Trade-offs between integration and isolation in Switzerland's energy policy

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.