An Exergy-Based Method for Allocating Carbon Dioxide Emissions from Cogeneration Systems - Part II: Justification for Exergy Basis

Government and industry have sought means to allocate emissions for cogeneration systems, and research has been undertaken to determine rational allocation methods. Previous research has yielded results that are not universally accepted. Some of the difficulties cited with previously developed allocation methods for cogeneration emissions are that the methods inconsistent, complex and difficult to use and, most importantly, not based on sound reasoning. In this article, the case is made for an exergy-based method for allocating emissions for cogeneration systems. In the part I of this two-part article, comparisons are made of methods for allocating carbon dioxide emissions from cogeneration. Here, in part II of the article, the author demonstrates that exergy methods can form the basis of sound and meaningful allocation methods for carbon dioxide emissions, and that there are problems associated with the other methods. In addition, the results indicate that the exergy-based emissions allocations method provides a sensible foundation for a meaningful overall approach to emissions trading. The results are expected to assist design efforts for energy systems, and decision making and policy development in industry and government.