TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Process: The silage renewable raw materials are mixed or sprayed with the washing water. The washing of the silage renewable raw material is carried out with specific mixing of the raw materials. The washing of the silage renewable raw material is carried out at 1-60 degrees C for 1 second to 10 hours. The washing water is removed by pressing, filtering or separating in the gravitation- or centrifugal-force of the washed silage. The silage raw material is mechanically crushed before the washing. The silage and raw material mixed with washing water are mechanically crushed simultaneously during the washing- and dehydration-process. The silage and at least partially dehydrated renewable raw material are mechanically crushed. The mechanical crushing step is carried out by slicing, squeezing, grinding and defibrating process. The mechanical crushing is carried out within 1 second to 10 minutes. The hydrolysis process comprises adding 10-40% of liquid manure or 10-70% of fermenting residue or 5-25% of liquid manure together with 5-25% of fermenting residue of the biogas extraction process after the washing of silage and at least partially dehydrated renewable raw material, related on the resulting total mixture, where all variants can be combined with 0-50% of activated sludge of a communal sewage treatment plant and/or 0-50% of process water. Preferred Components: The washing water is: a low-viscosity substance, which does not exert adverse effects on the subsequent anaerobic degradation step in the procedure for biogas production in fermenters; or waste water, sewage water, drinking water or process water of drainage system. The amount of washing water is 20-500 mass%, related on the silage mass (original substance) to be washed. The partially removed washing water is included in the subsequent procedure step for biogas production in the fermenter. EXAMPLE - Silage (1000 kg) containing corn (60%) and rye (40%) was added to a washing reactor. Subsequently liquid (1000 l) containing industrial water was added to the reactor and the silage was stirred for 10 minutes after the filling of the liquid. The washing water was removed to 100% from the silage by pressing of the silage comprising a composition of dry substance content (2.5%) and dissolved Chicago-Sky-Blue (50 g/l), which was added to the fermenter. The washed and partly watered silage, liquid manure, activated sludge (15 mass%) of a communal sewage treatment plant and fermenting residue (50 mass%) were fed into a hydrolysis reactor to obtain the fermented silage renewable raw materials. The materials were kept in the hydrolysis reactor for 2 days and then fed for the biogas production.