The value of the exergetic life cycle assessment besides the LCA

In this paper the value of the exergetic life cycle assessment (ELCA) has been analysed. The ELCA uses the framework of the life cycle assessment (LCA) and can be seen as the exergy analysis of a complete life cycle. The value of the ELCA besides the LCA has been discussed. It is shown that the ELCA is a more appropriate instrument to quantify the environmental problem of the depletion of natural resources. This has been tested with a case study of different waste wood treatment routes. In the first model waste wood is co-combusted in a coal power plant, while in the second model waste wood has been used to produce chipboard. The ELCA shows that the production of chipboard gives less depletion of natural resources. Furthermore, in model 3 and 4 coal for generating electricity has been replaced by green wood. The ELCA shows that replacing coal by green wood gives less depletion of natural resources than replacing the waste wood with green wood, while the waste wood is used for generating electricity. However, comparing the four models it can be seen that replacing coal by green wood causes more wasting of natural resources, while the depletion of natural resources decreases. It can be concluded that the ELCA can be used in two ways. First, the ELCA can be used to determine the consumption of natural resources and second, the ELCA can be used to calculate the depletion of natural resources. In the latter case, a distinction has been made between renewable and non-renewable exergy resources. (C) 2002 Elsevier Science Ltd. All rights reserved.