4.7. Impact of electricity supply source for biogas plant operation
and feedstock supply logistics
Fig. 10 shows the influence on environmental impacts with variation in electricity supply source for biogas plant operation and feedstock supply logistics in AD for corn silage, MSW and food residues feedstocks. Utilization of industry waste, MSW and food waste considered energy intensive pre treatment and/or sterilization process before qualifying to be used as AD feedstock (Pöschl et al., 2010). It was assumed that electricity was provided by Germany’s fuel mix or in contrast by biogas plant’s own electricity generated by CHP unit. It was shown that mitigation of environmental impacts between 35% (food residues, 6.1 pt) and 100% (MSW, 6.5 pt) could be reached using the biogas plant’s own electricity utilized in CHP unit compared to electricity supply from Germany’s fuel mix. Most significant improvements were realized for MSW and food residues, as electricity input for pre-treatment and sterilization (60 kWhel t1 and 24 kWhel t1) could be provided from renewable source
(Pöschl et al., 2010).