffin with the diesel and/or wax in the output module. The fermenter of the low-temperature- and the high-temperature gasifier and the Fischer-Tropsch vessel, is water-cooled, where the recovered waste heat is guided to the heat accumulator.