Economic optimization of feedstock mix for energy production with biogas technology in Germany with a special focus on sugar beets - Effects on greenhouse gas emissions and energy balances

Power production from biogas is quite common in Germany and other parts of the world. German biogas production, in particular, primarily uses silage corn as feedstock which is unpopular with the society because of the negative side effects. Sugar beets could be an alternative. This paper maps the aggregated results concerning the greenhouse gas (GHG) emissions and energy balances of power production from different energy crops at national level based on field experiments and all biogas plants registered in Germany. The regional feedstock production costs integrated into the objective function of a plant specific linear optimization model were calculated based on regional production circumstances and district specific yields. Different scenarios with e.g. a fixed share of sugar beets in biogas plant feedstock mix as well as yield increases due to biological and technical progress of silage corn and sugar beets were compared to a business as usual scenario in terms of their effects on GHG emissions and energy balances of power production. The results demonstrated that the GHG emissions and energy balances depend on regional production circumstances. Furthermore, forcing sugar beets into feedstock mix resulted in generally higher GHG emissions and deteriorated energy balances. (C) 2015 Elsevier Ltd. All rights reserved.