Gärrestaufbereitung als Beitrag zur Nährstoffentfrachtung von Überschussregionen – Kosten und Treibhausgasemissionen

The processing of slurry and biogas digestate reduces their volume and separates nutrient flows, especially in regions with nutrient surpluses. This makes it possible to cut transport costs for supra-regional utilisation and to configure tailor-made products for different customers. However, the additional capital and equipment costs can usually only be compensated by revenue from the CHP bonus for the use of excess heat from combined heat and power systems in biogas plants, unless high prices can be achieved for the products outside agriculture. The use of heat also has a considerable impact on the greenhouse gas emissions associated with processing. If reference emissions are charged because the heat is no longer available to replace fossil resources, this far outweighs savings from transport. However, it is not possible to draw general conclusions due to the diverse plant-specific conditions (amount and type of nutrient surplus, transport distance, heat availability, size of the plant, etc.). In individual cases, the processing of biogas digestate may well be economically viable, especially in the case of long transport distances.