Data envelopment analysis for assessing the efficiency of biogas plants: capabilities and limitations

In this paper two different approaches of the data envelopment analysis (DEA) method were used for assessing the efficiency of 10 Bavarian agricultural biogas plants. In the first approach, biogas plants were considered as energy conversion systems using appropriate parameters that are absolute. In this way, some important aspects were omitted from the assessment. In the second approach, all aspects of biogas production and utilization were considered by assessing specific parameters, i.e. characteristic performance figures. In both approaches, biogas plants were ranked similarly and, consequently, efficient and inefficient plants were recognized. Only a relative assessment was possible with no influence on criteria importance. The ranking results could be interpreted and confirmed by experts. The relevance of the DEA models that were used for the analysis is hard to prove.