The knowledge that wind power is very productive in winter and that photovoltaic (PV) installations can produce more electricity in alpine environments than in the valleys is not completely new. Yet these insights have remained little appreciated or acted upon. But with the energy transition pushing forward into a renewable future, this knowledge is of critical importance. As Switzerland is facing a substantial winter energy deficit with its nuclear power plants going offline, SCCER-SoE modelling results provide vital information as to how smart choices of installation location can help to fill this deficit with solar and wind power from the mountains.