Energy technology innovation - improving how we produce and use energy - is critical for a transition towards sustainability. This book presents a rich set of twenty case studies of energy technology innovation embedded within a unifying conceptual framework. It provides insights into why some innovation efforts have been more successful than others, and draws important policy conclusions. The case studies cover a wide range of energy technologies, ranging from energy supply to energy end use, from successes to failures and from industrialized, emerging and developing economies. The case studies are presented by an international group of eminent scholars under the auspices of the Global Energy Assessment (GEA), whose main volume was published in 2012 by Cambridge University Press. Energy Technology Innovation presents new data, new concepts and novel analytical and policy perspectives. It will prove to be invaluable for researchers, policy makers, economists, industrial innovators and entrepreneurs in the field of energy technology.