Method for assessing and improving the efficiency of agricultural biogas plants based on fuzzy logic and expert systems

From previous research and monitoring of agricultural biogas plants it is known that there are various possibilities and needs for improving their efficiency. However, a reliable methodological approach for this purpose was missing. Therefore, the objective of this research was to develop a method for assessing and improving the efficiency of agricultural biogas plant operation. Firstly, four performance figures for efficiency assessment and eight performance figures for efficiency improvement analysis of the technical aspect of a biogas plant operation were selected. Based on these, the method was developed by applying approaches of fuzzy logic and expert systems. Using these approaches, it was possible to handle uncertainty in the assessment data and to model expert knowledge from the field of biogas technology. The method was tested with performance data from five agricultural biogas plants with combined heat and power production, located in Bavaria. The method was verified and validated, and is proposed as a comprehensive approach for assessing and improving the efficiency of agricultural biogas plants with respect to the technical aspect. To disseminate the method among potential users such as biogas plant operators or consultants, a web application is being developed. According to changes in the state of the art of biogas technology, continuous updating and improvement of the method is needed. For further development, the method should be adapted to other types of biogas plants, and extended to environmental and socio-economic aspects of biogas plant operation.