Selected energy and material resource conversion systems are compared in this paper under an extended LCA point of view. A multi-method multi-scale assessment procedure is applied in order to generate consistent performance indicators based on the same set of input data, to ascertain the existence of constraints or crucial steps characterized by low conversion efficiency and to provide the basis for improvement patterns. Optimizing the performance of a given process requires that many different aspects are taken into account. Some of them, mostly of technical nature, relate to the local scale at which the process occurs. Other technological, economic and environmental aspects are likely to affect the dynamics of the larger space and time scales in which the process is embedded. These spatial and time scale effects require that a careful evaluation of the relation between the process and its surroundings is performed, so that hidden consequences and possible sources of inefficiency and impact are clearly identified. In this paper we analyse and compare selected electricity conversion systems, alternative fuels and biofuels, waste management strategies and finally the time evolution of an urban system, in order to show the importance of a multiple perspective point of view for the proper evaluation of a system's environmental and resource use performance.