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This case study examined the productivity and economic performance of a double recirculation aquaponic system in Germany with a total interior area of about 540 m2. Calculations were carried out as an ex post analysis based on one‐year production data. The initial situation was not profitable; therefore, two scenarios were developed, which envisaged a significantly improved productivity of the fish as well as of the plant unit and a more than threefold enlargement of the greenhouse to make maximum use of the fish effluent. An ex ante analysis was performed and showed that the second scenario was profitable with a payback period of about 12 years. On the basis of this scenario, a simple but comprehensive model case with the complete set of economic key indicators showed that aquaponics is feasible if it exploits its potential, regardless of the high initial investment costs. The model case would cover an overall space of about 2,000 m2, which is suitable for professional aquaponics in urban and peri‐urban areas with their limited space availability. Furthermore, multi‐loop aquaponics with its inherent circles fits into the circular city concept and implements resource‐efficient and sustainable food production into the urban fabric, which is important with increasing urbanization. [ABSTRACT FROM AUTHOR]

Bio-based technologies such as biorefineries and aquaponics are considered key factors for the transition towards a sustainable bioeconomy, but they may fail due to a lack of public acceptance. The present study explores the level and determinants of citizens' general and local acceptance of two technologies (biorefineries and aquaponics) in two regions (a transition and a non-transition region). Furthermore, the relevance of key determinants, – more specifically social trust, affect, and perceived benefits and risks – in predicting acceptance are explored using partial-least-squares structural equation modeling. In total, 1989 participants from the transition region Rheinische Revier and other non-transition regions of the German state of North-Rhine Westphalia completed the online survey. The results show considerable consistency across the investigated contexts regarding the importance of the behavioral constructs in explaining citizens' technology acceptance, confirming the derived conceptual framework. Our findings also reveal a lower local acceptance of both biorefineries and aquaponics when compared to general acceptance rates, pointing to the so-called NIMBY (Not In My Back Yard) effect. Moreover, local acceptance was lower in the transition region, underlining the particular need for effective communication and participation strategies in those regions to successfully implement a sustainable bioeconomy. • Online study conducted with 1989 participants in North-Rhine Westphalia, Germany. • Higher local compared to general acceptance of biorefineries and aquaponics. • Lower local technology acceptance in transition region Rheinisches Revier. • Role of affect and perceived benefit important for explaining technology acceptance. • Effective communication strategies needed to promote sustainable bioeconomy. [ABSTRACT FROM AUTHOR]