REGIONAL GREENHOUSE GAS ASSESSMENT OF POWER PRODUCTION BASED ON BIOGAS IN GERMANY

In Germany, nearly 8,000 biogas plants were in operation up to the end of 2014. Biogas plants are mostly operated by farms which use energy crops and manure as feedstock. Establishment and subsidies for this kind of renewable energy is justified by its environmental advantage in terms of mitigation global warming by reduced greenhouse gas emissions. Greenhouse gas emissions from power production based on biogas depends highly on the feedstock used and, in case of energy crops, on site specific production circumstances. To assess regional greenhouse gas emissions of German biogas production, we propose an economic-ecologic model approach which was based on almost 8,000 geocoded biogas plants. First, site specific production costs of silage corn, sugar beet, winter wheat as whole crop silage and grain were calculated. Second, a linear model approach minimized feedstock production costs and determined feedstock input to biogas plants. Third, greenhouse gas emissions based on feedstock input and biogas plant configuration were calculated and aggregated on district and national level. Results showed that power production based on biogas emitted, in general, less greenhouse gas emissions in comparison to current German power mix. Furthermore, site specific differences of greenhouse gas emissions were identified and mapped.