Luca Fraccascia

Economic sustainability of biogas production from animal manure: a regional circular economy model

Purpose This paper aims to understand the implementation of a circular economic business where animal manure is used to produce biogas and alternative fertilizer in a regional network of manure suppliers and biogas producers and to reveal the impacts of five variables (manure quantity, transportation distance, manure dry content, manure price and manure discharge price) on the economic sustainability of manure-based biogas supply chains. Design/methodology/approach An enterprise input-output approach is used to model physical and monetary flows of the manure-based biogas supply chain. Computational experiments are performed on all variables to identify under which conditions the cooperation is beneficial for all actors. Findings The cooperation is profitable for a large-scale farm (>20,000 t/year) if biogas producer (b) pays farmer (f) to receive its manure (5 €/t) or if f sells manure for free and manure disposal costs are >10 €/t. Cooperation is always profitable for b if f pays b to supply its manure (5€/t). If b receives manure for free, benefits are always positive if b is a medium-large-scale plant (>20,000 t/year). For a small-scale plant, benefits are positive if manure dry content (MDC) is ≥12 per cent and transportation distance is ≤10 km. Originality/value The paper adds value to the biogas production research, as it makes holistic analysis of five variables which might change under different policy and geographical conditions. The investors in biogas production, suppliers and transportation companies can find correspondence to empirical findings for their own site-specific cases.

Resilience of Complex Systems: State of the Art and Directions for Future Research

This paper reviews the state of the art on the resilience of complex systems by embracing different research areas and using bibliometric tools. The aim is to identify the main intellectual communities and leading scholars and to synthesize key knowledge of each research area. We also carry out a comparison across the research areas, aimed at analyzing how resilience is approached in any field, how the topic evolved starting from the ecological field of study, and the level of cross-fertilization among domains. Our analysis shows that resilience of complex systems is a multidisciplinary concept, which is particularly important in the fields of environmental science, ecology, and engineering. Areas of recent and increasing interest are also operation research, management science, business, and computer science. Except for environmental science and ecology, research is fragmented and carried out by isolated research groups. Integration is not only limited inside each field but also between research areas. In particular, we trace the citation links between different research areas and find a very limited number, revealing a scarce cross-fertilization among domains. We conclude by providing some directions for future research.