Environmental evaluation of a power plant using conventional and advanced exergy-based methods

An advanced exergoenvironmental analysis combines an advanced exergetic analysis with a life cycle assessment. This allows the environmental impacts of an energy conversion system to be split into avoidable/unavoidable and endogenous/exogenous parts, revealing improvement potential and component interactions. This paper presents the application of an advanced exergoenvironmental analysis to a combined-cycle power plant based on results obtained by a life cycle assessment and a conventional exergoenvironmental analysis. The results are discussed, while possible improvements for reducing the environmental impacts are noted. Due to its dominant role with respect to exergy destruction, the combustion chamber causes most of the environmental impact within the plant, 68% of which is found to be unavoidable. Evaluating the overall structure, we find that for the majority of the components, most of the environmental impact is unavoidable, a fact that limits the potential for improvement of the plant considerably. We also find that most of the environmental impact of the plant is endogenous, i.e., component interactions are of lower significance. In total, the plant can potentially be improved by enhancing the performance of the combustion chamber, the expander, the compressor and the low-pressure steam turbine. (C) 2012 Elsevier Ltd. All rights reserved.