Abstract
The cultivation of renewable raw materials on arable land is challenged by the ongoing fuel-versus-food debate resulting from increases in maize cultivation, shorter crop rotations and land competition. Accordingly, the current legal framework for biogas production in Germany focuses on limiting cultivation of traditional biogas substrates, such as silage maize, and promoting the use of various alternatives, such as waste materials and by-products. One new sustainable substrate alternative is the use of cereal straw compacted to pellets. Although straw pellets generally have good fermentation properties, they are still rarely used in German biogas production. Since earlier research on agricultural production practices in general has shown that farmers can be divided into groups regarding their acceptance behaviour and the speed to successfully adopt innovative practices and technologies on their farm, this study addresses the research question: How can biogas plant operators in Germany be categorised with regards to their intention to use straw pellets as innovative and sustainable substrate alternatives? In order to answer this question an exploratory factor analysis and subsequent hierarchical cluster analysis was conducted with survey data obtained from German biogas plant operators (n = 309) in early 2021. Based on variables indicating the intention to use and use behaviour regarding straw pellets in biogas plants, four clusters are identified. Plant operator’s innovativeness, perceived risk and the influence of social environment show differences between the clusters. Additionally, the characteristics of the innovation “straw pellets”, such as economic performance and sustainability, were assessed differently by the four clusters of German biogas plant operators. While the clusters do not show significant differences in the socio-demographic characteristics, they do so in the farm characteristics (farm activities besides biogas production, size of the plant, the proportion of slurry/dung and silage maize). According to the results two of the four clusters have a higher acceptance of straw pellets, which also means that they are earlier in considering the actual use. The initiation of regional working groups, information campaigns and financial incentives can support plant operators, especially in the two clusters of potential early adopters, in accepting straw pellets. This should ultimately result in a faster and wider use of straw pellets as substrates in the whole biogas sector.