A review of system dynamics modeling for the sustainability assessment of biorefineries

Abstract Bioeconomy has been incorporated into the national strategy for sustainable development by many countries, and the concept of biorefinery has been considered as one of the essential components of such strategies. The environmental, economic, and social implications of a biorefinery hinge upon both the endogenous interactions among its supply chain components and their responses to the exogenous factors. The system dynamics (SD) modeling approach is suitable for understanding such complex systems. This study provides a state‐of‐the‐art review of the methodological assumptions of existing SD studies relevant to the sustainability of biorefineries. Among the reviewed studies, common supply chain components of a biorefinery were feedstock supply, biomass conversion, market demand, distribution, and use of bioproducts. Components of a supply chain are interlinked through feedback loops. For instance, the preference for bioproduct use increases the corresponding market demand, which attracts more investment in biorefineries and changes the supply of feedstock. Exogenous variables investigated by the reviewed studies cover the market demand, population growth, GDP change, imposed regulations and incentives to evaluate endogenous factors such as the price of biomass and biofuel, change in land‐use pattern, and fuel or energy choices of consumers. Through analyzing the methodological assumptions, we also identified several limitations of the models/frameworks in the existing literature, including (1) the lack of a mechanism to represent the complex interactions within the supply chain of a biorefinery with a diverse product portfolio, and (2) the lack of feedback loops incorporating the environmental (e.g., via life cycle assessment), economic (e.g., via techno‐economic analysis), and social (e.g., via social life cycle assessment) influences into the interactions among supply chain components. Accordingly, we proposed a recommendation for methodology development to address these limitations.