Estimating the nutrient degradation in biogas-batch processes

By introducing the renewable energy law (EEG) in 2000 energy production out of energy crops increased significantly in Germany. Contrary to the increasing importance of biogas production the operation of agricultural biogas plants still is a trial and error process. Changes in substrate input, besides technical/mechanical problems, have major effects on the stability of the biogas production and fermentation parameters. Simulation models are needed to predict the behaviour and the biogas production rates of full scale agricultural biogas plants. Existing models and equations do not consider the real degradation rates of different plant components. By the use of the GRW (Göttingen, Rostock, Wahlstedt)-Batch Test and the In-Sacco-Batch-Test (ISBV) the degradation kinetics of energy crops and other different substrates can be evaluated. Biomass to be analysed is given into the anaerobic process in nylon bags with a pore size of 40 μm. The bags avoid contamination of the biomass with the inoculum, hence subsequent analysis are not affected by the inoculum. By knowing the digestibility of the different plant components it is possible to calculate the biogas yield on an analytical basis.

With a developed mathematical model based on the plant components analysis it was possible to predict the course of the biogas production rate of a full scale agricultural biogas plant. Using only the analysis data of the substrates fed into the fermenter the crash of biogas production and microbial activity could be reproduced in the computer. By the use of the presented tools (GRW, ISBV, simulation model 'Biogasanlage�)

− different substrates can be compared and monetary assessed

− pre-disintegration of substrates can be assessed

− impacts of changes within the biogas regime can be determined and pre-estimated

− Optimized substrate mixes can be evaluated

− Following the methodology of the different tests are presented and first results in estimating the degradation kinetics of the maize silage components are depict.

 

 

Stand der Pumpspeicher in Deutschland 2025
© Springer Vieweg | Springer Fachmedien Wiesbaden GmbH (12/2025)
Infolge des Ausbaus der Stromerzeugung aus erneuerbaren Energien ist ein erhöhter Speicherbedarf im Stromverbundnetz notwendig. Hierdurch steigt die Bedeutung von Pumpspeichern als bis auf weiteres einzige Möglichkeit für eine großmaßstäbliche Stromspeicherung.

Pumpspeicherkraftwerke - Empfehlungen zur Verkuerzung und Vereinfachung von Genehmigungsverfahren in Deutschland
© Springer Vieweg | Springer Fachmedien Wiesbaden GmbH (12/2025)
Die Genehmigungsverfahren sind sehr komplex sowie mit hohen Kosten und rechtlichen Unsicherheiten verbunden und dauern oftmals mehr als zehn Jahre.

Revitalisierung des Pumpspeicherwerks Happurg - Sanierung des Oberbeckens
© Springer Vieweg | Springer Fachmedien Wiesbaden GmbH (12/2025)
Im Rahmen der Revitalisierung des Pumpspeicherwerks Happurg haben im September 2024 auch die Arbeiten zur Sanierung des zugehörigen Oberbeckens begonnen.

 

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