a b s t r a c tTo decarbonise its electricity system, Europe must rapidly expand renewables. We analyse the controversy between two organisations, Eurosolar and Desertec, which seemingly pursue the same goal of 100% renewable electricity. We show that they interpret "100% renewables" differently and envision fundamentally different renewable electricity futures, to be reached through different governance pathways driven by different actors. Desertec reacts to mankind's violation of the Earth's carrying capacity and seeks secure decarbonisation through renewables, for which centrally regulated, large-scale imports of controllable concentrating solar power from the desert are necessary. Eurosolar, in contrast, seeks to decentralise the electricity supply and disempower the actors who caused the unsustainable and undemocratic energy system, for which renewables are suited as they are carbon-neutral and decentralised by nature. As the core aim of Desertec, controllable solar power imports through large-scale infrastructure, violates Eurosolar's core aim of decentralisation, a compromise is difficult: this would require one organisation to give up its primary objective. Our results show that the reason for this controversy among renewables proponents lies not in technology or cost, and can thus not be identified or resolved through techno-economic analysis or modelling, but in irreconcilable differences in normative aims and governance choices.