Since 1998, Nehlsen has been producing biogas in Sagard, on the island of Rügen. Using the process of co-digestion, agricultural waste, such as slurry and manure, as well as food wastes, cereals, and a glycerine-soap water mixture from the adjacent company-owned biodiesel plant are turned into biogas. The adjoining CHP plant uses the produced biogas to generate electricity, steam and heat.
During the co-digestion process, micro-organisms turn organic materials into biogas under anaerobic conditions. The fermentation takes place in three vertical concrete fermenters, using a plug-flow process/system, where each fermenter has a net capacity/operational volume of 660 m³.
A total of 20 000 m³/a organic material is utilised at the Sagard Plant. On average, the plant turns 60t biomass into
6.000 m³/a biogas, which is converted into ca. 12.500 kWhel/d in the adjacent CHP. The arising digestate (residue) is composted and produces a high quality compost as an additional product.
Power and heat generated from renewable resources, such as agricultural residues and food wastes, reduce the demand for primary fossil fuels like coal and gas and therefore contribute to climate protection and conserve precious raw materials.