Optimisation of acquisition and distribution logistics of large biogas plants

Due to the normally high water content of the utilised raw material, proportionally high masses in relation to the energy produced per kWh have to be moved and again removed from the plant as fermentation residue, and the logistic costs amount to about 66% of the variable costs in relation to the raising or raw material. The proposed project aims at increasing the added value of biogas production made of agricultural raw materials by logistic measures both on the input and the output side of a biogas plant. The results will support/improve the economic efficiency with regard to bio-gas production from energy crops and therefore the sustainable development. The investigations in terms of procurement logistics (supply of raw materials) and distribu-tion logistics (return of the fermenter residues) were accomplished at 11 biogas plants in Upper Austria, Lower Austria and Styria. The electrical capacity of the combined heat and power plants ranged between 250 and 1.050 kW. In the procurement logistics different representatives of renewable raw materials were ex-amined. With regard to farm manure the logistic chain of solid dung as well as semi-liquid manure from cattle, pigs and poultry were examined. The investigations with respect to feeding of the plant, which contains also the delivery from decentralized temporary storage facilities, are not finalised yet. The optimal use of separation techniques is examined with the aim to close cycles of mat-ter and energy in biogas production from energy crops. The investigations are accom-plished at two biogas plants in Upper Austria. The two measurement periods for the com-parative evaluation and classification of two separation techniques usually used in practice (sieve drum and screw extractor separators) according to technical, economical and eco-logical criteria was already conducted. The newly gained characteristics are used for an integrated evaluation for the distribution logistics. Within the distribution logistics for the liquid fermentation residues single-phase and multi-phase procedures were examined. In addition the liquid manure piping was examined. For the distribution of the solid phase (after the separation of the fermentation residues) sys-tems on basis of compost and universal spreaders were described. Basing on the submitted data the final economic evaluation and optimisation will be meas-ured. From this follows the preferential logistic chain depending on the determining factors. The results of this project is to propose a tool to optimise the logistic chains for supplying major biogas plants with agricultural raw materials and for recycling the fermentation resi-dues. The achieved results will be provided in a “Biogas – Logistics – Handbook” to plant operators, co-operators, planning enterprises and biogas consultants. The optimised sepa-ration techniques for the treatment of the fermentation residues will be proposed.