Is the renewables transformation a piece of cake or a pie in the sky?

Historically, long-waves have characterized transformations of the energy systems. There is not much reason to assume that our current energy system is here to stay. One possible future option is that renewables will provide all energy needed. While many scenarios exist showing that this is technically feasible, the related costs, speed of technology diffusion and social and political acceptance of such an energy transition are fiercely debated, both in the scientific field as well as in politics. Yet, there is growing consensus that renewables are becoming established as a key building block in the energy system, irrespective of the exact shares they represent. The focus should shift from a debate surrounding the feasibility of a 100% renewable system to how we can enable a speedy and immediate upscaling. •Tipping points within the energy system,•Strongly decreasing costs of renewable technologies,•Their multiple benefits vis-à-vis international policy objectives of the Sustainable Development Goals and the Paris Climate Agreement, and•Energy sufficiency.