Analysis of an urban energy metabolic system: Comparison of simple and complex model results

A fundamental difference between simple and complex systems is how the research objects are subdivided to support different study purposes. Based on a comparison between two urban energy system models - one with 5 and the other with 17 sectors - we concluded that the two models were most similar in terms of their description of the overall system structure and most different in terms of their description of specific intra-system relationships. The smaller number of system components and relationships in the 5-sector model facilitated judgments of the system's overall situation, thereby revealing where the key problems were found. In contrast, the 17-sector model provided enough details about the system to assist in the formulation of concrete operational measures to solve specific problems. Our results indicate that the division of a model into sectors should depend on the explicit problem to be solved and the context for that problem; different goals will require different numbers of system components. The results also demonstrate how simple and complex models can be used in tandem to examine a system from different perspectives. (C) 2011 Elsevier B.V. All rights reserved.