Energy for Sustainable Development is analyzed as a Technology challenge with a very large set of possibilities both in energy generation and energy consumption. The portfolio of emerging technologies in both domains is very large but also very demanding. Their learning curves show very different features, and inherent difficulties in each technology can be identified. Additionally, energy sustainability conveys rigorous considerations about Global Warming and ancillary subjects, which are not yet properly defined in terms of requirements on the energy sectors. Moreover, the evolution of energy generation sources in the first decade of this century clearly shows a mismatch between the theoretical boost to combat climate change, and the actual facts in energy markets. However, emerging technologies in the complete energy sector could give a suitable answer to a challenge not very well defined so far. (C) 2013 Elsevier Ltd. All rights reserved.