Virtually all goods and services that characterize modern societies' welfare depend on the provision of commercial energy. The core objective of this paper is to identify necessary changes in trends for achieving a transition towards more sustainable energy systems and development paths. The major conclusions of this analysis are (i) a rigorous rethinking process has to take place to identify which level of energy services per capita lead to enhancing human welfare and quality of life; (ii) a significant increase in energy conversion efficiency has to be triggered to finally provide energy services with far less input of energy than today; (iii) a continuous increase in the share of renewable energy sources and other low-emission options has to be brought about: (iv) however, as history has shown this process of technological learning has to be accompanied by proper energy price and regulatory policies. Otherwise, it is very likely that energy conservation gains due to technical efficiency improvements will be outweighed again by increases in energy service demand and, straightforward, energy consumption and CO2 emissions. (C) 2008 Elsevier Ltd. All rights reserved.