Renewable energy sources (RES) are becoming more and more cost-competitive globally. Generally, optimization methods are used to identify the most economic setup of individual power systems. In such cases, only the final state of the power system is of interest. This study contributes to the discussion on how to reach a 100% RES driven power system by assessing the importance of RES quality in selected European countries and identifies optimal strategies based on different objective functions (e.g., lowest capex requirement, lowest or largest curtailment). In a scenario in which economics is the only driver for optimal RES expansion, the 'min. LCOE' path with a strong focus on Wind would be used. If residential users are targeted to contribute as much as possible the 'max. capacity' case with a Solar PV-Wind ratio of 0.65 +/- 0.35 would be selected. If the overall aim is to produce maximal excess electricity to be used in other sectors the 'max. curtailment' or 'max. zero load' cases should be considered where mainly Solar PV would be the technology of choice. (C) 2020 The Author. Published by Elsevier Ltd.