Institute of Agricultural Engineering and Animal Husbandry

Freising, Germany

Institute of Agricultural Engineering and Animal Husbandry

Freising, Germany

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Djatkov D.,University of Novi Sad | Effenberger M.,Institute of Agricultural Engineering and Animal Husbandry | Lehner A.,Institute of Agricultural Engineering and Animal Husbandry | Martinov M.,University of Novi Sad | And 2 more authors.
Renewable Energy | Year: 2012

Around 5000 agricultural biogas plants were operating in Germany by the end of 2009. There is a recognized need for their assessment, comparison and performance improvement. Prerequisites for their reliable assessment include: 1) detailed and reliable performance data, 2) defined criteria for the assessment, and 3) comprehensive method. The limitations of existing assessment methods have been reviewed. The new method developed for assessing the overall performance of biogas plants is focused on four assessment aspects: biogas production, biogas utilization, environmental impact and socio-economic efficiency. Each assessment aspect was determined by two performance criteria. The method is based on fuzzy set theory and fuzzy mathematics, which enables use of imprecise and uncertain data. Incorporation of enough expertise from the field of biogas technology was enabled in this method as well. Pre-assessment of future biogas plants in their planning phase is possible, contributing to their effective development. The reliability of the method was tested using data from ten monitored biogas plants. The assessment of the ten biogas plants showed that biogas utilization is the aspect with the largest potential for performance improvement, by increasing the external heat utilization. The method developed is adjustable to accommodate new developments related to biogas technology and biogas plants in any geographical region. Future research should be focused on definition and inclusion of more assessment criteria and on developing the methods that are capable to handle compensation between individual criteria. © 2011 Elsevier Ltd.


Bachmaier J.,Institute of Agricultural Engineering and Animal Husbandry | Effenberger M.,Institute of Agricultural Engineering and Animal Husbandry | Gronauer A.,Institute of Agricultural Engineering and Animal Husbandry
Engineering in Life Sciences | Year: 2010

For ten agricultural biogas plants, a detailed balance of greenhouse gas (GHG) emissions and cumulated energy demand was calculated. Compared with the reference system based on fossil resources, electricity production in the biogas plants avoids GHG emissions of 573-910 g CO2-eq/kWhel (CO2-eq, carbon dioxide equivalents; kWhel, Kilowatt hours electrical energy). Without accounting for the substitution of electricity from the reference system, GHG emissions from electricity production in the biogas plants range from -85 to 251 g CO2-eq/kWhel. With savings of 2.31-3.16 kWhfossil/kWhel (kWhfossil, Kilowatt hours primary energy from fossil energy carriers), the cumulated energy demand of the biogas plants was also much lower than for the fossil reference system. The reduction of direct methane emissions together with the efficient utilization of the heat from cogeneration and the use of animal waste as input material can improve the GHG balance of electricity production from biogas, substantially. Currently, a reliable estimate of the GHG emissions of electricity production from biogas can only be made based on individual monitoring data. The validity of GHG balances should be enhanced by providing reliable data on nitrous oxide emissions from energy crop cultivation, methane leakage from biogas plants and emissions from uncovered storage of digested residues. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Bachmaier H.,Technology and Support Center | Effenberger M.,Institute of Agricultural Engineering and Animal Husbandry | Gronauer A.,University of Natural Resources and Life Sciences, Vienna | Boxberger J.,University of Natural Resources and Life Sciences, Vienna
Waste Management and Research | Year: 2013

For five agricultural biogas plants with a high share of energy crops in the input material, a detailed balance of greenhouse gas emissions (GHG) and cumulated energy demand (CED) was calculated for the years 2007 and 2010. The results vary considerably between plants and over time. In 2010 compared with 2007, all of the five biogas plants reduced their impact on climate change and four of them also reduced their consumption of fossil energy. The strongest influence was from the enhanced utilization of surplus heat energy, whereas variations of environmental impact due to direct emissions from the biogas plants were less distinctive. Compared with a reference system based on fossil resources, electricity production in the biogas plants avoided GHG emissions of 603 g to 940 g carbon dioxide equivalents (CO2-eq)•kilowatt hours electrical energy (kWhel-1) and saved 2.48 to 3.23 kilowatt hours primary energy from fossil energy carriers (kWhfossil)•kWhel-1 CED (results for 2010). © The Author(s) 2013.

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