Using scenario-based modeling, this study examines how cost efficiency in the German electricity system can be improved. Two scenarios are defined for this purpose. One scenario examines increased electricity generation with higher operating costs in controllable power plants. Another scenario examines ways to increase cost efficiency through various levers, including different choices of renewable energy technologies and spatially optimized siting of these plants within an energy system that relies entirely on renewable energy by 2045. Both scenarios are compared with a reference scenario designed to reflect current plans for the European energy system.