In response to the Fukushima nuclear accident, Switzerland has targeted to phase out nuclear power by 2050. Two diametrically opposite pathways to accomplish Switzerland's nuclear phase-out are quantitatively investigated for the year 2035 using a novel high-resolution power systems simulation framework. The first pathway, "Island in Europe", installs new natural gas power plants to ensure a self-sufficient Swiss energy system. The second pathway, "Battery of Europe", increases Switzerland's engagement with central Europe with new pumped hydro storages and increased cross-border electricity trade of European renewable energy. The results show that the "Battery of Europe" scenario enables a threefold increase in financial surplus of cross-border electricity trade compared to the "Island in Europe" scenario. This surplus translates to 15-23% lower domestic Swiss electricity prices, thereby enhancing the competitiveness of the Swiss marketplace; however, Switzerland is then exposed to more technical and political engagement with its neighbours. Additionally, successful implementation of the "Battery of Europe" scenario requires reinforcing 5% of the Swiss transmission grid, which necessitates more streamlined legal processes for new transmission infrastructure. Along a different political dimension, electricity price reductions of up to 22% are possible if the targeted increase of efficiency in Switzerland's energy policy is accomplished. (C) 2018 Elsevier Ltd. All rights reserved.