How flexible is the German biogas sector? Stakeholder acceptance of flexible feeding options to support better system integration

The fluctuation of wind and solar technologies calls for actors that can help securing overall supply security. On the other hand, the transition to flexible biogas production is a promising option for German biogas operators. While gas storage is an option, another considerable potential lies in producing gas in response to fluctuating demand using flexible substrate feeding. In this study, we consider the potential of flexible feeding from a social sciences perspective. We investigated the attitudes of German stakeholders towards further flexibilization of biogas production through flexible feeding, what aspects are important, and what changes may be necessary to increase acceptance and willingness to participate in flexible production. We did so through a qualitative interview study of 27 people from four stakeholder groups: biogas plant operators, energy marketers, electricity distribution grid operators, and policy makers. We find that most plant operators are critical of flexible feeding and are very skeptical about the adaptations needed to existing plants, primarily due to expected biological problems in the digestion process and expected changes to work organization. The energy marketers appreciate the potential and support the idea of on-demand production. The distribution grid operators do not see the topic as relevant but could see it becoming so in the future. While the policy makers admit uncertainties about their knowledge, they also question if flexible feeding is the best strategy. Our results suggest that the most important stakeholder group, the biogas plant operators, must be at the center of all further development processes and scenarios.