Advances in exergy analysis: a novel assessment of the Extended Exergy Accounting method

Objective This paper presents a theoretical reassessment of the Extended Exergy Accounting method (EEA in the following), a comprehensive exergy-based analytical paradigm for the evaluation of the total equivalent primary resource consumption in a generic system. In the paper, traditional and Advanced Exergy Analysis methods are briefly discussed and EEA theoretical foundations and details for its application are fully described. Methods The method converts not only material and energy flows, but externalities as well (labor, capital and environmental costs) into flows of equivalent primary exergy, so that all exchanges between the system and the environment can be completely accounted for on a rigorous thermodynamic basis. The current emphasis decision makers and by public opinion alike seem to be placing on sustainability generates the need for continue research in the field of systems analysis, and a preliminary review confirms that exergy may constitute a coherent and rational basis for developing global and local analysis methods. Moreover, Extended Exergy Accounting possesses some specific and peculiar characteristics that make it more suitable for life-cycle and cradle-to-grave (or well-to-wheel) applications. Results Taxonomy for the classification of exergy-based methods is proposed. A novel assessment of EEA method is provided, highlighting its advantages and drawbacks and identifying areas in need of further theoretical investigation. Conclusions Since EEA is founded on a life-cycle formulation, it is argued that it represents an improvement with regard to other current methods, in that it provides additional insight into the phenomenological aspects of any “energy conversion chain”. The paper demonstrates that the Extended Exergy cost function can be used within the traditional and very well formalized Thermo-Economic framework, replacing the economic cost function in order to evaluate and optimize the consumption of resources of a system in a more complete and rational way. Practical Implications This paper contains some specific proposals as to possible improvements of the EEA method, to increase its effectiveness and to improve its practical applicability for system analysis. Suggestions are made on how to include an EEA discussion in the current debate about sustainable development.