This work builds upon some long-term secular regularities concerning the relation between consumption of energy, technological progress and economic growth and reassesses the old question raised around forty years ago in the limits to growth discussion (Meadows et al. ), namely are the current patterns of development and in particular the current patterns of energy use environmentally sustainable? The questions we shall address are the following. First, the environmental sustainability of patterns of energy consumption that for long have implied the notion of the environment as a free good, without any negative social externalities and even less so any environmental threat. Second, the importance - and limits - of relative price changes with respect to the dynamics of consumption of energy. Third, the role of fundamental discontinuities between different technological paradigms.