Analysis of greenhouse gas emissions from 10 biogas plants within the agricultural sector

Abstract

With the increasing number of biogas plants in Germany the necessity for an exact determination of the actual effect on the greenhouse gas emissions related to the energy production gains importance. Hitherto the life cycle assessments have been based on estimations of emissions of biogas plants. The lack of actual emission evaluations has been addressed within a project from which the selected results are presented here. The data presented here have been obtained during a survey in which 10 biogas plants were analysed within two measurement periods each. As the major methane emission sources the open storage of digestates ranging from 0.22 to 11.2% of the methane utilized and the exhaust of the co-generation units ranging from 0.40 to 3.28% have been identified. Relevant ammonia emissions have been detected from the open digestate storage. The main source of nitrous oxide emissions was the co-generation unit. Regarding the potential of measures to reduce emissions it is highly recommended to focus on the digestate storage and the exhaust of the co-generation.

Agricultural biogas production in Germany - from practice to microbiology basics

“…Modeling the GHG balance of biogas from energy crops is limited by the very large uncertainty with respect to nitrous oxide emissions from cropland [26]. Dominant influencing technical factors on the GHG balance are methane emissions from open storage of digested residues and incomplete combustion in co-generation units [27]. Substantial emissions of methane from biogas plants due to leakage of digesters and pipes are limited to exceptional cases.…”

Net greenhouse gas emissions from manure management using anaerobic digestion technology in a beef cattle feedlot in Brazil

“…Therefore, for the present study we assumed daily emissions of 0.53 and 0.19 kg CO 2 eq m − 3 from these sources, with uncertainties comprising the same values, respectively. Biogas leakage from possible AD system malfunction (Liebetrau et al, 2013) was not considered in this work.…”

Lifecycle Greenhouse Gas Analysis of an Anaerobic Codigestion Facility Processing Dairy Manure and Industrial Food Waste

“…Canadian and German studies reported fugitive emissions ranging from 2.1% -3.1% of CH 4 utilized. 45,46 The nominal value of 3% of gas utilized was used. However, Liebetrau et al 46 noted that when leaks and malfunctions were eliminated, near zero fugitive emissions were measured.…”