Sustainable energy innovations are needed in order to achieve the transition towards a sustainable energy system. However the process of diffusion and implementation of these innovations is slow and tedious due to the carbon lock-in our current energy system resides in. Research on several historical developments of renewable energy technologies has been carried out to find out why the stimulation of sustainable energy innovations proves to be so problematic. In this paper we identify seven typical failures that hamper the development and diffusion of renewable energy technologies based on a scrutiny of a large number of case studies. These failures are related to a poor build up of sustainable energy innovation systems. The insights will provide handholds to formulate an appropriate policy view that can help to transform the current energy sector into a more sustainable one.