WIT Press

A common framework for emergy and exergy based LCA in accordance with environ theory


Free (open access)

Paper DOI



Volume 2 (2007), Issue 3



Page Range

170 - 185


S.N. Nielsen, S. Bastianoni


To estimate the environmental consequences of human activities with the purpose of achieving sustainable development, we need to carry out detailed analyses of the material and energy cycles of our society. The need to choose from several options is not a simple task. There are several reasons to this. First, the task contains an inherent problem of finding a common unit. Second, we need a common and unified methodology for matter and energy to compare results and evaluate systems using various types of analysis like life cycle assessment and material flux analysis. It is widely recognised that energy analysis following the first law does not bring us much further in this context as it hardly gives any reliable indications on where to take action. Two recent measures, exergy and emergy, seem to offer the possibility of facilitating the process, by making it possible to find a common unit to both matter and energy and in addition bring in the perspectives of total environmental costs (a sort of ‘ecological footprint’ – not in the strict sense) to the evaluation. The concepts may be used separately, but recent results from natural ecosystems indicate that the use of the two in combination might bring us even further in defining and achieving sustainable development. This in turn also allows us to construct new indicators specifically dedicated to and addressing the sustainability trends in the production systems or even society and may eventually be coupled to economics, at least at a micro-economic scale. The approach presented makes it possible to analyse the sustainability state of the systems in general software packages able to do a simple linear optimisation, and thus brings in the possibility of finding the most optimal way of coupling material and energetic fluxes and thus assist in implementation of cleaner production and industrial ecology. To our knowledge, this is the first time a common, unified approach to the analysis of both cultural and natural ecosystems is presented.


emergy, environ, exergy, LCA